fix(session-ui): share timeline tool headers

Move existing Session list and message queries into SessionStore. Preserve public response wrapping, Session existence checks, pagination, ordering, and typed message decoding errors.

.github/workflows/deploy.yml

@@ -5,6 +5,7 @@ on:
     branches:
       - dev
       - production
+      - beta
   workflow_dispatch:
 
 concurrency: ${{ github.workflow }}-${{ github.ref }}
@@ -15,7 +16,7 @@ permissions:
 
 jobs:
   deploy:
-    if: github.repository == 'anomalyco/opencode' && (github.ref_name == 'dev' || github.ref_name == 'production')
+    if: github.repository == 'anomalyco/opencode' && (github.ref_name == 'dev' || github.ref_name == 'production' || github.ref_name == 'beta')
     runs-on: ubuntu-latest
     environment: ${{ github.ref_name }}
     steps:
@@ -28,6 +29,7 @@ jobs:
           node-version: "24"
 
       - uses: aws-actions/configure-aws-credentials@7474bc4690e29a8392af63c5b98e7449536d5c3a # v4.3.1
+        if: github.ref_name != 'beta'
         with:
           role-to-assume: ${{ vars.AWS_DEPLOY_ROLE_ARN }}
           role-session-name: opencode-${{ github.run_id }}

infra/app.ts

@@ -1,4 +1,5 @@
 import { domain } from "./stage"
+import { createWebApp } from "./webapp"
 
 const GITHUB_APP_ID = new sst.Secret("GITHUB_APP_ID")
 const GITHUB_APP_PRIVATE_KEY = new sst.Secret("GITHUB_APP_PRIVATE_KEY")
@@ -59,12 +60,4 @@ new sst.cloudflare.x.Astro("Web", {
   },
 })
 
-new sst.cloudflare.StaticSite("WebApp", {
-  domain: "app." + domain,
-  path: "packages/app",
-  build: {
-    // Preserve Sentry credentials and run source-map uploads on every deployment.
-    command: "bun run build",
-    output: "./dist",
-  },
-})
+createWebApp("app." + domain)

infra/webapp.ts

@@ -0,0 +1,18 @@
+export function createWebApp(domain: string) {
+  return new sst.cloudflare.StaticSite("WebApp", {
+    domain,
+    path: "packages/app",
+    environment:
+      $app.stage === "beta"
+        ? {
+            OPENCODE_CHANNEL: "beta",
+            VITE_SENTRY_ENVIRONMENT: "beta",
+          }
+        : undefined,
+    build: {
+      // Preserve Sentry credentials and run source-map uploads on every deployment.
+      command: "bun run build",
+      output: "./dist",
+    },
+  })
+}

nix/hashes.json

@@ -1,8 +1,8 @@
 {
   "nodeModules": {
-    "x86_64-linux": "sha256-EtUp4pHl9TyPtRrLGvk/X7kd2LuIxNxCpUwF5aLtzN4=",
-    "aarch64-linux": "sha256-m0j/pMZCguclR3/T9JmzCfi11YzmIvBFyR2bVhIO37Y=",
-    "aarch64-darwin": "sha256-nqefk68ZTUfNU15q1WkXaGsFzPNwOjCtMHpp6WrpNqM=",
-    "x86_64-darwin": "sha256-syD7hX62E4yCDV/wux1QKw4q/zZr24f99Y2mmzMJo6o="
+    "x86_64-linux": "sha256-No3mCuG2tGQauX1HUpO+rebiWh+rrpSHUCC7rtXFu1s=",
+    "aarch64-linux": "sha256-8joWv1iDkc6TejEukGBEX0wW8DPs55wJEPY7+9+HDdM=",
+    "aarch64-darwin": "sha256-4MWGFQUIP1Ae4dujztTb4G8/uDJx2wiOoypcPSUWDbw=",
+    "x86_64-darwin": "sha256-BtvnraCJmVagtA3Iv+EbWodjFG74sTd2Purqgo7Wkr4="
   }
 }

packages/ai/src/protocols/anthropic-messages.ts

@@ -1343,20 +1343,28 @@ const onMessageDelta = (
   event: AnthropicEvent & { readonly delta?: AnthropicStreamDelta },
 ): StepResult => {
   const usage = mergeUsage(state.usage, mapUsage(event.usage, state.providerMetadataKey), state.providerMetadataKey)
+  const pendingFinish = (() => {
+    const stopReason = event.delta?.stop_reason
+    if (stopReason === null || stopReason === undefined) return state.pendingFinish
+
+    const stopSequence = event.delta?.stop_sequence
+    const finishMetadata =
+      stopSequence === null || stopSequence === undefined
+        ? state.pendingFinish?.providerMetadata
+        : providerMetadata(state.providerMetadataKey, { stopSequence })
+    return {
+      reason: {
+        normalized: mapFinishReason(stopReason),
+        raw: stopReason,
+      },
+      providerMetadata: finishMetadata,
+    }
+  })()
   return [
     {
       ...state,
       usage,
-      pendingFinish: {
-        reason: {
-          normalized: mapFinishReason(event.delta?.stop_reason),
-          raw: event.delta?.stop_reason ?? undefined,
-        },
-        providerMetadata:
-          event.delta?.stop_sequence === null || event.delta?.stop_sequence === undefined
-            ? undefined
-            : providerMetadata(state.providerMetadataKey, { stopSequence: event.delta.stop_sequence }),
-      },
+      pendingFinish,
     },
     NO_EVENTS,
   ]

packages/ai/test/provider/anthropic-messages.test.ts

@@ -949,6 +949,41 @@ describe("Anthropic Messages route", () => {
     }),
   )
 
+  it.effect("preserves terminal state across usage-only message deltas", () =>
+    Effect.gen(function* () {
+      const response = yield* LLMClient.generate(request).pipe(
+        Effect.provide(
+          fixedResponse(
+            sseEvents(
+              { type: "message_start", message: { usage: { input_tokens: 5 } } },
+              {
+                type: "message_delta",
+                delta: { stop_reason: "end_turn", stop_sequence: "X" },
+                usage: { output_tokens: 8 },
+              },
+              { type: "message_delta", delta: {}, usage: { output_tokens: 10 } },
+              { type: "message_stop" },
+            ),
+          ),
+        ),
+      )
+
+      expect(response.usage).toMatchObject({ inputTokens: 5, outputTokens: 10, totalTokens: 15 })
+      expect(response.finishReason).toEqual({ normalized: "stop", raw: "end_turn" })
+      expect(response.events.find((event) => event.type === "step-finish")).toMatchObject({
+        reason: { normalized: "stop", raw: "end_turn" },
+        usage: { inputTokens: 5, outputTokens: 10, totalTokens: 15 },
+        providerMetadata: { anthropic: { stopSequence: "X" } },
+      })
+      expect(response.events.at(-1)).toMatchObject({
+        type: "finish",
+        reason: { normalized: "stop", raw: "end_turn" },
+        usage: { inputTokens: 5, outputTokens: 10, totalTokens: 15 },
+        providerMetadata: { anthropic: { stopSequence: "X" } },
+      })
+    }),
+  )
+
   it.effect("requires message_stop before completing a streamed message", () =>
     Effect.gen(function* () {
       const error = yield* LLMClient.generate(request).pipe(

packages/app/.gitignore

@@ -1,5 +1,6 @@
 src/assets/theme.css
 e2e/test-results
+e2e/performance/results/
 e2e/playwright-report
 component-tests/test-results
 component-tests/playwright-report

packages/app/README.md

@@ -71,4 +71,25 @@ Environment options:
 
 ## Deployment
 
-You can deploy the `dist` folder to any static host provider (netlify, surge, now, etc.)
+The `deploy` GitHub Actions workflow uses SST to deploy the web app from these branches in `anomalyco/opencode`:
+
+| Branch       | Site                  |
+| ------------ | --------------------- |
+| `dev`        | `app.dev.opencode.ai` |
+| `production` | `app.opencode.ai`     |
+| `beta`       | `beta.opencode.ai`    |
+
+Changes merged into `v2` reach the beta site when they are promoted to `beta`. The beta SST stage deploys
+only the web app, using the same `WebApp` StaticSite definition as production. It sets the build channel
+and Sentry environment to `beta` without deploying the API, console, database, or billing infrastructure.
+
+The hosted app defaults to `http://localhost:49374`, matching the managed V2 service. Saved server selections
+override this default. Connecting still requires the service's credentials.
+
+The workflow reuses the repository's `CLOUDFLARE_API_TOKEN` and web Sentry settings. The Cloudflare token
+must cover SST's R2 state storage, KV assets, Workers, and custom-domain management in the account that
+owns `opencode.ai`. The beta GitHub environment must allow deployments from the `beta` branch; it does not
+need AWS credentials.
+
+SST manages the beta site's custom domain. The first deployment creates its DNS record and TLS certificate.
+Do not create a CNAME for `beta.opencode.ai` first, because it would conflict with the Workers custom domain.

packages/app/component-tests/composer.spec.ts

@@ -1,5 +1,36 @@
 import { expect, story } from "../../storybook/playwright/story"
 
+story("renders a draft once and supports editing, caret restoration, and failure recovery", async ({ mount, page }) => {
+  await page.addInitScript(() => {
+    const replace = Element.prototype.replaceChildren
+    Element.prototype.replaceChildren = function (this: Element, ...nodes) {
+      // The ref can run before data-component is assigned, so count on every target.
+      this.setAttribute("data-test-replacements", String(Number(this.getAttribute("data-test-replacements")) + 1))
+      return replace.apply(this, nodes)
+    }
+  })
+  const component = await mount("opencode-composer-flow--failed-submission-restoration")
+  const input = component.getByRole("textbox", { name: "Prompt", exact: true })
+  await expect(input).toHaveText("Preserve this draft on failure")
+  await expect(input).toHaveAttribute("data-test-replacements", "1")
+
+  await input.press("Home")
+  await input.press("Shift+ArrowRight")
+  await input.pressSequentially("XY")
+  await expect(input).toHaveText("XYreserve this draft on failure")
+  await expect(input).toHaveAttribute("data-test-replacements", "1")
+
+  // Closing the model picker restores the controller's saved caret through its editor ref.
+  await component.locator('[data-action="composer-model"]').click()
+  await page.getByRole("menu").getByRole("textbox").press("Escape")
+  await expect(input).toBeFocused()
+  await input.pressSequentially("!")
+  await expect(input).toHaveText("XY!reserve this draft on failure")
+  await component.getByRole("button", { name: "Send", exact: true }).click()
+  await expect(component.getByRole("status")).toHaveText("Submission failed; draft restored")
+  await expect(input).toHaveText("Preserve this draft on failure")
+})
+
 // Moved from packages/app/e2e/regression/prompt-thinking-level.spec.ts
 story("shows the thinking level control while relevant", async ({ mount, page }) => {
   const component = await mount("opencode-composer-flow--model-and-variant")

packages/app/component-tests/timeline-virtualizer.fixture.tsx

@@ -0,0 +1,135 @@
+import { TimelineRow } from "@opencode-ai/session-ui/timeline/projection"
+import { onCleanup } from "solid-js"
+import { createStore } from "solid-js/store"
+import { render } from "solid-js/web"
+import { LanguageProvider } from "../src/runtime/i18n/language"
+import { createTimelineVirtualizer } from "../src/session/timeline/virtualizer"
+
+export function mountTimelineVirtualizer(input: { count: number; rowHeight: number; immediate?: boolean }) {
+  const host = document.createElement("main")
+  host.dataset.testid = "timeline-virtualizer-fixture"
+  host.dataset.scrolls = "0"
+  host.dataset.viewportResizes = "0"
+  host.style.cssText = "position:fixed;top:24px;right:24px;width:400px;z-index:1000"
+  document.body.appendChild(host)
+
+  function Fixture() {
+    const [state, setState] = createStore({ pinned: true, ready: false })
+    const rows = Array.from(
+      { length: input.count },
+      (_, index) => new TimelineRow.UserMessage({ userMessageID: `message-${index}` }),
+    )
+    const rowByKey = new Map(rows.map((row) => [TimelineRow.key(row), row]))
+    const indexes = new Map(rows.map((row, index) => [row.userMessageID, index]))
+    let viewport!: HTMLDivElement
+    let content!: HTMLDivElement
+    let container!: HTMLDivElement
+    const timeline = createTimelineVirtualizer({
+      sessionKey: () => "cold-reveal-fixture",
+      projection: {
+        rows: () => rows,
+        rowByKey: () => rowByKey,
+        activeMessageID: () => undefined,
+        messageRowIndex: () => indexes,
+        messageLastRowIndex: () => indexes,
+      },
+      showHeader: () => false,
+      pinned: () => state.pinned,
+      scroll: () => ({ overflow: false, jump: false }),
+      setScrollRef: (element) => {
+        if (!element) return
+        viewport = element
+        resize.observe(element, { box: "border-box" })
+      },
+      setContentRef: (element) => {
+        content = element
+        reveal.observe(element, { attributes: true, attributeFilter: ["style"] })
+      },
+      onPin: () => setState("pinned", true),
+      onUnpin: () => setState("pinned", false),
+      onScheduleScrollState: (element) => {
+        host.dataset.scrolls = String(Number(host.dataset.scrolls) + 1)
+        host.dataset.lastScrollTop = String(element.scrollTop)
+      },
+      onResumeScroll: () => {},
+      onSelectionInteraction: () => {},
+      onUserScroll: () => {},
+      onHistoryScroll: () => {},
+      canRenderImmediately: () => input.immediate ?? false,
+    })
+
+    const resize = new ResizeObserver((entries) => {
+      host.dataset.observedHeight = String(entries[0].borderBoxSize[0].blockSize)
+      host.dataset.viewportResizes = String(Number(host.dataset.viewportResizes) + 1)
+    })
+    const reveal = new MutationObserver(() => {
+      if (content.style.visibility === "hidden" || host.dataset.firstReveal) return
+      // Capture the first reveal, not a later frame after geometry has recovered.
+      const mounted = [...content.querySelectorAll<HTMLElement>("[data-timeline-key]")]
+      host.dataset.firstReveal = JSON.stringify({
+        rows: mounted.map((element) => Number(element.firstElementChild!.getAttribute("data-index"))),
+        pendingMarkdown: content.querySelectorAll('[data-component="markdown"]:not([data-markdown-ready])').length,
+        viewportHeight: viewport.clientHeight,
+        scrollTop: viewport.scrollTop,
+        clipped: mounted
+          .filter((element) => element.firstElementChild!.getBoundingClientRect().height > element.offsetHeight + 1)
+          .map((element) => element.dataset.timelineKey),
+      })
+    })
+    onCleanup(() => {
+      resize.disconnect()
+      reveal.disconnect()
+    })
+
+    return (
+      <div data-testid="timeline-controls" data-pinned={state.pinned}>
+        <button type="button" onClick={() => setState("ready", true)}>
+          Complete Markdown
+        </button>
+        <button type="button" onClick={() => (container.style.display = "none")}>
+          Hide viewport
+        </button>
+        <button
+          type="button"
+          onClick={() => {
+            const parent = viewport.parentElement!
+            host.dataset.scrolls = "0"
+            // Keep the same scroller and complete Markdown while it has no layout box.
+            viewport.remove()
+            viewport.scrollTop = 0
+            setState("ready", true)
+            parent.prepend(viewport)
+            container.style.removeProperty("display")
+          }}
+        >
+          Reconnect ready rows
+        </button>
+        <div ref={container} style={{ height: "180px", width: "400px" }}>
+          <timeline.View
+            header={null}
+            workspaceSession={() => false}
+            deferred={() => false}
+            renderRow={(row) => (
+              <div
+                data-component="markdown"
+                data-markdown-ready={state.ready ? "" : undefined}
+                style={{ height: `${input.rowHeight}px` }}
+              >
+                {row().userMessageID}
+              </div>
+            )}
+          />
+        </div>
+      </div>
+    )
+  }
+
+  render(
+    () => (
+      <LanguageProvider locale="en">
+        <Fixture />
+      </LanguageProvider>
+    ),
+    host,
+  )
+}

packages/app/component-tests/timeline-virtualizer.spec.ts

@@ -0,0 +1,79 @@
+import { fileURLToPath } from "node:url"
+import { expect, story } from "../../storybook/playwright/story"
+
+const fixture = `/@fs/${fileURLToPath(new URL("./timeline-virtualizer.fixture.tsx", import.meta.url)).replaceAll("\\", "/")}`
+
+story.beforeEach(async ({ mount }) => {
+  const component = await mount("opencode-composer-flow--mixed-attachments")
+  await expect(component.getByRole("textbox", { name: "Prompt", exact: true })).toBeVisible()
+})
+
+story("bounds the cheap suffix and reveals only ready measured rows", async ({ page }) => {
+  await page.evaluate(async (fixture) => {
+    const { mountTimelineVirtualizer } = await import(fixture)
+    mountTimelineVirtualizer({ count: 100, rowHeight: 60, immediate: true })
+  }, fixture)
+  const root = page.getByTestId("timeline-virtualizer-fixture")
+  const content = root.locator("[data-timeline-virtual-content]")
+  await expect(root).toHaveAttribute("data-observed-height", "180")
+  await expect(content).toHaveCSS("visibility", "hidden")
+  await expect(content.locator("[data-timeline-key]")).toHaveCount(4)
+  await root.getByRole("button", { name: "Complete Markdown", exact: true }).click()
+  await expect(content).toHaveCSS("visibility", "visible")
+  await expect(root).toHaveAttribute("data-first-reveal", /.+/)
+  expect(await root.evaluate((element) => JSON.parse(element.dataset.firstReveal!))).toMatchObject({
+    rows: [96, 97, 98, 99],
+    pendingMarkdown: 0,
+    clipped: [],
+    viewportHeight: 180,
+  })
+})
+
+for (const input of [
+  { name: "offset-only", count: 1, rowHeight: 600 },
+  { name: "zero-height", count: 4, rowHeight: 60 },
+]) {
+  story(`reveals ready measured rows after an ${input.name} reconnect`, async ({ page }) => {
+    await page.evaluate(
+      async ({ fixture, input }) => {
+        const { mountTimelineVirtualizer } = await import(fixture)
+        mountTimelineVirtualizer(input)
+      },
+      { fixture, input },
+    )
+    const root = page.getByTestId("timeline-virtualizer-fixture")
+    const content = root.locator("[data-timeline-virtual-content]")
+    await expect(root).toHaveAttribute("data-observed-height", "180")
+    await expect(content).toHaveCSS("visibility", "hidden")
+    await expect(content.locator("[data-timeline-key]")).toHaveCount(1)
+
+    if (input.name === "offset-only") {
+      await expect(root).toHaveAttribute("data-last-scroll-top", "484")
+      await root.locator("[data-scrollable]").dispatchEvent("wheel", { deltaY: -1 })
+      await expect(root.getByTestId("timeline-controls")).toHaveAttribute("data-pinned", "false")
+    }
+    if (input.name === "zero-height") {
+      await root.getByRole("button", { name: "Hide viewport", exact: true }).click()
+      // Wait for ResizeObserver to clear the actual range, not just for display:none.
+      await expect(root).toHaveAttribute("data-observed-height", "0")
+      await expect(content.locator("[data-timeline-key]")).toHaveCount(0)
+    }
+    await expect(root).not.toHaveAttribute("data-first-reveal")
+    const resizes = await root.getAttribute("data-viewport-resizes")
+    await root.getByRole("button", { name: "Reconnect ready rows", exact: true }).click()
+    await expect(content).toHaveCSS("visibility", "visible")
+    await expect(root).toHaveAttribute("data-first-reveal", /.+/)
+    expect(await root.evaluate((element) => JSON.parse(element.dataset.firstReveal!))).toMatchObject({
+      rows: input.count === 1 ? [0] : [0, 1, 2, 3],
+      pendingMarkdown: 0,
+      clipped: [],
+      viewportHeight: 180,
+      ...(input.name === "offset-only" ? { scrollTop: 0 } : {}),
+    })
+    if (input.name === "offset-only") {
+      // This repair must not depend on another native scroll or resize delivery.
+      await expect(root).toHaveAttribute("data-scrolls", "0")
+      await expect(root).toHaveAttribute("data-viewport-resizes", resizes!)
+    }
+  })
+}

packages/app/e2e/performance/README.md

@@ -65,7 +65,7 @@ The fixture requires every benchmark to call `report()`, automatically names and
 BENCHMARK {"name":"...","context":{"project":"chromium","platform":"darwin"},"metrics":{...}}
 ```
 
-Every observed page also emits `BENCHMARK_PAGE` with the same run ID, navigation history, and optional trace path before the final status-bearing `BENCHMARK` record. Chrome traces are browser-wide page-lifetime diagnostics; scenario metrics use narrower explicitly named observation windows.
+Every observed page also emits `BENCHMARK_PAGE` with the same run ID, navigation history, optional trace path, and trace scope before the final status-bearing `BENCHMARK` record. Chrome traces are browser-wide; the default window is page lifetime. Tab-switch traces begin after scenario setup and include explicit interaction markers. Scenario metrics use their own narrower observation windows.
 
 This follows the stack's own guidance: [Electron recommends repeated Chrome DevTools and Chrome Tracing measurement](https://www.electronjs.org/docs/latest/tutorial/performance), [Chrome DevTools recommends Performance recordings for runtime work](https://developer.chrome.com/docs/devtools/performance), and [Playwright uses traces for test debugging rather than renderer profiling](https://playwright.dev/docs/trace-viewer).
 
@@ -81,13 +81,60 @@ Committed smoke and regression tests continue to own correctness coverage for pa
 
 Tab-switch timing starts at `mousedown`, when mouse-selected tabs actually navigate, with a `click` fallback for keyboard activation. The probe excludes hidden/transparent content and intersects answers with their virtual-row clip and viewport. The tab workload requires the destination's final answer to be visible with Markdown ready. These results are not directly comparable to older click-start, geometry-only measurements. `stableObservedMs` includes confirmation across three correct samples; `firstCorrectObservedMs` is the first sample meeting all content and geometry checks. Neither is a compositor presentation timestamp.
 
-Each tab scenario reports one sample, including its raw observations. Use Playwright's `--repeat-each=5` for repeated measurements. Cached scenarios warm the destination at the same panel width before leaving it; a separate resized scenario validates reuse after opening the review pane changes that width.
+Each tab scenario reports one sample, including its raw observations. Use Playwright's `--repeat-each=20` for a baseline distribution. Warm scenarios prepare the destination at the same panel width before leaving it; a separate resized scenario validates reuse after opening the review pane changes that width.
+
+The tab-switch workload uses two equally long sessions: 200 user/assistant exchanges (400 messages) per tab. Every answer includes headings, emphasis, links, a blockquote, task and nested lists, an eight-row table, and four highlighted code fences (TSX, JSON, SQL, Bash), alongside the stress fixture's reasoning and tools. The mock API deliberately returns all 400 messages in one response so every scenario measures a long loaded history, not a short paginated tail. The viewport is fixed at 1440 x 900. Results include the fixture version, Markdown and serialized-message byte counts, and message-request count. These numbers are not directly comparable to the earlier 12-exchange source / 72-exchange destination fixture.
+
+Cold means the destination transcript has never rendered in that fresh browser context. Warm means its complex answer was rendered and ready before switching away and back. Both use the app's normal restored-tab data prefetch, which completes before measurement; neither includes app startup, the source session's Markdown engine initialization, or a cold backend fetch. The suite asserts no message fetch during either measured switch. Setup waits for mounted Markdown to finish and for the review-pane width transition to complete. Service workers are blocked to exclude the web build's background asset precache from this renderer benchmark. Screenshots are attached after measurement for the first repetition; Playwright video and trace recording are disabled for this workload, while opt-in Chrome profiling remains available. For a baseline distribution, use `--repeat-each=20 --retries=0`, keep profiling disabled, and report the median and p95 of `firstCorrectObservedMs` separately from the three-observation `stableObservedMs`.
 
 ```sh
 bunx playwright test --config e2e/performance/playwright.config.ts \
-  timeline/session-tab-switch-benchmark.spec.ts --repeat-each=5
+  timeline/session-tab-switch-benchmark.spec.ts --repeat-each=20 --retries=0
 ```
 
+**The tab-switch fixture is not an end-to-end cold-data benchmark.** It prefetches destination messages and returns full history. Measure cold API navigation, Home-row opening, and prefetched-but-unvisited tabs separately with normal pagination. Do not combine these entry paths or compare different transports and machine-load periods as one experiment.
+
+Keep one-off reports, recorded results, and traces outside git, in the ignored `e2e/performance/results/` directory or an external artifact directory. Preserve raw observations locally and publish anonymized summaries and charts in the PR description, not as committed experiment files.
+
+For a repeatable tab-switch summary, run from `packages/app`:
+
+```sh
+bun run bench:tabs
+```
+
+This runs only the tab-switch benchmark against the production build with 20 serial repetitions and no retries. It prints the median (mean of the two middle values for even sample counts) and nearest-rank p95 for `firstCorrectObservedMs` and `stableObservedMs` per scenario. Only records whose benchmark and Playwright statuses are passed and whose two metrics are finite enter the summary. Test and record statuses, missing records, and excluded samples are reported separately.
+
+For fresh entry paths, run `bun run bench:entry` from `packages/app`. It uses the same production, serial-repetition, and reporting defaults. The cases open an empty draft from the actual Home button, create a draft with the titlebar plus from an active session, and open a cold paginated session from Home. Draft readiness requires a focused editable composer, the expected model, project control, and new tab; typing and absence of backend mutations are checked afterward. Session readiness requires the latest group, ready answer Markdown, and bottom anchoring. These cases are separate from prefetched tab remounts.
+
+For milestone charts, rerun frozen builds with one workload and counterbalanced serial order. Do not connect historical medians from different transports, preparation, or machine-load periods. Show samples or ranges, name the checkpoints accurately, and distinguish experimental build snapshots from Git commits.
+
+Complete original `BENCHMARK` JSON records, including samples, context, and failed records, are saved as `tab-switch-benchmark.jsonl` in Playwright's configured output directory (default: `e2e/test-results/performance`). Standard Playwright flags can override defaults when appended:
+
+```sh
+bun run bench:tabs --repeat-each=3 --output=e2e/test-results/tabs-smoke
+```
+
+Set `OPENCODE_PERFORMANCE_MEMORY=1` for an opt-in renderer-main-isolate heap and DOM sample after mounted content is ready and an explicit GC completes. Probe DOM references are released before collection. This is not total desktop memory; do not mix these diagnostic runs with unprofiled latency samples. Set `OPENCODE_PERFORMANCE_TRACE_DIR` for a separate Chrome trace of each tab interaction, starting after preparation, with `session-switch:start`, `session-switch:ready`, and `session-switch:stable` markers.
+
+### Cache-Enabled HTTP Fixture
+
+The default tab harness uses Playwright routing for API responses. Playwright routing disables the browser HTTP cache, including for unrelated SVG assets. To measure with HTTP caching enabled, the same API handlers and tab data can run on a real loopback HTTP endpoint:
+
+```sh
+bun run build
+bun e2e/performance/tab-switch-server.ts --port 4639 --dist dist
+```
+
+With that fixture running, run the benchmark in a separate terminal from `packages/app`:
+
+```powershell
+$env:PLAYWRIGHT_BASE_URL = "http://127.0.0.1:4639"
+$env:OPENCODE_PERFORMANCE_HTTP_FIXTURE = "1"
+bun run bench:tabs
+```
+
+Use `--dist` to select a frozen production bundle when comparing revisions. An explicit `PLAYWRIGHT_BASE_URL` means the benchmark does not rebuild or start another preview. The fixture gives hashed assets immutable cache headers; it serves the deterministic read workload, not the live OpenCode service. Each test still gets a fresh browser context, and source-session setup still occurs before the measured switch. API responses use `no-store`, service workers remain blocked, and no destination Markdown is rendered before a cold switch. Records identify the transport as `http` or `playwright-route`; keep these series separate. Unset `OPENCODE_PERFORMANCE_HTTP_FIXTURE` when returning to the default routed harness.
+
 ## Retained renderer memory
 
 Run the catalog workload against the production app bundle:
@@ -111,7 +158,7 @@ bunx playwright test --config e2e/performance/playwright.config.ts \
 
 The emitted JSON is a standard Chrome trace and can be loaded directly into the Chrome DevTools Performance panel. `devtools-tracing` can optionally inspect it from the command line without adding package scripts or dependencies:
 
-Trace capture mirrors [Puppeteer's official tracing defaults and lifecycle](https://pptr.dev/api/puppeteer.tracing), using Chrome's `ReturnAsStream` transfer mode and failing when Chromium reports trace data loss.
+Trace capture follows [Puppeteer's tracing lifecycle](https://pptr.dev/api/puppeteer.tracing), using Chrome's `ReturnAsStream` transfer mode and failing when Chromium reports trace data loss. V8 CPU sample stacks support attribution through the frozen build's source maps. Set `OPENCODE_PERFORMANCE_STACK_TRACE=1` only when per-event timeline stacks are needed; they add substantial overhead. Keep profiled runs separate from latency distributions, including when comparing the stack-capture modes.
 
 ```sh
 bunx devtools-tracing stats <trace-path-from-BENCHMARK_PAGE>

packages/app/e2e/performance/benchmark.ts

@@ -5,16 +5,20 @@ type BenchmarkFixtures = {
   report: (metrics: Record<string, unknown>, context?: Record<string, unknown>) => void
   reportState: { payload?: { metrics: Record<string, unknown>; context: Record<string, unknown> } }
   benchmarkResult: void
+  traceScope: "page" | "interaction"
 }
 
 export type PerformancePageDiagnostics = {
   navigations: string[]
+  traceScope: "page" | "interaction"
+  startTrace: () => Promise<void>
   stop: () => Promise<string | undefined>
 }
 
 const pages = new WeakMap<Page, PerformancePageDiagnostics>()
 
 export const benchmark = base.extend<BenchmarkFixtures>({
+  traceScope: ["page", { option: true }],
   reportState: async ({}, use) => use({}),
   report: async ({ reportState }, use) => {
     await use((metrics, context = {}) => {
@@ -49,9 +53,9 @@ export const benchmark = base.extend<BenchmarkFixtures>({
     },
     { auto: true },
   ],
-  page: async ({ page }, use, testInfo) => {
+  page: async ({ page, traceScope }, use, testInfo) => {
     const name = benchmarkName(testInfo)
-    const diagnostics = await observePerformancePage(page, name)
+    const diagnostics = await observePerformancePage(page, name, traceScope)
     try {
       await use(page)
     } finally {
@@ -75,25 +79,30 @@ function benchmarkName(testInfo: TestInfo) {
 
 export { expect }
 
-async function observePerformancePage(page: Page, name: string) {
+async function observePerformancePage(page: Page, name: string, traceScope: "page" | "interaction" = "page") {
   const navigations: string[] = []
   const onNavigation = (frame: ReturnType<Page["mainFrame"]>) => {
     if (frame === page.mainFrame()) navigations.push(frame.url())
   }
   page.on("framenavigated", onNavigation)
-  const stopTrace = await startChromeTrace(page, name).catch((error) => {
-    page.off("framenavigated", onNavigation)
-    throw error
-  })
+  let stopTrace: Awaited<ReturnType<typeof startChromeTrace>>
   let stopping: Promise<string | undefined> | undefined
   const diagnostics: PerformancePageDiagnostics = {
     navigations,
+    traceScope,
+    async startTrace() {
+      stopTrace ??= await startChromeTrace(page, name).catch((error) => {
+        page.off("framenavigated", onNavigation)
+        throw error
+      })
+    },
     stop() {
       page.off("framenavigated", onNavigation)
       return (stopping ??= stopTrace?.() ?? Promise.resolve(undefined))
     },
   }
   pages.set(page, diagnostics)
+  if (traceScope === "page") await diagnostics.startTrace()
   return diagnostics
 }
 
@@ -130,6 +139,7 @@ async function reportPerformancePage(name: string, diagnostics: PerformancePageD
       context: {
         platform: process.platform,
         trace,
+        traceScope: diagnostics.traceScope,
         selectorTrace: process.env.OPENCODE_PERFORMANCE_SELECTOR_TRACE === "1",
       },
       navigations: diagnostics.navigations,

packages/app/e2e/performance/chrome-trace.ts

@@ -14,7 +14,6 @@ const categories = [
   "blink.console",
   "blink.user_timing",
   "latencyInfo",
-  "disabled-by-default-devtools.timeline.stack",
   "disabled-by-default-v8.cpu_profiler",
 ]
 
@@ -34,6 +33,9 @@ export async function startChromeTrace(page: Page, name: string): Promise<undefi
           .map((category) => category.slice(1)),
         includedCategories: [
           ...categories.filter((category) => !category.startsWith("-")),
+          ...(process.env.OPENCODE_PERFORMANCE_STACK_TRACE === "1"
+            ? ["disabled-by-default-devtools.timeline.stack"]
+            : []),
           ...(selectors
             ? ["disabled-by-default-blink.debug", "disabled-by-default-devtools.timeline.invalidationTracking"]
             : []),

packages/app/e2e/performance/tab-switch-reporter.ts

@@ -0,0 +1,99 @@
+import type { FullConfig, FullResult, Reporter, Suite, TestCase, TestResult } from "@playwright/test/reporter"
+import { mkdir, writeFile } from "node:fs/promises"
+import path from "node:path"
+
+type BenchmarkRecord = {
+  status?: string
+  metrics?: { firstCorrectObservedMs?: unknown; stableObservedMs?: unknown } | null
+}
+
+export default class TabSwitchReporter implements Reporter {
+  private output = ""
+  private tests: TestCase[] = []
+  private results: { test: TestCase; status: TestResult["status"]; records: string[] }[] = []
+
+  onBegin(config: FullConfig, suite: Suite) {
+    this.output = config.projects[0].outputDir
+    this.tests = suite.allTests()
+  }
+
+  onTestEnd(test: TestCase, result: TestResult) {
+    this.results.push({
+      test,
+      status: result.status,
+      records: Buffer.concat(result.stdout.map((chunk) => (typeof chunk === "string" ? Buffer.from(chunk) : chunk)))
+        .toString("utf8")
+        .split(/\r?\n/)
+        .filter((line) => line.startsWith("BENCHMARK "))
+        .map((line) => line.slice("BENCHMARK ".length)),
+    })
+  }
+
+  async onEnd(result: FullResult) {
+    const file = path.join(this.output, "tab-switch-benchmark.jsonl")
+    try {
+      await mkdir(this.output, { recursive: true })
+      await writeFile(file, this.results.flatMap((entry) => entry.records.map((raw) => `${raw}\n`)).join(""), "utf8")
+    } catch (error) {
+      console.error("Could not save tab-switch benchmark records:", error)
+      return { status: "failed" as const }
+    }
+
+    console.log(`\nTab-switch benchmark: ${result.status}`)
+    Array.from(new Set(this.tests.map((test) => test.title))).forEach((name) => {
+      const results = this.results.filter((entry) => entry.test.title === name)
+      const unrun = this.tests.filter(
+        (test) => test.title === name && !results.some((entry) => entry.test.id === test.id),
+      ).length
+      const records = results.flatMap((entry) =>
+        entry.records.map((raw) => {
+          try {
+            return { status: entry.status, record: JSON.parse(raw) as BenchmarkRecord | null }
+          } catch {
+            return { status: entry.status, record: { status: "invalid JSON", metrics: null } }
+          }
+        }),
+      )
+      const passed = records.filter((entry) => entry.status === "passed" && entry.record?.status === "passed")
+      const valid = passed
+        .map((entry) => ({
+          firstCorrectObservedMs: entry.record?.metrics?.firstCorrectObservedMs,
+          stableObservedMs: entry.record?.metrics?.stableObservedMs,
+        }))
+        .filter(
+          (metrics): metrics is { firstCorrectObservedMs: number; stableObservedMs: number } =>
+            typeof metrics.firstCorrectObservedMs === "number" &&
+            Number.isFinite(metrics.firstCorrectObservedMs) &&
+            typeof metrics.stableObservedMs === "number" &&
+            Number.isFinite(metrics.stableObservedMs),
+        )
+
+      console.log(`\n${name}`)
+      console.log(`  Tests: ${counts(results.map((entry) => entry.status))}; unrun=${unrun}`)
+      console.log(
+        `  Records: ${counts(records.map((entry) => entry.record?.status ?? "missing status"))}; ` +
+          `missing=${results.filter((entry) => entry.records.length === 0).length + unrun}; ` +
+          `excluded=${records.length - valid.length}; invalid metrics=${passed.length - valid.length}`,
+      )
+      ;(["firstCorrectObservedMs", "stableObservedMs"] as const).forEach((metric) => {
+        const values = valid.map((entry) => entry[metric]).sort((a, b) => a - b)
+        if (values.length === 0) {
+          console.log(`  ${metric}: n=0, median=n/a, p95=n/a`)
+          return
+        }
+        const median = (values[Math.floor((values.length - 1) / 2)] + values[Math.floor(values.length / 2)]) / 2
+        const p95 = values[Math.ceil(values.length * 0.95) - 1]
+        console.log(`  ${metric}: n=${values.length}, median=${median.toFixed(2)} ms, p95=${p95.toFixed(2)} ms`)
+      })
+    })
+    console.log(`\nRaw BENCHMARK records: ${file}`)
+  }
+}
+
+function counts(statuses: string[]) {
+  return (
+    Array.from(new Set(statuses))
+      .map((status) => `${status}=${statuses.filter((value) => value === status).length}`)
+      .join(", ") || "none"
+  )
+}

packages/app/e2e/performance/tab-switch-server.ts

@@ -0,0 +1,61 @@
+import path from "node:path"
+import { parseArgs } from "node:util"
+import { createMockServerHandler } from "../utils/mock-server"
+import { fixture } from "./timeline/session-timeline-stress.fixture"
+import { messages } from "./timeline/session-tab-switch.fixture"
+import { createReviewDiffs } from "./timeline/timeline-test-helpers"
+
+const args = parseArgs({
+  args: Bun.argv.slice(2),
+  options: { port: { type: "string", default: "4639" }, dist: { type: "string", default: "dist" } },
+})
+const directory = path.resolve(args.values.dist)
+const api = createMockServerHandler({
+  directory: fixture.directory,
+  project: fixture.project,
+  provider: fixture.provider,
+  sessions: fixture.sessions,
+  pageMessages: (sessionID) => ({ items: messages[sessionID] ?? [] }),
+  vcsDiff: createReviewDiffs(),
+})
+const server = Bun.serve({
+  hostname: "127.0.0.1",
+  port: Number(args.values.port),
+  idleTimeout: 0,
+  async fetch(request) {
+    const url = new URL(request.url)
+    if (url.pathname === "/api/event") {
+      return new Response(
+        new ReadableStream({
+          start(controller) {
+            controller.enqueue(
+              new TextEncoder().encode('data: {"id":"evt_fixture_connected","type":"server.connected","data":{}}\n\n'),
+            )
+          },
+        }),
+        { headers: { "content-type": "text/event-stream", "cache-control": "no-store" } },
+      )
+    }
+    if (url.pathname.startsWith("/api/")) {
+      const response = await api.handler(request)
+      response.headers.set("cache-control", "no-store")
+      return response
+    }
+    const file = Bun.file(path.join(directory, url.pathname))
+    if (!url.pathname.endsWith("/") && (await file.exists())) {
+      return new Response(file, {
+        headers: {
+          "cache-control": url.pathname.startsWith("/_assets/") ? "public, max-age=31536000, immutable" : "no-cache",
+        },
+      })
+    }
+    return new Response(Bun.file(path.join(directory, "index.html")), { headers: { "cache-control": "no-cache" } })
+  },
+})
+console.log(`Tab fixture: ${server.url} (${directory})`)
+const close = async () => {
+  await server.stop(true)
+  await api.dispose()
+}
+process.once("SIGINT", close)
+process.once("SIGTERM", close)

packages/app/e2e/performance/timeline/navigation-milestones.spec.ts

@@ -0,0 +1,33 @@
+import type { NavigationMilestoneSample } from "./navigation-milestones"
+import { measureNavigationMilestones } from "./navigation-milestones"
+import { benchmark, expect } from "../benchmark"
+
+benchmark(
+  "navigation milestones start at mousedown and wait for the expected ready controls",
+  async ({ page, report }) => {
+    await page.setContent('<button id="open">Open</button><input id="editor" disabled><span id="model">Loading</span>')
+    const result = await measureNavigationMilestones(page, {
+      triggerSelector: "#open",
+      milestones: { editor: { selector: "#editor:enabled:focus" }, model: { selector: "#model", text: "Ready model" } },
+      navigate: async () => {
+        await page.getByRole("button", { name: "Open", exact: true }).dispatchEvent("mousedown", { button: 0 })
+        await page.locator("#editor").evaluate((element: HTMLInputElement) => {
+          element.disabled = false
+          element.focus()
+        })
+        await page.waitForFunction(() => {
+          const samples = (window as Window & { __navigationMilestones?: { samples: NavigationMilestoneSample[] } })
+            .__navigationMilestones?.samples
+          return samples?.some((sample) => sample.milestones.editor && !sample.milestones.model)
+        })
+        await page.locator("#model").evaluate((element) => {
+          element.textContent = "Ready model"
+        })
+      },
+    })
+    expect(result.summary.all.firstObservedMs).not.toBeNull()
+    expect(result.summary.all.firstObservedMs).toBeGreaterThan(result.summary.milestones.editor.firstObservedMs!)
+    expect(await page.evaluate(() => "__navigationMilestones" in window)).toBe(false)
+    report(result)
+  },
+)

packages/app/e2e/performance/timeline/navigation-milestones.ts

@@ -36,7 +36,7 @@ export async function measureNavigationMilestones(
   page: Page,
   input: {
     triggerSelector: string
-    milestones: Record<string, { selector: string; visible?: boolean }>
+    milestones: Record<string, { selector: string; visible?: boolean; text?: string }>
     navigate: () => Promise<void>
   },
 ) {
@@ -47,11 +47,19 @@ export async function measureNavigationMilestones(
       const marked = new Set<string>()
       let started: number | undefined
       let running = true
-      const visible = (selector: string) =>
+      const visible = (selector: string, text?: string) =>
         [...document.querySelectorAll<HTMLElement>(selector)].some((element) => {
+          if (!element.checkVisibility({ checkOpacity: true, checkVisibilityCSS: true })) return false
+          if (text !== undefined && element.textContent?.replace(/\s+/g, " ").trim() !== text) return false
           const rect = element.getBoundingClientRect()
-          const style = getComputedStyle(element)
-          return rect.width > 0 && rect.height > 0 && style.visibility !== "hidden" && style.display !== "none"
+          return (
+            rect.width > 0 &&
+            rect.height > 0 &&
+            rect.bottom > 0 &&
+            rect.top < innerHeight &&
+            rect.right > 0 &&
+            rect.left < innerWidth
+          )
         })
       const sample = () => {
         if (!running || started === undefined) return
@@ -61,7 +69,9 @@ export async function measureNavigationMilestones(
             const current = Object.fromEntries(
               Object.entries(milestones).map(([name, milestone]) => [
                 name,
-                milestone.visible === false ? !document.querySelector(milestone.selector) : visible(milestone.selector),
+                milestone.visible === false
+                  ? !document.querySelector(milestone.selector)
+                  : visible(milestone.selector, milestone.text),
               ]),
             )
             samples.push({
@@ -93,36 +103,46 @@ export async function measureNavigationMilestones(
           }, 0)
         })
       }
-      document.addEventListener(
-        "click",
-        (event) => {
-          if (!(event.target instanceof Element) || !event.target.closest(triggerSelector)) return
-          started = performance.now()
-          performance.mark("opencode.navigation.click")
-          sample()
-        },
-        { capture: true, once: true },
-      )
+      const start = (event: MouseEvent) => {
+        if (started !== undefined || event.button !== 0) return
+        if (!(event.target instanceof Element) || !event.target.closest(triggerSelector)) return
+        started = performance.now()
+        performance.mark("opencode.navigation.start")
+        sample()
+      }
+      document.addEventListener("mousedown", start, true)
+      document.addEventListener("click", start, true)
       ;(window as Window & { __navigationMilestones?: NavigationMilestoneProbe }).__navigationMilestones = {
         samples,
         stop: () => {
           running = false
+          document.removeEventListener("mousedown", start, true)
+          document.removeEventListener("click", start, true)
         },
       }
     },
     { triggerSelector: input.triggerSelector, milestones: input.milestones },
   )
-  await input.navigate()
-  await page.waitForFunction(() => {
-    const samples = (window as Window & { __navigationMilestones?: NavigationMilestoneProbe }).__navigationMilestones
-      ?.samples
-    if (!samples || samples.length < 3) return false
-    return samples.slice(-3).every((sample) => Object.values(sample.milestones).every(Boolean))
-  })
-  const samples = await page.evaluate(() => {
-    const probe = (window as Window & { __navigationMilestones?: NavigationMilestoneProbe }).__navigationMilestones!
-    probe.stop()
-    return probe.samples
-  })
-  return { summary: summarizeNavigationMilestones(samples), samples }
+  try {
+    await input.navigate()
+    await page.waitForFunction(() => {
+      const samples = (window as Window & { __navigationMilestones?: NavigationMilestoneProbe }).__navigationMilestones
+        ?.samples
+      return (
+        samples &&
+        samples.length >= 3 &&
+        samples.slice(-3).every((sample) => Object.values(sample.milestones).every(Boolean))
+      )
+    })
+    const samples = await page.evaluate(
+      () => (window as Window & { __navigationMilestones?: NavigationMilestoneProbe }).__navigationMilestones!.samples,
+    )
+    return { summary: summarizeNavigationMilestones(samples), samples }
+  } finally {
+    await page.evaluate(() => {
+      const host = window as Window & { __navigationMilestones?: NavigationMilestoneProbe }
+      host.__navigationMilestones?.stop()
+      delete host.__navigationMilestones
+    })
+  }
 }

packages/app/e2e/performance/timeline/session-entry-benchmark.spec.ts

@@ -0,0 +1,91 @@
+import { benchmark, benchmarkDiagnostics, expect } from "../benchmark"
+import { measureNavigationMilestones } from "./navigation-milestones"
+import { fixture } from "./session-timeline-stress.fixture"
+import { measureSessionSwitch, waitForStableTimeline } from "./session-tab-switch-probe"
+import { installStressSessionTabs, mockStressTimeline, stressSessionHref } from "./timeline-test-helpers"
+
+benchmark.use({
+  viewport: { width: 1440, height: 900 },
+  serviceWorkers: "block",
+  traceScope: "interaction",
+  trace: "off",
+  video: "off",
+})
+
+for (const entry of ["home", "session"] as const) {
+  benchmark(`entry: new session from ${entry}`, async ({ page, report }) => {
+    await mockStressTimeline(page)
+    await installStressSessionTabs(page, { sessionIDs: entry === "home" ? [] : [fixture.sourceID] })
+    await page.goto(entry === "home" ? "/" : stressSessionHref(fixture.sourceID))
+    if (entry === "session") await waitForStableTimeline(page, fixture.expected.sourceMessageIDs.at(-1)!)
+    const trigger = entry === "home" ? '[data-action="home-new-session"]' : 'button[aria-label="New session"]'
+    await expect(page.locator(trigger)).toBeVisible()
+    await expect(page.locator('[data-component="new-session"]')).toHaveCount(0)
+    const writes: string[] = []
+    page.on("request", (request) => {
+      if (new URL(request.url()).pathname.startsWith("/api/") && !["GET", "HEAD", "OPTIONS"].includes(request.method()))
+        writes.push(request.method())
+    })
+    await benchmarkDiagnostics(page).startTrace()
+    const result = await measureNavigationMilestones(page, {
+      triggerSelector: trigger,
+      milestones: {
+        editor: {
+          selector: '[data-component="new-session"] [data-component="composer-editor"][contenteditable="true"]:focus',
+        },
+        model: { selector: '[data-component="new-session"] [data-action="composer-model"]', text: "Claude Opus 4.6" },
+        project: { selector: '[data-component="new-session"] [data-action="prompt-project"]' },
+        tab: { selector: '[data-titlebar-tab-link][href^="/new-session?draftId="]' },
+      },
+      navigate: () => page.locator(trigger).click(),
+    })
+    await benchmarkDiagnostics(page).stop()
+    const editor = page.locator('[data-component="new-session"] [data-component="composer-editor"]')
+    await expect(editor).toHaveText("")
+    await page.keyboard.type("Draft input")
+    await expect(editor).toHaveText("Draft input")
+    expect(writes).toEqual([])
+    report(
+      {
+        firstCorrectObservedMs: result.summary.all.firstObservedMs,
+        stableObservedMs: result.summary.all.stableObservedMs,
+        ...result,
+      },
+      { entry, data: "fixture", inputEvent: "mousedown" },
+    )
+  })
+}
+
+benchmark("entry: cold session from Home", async ({ page, report }) => {
+  const requests: string[] = []
+  await mockStressTimeline(page, {
+    onMessages: (request) => {
+      if (request.phase === "start") requests.push(request.sessionID)
+    },
+  })
+  await installStressSessionTabs(page, { sessionIDs: [] })
+  await page.goto("/")
+  const selector = `[data-component="home-session-row-container"][data-session-id="${fixture.targetID}"] [data-component="home-session-row"]`
+  await expect(page.locator(selector)).toBeVisible()
+  expect(requests).not.toContain(fixture.targetID)
+  const href = stressSessionHref(fixture.targetID)
+  await benchmarkDiagnostics(page).startTrace()
+  const result = await measureSessionSwitch(page, {
+    destinationIDs: fixture.messages[fixture.targetID].map((message) => message.id),
+    sourceIDs: [],
+    lastID: fixture.expected.targetMessageIDs.at(-1)!,
+    requiredPartID: fixture.expected.targetPartIDs.at(-1)!,
+    href,
+    triggerSelector: selector,
+    switch: async () => {
+      await page.locator(selector).click()
+      await waitForStableTimeline(page, fixture.expected.targetMessageIDs.at(-1)!)
+    },
+  })
+  await benchmarkDiagnostics(page).stop()
+  await expect(
+    page.locator(`[data-titlebar-tab-slot][data-active="true"] [data-titlebar-tab-link][href="${href}"]`),
+  ).toHaveCount(1)
+  expect(requests).toContain(fixture.targetID)
+  report(result, { entry: "home", data: "cold paginated fixture", inputEvent: "mousedown" })
+})

packages/app/e2e/performance/timeline/session-tab-switch-benchmark.spec.ts

@@ -1,71 +1,129 @@
 import type { Page } from "@playwright/test"
+import { mockOpenCodeServer } from "../../utils/mock-server"
 import { expectSessionTitle } from "../../utils/waits"
-import { benchmark, expect, withBenchmarkPage } from "../benchmark"
+import { benchmark, benchmarkDiagnostics, expect } from "../benchmark"
 import { fixture } from "./session-timeline-stress.fixture"
+import { expected, messages, workload } from "./session-tab-switch.fixture"
 import {
   createReviewDiffs,
   installStressSessionTabs,
   installTimelineSettings,
-  mockStressTimeline,
   stressSessionHref,
 } from "./timeline-test-helpers"
 import { measureSessionSwitch, waitForStableTimeline } from "./session-tab-switch-probe"
 
 const scenarios = [
-  { cached: false, review: false, resized: false },
-  { cached: false, review: true, resized: false },
-  { cached: true, review: false, resized: false },
-  { cached: true, review: true, resized: false },
-  { cached: true, review: true, resized: true },
-]
+  { cache: "cold", review: "closed" },
+  { cache: "cold", review: "open" },
+  { cache: "warm", review: "closed" },
+  { cache: "warm", review: "open" },
+  { cache: "warm", review: "resized" },
+] as const
+
+const viewport = { width: 1440, height: 900 }
+const reviewDiffs = createReviewDiffs()
+benchmark.use({ viewport, video: "off", trace: "off", serviceWorkers: "block", traceScope: "interaction" })
 
 scenarios.forEach((scenario) => {
-  const name = `tab switch: ${scenario.cached ? "cached" : "unmounted"}, review ${scenario.review ? "open" : "closed"}${scenario.resized ? ", resized" : ""}`
-  benchmark(name, async ({ browser, report }, testInfo) => {
-    const result = await withBenchmarkPage(
-      browser,
-      name,
-      async (page) => {
-        await mockStressTimeline(page, { vcsDiff: createReviewDiffs() })
-        await installTimelineSettings(page)
-        await installStressSessionTabs(page)
-        await page.goto(stressSessionHref(fixture.sourceID))
-        await expectSessionTitle(page, fixture.expected.sourceTitle)
-        await waitForStableTimeline(page, fixture.expected.sourceMessageIDs.at(-1)!)
-        if (scenario.review && !scenario.resized) await openReviewPane(page)
-        if (scenario.cached) {
-          await switchSession(page, fixture.targetID, fixture.expected.targetTitle)
-          const answer = page.locator(`[data-timeline-part-id="${fixture.expected.targetPartIDs.at(-1)}"]`)
-          await expect(answer.locator('[data-component="markdown"]')).toHaveAttribute("data-markdown-ready", "")
-          await expect
-            .poll(() =>
-              answer.evaluate((element) => element.checkVisibility({ checkOpacity: true, checkVisibilityCSS: true })),
-            )
-            .toBe(true)
-          await waitForStableTimeline(page, fixture.expected.targetMessageIDs.at(-1)!)
-          await switchSession(page, fixture.sourceID, fixture.expected.sourceTitle)
-        }
-        if (scenario.resized) await openReviewPane(page)
-        await waitForStableTimeline(page, fixture.expected.sourceMessageIDs.at(-1)!)
+  benchmark(`tab switch: ${scenario.cache}, review ${scenario.review}`, async ({ page, report }, testInfo) => {
+    const requests = await prepareSessionTabs(page)
+    if (scenario.review === "open") await openReviewPane(page)
+    if (scenario.cache === "warm") {
+      await switchSession(page, fixture.targetID, fixture.expected.targetTitle)
+      await expectReadyTimeline(page, fixture.targetID)
+      await switchSession(page, fixture.sourceID, fixture.expected.sourceTitle)
+    }
+    if (scenario.review === "resized") await openReviewPane(page)
+    await expectReadyTimeline(page, fixture.sourceID)
+    await benchmarkDiagnostics(page).startTrace()
+    const requestsBefore = requests.length
 
-        return measureSessionSwitch(page, {
-          destinationIDs: fixture.messages[fixture.targetID].map((message) => message.id),
-          sourceIDs: fixture.messages[fixture.sourceID].map((message) => message.id),
-          lastID: fixture.expected.targetMessageIDs.at(-1)!,
-          requiredPartID: fixture.expected.targetPartIDs.at(-1),
-          href: stressSessionHref(fixture.targetID),
-          switch: () => switchSession(page, fixture.targetID, fixture.expected.targetTitle),
-        })
+    const result = await measureSessionSwitch(page, {
+      destinationIDs: messages[fixture.targetID].map((message) => message.id),
+      sourceIDs: messages[fixture.sourceID].map((message) => message.id),
+      lastID: expected[fixture.targetID].lastID,
+      requiredPartID: expected[fixture.targetID].answerID,
+      href: stressSessionHref(fixture.targetID),
+      switch: () => switchSession(page, fixture.targetID, fixture.expected.targetTitle),
+    })
+
+    expect(result.firstCorrectObservedMs).not.toBeNull()
+    expect(result.stableObservedMs).not.toBeNull()
+    expect(requests).toHaveLength(requestsBefore)
+    await expectReadyTimeline(page, fixture.targetID)
+    report(
+      {
+        ...result,
+        messageRequestsDuringSwitch: requests.length - requestsBefore,
+        rendererMemory:
+          process.env.OPENCODE_PERFORMANCE_MEMORY === "1" ? await retainedRendererMemory(page) : undefined,
+      },
+      {
+        ...scenario,
+        ...workload,
+        viewport,
+        browserVersion: page.context().browser()!.version(),
+        serviceWorkers: "blocked",
+        reviewFiles: scenario.review === "closed" ? 0 : reviewDiffs.length,
+        data: "prefetched",
+        transport: process.env.OPENCODE_PERFORMANCE_HTTP_FIXTURE === "1" ? "http" : "playwright-route",
+        inputEvent: "mousedown",
+        requireReadyAnswer: true,
       },
-      testInfo,
     )
-    expect(result.unknownSamples).toBe(0)
-    expect(result.wrongDestinationSamples).toBe(0)
-    if (scenario.cached) expect(result.blankSamples).toBe(0)
-    report(result, { ...scenario, inputEvent: "mousedown", requireReadyAnswer: true })
+    if (testInfo.repeatEachIndex === 0) {
+      await page.screenshot({ path: testInfo.outputPath("destination.png") })
+      await testInfo.attach("destination", { path: testInfo.outputPath("destination.png"), contentType: "image/png" })
+    }
   })
 })
 
+async function prepareSessionTabs(page: Page) {
+  const requests: string[] = []
+  page.on("request", (request) => {
+    if (request.method() !== "GET") return
+    const match = new URL(request.url()).pathname.match(/^\/api\/session\/([^/]+)\/message$/)
+    if (match) requests.push(decodeURIComponent(match[1]))
+  })
+  if (process.env.OPENCODE_PERFORMANCE_HTTP_FIXTURE !== "1")
+    await mockOpenCodeServer(page, {
+      sessions: fixture.sessions,
+      provider: fixture.provider,
+      directory: fixture.directory,
+      project: fixture.project,
+      // Return the full history so every scenario exercises a long loaded timeline.
+      pageMessages: (sessionID) => ({ items: messages[sessionID] ?? [] }),
+      vcsDiff: reviewDiffs,
+    })
+  await installTimelineSettings(page)
+  await installStressSessionTabs(page)
+  // Restored tabs prefetch their data even when their transcript has never rendered.
+  const prefetch = page.waitForResponse((response) =>
+    new URL(response.url()).pathname.endsWith(`/session/${fixture.targetID}/message`),
+  )
+  await page.goto(stressSessionHref(fixture.sourceID))
+  expect(await (await prefetch).finished()).toBeNull()
+  await expectSessionTitle(page, fixture.expected.sourceTitle)
+  await expectReadyTimeline(page, fixture.sourceID)
+  await expect(page.locator(`[data-timeline-part-id="${expected[fixture.targetID].answerID}"]`)).toHaveCount(0)
+  expect(requests.toSorted()).toEqual([fixture.sourceID, fixture.targetID].toSorted())
+  return requests
+}
+
+async function expectReadyTimeline(page: Page, sessionID: string) {
+  const answer = page.locator(`[data-timeline-part-id="${expected[sessionID].answerID}"]`)
+  await expect(answer.locator('[data-component="markdown"]')).toHaveAttribute("data-markdown-ready", "")
+  await expect(answer.getByRole("table")).toHaveCount(1)
+  await expect(answer.locator("pre")).toHaveCount(4)
+  await expect
+    .poll(() => answer.evaluate((element) => element.checkVisibility({ checkOpacity: true, checkVisibilityCSS: true })))
+    .toBe(true)
+  await waitForStableTimeline(page, expected[sessionID].lastID)
+  await expect(page.locator('[data-timeline-key] [data-component="markdown"]:not([data-markdown-ready])')).toHaveCount(
+    0,
+  )
+}
+
 async function switchSession(page: Page, sessionID: string, title: string) {
   const tab = page.locator(`[data-slot="titlebar-tabs"] a[href="${stressSessionHref(sessionID)}"]`)
   await expect(tab).toHaveCount(1)
@@ -80,4 +138,20 @@ async function openReviewPane(page: Page) {
     const text = document.querySelector("#review-panel")?.textContent ?? ""
     return text.includes("generated-000.ts") && text.includes("+3")
   })
+  await page.locator('[data-slot="session-chat-panel"]').evaluate(async (panel) => {
+    await Promise.all(panel.getAnimations().map((animation) => animation.finished))
+  })
+}
+
+async function retainedRendererMemory(page: Page) {
+  const cdp = await page.context().newCDPSession(page)
+  try {
+    await cdp.send("HeapProfiler.collectGarbage")
+    return {
+      heap: await cdp.send("Runtime.getHeapUsage"),
+      dom: await cdp.send("Memory.getDOMCounters"),
+    }
+  } finally {
+    await cdp.detach()
+  }
 }

packages/app/e2e/performance/timeline/session-tab-switch-probe.spec.ts

@@ -2,66 +2,77 @@ import { benchmark, expect } from "../benchmark"
 import { measureSessionSwitch } from "./session-tab-switch-probe"
 import type { SessionSwitchSample } from "./session-tab-switch-metrics"
 
-benchmark("starts at mousedown and excludes hidden or unfinished destination content", async ({ page, report }) => {
-  await page.setContent(`
-    <a href="/session/destination">Destination</a>
+for (const tag of ["a", "button"] as const) {
+  benchmark(
+    `starts at ${tag} mousedown and excludes hidden or unfinished destination content`,
+    async ({ page, report }) => {
+      await page.setContent(`
+    <${tag} id="destination" ${tag === "a" ? 'href="/session/destination"' : 'type="button"'}>Destination</${tag}>
     <div class="scroll-view__viewport" style="height:200px;overflow:auto">
       <div data-timeline-row="message" data-timeline-key="row" data-message-id="source">
         <div data-timeline-part-id="answer"><div data-component="markdown">Destination answer</div></div>
       </div>
     </div>
   `)
-  await page.evaluate(() => {
-    document.querySelector("a")!.addEventListener("mousedown", () => {
-      const row = document.querySelector<HTMLElement>("[data-message-id]")!
-      row.dataset.messageId = "destination"
-      row.style.visibility = "hidden"
-    })
-  })
-  const result = await measureSessionSwitch(page, {
-    destinationIDs: ["destination"],
-    sourceIDs: ["source"],
-    lastID: "destination",
-    requiredPartID: "answer",
-    requireBottomAnchor: false,
-    href: "/session/destination",
-    switch: async () => {
-      // No click is dispatched: the probe must observe the event that activates tabs.
-      await page.getByRole("link", { name: "Destination" }).dispatchEvent("mousedown", { button: 0 })
-      await page.waitForFunction(() => {
-        const host = window as Window & { __sessionSwitchProbe?: { samples: SessionSwitchSample[] } }
-        return host.__sessionSwitchProbe?.samples.some((sample) => !sample.hasVisibleRows)
+      await page.evaluate(() => {
+        document.querySelector("#destination")!.addEventListener("mousedown", () => {
+          const row = document.querySelector<HTMLElement>("[data-message-id]")!
+          row.dataset.messageId = "destination"
+          row.style.visibility = "hidden"
+        })
       })
-      await page.locator("[data-message-id]").evaluate((row) => row.style.removeProperty("visibility"))
-      await page.waitForFunction(() => {
-        const host = window as Window & { __sessionSwitchProbe?: { samples: SessionSwitchSample[] } }
-        return host.__sessionSwitchProbe?.samples.some(
-          (sample) => sample.destination.length > 0 && sample.requiredPartVisible === false,
-        )
-      })
-      const beforeClip = await page.evaluate(() => {
-        const row = document.querySelector<HTMLElement>("[data-timeline-key]")!
-        row.style.cssText = "height:10px;position:relative;overflow:clip"
-        const answer = row.querySelector<HTMLElement>("[data-timeline-part-id]")!
-        answer.style.cssText = "position:absolute;top:30px;width:150px"
-        answer.querySelector('[data-component="markdown"]')!.setAttribute("data-markdown-ready", "")
-        return (
-          (window as Window & { __sessionSwitchProbe?: { samples: SessionSwitchSample[] } }).__sessionSwitchProbe
-            ?.samples.length ?? 0
-        )
-      })
-      await page.waitForFunction((count) => {
-        const host = window as Window & { __sessionSwitchProbe?: { samples: SessionSwitchSample[] } }
-        return host.__sessionSwitchProbe?.samples.slice(count).some((sample) => sample.requiredPartVisible === false)
-      }, beforeClip)
-      await page.locator("[data-timeline-key]").evaluate((row) => {
-        row.style.height = "100px"
+      const result = await measureSessionSwitch(page, {
+        destinationIDs: ["destination"],
+        sourceIDs: ["source"],
+        lastID: "destination",
+        requiredPartID: "answer",
+        requireBottomAnchor: false,
+        href: "/session/destination",
+        triggerSelector: tag === "button" ? "#destination" : undefined,
+        switch: async () => {
+          // No click is dispatched: the probe must observe the event that activates tabs.
+          await page
+            .getByRole(tag === "a" ? "link" : "button", { name: "Destination", exact: true })
+            .dispatchEvent("mousedown", { button: 0 })
+          await page.waitForFunction(() => {
+            const host = window as Window & { __sessionSwitchProbe?: { samples: SessionSwitchSample[] } }
+            return host.__sessionSwitchProbe?.samples.some((sample) => !sample.hasVisibleRows)
+          })
+          await page.locator("[data-message-id]").evaluate((row) => row.style.removeProperty("visibility"))
+          await page.waitForFunction(() => {
+            const host = window as Window & { __sessionSwitchProbe?: { samples: SessionSwitchSample[] } }
+            return host.__sessionSwitchProbe?.samples.some(
+              (sample) => sample.destination.length > 0 && sample.requiredPartVisible === false,
+            )
+          })
+          const beforeClip = await page.evaluate(() => {
+            const row = document.querySelector<HTMLElement>("[data-timeline-key]")!
+            row.style.cssText = "height:10px;position:relative;overflow:clip"
+            const answer = row.querySelector<HTMLElement>("[data-timeline-part-id]")!
+            answer.style.cssText = "position:absolute;top:30px;width:150px"
+            answer.querySelector('[data-component="markdown"]')!.setAttribute("data-markdown-ready", "")
+            return (
+              (window as Window & { __sessionSwitchProbe?: { samples: SessionSwitchSample[] } }).__sessionSwitchProbe
+                ?.samples.length ?? 0
+            )
+          })
+          await page.waitForFunction((count) => {
+            const host = window as Window & { __sessionSwitchProbe?: { samples: SessionSwitchSample[] } }
+            return host.__sessionSwitchProbe?.samples
+              .slice(count)
+              .some((sample) => sample.requiredPartVisible === false)
+          }, beforeClip)
+          await page.locator("[data-timeline-key]").evaluate((row) => {
+            row.style.height = "100px"
+          })
+        },
       })
+      expect(result.blankSamples).toBeGreaterThan(0)
+      expect(result.firstCorrectObservedMs).not.toBeNull()
+      expect(result.stableObservedMs).not.toBeNull()
+      expect(result.firstCorrectObservedMs).toBeGreaterThan(result.firstDestinationObservedMs!)
+      expect(await page.evaluate(() => "__sessionSwitchProbe" in window)).toBe(false)
+      report(result)
     },
-  })
-  expect(result.blankSamples).toBeGreaterThan(0)
-  expect(result.firstCorrectObservedMs).not.toBeNull()
-  expect(result.stableObservedMs).not.toBeNull()
-  expect(result.firstCorrectObservedMs).toBeGreaterThan(result.firstDestinationObservedMs!)
-  report(result)
-})
+  )
+}

packages/app/e2e/performance/timeline/session-tab-switch-probe.ts

@@ -14,124 +14,132 @@ async function installSessionSwitchProbe(
     lastID: string
     requiredPartID?: string
     requireBottomAnchor?: boolean
+    triggerSelector?: string
     href: string
   },
 ) {
-  await page.evaluate(({ destinationIDs, sourceIDs, lastID, requiredPartID, requireBottomAnchor, href }) => {
-    const destination = new Set(destinationIDs)
-    const source = new Set(sourceIDs)
-    const samples: SessionSwitchSample[] = []
-    let started: number | undefined
-    let running = true
-    const reviewLevels: Record<string, string> = {
-      panel: "#review-panel",
-      tabs: '#review-panel [data-component="tabs"]',
-      body: '#review-panel [data-slot="session-review-v2-body"]',
-      review: '#review-panel [data-component="session-review-v2"]',
-      preview: '#review-panel [data-slot="session-review-v2-preview"]',
-      scroll: '#review-panel [data-slot="session-review-v2-diff-scroll"]',
-      file: '#review-panel [data-component="file"][data-mode="diff"]',
-    }
-    const initialReviewNodes: Record<string, Element | null> = {}
-    const sample = () => {
-      if (!running || started === undefined) return
-      setTimeout(() => {
+  await page.evaluate(
+    ({ destinationIDs, sourceIDs, lastID, requiredPartID, requireBottomAnchor, triggerSelector, href }) => {
+      const destination = new Set(destinationIDs)
+      const source = new Set(sourceIDs)
+      const samples: SessionSwitchSample[] = []
+      let started: number | undefined
+      let running = true
+      const reviewLevels: Record<string, string> = {
+        panel: "#review-panel",
+        tabs: '#review-panel [data-component="tabs"]',
+        body: '#review-panel [data-slot="session-review-v2-body"]',
+        review: '#review-panel [data-component="session-review-v2"]',
+        preview: '#review-panel [data-slot="session-review-v2-preview"]',
+        scroll: '#review-panel [data-slot="session-review-v2-diff-scroll"]',
+        file: '#review-panel [data-component="file"][data-mode="diff"]',
+      }
+      const initialReviewNodes: Record<string, Element | null> = {}
+      const sample = () => {
         if (!running || started === undefined) return
-        const reviewPanel = document.querySelector<HTMLElement>("#review-panel")
-        const reviewFile = reviewPanel?.querySelector('[data-component="file"][data-mode="diff"]')
-        const initialReviewFile = initialReviewNodes.file
-        const replacedLevels = Object.entries(reviewLevels).flatMap(([name, selector]) => {
-          const initial = initialReviewNodes[name]
-          if (!initial) return []
-          const current = document.querySelector(selector)
-          return current && current !== initial ? [name] : []
-        })
-        const review = reviewPanel
-          ? {
-              fileHost: !!reviewFile,
-              fileHostReplaced: !!initialReviewFile && !!reviewFile && reviewFile !== initialReviewFile,
-              header:
-                reviewPanel
-                  .querySelector<HTMLElement>('[data-slot="session-review-v2-file-header"]')
-                  ?.textContent?.trim() ?? "",
-              replacedLevels,
-            }
-          : undefined
-        const root = [...document.querySelectorAll<HTMLElement>(".scroll-view__viewport")].find((element) =>
-          element.querySelector("[data-timeline-row]"),
-        )
-        if (root) {
-          const view = root.getBoundingClientRect()
-          const inViewport = (element: HTMLElement) => {
-            if (!element.checkVisibility({ checkOpacity: true, checkVisibilityCSS: true })) return false
-            const rect = element.getBoundingClientRect()
-            const clip = element.closest<HTMLElement>("[data-timeline-key]")?.getBoundingClientRect() ?? view
-            return (
-              Math.min(rect.bottom, clip.bottom, view.bottom) > Math.max(rect.top, clip.top, view.top) &&
-              Math.min(rect.right, clip.right, view.right) > Math.max(rect.left, clip.left, view.left)
-            )
-          }
-          const visible = [...root.querySelectorAll<HTMLElement>("[data-message-id]")]
-            .filter(inViewport)
-            .map((element) => element.dataset.messageId!)
-          const hasVisibleRows = [...root.querySelectorAll<HTMLElement>("[data-timeline-key]")].some(inViewport)
-          const requiredPartVisible = requiredPartID
-            ? [...root.querySelectorAll<HTMLElement>("[data-timeline-part-id]")].some((element) => {
-                if (element.dataset.timelinePartId !== requiredPartID) return false
-                if (!element.textContent?.trim()) return false
-                if (element.querySelector('[data-component="markdown"]:not([data-markdown-ready])')) return false
-                return inViewport(element)
-              })
+        setTimeout(() => {
+          if (!running || started === undefined) return
+          const reviewPanel = document.querySelector<HTMLElement>("#review-panel")
+          const reviewFile = reviewPanel?.querySelector('[data-component="file"][data-mode="diff"]')
+          const initialReviewFile = initialReviewNodes.file
+          const replacedLevels = Object.entries(reviewLevels).flatMap(([name, selector]) => {
+            const initial = initialReviewNodes[name]
+            if (!initial) return []
+            const current = document.querySelector(selector)
+            return current && current !== initial ? [name] : []
+          })
+          const review = reviewPanel
+            ? {
+                fileHost: !!reviewFile,
+                fileHostReplaced: !!initialReviewFile && !!reviewFile && reviewFile !== initialReviewFile,
+                header:
+                  reviewPanel
+                    .querySelector<HTMLElement>('[data-slot="session-review-v2-file-header"]')
+                    ?.textContent?.trim() ?? "",
+                replacedLevels,
+              }
             : undefined
-          const spacer = root.querySelector<HTMLElement>('[data-timeline-row="bottom-spacer"]')?.getBoundingClientRect()
-          samples.push({
-            observedAtMs: performance.now() - started,
-            destination: visible.filter((id) => destination.has(id)),
-            source: visible.filter((id) => source.has(id)),
-            hasVisibleRows,
-            last: visible.includes(lastID),
-            requiredPartVisible,
-            bottomAnchorRequired: requireBottomAnchor !== false,
-            bottomErrorPx: spacer ? spacer.bottom - view.bottom : undefined,
-            review,
-          })
-        } else {
-          samples.push({
-            observedAtMs: performance.now() - started,
-            destination: [],
-            source: [],
-            hasVisibleRows: false,
-            last: false,
-            requiredPartVisible: requiredPartID ? false : undefined,
-            bottomAnchorRequired: requireBottomAnchor !== false,
-            review,
-          })
+          const root = [...document.querySelectorAll<HTMLElement>(".scroll-view__viewport")].find((element) =>
+            element.querySelector("[data-timeline-row]"),
+          )
+          if (root) {
+            const view = root.getBoundingClientRect()
+            const inViewport = (element: HTMLElement) => {
+              if (!element.checkVisibility({ checkOpacity: true, checkVisibilityCSS: true })) return false
+              const rect = element.getBoundingClientRect()
+              const clip = element.closest<HTMLElement>("[data-timeline-key]")?.getBoundingClientRect() ?? view
+              return (
+                Math.min(rect.bottom, clip.bottom, view.bottom) > Math.max(rect.top, clip.top, view.top) &&
+                Math.min(rect.right, clip.right, view.right) > Math.max(rect.left, clip.left, view.left)
+              )
+            }
+            const visible = [...root.querySelectorAll<HTMLElement>("[data-message-id]")]
+              .filter(inViewport)
+              .map((element) => element.dataset.messageId!)
+            const hasVisibleRows = [...root.querySelectorAll<HTMLElement>("[data-timeline-key]")].some(inViewport)
+            const requiredPartVisible = requiredPartID
+              ? [...root.querySelectorAll<HTMLElement>("[data-timeline-part-id]")].some((element) => {
+                  if (element.dataset.timelinePartId !== requiredPartID) return false
+                  if (!element.textContent?.trim()) return false
+                  if (element.querySelector('[data-component="markdown"]:not([data-markdown-ready])')) return false
+                  return inViewport(element)
+                })
+              : undefined
+            const spacer = root
+              .querySelector<HTMLElement>('[data-timeline-row="bottom-spacer"]')
+              ?.getBoundingClientRect()
+            samples.push({
+              observedAtMs: performance.now() - started,
+              destination: visible.filter((id) => destination.has(id)),
+              source: visible.filter((id) => source.has(id)),
+              hasVisibleRows,
+              last: visible.includes(lastID),
+              requiredPartVisible,
+              bottomAnchorRequired: requireBottomAnchor !== false,
+              bottomErrorPx: spacer ? spacer.bottom - view.bottom : undefined,
+              review,
+            })
+          } else {
+            samples.push({
+              observedAtMs: performance.now() - started,
+              destination: [],
+              source: [],
+              hasVisibleRows: false,
+              last: false,
+              requiredPartVisible: requiredPartID ? false : undefined,
+              bottomAnchorRequired: requireBottomAnchor !== false,
+              review,
+            })
+          }
+          requestAnimationFrame(sample)
+        }, 0)
+      }
+      const start = (event: MouseEvent) => {
+        if (started !== undefined || event.button !== 0) return
+        const trigger = event.target instanceof Element ? event.target.closest(triggerSelector ?? "a") : undefined
+        if (!trigger || (!triggerSelector && trigger.getAttribute("href") !== href)) return
+        started = performance.now()
+        performance.mark("session-switch:start", { startTime: started })
+        for (const [name, selector] of Object.entries(reviewLevels)) {
+          initialReviewNodes[name] = document.querySelector(selector)
         }
         requestAnimationFrame(sample)
-      }, 0)
-    }
-    const start = (event: MouseEvent) => {
-      if (started !== undefined || event.button !== 0) return
-      const link = event.target instanceof Element ? event.target.closest("a") : undefined
-      if (link?.getAttribute("href") !== href) return
-      started = performance.now()
-      for (const [name, selector] of Object.entries(reviewLevels)) {
-        initialReviewNodes[name] = document.querySelector(selector)
       }
-      requestAnimationFrame(sample)
-    }
-    // Tabs activate on mousedown; click alone misses the synchronous navigation work.
-    document.addEventListener("mousedown", start, true)
-    document.addEventListener("click", start, true)
-    ;(window as Window & { __sessionSwitchProbe?: SessionSwitchProbe }).__sessionSwitchProbe = {
-      samples,
-      stop: () => {
-        running = false
-        document.removeEventListener("mousedown", start, true)
-        document.removeEventListener("click", start, true)
-      },
-    }
-  }, input)
+      // Tabs activate on mousedown; click alone misses the synchronous navigation work.
+      document.addEventListener("mousedown", start, true)
+      document.addEventListener("click", start, true)
+      ;(window as Window & { __sessionSwitchProbe?: SessionSwitchProbe }).__sessionSwitchProbe = {
+        samples,
+        stop: () => {
+          running = false
+          document.removeEventListener("mousedown", start, true)
+          document.removeEventListener("click", start, true)
+          Object.keys(initialReviewNodes).forEach((key) => (initialReviewNodes[key] = null))
+        },
+      }
+    },
+    input,
+  )
 }
 
 async function waitForStableSessionSwitch(page: Page) {
@@ -159,9 +167,17 @@ async function collectSessionSwitchResult(page: Page) {
   const samples = await page.evaluate(() => {
     const probe = (window as Window & { __sessionSwitchProbe?: SessionSwitchProbe }).__sessionSwitchProbe!
     probe.stop()
+    delete (window as Window & { __sessionSwitchProbe?: SessionSwitchProbe }).__sessionSwitchProbe
     return probe.samples
   })
-  return classifySessionSwitch(samples)
+  const result = classifySessionSwitch(samples)
+  await page.evaluate(({ firstCorrectObservedMs, stableObservedMs }) => {
+    const start = performance.getEntriesByName("session-switch:start").at(-1)!.startTime
+    if (firstCorrectObservedMs !== null)
+      performance.mark("session-switch:ready", { startTime: start + firstCorrectObservedMs })
+    if (stableObservedMs !== null) performance.mark("session-switch:stable", { startTime: start + stableObservedMs })
+  }, result)
+  return result
 }
 
 export async function measureSessionSwitch(
@@ -172,6 +188,7 @@ export async function measureSessionSwitch(
     lastID: string
     requiredPartID?: string
     requireBottomAnchor?: boolean
+    triggerSelector?: string
     href: string
     switch: () => Promise<void>
   },
@@ -185,6 +202,7 @@ export async function measureSessionSwitch(
   } finally {
     await page.evaluate(() => {
       ;(window as Window & { __sessionSwitchProbe?: SessionSwitchProbe }).__sessionSwitchProbe?.stop()
+      delete (window as Window & { __sessionSwitchProbe?: SessionSwitchProbe }).__sessionSwitchProbe
     })
   }
 }

packages/app/e2e/performance/timeline/session-tab-switch.fixture.ts

@@ -0,0 +1,143 @@
+import type { SessionMessageInfo } from "@opencode-ai/client/promise"
+import { fixture } from "./session-timeline-stress.fixture"
+
+export const exchanges = 200
+
+export const messages: Record<string, SessionMessageInfo[]> = Object.fromEntries(
+  [fixture.sourceID, fixture.targetID].map((sessionID) => [
+    sessionID,
+    Array.from({ length: exchanges }, (_, index) => {
+      const seed = fixture.messages[fixture.targetID]
+      const user = seed[(index % (seed.length / 2)) * 2]!
+      const assistant = seed[(index % (seed.length / 2)) * 2 + 1]!
+      if (user.type !== "user" || assistant.type !== "assistant") throw new Error("Expected a user/assistant pair")
+      const suffix = `${sessionID}_${String(index).padStart(4, "0")}`
+      return [
+        {
+          ...user,
+          id: `msg_user_${suffix}`,
+          time: { created: 1700000000000 + index * 10_000 },
+        },
+        {
+          ...assistant,
+          id: `msg_assistant_${suffix}`,
+          time: { created: 1700000001000 + index * 10_000, completed: 1700000008000 + index * 10_000 },
+          content: [
+            ...assistant.content
+              .filter((part) => part.type !== "text")
+              .map((part) => (part.type === "tool" ? { ...part, id: `${part.id}_${suffix}` } : part)),
+            { type: "text", text: complexMarkdown(sessionID, index) },
+          ],
+        },
+      ] satisfies SessionMessageInfo[]
+    }).flat(),
+  ]),
+)
+
+export const expected = Object.fromEntries(
+  [fixture.sourceID, fixture.targetID].map((sessionID) => [
+    sessionID,
+    {
+      lastID: messages[sessionID].at(-2)!.id,
+      answerID: `${messages[sessionID].at(-1)!.id}:text:0`,
+    },
+  ]),
+)
+
+export const workload = {
+  fixture: "long-complex-markdown-v1",
+  exchangesPerSession: exchanges,
+  messagesPerSession: exchanges * 2,
+  history: "full fixture history in one response",
+  sessions: Object.fromEntries(
+    Object.entries(messages).map(([sessionID, items]) => [
+      sessionID,
+      {
+        payloadBytes: Buffer.byteLength(JSON.stringify(items)),
+        markdownBytes: items.reduce(
+          (total, message) =>
+            total +
+            (message.type === "assistant"
+              ? message.content.reduce(
+                  (size, part) => size + (part.type === "text" ? Buffer.byteLength(part.text) : 0),
+                  0,
+                )
+              : 0),
+          0,
+        ),
+      },
+    ]),
+  ),
+}
+
+function complexMarkdown(sessionID: string, index: number) {
+  return `## Renderer review ${sessionID} / ${index}
+
+Preserve **semantic identity**, *measured geometry*, and ~~obsolete estimates~~ when switching sessions. The \`measureElement(node)\` result must agree with the [rendering contract](https://example.com/rendering/${sessionID}/${index}).
+
+> A completed answer contains formatted prose, highlighted source, and structured results.
+> Keep the previous view until the destination is ready, rather than exposing partially formatted content.
+
+### Readiness checklist
+
+- [x] Resolve the destination session and its messages.
+- [x] Parse Markdown and highlight fenced code.
+- [ ] Verify a different panel width.
+  - Preserve the bottom anchor.
+  - Reuse the measured rows when their width matches.
+
+| Stage | Input | Expected result | Verification |
+| :--- | ---: | :--- | :--- |
+${Array.from({ length: 8 }, (_, row) => `| stage-${index}-${row} | ${index * 8 + row} | **ready** with \`row[${row}]\` | stable geometry and visible content |`).join("\n")}
+
+### Implementation
+
+\`\`\`tsx
+import { For, Show, createMemo } from "solid-js"
+
+type Row = { id: string; title: string; ready: boolean; height: number }
+
+export function SessionRows${index}(props: { rows: Row[]; selected: string }) {
+  const visible = createMemo(() => props.rows.filter((row) => row.ready))
+  return (
+    <section aria-label="${sessionID}-${index}">
+      <For each={visible()}>{(row) => (
+        <article data-selected={row.id === props.selected}>
+          <h3>{row.title}</h3>
+          <Show when={row.height > 0} fallback={<span>Measuring</span>}>
+            <output>{row.height.toFixed(2)} pixels</output>
+          </Show>
+        </article>
+      )}</For>
+    </section>
+  )
+}
+\`\`\`
+
+\`\`\`json
+${JSON.stringify({ session: sessionID, exchange: index, stages: ["hydrate", "parse", "highlight", "measure"], viewport: { width: 1440, height: 900 }, cache: { markdown: true, geometry: true } }, null, 2)}
+\`\`\`
+
+\`\`\`sql
+SELECT session_id, COUNT(*) AS messages, MAX(created_at) AS latest
+FROM session_message
+WHERE session_id = '${sessionID}' AND ordinal >= ${index}
+GROUP BY session_id
+ORDER BY latest DESC;
+\`\`\`
+
+### Verification
+
+1. Open the long source session and wait for its final answer.
+2. Select the destination tab, without changing the viewport.
+3. Confirm that **all Markdown is ready** and the bottom anchor is correct.
+
+\`\`\`bash
+bun typecheck
+bunx playwright test --config e2e/performance/playwright.config.ts
+git diff --check # ${sessionID}-${index}
+\`\`\`
+
+**Review complete: ${sessionID} / ${index}.**
+`
+}

packages/app/e2e/performance/unit/tab-switch-reporter.test.ts

@@ -0,0 +1,114 @@
+import { expect, spyOn, test } from "bun:test"
+import type { FullConfig, Suite, TestCase, TestResult } from "@playwright/test/reporter"
+import { mkdtemp, readFile, rm } from "node:fs/promises"
+import os from "node:os"
+import path from "node:path"
+import TabSwitchReporter from "../tab-switch-reporter"
+
+test("summarizes each scenario and saves complete records in the configured output directory", async () => {
+  const root = await mkdtemp(path.join(os.tmpdir(), "tab-switch-reporter-"))
+  const output = path.join(root, "configured-output")
+  const log = spyOn(console, "log").mockImplementation(() => {})
+  try {
+    const reporter = new TabSwitchReporter()
+    const cases = Array.from(
+      { length: 23 },
+      (_, index) => ({ id: String(index), title: index < 20 ? "cold" : "warm" }) as TestCase,
+    )
+    const records = cases.map((_, index) => {
+      const first = index < 20 ? 20 - index : [40, 0, 20][index - 20]
+      return JSON.stringify({
+        status: "passed",
+        metrics: {
+          firstCorrectObservedMs: first,
+          stableObservedMs: first * 2,
+          samples: [{ observedAtMs: first, destination: ["answer"], source: [] }],
+        },
+        extra: { preserved: "\u03b1" },
+      })
+    })
+    reporter.onBegin({ projects: [{ outputDir: output }] } as FullConfig, { allTests: () => cases } as Suite)
+    cases.forEach((item, index) => {
+      const bytes = Buffer.from(`BENCHMARK ${records[index]}\r\n`)
+      const split = bytes.indexOf(Buffer.from("\u03b1")) + 1
+      reporter.onTestEnd(item, {
+        status: "passed",
+        stdout:
+          index === 0
+            ? [bytes.subarray(0, split), bytes.subarray(split)]
+            : ["other output\nBENCHMARK_PAGE {}\nBENCH", "MARK ", records[index], "\n"],
+      } as TestResult)
+    })
+    await reporter.onEnd({ status: "passed", startTime: new Date(0), duration: 0 })
+
+    expect(await readFile(path.join(output, "tab-switch-benchmark.jsonl"), "utf8")).toBe(`${records.join("\n")}\n`)
+    const summary = log.mock.calls.map((call) => call.join(" ")).join("\n")
+    expect(summary).toContain("cold\n  Tests: passed=20; unrun=0")
+    expect(summary).toContain("warm\n  Tests: passed=3; unrun=0")
+    expect(summary).toContain("firstCorrectObservedMs: n=20, median=10.50 ms, p95=19.00 ms")
+    expect(summary).toContain("stableObservedMs: n=20, median=21.00 ms, p95=38.00 ms")
+    expect(summary).toContain("firstCorrectObservedMs: n=3, median=20.00 ms, p95=40.00 ms")
+    expect(summary).toContain("stableObservedMs: n=3, median=40.00 ms, p95=80.00 ms")
+  } finally {
+    log.mockRestore()
+    await rm(root, { recursive: true, force: true })
+  }
+})
+
+test("reports failures, missing records, and invalid metrics without discarding raw data", async () => {
+  const output = await mkdtemp(path.join(os.tmpdir(), "tab-switch-reporter-"))
+  const log = spyOn(console, "log").mockImplementation(() => {})
+  try {
+    const reporter = new TabSwitchReporter()
+    const entries = [
+      {
+        status: "passed",
+        raw: '{"status":"passed","metrics":{"firstCorrectObservedMs":12,"stableObservedMs":24}}',
+      },
+      {
+        status: "failed",
+        raw: '{"status":"passed","metrics":{"firstCorrectObservedMs":900,"stableObservedMs":950}}',
+      },
+      {
+        status: "passed",
+        raw: '{"status":"failed","metrics":{"firstCorrectObservedMs":900,"stableObservedMs":950}}',
+      },
+      { status: "timedOut", raw: '{"status":"failed","metrics":null,"error":"Benchmark did not report metrics"}' },
+      {
+        status: "passed",
+        raw: '{"status":"passed","metrics":{"firstCorrectObservedMs":null,"stableObservedMs":40}}',
+      },
+      { status: "failed", raw: '{"status":' },
+      { status: "skipped", raw: undefined },
+    ] as const
+    const cases = Array.from(
+      { length: entries.length + 2 },
+      (_, index) => ({ id: String(index), title: index <= entries.length ? "cold" : "empty" }) as TestCase,
+    )
+    reporter.onBegin({ projects: [{ outputDir: output }] } as FullConfig, { allTests: () => cases } as Suite)
+    entries.forEach((entry, index) => {
+      reporter.onTestEnd(cases[index], {
+        status: entry.status,
+        stdout: entry.raw === undefined ? [] : [`BENCHMARK ${entry.raw}\n`],
+      } as TestResult)
+    })
+    await reporter.onEnd({ status: "interrupted", startTime: new Date(0), duration: 0 })
+
+    expect(await readFile(path.join(output, "tab-switch-benchmark.jsonl"), "utf8")).toBe(
+      entries.flatMap((entry) => (entry.raw === undefined ? [] : [`${entry.raw}\n`])).join(""),
+    )
+    const summary = log.mock.calls.map((call) => call.join(" ")).join("\n")
+    expect(summary).toContain("Tab-switch benchmark: interrupted")
+    expect(summary).toContain("Tests: passed=3, failed=2, timedOut=1, skipped=1; unrun=1")
+    expect(summary).toContain("Records: passed=3, failed=2, invalid JSON=1; missing=2; excluded=5; invalid metrics=1")
+    expect(summary).toContain("firstCorrectObservedMs: n=1, median=12.00 ms, p95=12.00 ms")
+    expect(summary).toContain("stableObservedMs: n=1, median=24.00 ms, p95=24.00 ms")
+    expect(summary).toContain("empty\n  Tests: none; unrun=1")
+    expect(summary).toContain("Records: none; missing=1; excluded=0; invalid metrics=0")
+    expect(summary).toContain("firstCorrectObservedMs: n=0, median=n/a, p95=n/a")
+    expect(summary).toContain("stableObservedMs: n=0, median=n/a, p95=n/a")
+  } finally {
+    log.mockRestore()
+    await rm(output, { recursive: true, force: true })
+  }
+})

packages/app/e2e/regression/session-timeline-hydration.spec.ts

@@ -0,0 +1,99 @@
+import type { SessionMessageInfo } from "@opencode-ai/client/promise"
+import { expect, test } from "@playwright/test"
+import { fixture } from "../performance/timeline/session-timeline-stress.fixture"
+import { stressSessionHref } from "../performance/timeline/timeline-test-helpers"
+import { mockOpenCodeServer } from "../utils/mock-server"
+
+test.use({ viewport: { width: 1440, height: 900 }, serviceWorkers: "block" })
+
+for (const window of ["assistant-only", "mixed"] as const) {
+  test(`renders the ${window} latest page before parent hydration and preserves it afterward`, async ({ page }) => {
+    const session = { ...fixture.sessions[0]!, id: `ses_hydration_${window}` }
+    // Both 20-message pages begin with an assistant; only page three supplies its parent.
+    const messages = Array.from({ length: 41 }, (_, index): SessionMessageInfo => {
+      const id = `msg_hydration_${index}`
+      const time = { created: 1700000000000 + index * 1_000 }
+      if (index === 0 || (window === "mixed" && index === 39))
+        return { id, type: "user", time, text: `Prompt ${index}` }
+      return {
+        id,
+        type: "assistant",
+        time: { ...time, completed: time.created + 500 },
+        model: { id: "claude-opus-4-6", providerID: "opencode" },
+        agent: "build",
+        content: [{ type: "text", text: index === 40 ? "## Hydrated tail\n\n**Ready.**" : `Answer ${index}` }],
+      }
+    })
+    const gates = [21, 1].map((index) => ({
+      before: messages[index]!.id,
+      parent: messages[index === 21 ? 1 : 0]!.id,
+      requested: Promise.withResolvers<void>(),
+      release: Promise.withResolvers<void>(),
+    }))
+    const requests: (string | undefined)[] = []
+    await mockOpenCodeServer(page, {
+      ...fixture,
+      sessions: [session],
+      beforeMessagesResponse: async ({ before }) => {
+        requests.push(before)
+        if (!before) return
+        const gate = gates.find((gate) => gate.before === before)
+        if (!gate) throw new Error(`Unexpected older-page boundary: ${before}`)
+        gate.requested.resolve()
+        await gate.release.promise
+      },
+      pageMessages: (_, limit, before) => {
+        expect(limit).toBe(20)
+        const end = before ? messages.findIndex((message) => message.id === before) : messages.length
+        const start = Math.max(0, end - limit)
+        return { items: messages.slice(start, end), cursor: start > 0 ? messages[start]!.id : undefined }
+      },
+    })
+    const tail = page.locator('[data-timeline-part-id="msg_hydration_40:text:0"]')
+    const markdown = tail.locator('[data-component="markdown"]')
+    const content = page.locator("[data-timeline-virtual-content]", { has: tail })
+    const viewport = page.locator(".scroll-view__viewport", { has: tail })
+    const orphan = page.locator('[data-timeline-row="AssistantPart"]', {
+      has: page.locator('[data-timeline-part-id="msg_hydration_38:text:0"]'),
+    })
+    const expectReadyTail = async () => {
+      await expect(content).toHaveCSS("visibility", "visible")
+      await expect(markdown).toHaveAttribute("data-markdown-ready", "")
+      await expect(markdown.getByRole("heading", { name: "Hydrated tail", exact: true })).toBeInViewport({ ratio: 1 })
+      await expect
+        .poll(() =>
+          viewport.evaluate((element) => Math.abs(element.scrollHeight - element.clientHeight - element.scrollTop)),
+        )
+        .toBeLessThanOrEqual(1)
+    }
+
+    try {
+      await page.goto(stressSessionHref(session.id))
+      await gates[0]!.requested.promise
+      // This must pass while the first older response is still held.
+      await expectReadyTail()
+      await expect(orphan).toHaveAttribute("data-message-id", "msg_hydration_21")
+      if (window === "mixed")
+        await expect(
+          page.locator('[data-timeline-row="UserMessage"][data-message-id="msg_hydration_39"]'),
+        ).toBeInViewport()
+      const original = await markdown.elementHandle()
+
+      for (const gate of gates) {
+        await gate.requested.promise
+        gate.release.resolve()
+        // Parent ownership proves the page reached the projection, not just the network.
+        await expect(orphan).toHaveAttribute("data-message-id", gate.parent)
+        await expectReadyTail()
+        expect(await markdown.evaluate((element, original) => element === original, original)).toBe(true)
+      }
+      expect(requests).toEqual([undefined, ...gates.map((gate) => gate.before)])
+      const ids = await content
+        .locator("[data-timeline-part-id]")
+        .evaluateAll((elements) => elements.map((element) => element.getAttribute("data-timeline-part-id")))
+      expect(new Set(ids).size).toBe(ids.length)
+    } finally {
+      gates.forEach((gate) => gate.release.resolve())
+    }
+  })
+}

packages/app/e2e/regression/session-timeline-mount.spec.ts

@@ -0,0 +1,123 @@
+import { expect, test, type Page } from "@playwright/test"
+import type { SessionMessageInfo } from "@opencode-ai/client/promise"
+import { mockOpenCodeServer } from "../utils/mock-server"
+import { fixture } from "../performance/timeline/session-timeline-stress.fixture"
+import { expected, messages } from "../performance/timeline/session-tab-switch.fixture"
+import { installTimelineSettings, stressSessionHref } from "../performance/timeline/timeline-test-helpers"
+
+test.use({ viewport: { width: 1440, height: 900 }, serviceWorkers: "block" })
+
+type Reveal = { pending: number; clipped: string[]; bottomError: number; tables: number; codeBlocks: number }
+
+for (const width of [1440, 390]) {
+  test(`reveals measured Markdown after the worker completes at ${width}px`, async ({ page }) => {
+    await page.setViewportSize({ width, height: 900 })
+    const requested = Promise.withResolvers<void>()
+    const release = Promise.withResolvers<void>()
+    await page.route(/markdown\.worker(?:-[^/?]+\.js|\.ts)(?:\?.*)?$/, async (route) => {
+      requested.resolve()
+      await release.promise
+      await route.continue()
+    })
+    await page.addInitScript((partID) => {
+      const observer = new MutationObserver(() => {
+        const answer = document.querySelector<HTMLElement>(`[data-timeline-part-id="${partID}"]`)
+        const content = answer?.closest<HTMLElement>("[data-timeline-virtual-content]")
+        const root = content?.closest<HTMLElement>(".scroll-view__viewport")
+        if (!answer || !content || !root || !content.checkVisibility({ checkVisibilityCSS: true })) return
+        const spacer = content.querySelector('[data-timeline-row="bottom-spacer"]')
+        ;(window as Window & { __coldReveal?: Reveal }).__coldReveal = {
+          pending: content.querySelectorAll('[data-component="markdown"]:not([data-markdown-ready])').length,
+          clipped: [...content.querySelectorAll<HTMLElement>("[data-timeline-key]")].flatMap((row) =>
+            (row.firstElementChild?.getBoundingClientRect().height ?? 0) > row.getBoundingClientRect().height + 1
+              ? [row.dataset.timelineKey!]
+              : [],
+          ),
+          bottomError: (spacer?.getBoundingClientRect().bottom ?? Infinity) - root.getBoundingClientRect().bottom,
+          tables: answer.querySelectorAll("table").length,
+          codeBlocks: answer.querySelectorAll("pre").length,
+        }
+        observer.disconnect()
+      })
+      observer.observe(document, { childList: true, subtree: true, attributes: true, attributeFilter: ["style"] })
+    }, expected[fixture.sourceID].answerID)
+    await mockOpenCodeServer(page, {
+      sessions: fixture.sessions,
+      project: fixture.project,
+      provider: fixture.provider,
+      directory: fixture.directory,
+      pageMessages: () => ({ items: messages[fixture.sourceID] }),
+    })
+    await installTimelineSettings(page)
+    try {
+      await page.goto(stressSessionHref(fixture.sourceID), { waitUntil: "domcontentloaded" })
+      await requested.promise
+      await expect(page.locator("[data-timeline-virtual-content]")).toHaveCSS("visibility", "hidden")
+      release.resolve()
+      await expect(page.locator("[data-timeline-virtual-content]")).toHaveCSS("visibility", "visible")
+      const reveal = await page.evaluate(() => (window as Window & { __coldReveal?: Reveal }).__coldReveal)
+      expect(reveal).toMatchObject({ pending: 0, clipped: [], tables: 1, codeBlocks: 4 })
+      expect(Math.abs(reveal?.bottomError ?? Infinity)).toBeLessThanOrEqual(1)
+    } finally {
+      release.resolve()
+    }
+  })
+}
+
+test("scrolls within a long answer without mounting unrelated history", async ({ page }) => {
+  await openTimeline(page, messages[fixture.sourceID])
+  const answer = page.locator(`[data-timeline-part-id="${expected[fixture.sourceID].answerID}"]`)
+  await expect(answer.locator('[data-component="markdown"]')).toHaveAttribute("data-markdown-ready", "")
+  await expect(answer.getByRole("table")).toHaveCount(1)
+  const scroller = page.locator(".scroll-view__viewport", { has: answer })
+  await expect
+    .poll(() => scroller.evaluate((element) => element.scrollHeight - element.clientHeight - element.scrollTop))
+    .toBeLessThanOrEqual(1)
+  const rows = page.locator("[data-timeline-key]")
+  const keys = await rows.evaluateAll((elements) =>
+    elements.map((element) => element.getAttribute("data-timeline-key")),
+  )
+  const top = await answer.evaluate((element) => element.getBoundingClientRect().top)
+
+  await scroller.hover()
+  await page.mouse.wheel(0, -240)
+
+  await expect.poll(() => answer.evaluate((element) => element.getBoundingClientRect().top)).toBeCloseTo(top + 240, 0)
+  expect(
+    await rows.evaluateAll((elements) => elements.map((element) => element.getAttribute("data-timeline-key"))),
+  ).toEqual(keys)
+  await expect(answer.locator('[data-component="markdown"]')).toHaveAttribute("data-markdown-ready", "")
+})
+
+test("fills a short cold transcript before revealing it", async ({ page }) => {
+  const history = messages[fixture.sourceID].slice(-6).map((message, index) => {
+    if (message.type === "user") return { ...message, text: `Prompt ${index}`, metadata: undefined }
+    if (message.type === "assistant")
+      return { ...message, content: [{ type: "text" as const, text: `**Answer ${index}**` }] }
+    return message
+  })
+  await openTimeline(page, history)
+  for (const message of history) {
+    if (message.type === "user") {
+      await expect(page.locator(`[data-timeline-row="UserMessage"][data-message-id="${message.id}"]`)).toBeInViewport()
+    }
+    if (message.type === "assistant") {
+      const answer = page.locator(`[data-timeline-part-id="${message.id}:text:0"]`)
+      await expect(answer).toBeInViewport()
+      await expect(answer.locator('[data-component="markdown"]')).toHaveAttribute("data-markdown-ready", "")
+    }
+  }
+})
+
+async function openTimeline(page: Page, history: SessionMessageInfo[]) {
+  await mockOpenCodeServer(page, {
+    sessions: fixture.sessions,
+    project: fixture.project,
+    provider: fixture.provider,
+    directory: fixture.directory,
+    pageMessages: () => ({ items: history }),
+  })
+  await installTimelineSettings(page)
+  await page.goto(stressSessionHref(fixture.sourceID))
+  await expect(page.locator("[data-timeline-virtual-content]")).toHaveCSS("visibility", "visible")
+}

packages/app/e2e/regression/tab-navigate-mousedown.spec.ts

@@ -102,6 +102,14 @@ test("cramped tabs only show the close button for the active tab", async ({ page
   await expect(page).toHaveURL(new RegExp(`${hrefB.replace(/[.*+?^${}()|[\]\\]/g, "\\$&")}$`))
   await expect(tabA.locator('[data-slot="tab-close"]')).toBeHidden()
   await expect(tabB.locator('[data-slot="tab-close"]')).toBeVisible()
+
+  for (const direction of ["ltr", "rtl"]) {
+    await page.evaluate((direction) => document.documentElement.setAttribute("dir", direction), direction)
+    await page.setViewportSize({ width: 450, height: 720 })
+    await expect(tabA.locator("[data-titlebar-tab]")).toHaveAttribute("data-title-overflow", "true")
+    await page.setViewportSize({ width: 1280, height: 720 })
+    await expect(tabA.locator("[data-titlebar-tab]")).toHaveAttribute("data-title-overflow", "false")
+  }
 })
 
 test("vertical tabs show project details, resize, and navigate", async ({ page }) => {
@@ -288,11 +296,12 @@ async function mockServer(page: Page) {
     if (currentSessionInfo) return json(route, { data: currentSession(currentSessionInfo) })
     if (sessions.some((item) => url.pathname === `/api/session/${item.id}/message`))
       return json(route, { data: [], cursor: {} })
+    if (sessions.some((item) => url.pathname === `/api/session/${item.id}/inbox`)) return json(route, { data: [] })
     if (["/api/agent", "/api/provider", "/api/model", "/api/command", "/api/reference"].includes(url.pathname))
       return json(route, { location: { directory: sessionA.directory }, data: [] })
     if (url.pathname === "/api/model/default")
       return json(route, { location: { directory: sessionA.directory }, data: null })
-    if (url.pathname === "/api/permission/request" || url.pathname === "/api/question/request")
+    if (url.pathname === "/api/permission/request" || url.pathname === "/api/form/request")
       return json(route, { location: { directory: sessionA.directory }, data: [] })
     if (url.pathname === "/api/mcp") return json(route, { location: { directory: sessionA.directory }, data: [] })
     if (url.pathname === "/api/mcp/resource")

packages/app/e2e/smoke/session-timeline.spec.ts

@@ -355,6 +355,14 @@ test.describe("smoke: session timeline", () => {
     await expectCanScrollToStart(page, expectedPartIDs, expectedMessageIDs, errors)
 
     const shell = page.locator(`[data-timeline-part-id="${fixture.expected.expandedShellPartID}"]`)
+    // The shell is below a long diff; reveal it rather than depending on offscreen overscan.
+    while ((await shell.count()) === 0) {
+      const before = await timelineState(page)
+      await timelineScroller(page).press("PageDown")
+      await expect.poll(async () => (await timelineState(page)).signature).not.toBe(before.signature)
+    }
+    await shell.scrollIntoViewIfNeeded()
+    await expect(shell).toBeInViewport()
     const shellTrigger = shell.locator('[data-slot="collapsible-trigger"]')
     const shellSubtitle = shell.locator('[data-slot="basic-tool-tool-subtitle"]')
     await expect(shellSubtitle).toHaveCount(0)
@@ -694,6 +702,7 @@ async function expectSessionTimelineReady(
   expectedMessageIDs: string[],
   errors: string[],
 ) {
+  await expect(page.locator("[data-timeline-virtual-content]")).toHaveCSS("visibility", "visible")
   await waitForTimelineStable(page)
   for (const text of forbiddenText) await expect(page.getByText(text)).toHaveCount(0)
   const currentState = await timelineState(page)

packages/app/e2e/user-story/model-selection-flow.spec.ts

@@ -1,10 +1,16 @@
 import { expect, test } from "@playwright/test"
+import { fixture } from "../performance/timeline/session-timeline-stress.fixture"
+import { installStressSessionTabs, stressSessionHref } from "../performance/timeline/timeline-test-helpers"
 import { mockOpenCodeServer } from "../utils/mock-server"
 import { expectAppVisible } from "../utils/waits"
 
 const directory = "C:/OpenCode/NewProject"
 
 test("creates a session in a new project and selects its model", async ({ page }) => {
+  // An empty draft must remain usable when the file viewer is unavailable.
+  await page.route(/(?:\/_assets\/file-(?!icon-)[^/]+\.js|\/session-ui\/src\/components\/file\.tsx)(?:\?|$)/, (route) =>
+    route.abort(),
+  )
   await mockOpenCodeServer(page, {
     directory,
     project: {
@@ -60,7 +66,7 @@ test("creates a session in a new project and selects its model", async ({ page }
           { providerID: "opencode", modelID: "free-model", visibility: "show" },
           { providerID: "opencode-go", modelID: "go-model-1", visibility: "show" },
         ],
-        recent: [],
+        recent: [{ providerID: "opencode-go", modelID: "go-model-1" }],
         variant: {},
       }),
     )
@@ -81,11 +87,73 @@ test("creates a session in a new project and selects its model", async ({ page }
   await expectAppVisible(page.locator('[data-component="composer"]'))
 
   const modelControl = page.locator('[data-action="composer-model"]')
+  await expect(modelControl).toContainText("Go Model 1")
+  await modelControl.click()
+  await page.locator('[data-option-key="opencode:free-model"]').click()
+  await expect(modelControl).toContainText("Free Model")
+
   await modelControl.click()
-  await expect(page.locator('[data-option-key="opencode:free-model"]')).toBeVisible()
   const goModel = page.locator('[data-option-key="opencode-go:go-model-1"]')
   await expect(goModel).toBeVisible()
   await goModel.click()
 
   await expect(modelControl).toContainText("Go Model 1")
 })
+
+test("restores each existing session's model and variant when switching tabs", async ({ page }) => {
+  const sessions = ["A", "B"].map((name) => ({
+    ...fixture.sessions[0],
+    id: `ses_model_${name}`,
+    title: `Model ${name}`,
+    model: { id: `model-${name}`, providerID: "opencode", variant: "balanced" },
+  }))
+  await mockOpenCodeServer(page, {
+    ...fixture,
+    sessions,
+    provider: {
+      all: [
+        {
+          id: "opencode",
+          name: "OpenCode",
+          models: Object.fromEntries(
+            sessions.map((session) => [
+              session.model.id,
+              {
+                id: session.model.id,
+                name: session.title,
+                limit: { context: 200_000 },
+                variants: { balanced: {}, high: {} },
+              },
+            ]),
+          ),
+        },
+      ],
+      connected: ["opencode"],
+      default: { providerID: "opencode", modelID: sessions[0]!.model.id },
+    },
+    pageMessages: () => ({ items: [] }),
+  })
+  await installStressSessionTabs(page, { sessionIDs: sessions.map((session) => session.id) })
+
+  const hrefA = stressSessionHref(sessions[0]!.id)
+  const hrefB = stressSessionHref(sessions[1]!.id)
+  await page.goto(hrefA)
+  const composer = page.locator('[data-component="composer"]')
+  const modelControl = composer.locator('[data-action="composer-model"]')
+  const variant = composer.getByRole("button", { name: "Choose model variant", exact: true })
+  await expect(modelControl).toHaveText("Model A")
+  await expect(variant).toHaveText("balanced")
+  await variant.click()
+  await page.getByRole("menuitemradio", { name: "high", exact: true }).click()
+  await expect(variant).toHaveText("high")
+
+  await page.locator(`[data-titlebar-tab-link][href="${hrefB}"]`).click()
+  await expect(page).toHaveURL(hrefB)
+  await expect(modelControl).toHaveText("Model B")
+  await expect(variant).toHaveText("balanced")
+
+  await page.locator(`[data-titlebar-tab-link][href="${hrefA}"]`).click()
+  await expect(page).toHaveURL(hrefA)
+  await expect(modelControl).toHaveText("Model A")
+  await expect(variant).toHaveText("high")
+})

packages/app/e2e/utils/mock-server.ts

@@ -47,7 +47,6 @@ type MockStreamWindow = Window & {
 }
 
 export async function mockOpenCodeServer(page: Page, config: MockServerConfig) {
-  const state = { cursors: new Map<string, string>(), nextCursor: 0 }
   const server = `http://${process.env.PLAYWRIGHT_SERVER_HOST ?? "127.0.0.1"}:${process.env.PLAYWRIGHT_SERVER_PORT ?? "4096"}`
 
   await page.addInitScript(
@@ -135,13 +134,7 @@ export async function mockOpenCodeServer(page: Page, config: MockServerConfig) {
     }, 50)
     page.on("close", () => clearInterval(timer))
   }
-  const transport = HttpRouter.toWebHandler(
-    HttpApiBuilder.layer(MockApi).pipe(
-      Layer.provide(mockHandlers(config, state)),
-      Layer.provide(HttpServer.layerServices),
-    ),
-    { disableLogger: true },
-  )
+  const transport = createMockServerHandler(config)
   page.on("close", () => void transport.dispose())
 
   await page.route("**/api/**", async (route) => {
@@ -173,6 +166,16 @@ export async function mockOpenCodeServer(page: Page, config: MockServerConfig) {
   })
 }
 
+export function createMockServerHandler(config: MockServerConfig) {
+  return HttpRouter.toWebHandler(
+    HttpApiBuilder.layer(MockApi).pipe(
+      Layer.provide(mockHandlers(config, { cursors: new Map<string, string>(), nextCursor: 0 })),
+      Layer.provide(HttpServer.layerServices),
+    ),
+    { disableLogger: true },
+  )
+}
+
 const corsHeaders = {
   "access-control-allow-origin": "*",
   "access-control-allow-headers": "*",

packages/app/package.json

@@ -34,6 +34,8 @@
     "test:service-worker": "bun run build && playwright test --config e2e/service-worker/playwright.config.ts",
     "test:stability": "bun test ./e2e/performance/unit/visual-stability.test.ts && playwright test --config e2e/performance/timeline-stability/playwright.config.ts",
     "test:bench": "bun test ./e2e/performance/unit && playwright test --config e2e/performance/playwright.config.ts",
+    "bench:tabs": "PLAYWRIGHT_BUILD=1 playwright test --config e2e/performance/playwright.config.ts timeline/session-tab-switch-benchmark.spec.ts --repeat-each=20 --workers=1 --retries=0 --reporter=line,./e2e/performance/tab-switch-reporter.ts",
+    "bench:entry": "PLAYWRIGHT_BUILD=1 playwright test --config e2e/performance/playwright.config.ts timeline/session-entry-benchmark.spec.ts --repeat-each=20 --workers=1 --retries=0 --reporter=line,./e2e/performance/tab-switch-reporter.ts",
     "test:bench:devex": "bun test ./e2e/performance/unit/desktop-startup.test.ts && playwright test --config e2e/performance/devex/playwright.config.ts"
   },
   "license": "MIT",

packages/app/src/composer/editor/editor.tsx

@@ -150,7 +150,6 @@ export function ComposerEditor(props: ComposerEditorProps) {
             ref={(element) => {
               editor = element
               props.controller.setEditor(element)
-              renderComposerEditor(element, props.controller.parts())
             }}
             data-component="composer-editor"
             role="textbox"

packages/app/src/home/sessions/controller.tsx

@@ -278,16 +278,15 @@ export function createHomeSessionsController(home: HomeController) {
         const directory = project?.worktree ?? session.location.directory
         const ctx = home.server.focusedContext()
         if (!ctx) return
-        ctx.data.session.remember(session)
-        ctx.projects.open(directory)
-        if (options?.background) {
-          tabs.addSessionTab({ server: connKey, sessionId: session.id })
-          return
-        }
-        ctx.projects.touch(directory)
+        if (!options?.background) void ctx.data.session.message.sync(session.id).catch(() => undefined)
+        // Commit cache/project changes with navigation instead of rebuilding
+        // the outgoing Home list before leaving it.
         void startTransition(() => {
           const tab = tabs.addSessionTab({ server: connKey, sessionId: session.id })
-          tabs.select(tab)
+          if (!options?.background) tabs.select(tab)
+          ctx.data.session.remember(session)
+          ctx.projects.open(directory)
+          if (!options?.background) ctx.projects.touch(directory)
         })
       },
       archive: async (session: SessionInfo) => {

packages/app/src/providers/models/selection.tsx

@@ -221,7 +221,7 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
       },
     }
 
-    const current = () => {
+    const current = createMemo(() => {
       const item = firstModel(
         () => scope()?.model,
         () => agent.current()?.model,
@@ -229,7 +229,7 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
       )
       if (!item) return
       return models.find(item)
-    }
+    })
 
     const configured = () => {
       const item = agent.current()

packages/app/src/runtime/platform/web.ts

@@ -53,7 +53,7 @@ export function createWebPlatform(version: string) {
 }
 
 function getCurrentServerUrl() {
-  if (location.hostname.includes("opencode.ai")) return "http://localhost:4096"
+  if (location.hostname.includes("opencode.ai")) return "http://localhost:49374"
   if (import.meta.env.DEV)
     return `http://${import.meta.env.VITE_OPENCODE_SERVER_HOST ?? "localhost"}:${import.meta.env.VITE_OPENCODE_SERVER_PORT ?? "4096"}`
   return location.origin

packages/app/src/session/requests/background.ts

@@ -0,0 +1,117 @@
+import type { SessionInfo, SessionMessageAssistant, SessionMessageInfo, ShellInfo } from "@opencode-ai/client/promise"
+import { createMemo } from "solid-js"
+
+type Task =
+  | { id: string; type: "subagent"; label: string; agent?: string }
+  | { id: string; type: "shell"; label: string }
+
+export function createSessionBackground(input: {
+  sessionID: () => string | undefined
+  messages: (id: string) => SessionMessageInfo[]
+  sessions: () => SessionInfo[]
+  status: (id: string) => "idle" | "running"
+  shells: () => ShellInfo[]
+}) {
+  const history = createMemo(() => {
+    const completed = new Set<string>()
+    const subagents: { id: string; type: "subagent"; label: string; agent: string | undefined }[] = []
+    const shells: { partID: string; task: { id: string; type: "shell"; label: string } }[] = []
+    const id = input.sessionID()
+    const assistant = (id ? input.messages(id) : []).reduce<SessionMessageAssistant | undefined>((latest, message) => {
+      if (message.type === "synthetic") {
+        if (message.metadata?.source === "subagent" && typeof message.metadata.childID === "string")
+          completed.add(message.metadata.childID)
+        if (message.metadata?.source === "shell") {
+          if (typeof message.metadata.shellID === "string") completed.add(message.metadata.shellID)
+          if (typeof message.metadata.jobID === "string") completed.add(message.metadata.jobID)
+        }
+        return latest
+      }
+      if (message.type !== "assistant") return latest
+      message.content.forEach((part) => {
+        if (part.type !== "tool" || (part.name !== "subagent" && part.name !== "shell")) return
+        if (part.state.status !== "completed" || part.state.metadata?.status !== "running") return
+        if (part.name === "subagent") {
+          const sessionID = part.state.metadata.sessionID
+          if (typeof sessionID !== "string") return
+          const description = part.state.input.description
+          const agent = part.state.input.agent
+          subagents.push({
+            id: sessionID,
+            type: "subagent",
+            label: typeof description === "string" ? description : sessionID,
+            agent: typeof agent === "string" ? agent : undefined,
+          })
+          return
+        }
+        const shellID = part.state.metadata.shellID
+        const command = part.state.input.command
+        shells.push({
+          partID: part.id,
+          task: {
+            id: typeof shellID === "string" ? shellID : part.id,
+            type: "shell",
+            label: typeof command === "string" ? command : part.id,
+          },
+        })
+      })
+      return message.time.completed === undefined ? message : latest
+    }, undefined)
+
+    return {
+      // Completion notices can identify the shell or its original tool call.
+      subagents: subagents.filter((task) => !completed.has(task.id)),
+      shells: shells
+        .filter((item) => !completed.has(item.partID) && !completed.has(item.task.id))
+        .map((item) => item.task),
+      blocking:
+        assistant?.content.flatMap((part) => {
+          if (part.type !== "tool" || part.state.status !== "running") return []
+          if (part.name !== "shell" && part.name !== "subagent") return []
+          const value = part.name === "shell" ? part.state.metadata.shellID : part.state.metadata.sessionID
+          const label = part.name === "shell" ? part.state.input.command : part.state.input.description
+          return [
+            {
+              type: part.name as "shell" | "subagent",
+              partID: part.id,
+              id: typeof value === "string" ? value : undefined,
+              label: typeof label === "string" ? label : undefined,
+            },
+          ]
+        }) ?? [],
+    }
+  })
+  const blocking = createMemo(() => history().blocking)
+  const tasks = createMemo(() => {
+    const id = input.sessionID()
+    if (!id) return []
+    const current = history()
+    const active = input.sessions().flatMap((info) => {
+      if (info?.parentID !== id) return []
+      if (input.status(info.id) === "idle") return []
+      if (
+        current.blocking.some(
+          (item) => item.type === "subagent" && (item.id === info.id || (!!item.label && info.title === item.label)),
+        )
+      )
+        return []
+      return [{ id: info.id, type: "subagent" as const, label: info.title ?? info.id }]
+    })
+    const running = input.shells().flatMap((shell) => {
+      if (shell.status !== "running" || shell.metadata.sessionID !== id) return []
+      if (
+        current.blocking.some(
+          (item) => item.type === "shell" && (item.id === shell.id || (!!item.label && shell.command === item.label)),
+        )
+      )
+        return []
+      return [{ id: shell.id, type: "shell" as const, label: shell.command }]
+    })
+    return [
+      ...new Map<string, Task>(
+        [...current.subagents, ...active, ...current.shells, ...running].map((task) => [task.id, task]),
+      ).values(),
+    ]
+  })
+  return { blocking, tasks }
+}

packages/app/src/session/requests/model.ts

@@ -8,6 +8,7 @@ import { useLanguage } from "@/runtime/i18n/language"
 import { useSettings } from "@/settings/model"
 import { useWorkspaceLocation } from "@/workspaces/location"
 import { sessionPermissionRequest, sessionQuestionForm } from "@/session/requests/session-request-tree"
+import { createSessionBackground } from "@/session/requests/background"
 import { useData } from "@/runtime/server/current"
 
 export function createSessionRequestModel() {
@@ -46,105 +47,12 @@ export function createSessionRequestModel() {
     const id = params.id
     return !!id && !data.session.get(id)?.parentID
   }
-  const backgroundBlocking = createMemo(() => {
-    if (!primary()) return []
-    const id = params.id
-    if (!id) return []
-    const assistant = data.session.message
-      .list(id)
-      .findLast((message) => message.type === "assistant" && message.time.completed === undefined)
-    if (assistant?.type !== "assistant") return []
-    return assistant.content.flatMap((part) => {
-      if (part.type !== "tool" || part.state.status !== "running") return []
-      if (part.name !== "shell" && part.name !== "subagent") return []
-      const value = part.name === "shell" ? part.state.metadata.shellID : part.state.metadata.sessionID
-      const label = part.name === "shell" ? part.state.input.command : part.state.input.description
-      return [
-        {
-          type: part.name as "shell" | "subagent",
-          partID: part.id,
-          id: typeof value === "string" ? value : undefined,
-          label: typeof label === "string" ? label : undefined,
-        },
-      ]
-    })
-  })
-  const backgroundTasks = createMemo(() => {
-    if (!primary()) return []
-    const id = params.id
-    if (!id) return []
-    const blocking = backgroundBlocking()
-    const messages = data.session.message.list(id)
-    const completed = new Set(
-      messages.flatMap((message) => {
-        if (message.type !== "synthetic") return []
-        if (message.metadata?.source === "subagent" && typeof message.metadata.childID === "string")
-          return [message.metadata.childID]
-        if (message.metadata?.source === "shell")
-          return [message.metadata.shellID, message.metadata.jobID].filter((id): id is string => typeof id === "string")
-        return []
-      }),
-    )
-    const backgrounded = messages.flatMap((message) => {
-      if (message.type !== "assistant") return []
-      return message.content.flatMap((part) => {
-        if (part.type !== "tool" || part.name !== "subagent") return []
-        if (part.state.status !== "completed" || part.state.metadata?.status !== "running") return []
-        const sessionID = part.state.metadata.sessionID
-        if (typeof sessionID !== "string" || completed.has(sessionID)) return []
-        const description = part.state.input.description
-        const agent = part.state.input.agent
-        return [
-          {
-            id: sessionID,
-            type: "subagent" as const,
-            label: typeof description === "string" ? description : sessionID,
-            agent: typeof agent === "string" ? agent : undefined,
-          },
-        ]
-      })
-    })
-    const active = data.session.list().flatMap((info) => {
-      if (info?.parentID !== id) return []
-      if (data.session.status(info.id) === "idle") return []
-      if (
-        blocking.some(
-          (item) => item.type === "subagent" && (item.id === info.id || (!!item.label && info.title === item.label)),
-        )
-      )
-        return []
-      return [{ id: info.id, type: "subagent" as const, label: info.title ?? info.id }]
-    })
-    const backgroundShells = messages.flatMap((message) => {
-      if (message.type !== "assistant") return []
-      return message.content.flatMap((part) => {
-        if (part.type !== "tool" || part.name !== "shell" || completed.has(part.id)) return []
-        if (part.state.status !== "completed" || part.state.metadata?.status !== "running") return []
-        const shellID = part.state.metadata.shellID
-        if (typeof shellID === "string" && completed.has(shellID)) return []
-        const command = part.state.input.command
-        return [
-          {
-            id: typeof shellID === "string" ? shellID : part.id,
-            type: "shell" as const,
-            label: typeof command === "string" ? command : part.id,
-          },
-        ]
-      })
-    })
-    const running = data.shell.list({ directory: sdk().directory }).flatMap((shell) => {
-      if (shell.status !== "running" || shell.metadata.sessionID !== id) return []
-      if (
-        blocking.some(
-          (item) => item.type === "shell" && (item.id === shell.id || (!!item.label && shell.command === item.label)),
-        )
-      )
-        return []
-      return [{ id: shell.id, type: "shell" as const, label: shell.command }]
-    })
-    return [
-      ...new Map([...backgrounded, ...active, ...backgroundShells, ...running].map((task) => [task.id, task])).values(),
-    ]
+  const background = createSessionBackground({
+    sessionID: () => (primary() ? params.id : undefined),
+    messages: data.session.message.list,
+    sessions: data.session.list,
+    status: data.session.status,
+    shells: () => data.shell.list({ directory: sdk().directory }),
   })
   const moveToBackground = async () => {
     if (!primary()) return
@@ -191,8 +99,8 @@ export function createSessionRequestModel() {
     permissionRequest,
     permissionResponding,
     background: {
-      blocking: backgroundBlocking,
-      tasks: backgroundTasks,
+      blocking: background.blocking,
+      tasks: background.tasks,
       move: moveToBackground,
     },
     decide,

packages/app/src/session/session-resolution.test.ts

@@ -5,18 +5,27 @@ import { createSessionResolution } from "./session-resolution"
 describe("session resolution", () => {
   test("waits for a route session ID", () => {
     createRoot((dispose) => {
-      let syncs = 0
+      const syncs = { session: 0, message: 0 }
       const sessions = {
         get: () => undefined,
         sync: () => {
-          syncs++
+          syncs.session++
           return Promise.resolve()
         },
+        message: {
+          sync: () => {
+            syncs.message++
+            return Promise.resolve()
+          },
+        },
       }
-      const session = createSessionResolution(() => undefined, () => sessions)
+      const session = createSessionResolution(
+        () => undefined,
+        () => sessions,
+      )
 
       expect(session()).toBeUndefined()
-      expect(syncs).toBe(0)
+      expect(syncs).toEqual({ session: 0, message: 0 })
       dispose()
     })
   })

packages/app/src/session/session-resolution.ts

@@ -1,9 +1,12 @@
-import { createEffect, createMemo, createSignal, on, onCleanup } from "solid-js"
+import { createMemo, createRenderEffect, createSignal, on, onCleanup } from "solid-js"
 import { sessionNotFoundError } from "@/runtime/server/errors"
 
 type SessionStore<T> = {
   get: (id: string) => T | undefined
   sync: (id: string, options?: { children?: boolean }) => Promise<unknown>
+  message: {
+    sync: (id: string) => Promise<unknown>
+  }
 }
 
 type Resolution<T> = { id: string; store: SessionStore<T> } & (
@@ -40,13 +43,17 @@ export function createSessionResolution<T>(
   })
   const [status, setStatus] = createSignal<Resolution<T>>()
 
-  createEffect(
+  // Start independent reads before constructing the selected view, including
+  // when its metadata is cached but its transcript has never been loaded.
+  createRenderEffect(
     on([sessionID, sessions] as const, ([id, store]) => {
       if (!id) return
       let stale = false
       onCleanup(() => {
         stale = true
       })
+      // The timeline owns message errors; metadata resolution stays independent.
+      void store.message.sync(id).catch(() => undefined)
       if (cached() && !options?.children) {
         setStatus({ id, store, state: "settled" })
         return

packages/app/src/session/timeline/controller-projection.test.ts

@@ -79,6 +79,17 @@ describe("visibleTimelineMessages", () => {
           ?.map((message) => message.id),
       ).toEqual(["msg_2", "msg_5"])
       expect(projection.assistantMessagesByParent().has(steer.id)).toBe(false)
+      expect([...projection.messageRowIndex()]).toEqual([
+        ["msg_1", 0],
+        ["msg_3", 2],
+      ])
+      expect([...projection.messageLastRowIndex()]).toEqual([
+        ["msg_1", 1],
+        ["msg_3", 3],
+      ])
+      expect([...projection.lastAssistantGroupKey()]).toEqual([["msg_1", "context:msg_5:tool_read"]])
+      expect(projection.rowByKey().get("user-message:msg_1")).toBe(projection.rows()[0])
+      expect(projection.rowByKey().size).toBe(projection.rows().length)
       dispose()
     })
   })

packages/app/src/session/timeline/message-timeline.tsx

@@ -21,6 +21,7 @@ import { useData, useServer } from "@/runtime/server/current"
 import { useWorkspaceLocation } from "@/workspaces/location"
 import { Timeline, TimelineRow } from "@opencode-ai/session-ui/timeline/projection"
 import { createSessionTimelineRowRenderer } from "@opencode-ai/session-ui/timeline/row"
+import { getReadyMarkdown, preloadMarkdown } from "@opencode-ai/session-ui/markdown-cache"
 import { createTimelineController, type TimelineController, type TimelineSessionSource } from "./controller"
 import { createTimelineVirtualizer } from "./virtualizer"
 import { containsDirectory, isWorkspaceDirectory, workspaceDirectories } from "@/workspaces/paths"
@@ -316,6 +317,16 @@ type MessageTimelineProps = {
 
 export function MessageTimeline(props: MessageTimelineProps) {
   const controller = createTimelineController({ session: props.session })
+  const tail = props.pinned ? controller.data.projection.rows().at(-1) : undefined
+  if (tail?._tag === "AssistantPart" && tail.group.type === "part") {
+    const message = controller.data.projection.messageByID().get(tail.group.ref.messageID)
+    if (message?.type === "assistant" && message.time.completed !== undefined) {
+      const content = Timeline.resolveContent(message, tail.group.ref.partID)
+      // Start the required worker job while the rest of the selected view is constructed.
+      if (content?.type === "text" && content.text.trim())
+        void preloadMarkdown(content.text, tail.group.ref.partID).catch(() => undefined)
+    }
+  }
   return (
     <MessageTimelineView {...props} data={controller.data} action={controller.action} pending={controller.pending} />
   )
@@ -400,6 +411,38 @@ function MessageTimelineView(
     onSelectionInteraction: props.onSelectionInteraction,
     onUserScroll: props.onUserScroll,
     onHistoryScroll: props.onHistoryScroll,
+    canRenderImmediately: (row, disclosure) => {
+      if (row._tag === "TurnGap" || row._tag === "TurnDivider") return true
+      if (row._tag === "Notice") {
+        const message = messageByID().get(row.messageID)
+        return (
+          (message?.type === "system" || message?.type === "synthetic") &&
+          (message.description ?? message.text).length <= 1024
+        )
+      }
+      if (row._tag === "UserMessage") {
+        const message = messageByID().get(row.userMessageID)
+        if (message?.type !== "user" || message.text.length > 1024 || message.files?.length || message.agents?.length)
+          return false
+        const presentation = readPromptPresentation(message.metadata)
+        return (
+          (presentation?.displayText ?? message.text).length <= 1024 &&
+          !presentation?.comments?.length &&
+          !parseCommentNote(message.text)
+        )
+      }
+      if (row._tag !== "AssistantPart" || row.group.type !== "part") return false
+      const message = messageByID().get(row.group.ref.messageID)
+      if (message?.type !== "assistant" || message.time.completed === undefined) return false
+      const content = Timeline.resolveContent(message, row.group.ref.partID)
+      if (content?.type === "reasoning")
+        return !(disclosure[row.group.ref.partID] ?? props.data.reasoningMode() === "full")
+      return (
+        content?.type === "text" &&
+        content.text.length <= 1024 &&
+        !!getReadyMarkdown({ raw: content.text, src: content.text }, `${row.group.ref.partID}:0:full`)
+      )
+    },
     setRevealMessage: props.setRevealMessage,
     setScrollToEnd: props.setScrollToEnd,
   })

packages/app/src/session/timeline/model.ts

@@ -13,7 +13,6 @@ export {
 
 export function createTimelineModel(input: { session: Pick<SessionModel, "identity" | "history"> }) {
   const data = useData()
-  const prepared = new Set<string>()
 
   const [resource] = createResource(
     () => input.session.identity.sessionID(),
@@ -30,14 +29,12 @@ export function createTimelineModel(input: { session: Pick<SessionModel, "identi
         pause: () => new Promise((resolve) => setTimeout(resolve, leadingTurnPageDelay)),
         maxPages: leadingTurnPageLimit,
       }).catch(() => undefined)
-      if (input.session.identity.sessionKey() === key) prepared.add(key)
     },
   )
   const ready = createMemo(() => {
     const id = input.session.identity.sessionID()
-    if (!id || prepared.has(input.session.identity.sessionKey()) || !resource.loading) return true
-    const messages = data.session.message.list(id)
-    return messages.length > 0 && !leadingTurnNeedsParent(messages)
+    // Enrich the partial leading group without withholding the already loaded tail.
+    return !id || data.session.message.list(id).length > 0 || !resource.loading
   })
   const more = () => {
     const id = input.session.identity.sessionID()

packages/app/src/session/timeline/projection.ts

@@ -96,38 +96,29 @@ export function createTimelineProjection(input: {
   const rows = createMemo((previous: TimelineRow.TimelineRow[] | undefined) =>
     reuseTimelineRows(previous, projection().rows),
   )
-  const rowByKey = createMemo(() => new Map(rows().map((row) => [TimelineRow.key(row), row] as const)))
-  const messageRowIndex = createMemo(() => {
-    const result = new Map<string, number>()
+  const indexes = createMemo(() => {
+    const rowByKey = new Map<string, TimelineRow.TimelineRow>()
+    const messageRowIndex = new Map<string, number>()
+    const messageLastRowIndex = new Map<string, number>()
+    const lastAssistantGroupKey = new Map<string, string>()
     rows().forEach((row, index) => {
-      if (!("userMessageID" in row) || result.has(row.userMessageID)) return
-      result.set(row.userMessageID, index)
+      rowByKey.set(TimelineRow.key(row), row)
+      if (!("userMessageID" in row)) return
+      if (!messageRowIndex.has(row.userMessageID)) messageRowIndex.set(row.userMessageID, index)
+      messageLastRowIndex.set(row.userMessageID, index)
+      if (row._tag === "AssistantPart") lastAssistantGroupKey.set(row.userMessageID, row.group.key)
     })
-    return result
-  })
-  const messageLastRowIndex = createMemo(() => {
-    const result = new Map<string, number>()
-    rows().forEach((row, index) => {
-      if ("userMessageID" in row) result.set(row.userMessageID, index)
-    })
-    return result
-  })
-  const lastAssistantGroupKey = createMemo(() => {
-    const result = new Map<string, string>()
-    rows().forEach((row) => {
-      if (row._tag === "AssistantPart") result.set(row.userMessageID, row.group.key)
-    })
-    return result
+    return { rowByKey, messageRowIndex, messageLastRowIndex, lastAssistantGroupKey }
   })
 
   return {
     activeMessageID,
     assistantMessagesByParent,
-    lastAssistantGroupKey,
+    lastAssistantGroupKey: () => indexes().lastAssistantGroupKey,
     messageByID: sessionMessageByID,
-    messageRowIndex,
-    messageLastRowIndex,
-    rowByKey,
+    messageRowIndex: () => indexes().messageRowIndex,
+    messageLastRowIndex: () => indexes().messageLastRowIndex,
+    rowByKey: () => indexes().rowByKey,
     rows,
     sessionMessageByID,
     userContextByID,

packages/app/src/session/timeline/virtualizer.tsx

@@ -55,6 +55,10 @@ type Input = {
   onSelectionInteraction: (event: MouseEvent) => void
   onUserScroll: (target?: EventTarget | null) => void
   onHistoryScroll: () => void
+  canRenderImmediately?: (
+    row: TimelineRow.TimelineRow,
+    disclosure: Readonly<Record<string, boolean | undefined>>,
+  ) => boolean
   setRevealMessage?: (fn: (id: string) => void) => void
   setScrollToEnd?: (fn: () => void) => void
 }
@@ -75,17 +79,63 @@ export function createTimelineVirtualizer(input: Input) {
   const coldBottomMount = !initialMeasurements?.length && input.pinned()
   const [listRoot, setListRoot] = createSignal<HTMLDivElement>()
   const [toolOpen, setToolOpen] = createStore<Record<string, boolean | undefined>>(cached?.toolOpen ?? {})
-  const [overscan, setOverscan] = createSignal(2)
+  const [rendering, setRendering] = createStore({ initialTail: coldBottomMount })
   const rows = input.projection.rows
   const rowByKey = input.projection.rowByKey
-  const knownKeys = new Set(rows().map(TimelineRow.key))
+  const rowKeys = createMemo(() => rows().map(TimelineRow.key), undefined, {
+    equals: (previous, next) => previous.length === next.length && previous.every((key, index) => key === next[index]),
+  })
+  const knownKeys = new Set(rowKeys())
   const addedKeys = new Set<string>()
+  const getItemKey = createMemo(() => {
+    const keys = rowKeys()
+    keys
+      .filter((key) => !knownKeys.has(key))
+      .forEach((key) => {
+        knownKeys.add(key)
+        addedKeys.add(key)
+      })
+    return (index: number) => keys[index] ?? `removed:${index}`
+  })
+  const rangeExtractor = createMemo(() => {
+    const id = input.projection.activeMessageID()
+    const active = id ? (input.projection.messageLastRowIndex().get(id) ?? -1) : -1
+    const initialTail = rendering.initialTail && input.pinned()
+    return (range: Range) => {
+      // Batch a bounded cheap suffix, but stop before unknown/large content.
+      // A large tail still mounts alone before estimates expose earlier history.
+      const start = Math.max(0, range.startIndex - 2)
+      const boundary = initialTail
+        ? rows()
+            .slice(start, range.count)
+            .findLastIndex(
+              (row) =>
+                !(
+                  row._tag === "AssistantPart" &&
+                  row.group.type === "context" &&
+                  row.group.refs.length <= 16 &&
+                  !toolOpen[`context:${row.group.key}`]
+                ) && !input.canRenderImmediately?.(row, toolOpen),
+            )
+        : -1
+      const first = Math.min(range.count - 1, start + boundary + 1)
+      const indexes = initialTail
+        ? Array.from({ length: range.count - first }, (_, index) => first + index)
+        : defaultRangeExtractor({ ...range, overscan: 2 })
+      return filterVirtualIndexes(
+        [...new Set([...indexes, ...(active < 0 ? [] : [active])])].sort((a, b) => a - b),
+        range.count,
+      )
+    }
+  })
   const measuredElements = new WeakSet<Element>()
   let touchStart: number | undefined
   let pointerHeld = false
   let maxScroll = 0
   let virtualContent: HTMLDivElement | undefined
   let scrollTop = 0
+  let reportOffset: ((offset: number, scrolling: boolean) => void) | undefined
+  let batchingColdSizes = false
 
   const virtualizer = createVirtualizer<HTMLDivElement, HTMLDivElement>({
     get count() {
@@ -93,10 +143,16 @@ export function createTimelineVirtualizer(input: Input) {
     },
     getScrollElement: () => listRoot() ?? null,
     // Route navigation detaches and reattaches the scroll element, which drops its offset.
-    observeElementOffset: (instance, callback) =>
-      observeElementOffsetReconnectAware(instance, callback, () => {
+    observeElementOffset: (instance, callback) => {
+      reportOffset = (offset, scrolling) => {
+        callback(offset, scrolling)
+        settleColdBottom()
+      }
+      return observeElementOffsetReconnectAware(instance, reportOffset, () => {
         if (input.pinned()) virtualizer.scrollToEnd()
-      }),
+        settleColdBottom()
+      })
+    },
     initialOffset: () => (input.pinned() ? Number.MAX_SAFE_INTEGER : 0),
     initialMeasurementsCache: initialMeasurements,
     estimateSize: () => fallbackItemSize,
@@ -110,28 +166,17 @@ export function createTimelineVirtualizer(input: Input) {
       if (box) return Math.round(box.blockSize)
       if (initial) {
         const size = instance.itemSizeCache.get(instance.options.getItemKey(instance.indexFromElement(element)))
-        if (size !== undefined) return size
+        if (size !== undefined || coldPending) return size ?? fallbackItemSize
       }
       return element.offsetHeight
     },
     scrollToFn: (offset, options, instance) => {
+      if (batchingColdSizes && input.pinned()) return
       if (virtualContent) virtualContent.style.height = `${instance.getTotalSize()}px`
       elementScroll(offset, options, instance)
     },
     get getItemKey() {
-      const items = rows()
-      items
-        .map(TimelineRow.key)
-        .filter((key) => !knownKeys.has(key))
-        .forEach((key) => {
-          knownKeys.add(key)
-          addedKeys.add(key)
-        })
-      return (index: number) => {
-        const row = items[index]
-        if (!row) return `removed:${index}`
-        return TimelineRow.key(row)
-      }
+      return getItemKey()
     },
     get anchorTo() {
       return input.pinned() ? "end" : "start"
@@ -145,16 +190,7 @@ export function createTimelineVirtualizer(input: Input) {
     },
     paddingEnd: 64,
     get rangeExtractor() {
-      const id = input.projection.activeMessageID()
-      const active = id ? (input.projection.messageLastRowIndex().get(id) ?? -1) : -1
-      const buffer = overscan()
-      return (range: Range) => {
-        const indexes = defaultRangeExtractor({ ...range, overscan: buffer })
-        return filterVirtualIndexes(
-          [...new Set([...indexes, ...(active < 0 ? [] : [active])])].sort((a, b) => a - b),
-          range.count,
-        )
-      }
+      return rangeExtractor()
     },
   })
   const resizeItem = virtualizer.resizeItem
@@ -166,7 +202,7 @@ export function createTimelineVirtualizer(input: Input) {
     const row = rows()[index]
     if (!row) return
     const key = TimelineRow.key(row)
-    if (virtualizer.itemSizeCache.get(key) === size) {
+    if ((virtualizer.itemSizeCache.get(key) ?? fallbackItemSize) === size) {
       pendingSizes.delete(index)
       return
     }
@@ -178,12 +214,19 @@ export function createTimelineVirtualizer(input: Input) {
       if (!pendingSizes.size) return
       const sizes = [...pendingSizes]
       pendingSizes.clear()
+      // The hidden pinned mount needs one bottom write after the whole batch,
+      // not a layout-forcing scroll adjustment for every measured row.
+      batchingColdSizes = coldPending && input.pinned()
       batch(() => {
         sizes.forEach(([index, value]) => {
           const row = rows()[index]
           if (row && TimelineRow.key(row) === value.key) resizeItem(index, value.size)
         })
       })
+      batchingColdSizes = false
+      if (coldPending) pinColdBottom()
+      settleColdBottom()
+      if (coldPending) return
       if (!input.pinned()) return
       const root = listRoot()
       // Reopening a settled scroll-to-end operation can fight subsequent keyboard scrolling.
@@ -217,41 +260,73 @@ export function createTimelineVirtualizer(input: Input) {
     })
   })
 
-  let settleFrame: number | undefined
-  let overscanFrame: number | undefined
-  let overscanTimer: number | undefined
-  const expandOverscan = () => {
-    overscanFrame = requestAnimationFrame(() => {
-      overscanFrame = undefined
-      // Let the visible rows paint before building the normal interaction buffer.
-      overscanTimer = window.setTimeout(() => {
-        overscanTimer = undefined
-        setOverscan(20)
-      }, 0)
-    })
+  let coldPending = coldBottomMount
+  let settleQueued = false
+  let contentObserver: MutationObserver | undefined
+  let viewportObserver: ResizeObserver | undefined
+  const pinColdBottom = () => {
+    const root = listRoot()
+    if (!input.pinned() || !virtualContent || !root) return
+    // scrollToEnd computes its target from the DOM, not the new size cache.
+    virtualContent.style.height = `${virtualizer.getTotalSize()}px`
+    if (Math.abs(root.scrollHeight - root.clientHeight - root.scrollTop) > endEpsilon) virtualizer.scrollToEnd()
+    // Report after core size adjustments finish so they cannot apply a delta
+    // twice. This avoids waiting a frame for the native scroll event.
+    if (virtualizer.scrollOffset !== root.scrollTop) reportOffset?.(root.scrollTop, false)
+  }
+  const pendingMeasurements = () => {
+    const items = virtualizer.getVirtualItems()
+    return (
+      (rows().length > 0 && items.length === 0) ||
+      items.some((item) => !virtualizer.elementsCache.get(item.key)?.isConnected)
+    )
   }
-  const pendingMeasurements = () =>
-    virtualizer.getVirtualItems().some((item) => !virtualizer.itemSizeCache.has(item.key))
   const settleColdBottom = () => {
-    if (input.pinned()) virtualizer.scrollToEnd()
-    if (virtualContent?.querySelector(pendingMarkdown) || pendingMeasurements()) {
-      settleFrame = requestAnimationFrame(settleColdBottom)
-      return
-    }
-    settleFrame = requestAnimationFrame(() => {
-      if (input.pinned()) virtualizer.scrollToEnd()
-      if (virtualContent?.querySelector(pendingMarkdown) || pendingMeasurements()) {
+    if (!coldPending || settleQueued) return
+    settleQueued = true
+    queueMicrotask(() => {
+      settleQueued = false
+      const root = listRoot()
+      if (!coldPending || !virtualContent?.isConnected || !root) return
+      if (virtualContent.querySelector(pendingMarkdown)) return
+      if (!root.clientHeight) return
+      // Markdown can finish before ResizeObserver delivers its new box. The
+      // normal measureElement path skips reads while scrolling; this gate needs
+      // current boxes before expanding the estimated range or revealing it.
+      virtualizer.elementsCache.forEach((element) => {
+        if (element.isConnected) virtualizer.resizeItem(virtualizer.indexFromElement(element), element.offsetHeight)
+      })
+      if (pendingSizes.size || pendingMeasurements()) return
+      pinColdBottom()
+      if (input.pinned() && Math.abs(root.scrollHeight - root.clientHeight - root.scrollTop) > 1) return
+      // The scroll event must update the range before newly exposed rows can reveal.
+      if (root.scrollHeight > root.clientHeight && Math.abs((virtualizer.scrollOffset ?? 0) - root.scrollTop) > 1)
+        return
+      if (rendering.initialTail) {
+        setRendering("initialTail", false)
         settleColdBottom()
         return
       }
-      settleFrame = undefined
-      virtualContent?.style.removeProperty("visibility")
-      expandOverscan()
+      if (pendingSizes.size || pendingMeasurements() || virtualContent.querySelector(pendingMarkdown)) return
+      coldPending = false
+      contentObserver?.disconnect()
+      viewportObserver?.disconnect()
+      virtualContent.style.removeProperty("visibility")
     })
   }
   onMount(() => {
-    if (coldBottomMount) settleFrame = requestAnimationFrame(settleColdBottom)
-    if (!coldBottomMount) expandOverscan()
+    if (!coldPending || !virtualContent) return
+    contentObserver = new MutationObserver(settleColdBottom)
+    contentObserver.observe(virtualContent, {
+      childList: true,
+      subtree: true,
+      attributes: true,
+      attributeFilter: ["data-markdown-ready"],
+    })
+    viewportObserver = new ResizeObserver(settleColdBottom)
+    const root = listRoot()
+    if (root) viewportObserver.observe(root)
+    settleColdBottom()
   })
 
   let measuredSessionKey = input.sessionKey()
@@ -265,12 +340,14 @@ export function createTimelineVirtualizer(input: Input) {
 
   const bindListRoot = (root: HTMLDivElement) => {
     if (root === listRoot()) return
-    setListRoot(root)
     // TanStack owns anchoring; browser scroll anchoring would fight its adjustments.
     root.style.overflowAnchor = "none"
+    setListRoot(root)
     scrollTop = root.scrollTop
     maxScroll = root.scrollHeight - root.clientHeight
     input.setScrollRef(root)
+    viewportObserver?.observe(root)
+    settleColdBottom()
   }
 
   // Upward input is the one intent geometry cannot recover: nudging up while still a pixel from
@@ -278,13 +355,11 @@ export function createTimelineVirtualizer(input: Input) {
   const handleListWheel = (event: WheelEvent & { currentTarget: HTMLDivElement }) => {
     input.onUserScroll(event.target)
     if (event.deltaY < 0) input.onUnpin()
-    setOverscan(20)
   }
 
   const handleListTouchStart = (event: TouchEvent) => {
     input.onUserScroll(event.target)
     touchStart = event.touches[0]?.clientY
-    setOverscan(20)
   }
 
   const handleListTouchMove = (event: TouchEvent & { currentTarget: HTMLDivElement }) => {
@@ -301,7 +376,6 @@ export function createTimelineVirtualizer(input: Input) {
   const handleListPointerDown = (event: PointerEvent & { currentTarget: HTMLDivElement }) => {
     input.onUserScroll(event.target)
     pointerHeld = true
-    setOverscan(20)
   }
   const releasePointer = () => {
     pointerHeld = false
@@ -322,7 +396,6 @@ export function createTimelineVirtualizer(input: Input) {
     if (scrollKeyOwner(event.currentTarget, event.target, key) !== event.currentTarget) return
     input.onUserScroll(event.currentTarget)
     if (upwardKeys.has(key)) input.onUnpin()
-    setOverscan(20)
   }
 
   // Following resumes by arriving at the end, either by scrolling there or by content shrinking
@@ -338,6 +411,7 @@ export function createTimelineVirtualizer(input: Input) {
     const arrived = scrollTop > previousTop + endEpsilon || maxScroll < previousMaxScroll
     if (maxScroll <= 1 || (atEnd && arrived)) input.onPin()
     else if (pointerHeld && scrollTop < previousTop - endEpsilon) input.onUnpin()
+    settleColdBottom()
     input.onScheduleScrollState(root)
     input.onHistoryScroll()
   }
@@ -476,9 +550,9 @@ export function createTimelineVirtualizer(input: Input) {
     cache.delete(ownerSessionKey)
     cache.set(ownerSessionKey, { measurements: virtualizer.takeSnapshot(), toolOpen: { ...toolOpen } })
     while (cache.size > 16) cache.delete(cache.keys().next().value!)
-    if (settleFrame !== undefined) cancelAnimationFrame(settleFrame)
-    if (overscanFrame !== undefined) cancelAnimationFrame(overscanFrame)
-    if (overscanTimer !== undefined) window.clearTimeout(overscanTimer)
+    coldPending = false
+    contentObserver?.disconnect()
+    viewportObserver?.disconnect()
     input.setScrollRef(undefined)
     input.setRevealMessage?.(() => {})
     input.setScrollToEnd?.(() => {})

packages/app/src/shell/routes/routes.tsx

@@ -11,9 +11,8 @@ import Shell from "@/shell/shell"
 import { requireServerKey } from "./session"
 
 export const File = lazy(() => import("@opencode-ai/session-ui/file").then((module) => ({ default: module.File })))
-const loadDraftRoute = () => Promise.all([import("@/new-session/route"), File.preload()]).then(([module]) => module)
 const loadSessionRoute = () => Promise.all([import("@/session/route"), File.preload()]).then(([module]) => module)
-const DraftRoute = lazy(() => loadDraftRoute().then((module) => ({ default: module.DraftRoute })))
+const DraftRoute = lazy(() => import("@/new-session/route").then((module) => ({ default: module.DraftRoute })))
 const TargetSessionRouteContent = lazy(() =>
   loadSessionRoute().then((module) => ({ default: module.TargetSessionRouteContent })),
 )

packages/app/src/shell/shell.tsx

@@ -43,12 +43,12 @@ export default function Layout(props: ParentProps) {
         style={{
           "padding-top": "env(safe-area-inset-top, 0px)",
           "padding-bottom": "env(safe-area-inset-bottom, 0px)",
-          // The native Windows titlebar already includes the gap above the content panels.
+          // Native Windows chrome supplies the gap; retain paint clearance for the panels' outer outlines.
           "--shell-top-inset":
             platform.platform === "desktop" &&
             platform.os === "windows" &&
             !(mobile() && preferences.general.mobileTitlebarPosition() === "bottom")
-              ? "0px"
+              ? "1px"
               : "8px",
         }}
       >

packages/app/src/shell/titlebar/tab-nav.tsx

@@ -28,7 +28,6 @@ export function TabNavItem(props: {
   onClose: () => void
   onNavigate: () => void
   active?: boolean
-  forceTruncate?: boolean
   suppressNavigation?: boolean
   dragging?: boolean
   pressed?: boolean
@@ -98,11 +97,13 @@ export function TabNavItem(props: {
 
   createEffect(() => {
     title()
-    props.forceTruncate
+    props.active
+    props.orientation
     editing()
     scheduleTitleOverflow()
   })
 
+  // The overflow fade changes title padding; observe the stable tab box, not that feedback.
   createResizeObserver(() => tabRoot, scheduleTitleOverflow)
   onCleanup(() => {
     if (measureFrame !== undefined) cancelAnimationFrame(measureFrame)

packages/app/src/shell/titlebar/tab-strip.tsx

@@ -1,6 +1,5 @@
-import { createEffect, createMemo, createResource, For, onCleanup, onMount, Show } from "solid-js"
+import { createEffect, createMemo, createResource, For, onCleanup, Show } from "solid-js"
 import { createStore } from "solid-js/store"
-import { createResizeObserver } from "@solid-primitives/resize-observer"
 import { DragDropProvider, PointerSensor } from "@dnd-kit/solid"
 import { isSortable, useSortable } from "@dnd-kit/solid/sortable"
 import { Accessibility, AutoScroller, Feedback, PointerActivationConstraints } from "@dnd-kit/dom"
@@ -26,7 +25,6 @@ function SessionTabSlot(props: {
   id: string
   index: number
   active: boolean
-  forceTruncate: boolean
   orientation: "horizontal" | "vertical"
   session: SessionInfo | undefined
   fallbackTitle?: string
@@ -69,7 +67,6 @@ function SessionTabSlot(props: {
         onNavigate={() => props.onNavigate(ref)}
         onClose={props.onClose}
         active={props.active}
-        forceTruncate={props.forceTruncate}
         dragging={sortable.isDragSource()}
         orientation={props.orientation}
       />
@@ -82,7 +79,6 @@ function SessionTabEntry(props: {
   id: string
   index: number
   active: boolean
-  forceTruncate: boolean
   orientation: "horizontal" | "vertical"
   serverCtx: ServerCtx | undefined
   onVisibleChange: (visible: boolean) => void
@@ -169,7 +165,6 @@ function SessionTabEntry(props: {
         id={props.id}
         index={props.index}
         active={props.active}
-        forceTruncate={props.forceTruncate}
         orientation={props.orientation}
         session={session()}
         fallbackTitle={
@@ -238,19 +233,15 @@ export function TitlebarTabStrip(props: {
   orientation?: "horizontal" | "vertical"
   tabs: Tab[]
   currentTab: Tab | undefined
-  forceTruncate: boolean
   onNavigate: (tab: Tab, el?: HTMLDivElement) => void
   onClose: (tab: Tab) => void
   onReorder: (keys: string[]) => void
-  onOverflowChange: (overflowing: boolean) => void
 }) {
   const global = useGlobal()
   const language = useLanguage()
   const command = useCommand()
   const vertical = () => props.orientation === "vertical"
-  let scrollRef!: HTMLDivElement
   let listRef!: HTMLDivElement
-  let resizeFrame: number | undefined
   const [visibility, setVisibility] = createStore<Record<string, boolean>>({})
   const visibleTabs = createMemo(() => props.tabs.filter((tab) => tab.type === "draft" || visibility[tabKey(tab)]))
   const visibleTabIds = () => visibleTabs().map(tabKey)
@@ -281,38 +272,6 @@ export function TitlebarTabStrip(props: {
     if (next) props.onNavigate(next)
   }
 
-  function refreshOverflow() {
-    if (!scrollRef) return
-    props.onOverflowChange(
-      vertical() ? scrollRef.scrollHeight > scrollRef.clientHeight : scrollRef.scrollWidth > scrollRef.clientWidth,
-    )
-  }
-
-  createResizeObserver(
-    () => [scrollRef, listRef],
-    () => {
-      if (resizeFrame !== undefined) return
-      resizeFrame = requestAnimationFrame(() => {
-        resizeFrame = undefined
-        refreshOverflow()
-      })
-    },
-  )
-
-  onMount(() => {
-    refreshOverflow()
-  })
-
-  onCleanup(() => {
-    if (resizeFrame !== undefined) cancelAnimationFrame(resizeFrame)
-  })
-
-  createEffect(() => {
-    props.tabs.length
-    visibleTabIds()
-    refreshOverflow()
-  })
-
   return (
     <div
       data-slot={vertical() ? "vertical-tabs" : "titlebar-tabs"}
@@ -327,7 +286,6 @@ export function TitlebarTabStrip(props: {
           "flex-row items-center gap-1.5 overflow-x-auto": !vertical(),
           "max-h-full flex-col overflow-y-auto overflow-x-hidden": vertical(),
         }}
-        ref={scrollRef}
       >
         <DragDropProvider
           sensors={[
@@ -398,7 +356,6 @@ export function TitlebarTabStrip(props: {
                       id={id}
                       index={visibleIndex()}
                       active={props.currentTab === tab}
-                      forceTruncate={props.forceTruncate}
                       orientation={vertical() ? "vertical" : "horizontal"}
                       serverCtx={serverCtx()}
                       onVisibleChange={(visible) => setVisibility(id, visible)}

packages/app/src/shell/titlebar/titlebar.tsx

@@ -1,4 +1,4 @@
-import { createEffect, createMemo, createResource, Match, createSignal, Show, Switch, untrack } from "solid-js"
+import { createEffect, createMemo, createResource, Match, Show, Switch, untrack } from "solid-js"
 import { createStore } from "solid-js/store"
 import { Portal } from "solid-js/web"
 import { useLocation, useNavigate } from "@solidjs/router"
@@ -336,8 +336,6 @@ export function Titlebar(props: {
               ].filter((v) => v !== undefined)
             })
 
-            const [tabsAreOverflowing, setTabsAreOverflowing] = createSignal(false)
-
             return (
               <div
                 class="h-full flex-1 overflow-hidden flex flex-row items-center gap-1.5 px-2 md:pr-3"
@@ -382,8 +380,6 @@ export function Titlebar(props: {
                       <TitlebarTabStrip
                         tabs={tabsStore}
                         currentTab={currentTab()}
-                        forceTruncate={tabsAreOverflowing()}
-                        onOverflowChange={setTabsAreOverflowing}
                         onNavigate={(tab, el) => {
                           tabs.select(tab)
                           el?.scrollIntoView({ behavior: "instant" })
@@ -424,8 +420,6 @@ export function Titlebar(props: {
                             orientation="vertical"
                             tabs={tabsStore}
                             currentTab={currentTab()}
-                            forceTruncate={false}
-                            onOverflowChange={setTabsAreOverflowing}
                             onNavigate={(tab, el) => {
                               tabs.select(tab)
                               el?.scrollIntoView({ behavior: "instant", block: "nearest" })

packages/app/test-browser/session-background.test.ts

@@ -0,0 +1,196 @@
+import { describe, expect, test } from "bun:test"
+import type { SessionInfo, SessionMessageAssistantTool, ShellInfo } from "@opencode-ai/client/promise"
+import { createRoot } from "solid-js"
+import { createStore } from "solid-js/store"
+import { createSessionBackground } from "@/session/requests/background"
+
+const tool = (
+  id: string,
+  name: string,
+  metadata: Record<string, string>,
+  input: Record<string, string> = {},
+  status: "completed" | "running" = "completed",
+): SessionMessageAssistantTool => ({
+  id,
+  name,
+  type: "tool",
+  state:
+    status === "running"
+      ? { status, input, metadata }
+      : { status, input, metadata, content: [{ type: "text", text: "backgrounded" }] },
+  time: { created: 0 },
+})
+
+const assistant = (id: string, content: SessionMessageAssistantTool[], completed?: number) => ({
+  id,
+  type: "assistant" as const,
+  agent: "build",
+  model: { id: "model", providerID: "provider" },
+  content,
+  time: { created: 0, completed },
+})
+
+const session = (id: string): SessionInfo => ({
+  id,
+  title: id,
+  parentID: "root",
+  projectID: "project",
+  location: { directory: "/project" },
+  cost: 0,
+  tokens: { input: 0, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
+  time: { created: 0, updated: 0 },
+})
+
+const shell = (id: string, command: string): ShellInfo => ({
+  id,
+  command,
+  status: "running",
+  cwd: "/project",
+  shell: "sh",
+  file: "output",
+  metadata: { sessionID: "root" },
+  time: { started: 0 },
+})
+
+const notification = (id: string, metadata: Record<string, string>) => ({
+  id,
+  type: "synthetic" as const,
+  text: "complete",
+  metadata,
+  time: { created: 0 },
+})
+
+describe("createSessionBackground", () => {
+  test("excludes completed children and shells using either shell or tool-call IDs", () => {
+    createRoot((dispose) => {
+      const background = createSessionBackground({
+        sessionID: () => "root",
+        messages: () => [
+          notification("before", { source: "subagent", childID: "before-child" }),
+          assistant("assistant", [
+            tool("before-part", "subagent", { status: "running", sessionID: "before-child" }),
+            tool("shell-part", "shell", { status: "running", shellID: "process" }),
+            tool("shell-call", "shell", { status: "running", shellID: "shell-id" }),
+            tool("legacy-call", "shell", { status: "running", shellID: "legacy-shell" }),
+            tool("child-part", "subagent", { status: "running", sessionID: "child" }, { agent: "explore" }),
+          ]),
+          notification("shell-done", { source: "shell", jobID: "shell-part" }),
+          notification("shell-id-done", { source: "shell", shellID: "shell-id" }),
+          notification("legacy-done", { source: "shell", jobID: "legacy-shell" }),
+        ],
+        sessions: () => [],
+        status: () => "idle",
+        shells: () => [],
+      })
+      expect(background.tasks()).toEqual([{ id: "child", type: "subagent", label: "child", agent: "explore" }])
+      dispose()
+    })
+  })
+
+  test("joins live tasks while idle without rescanning history, then switches sessions", () => {
+    createRoot((dispose) => {
+      const [store, setStore] = createStore({
+        id: "root" as string | undefined,
+        messages: [
+          assistant("assistant", [
+            tool("shell-part", "shell", { status: "running", shellID: "shell" }, { command: "old command" }),
+            tool("child-part", "subagent", { status: "running", sessionID: "child" }),
+          ]),
+        ],
+        sessions: [session("live-child"), session("child")],
+        status: { root: "idle", child: "idle", "live-child": "idle" } as Record<string, "idle" | "running">,
+        shells: [{ ...shell("shell", "command"), status: "exited" as ShellInfo["status"] }],
+      })
+      let scans = 0
+      const background = createSessionBackground({
+        sessionID: () => store.id,
+        messages: (id) => {
+          scans += 1
+          return id === "root" ? store.messages : []
+        },
+        sessions: () => store.sessions,
+        status: (id) => store.status[id],
+        shells: () => store.shells,
+      })
+      const blocking = background.blocking()
+      const initial = background.tasks()
+      expect(initial.map((task) => task.id)).toEqual(["child", "shell"])
+
+      setStore("status", { child: "running", "live-child": "running" })
+      expect(background.tasks().map((task) => task.id)).toEqual(["child", "live-child", "shell"])
+      setStore("shells", 0, "status", "running")
+      expect(background.tasks().at(-1)?.label).toBe("command")
+      setStore("sessions", 1, "title", "renamed")
+      expect(background.tasks()[0]?.label).toBe("renamed")
+      setStore("shells", 0, "command", "updated command")
+      const live = background.tasks()
+      expect(live).toEqual([
+        { id: "child", type: "subagent", label: "renamed" },
+        { id: "live-child", type: "subagent", label: "live-child" },
+        { id: "shell", type: "shell", label: "updated command" },
+      ])
+      expect(background.blocking()).toBe(blocking)
+      expect(scans).toBe(1)
+
+      setStore("id", "other")
+      expect(background.tasks()).toEqual([])
+      setStore("id", "root")
+      expect(background.tasks()).toEqual(live)
+      setStore("status", { child: "idle", "live-child": "idle" })
+      setStore("shells", 0, "status", "exited")
+      expect(background.tasks()).toEqual(initial)
+      expect(scans).toBe(3)
+      setStore("id", undefined)
+      expect(background.tasks()).toEqual([])
+      dispose()
+    })
+  })
+
+  test("tracks blocking, backgrounding, and completion through nested store updates", () => {
+    createRoot((dispose) => {
+      const [store, setStore] = createStore({
+        messages: [
+          assistant("earlier", [tool("old-part", "subagent", { sessionID: "old-child" }, {}, "running")]),
+          assistant("current", [
+            tool("child-part", "subagent", { sessionID: "child" }, {}, "running"),
+            tool("shell-part", "shell", {}, { command: "build" }, "running"),
+          ]),
+          assistant("completed", [], 0),
+        ],
+        notification: notification("notice", { source: "subagent", childID: "other-child" }),
+        status: { child: "running", "old-child": "running" } as Record<string, "idle" | "running">,
+      })
+      const messages = store.messages
+      const background = createSessionBackground({
+        sessionID: () => "root",
+        messages: () => [...store.messages, store.notification],
+        sessions: () => [session("child"), session("old-child")],
+        status: (id) => store.status[id],
+        shells: () => [shell("shell", "build")],
+      })
+      expect(background.blocking()).toEqual([
+        { type: "subagent", partID: "child-part", id: "child", label: undefined },
+        { type: "shell", partID: "shell-part", id: undefined, label: "build" },
+      ])
+      expect(background.tasks().map((task) => task.id)).toEqual(["old-child"])
+
+      setStore("messages", 1, "content", 0, "state", {
+        status: "completed",
+        input: { description: "background child" },
+        metadata: { status: "running", sessionID: "child" },
+        content: [{ type: "text", text: "backgrounded" }],
+      })
+      expect(store.messages).toBe(messages)
+      expect(background.blocking().map((task) => task.partID)).toEqual(["shell-part"])
+      setStore("status", "child", "idle")
+      expect(background.tasks().map((task) => task.id)).toEqual(["child", "old-child"])
+      expect(background.tasks()[0]?.label).toBe("background child")
+      setStore("notification", "metadata", "childID", "child")
+      expect(background.tasks().map((task) => task.id)).toEqual(["old-child"])
+      setStore("messages", [0, 1], "time", "completed", 1)
+      expect(background.blocking()).toEqual([])
+      expect(background.tasks().map((task) => task.id)).toEqual(["old-child", "shell"])
+      dispose()
+    })
+  })
+})

packages/app/test-browser/session-resolution.test.ts

@@ -15,8 +15,10 @@ function createFixture(initial: Record<string, Session> = {}) {
   const [cache, setCache] = createSignal(initial)
   const deferred = new Map<string, PromiseWithResolvers<unknown>>()
   const resolves: string[] = []
+  const messages = { syncs: [] as string[], ...Promise.withResolvers<unknown>() }
   return {
     resolves,
+    messages,
     sessions: {
       get: (id: string) => cache()[id],
       sync: (id: string) => {
@@ -25,6 +27,12 @@ function createFixture(initial: Record<string, Session> = {}) {
         deferred.set(id, entry)
         return entry.promise
       },
+      message: {
+        sync: (id: string) => {
+          messages.syncs.push(id)
+          return messages.promise
+        },
+      },
     },
     settle(id: string) {
       setCache({ ...cache(), [id]: sessionOf(id) })
@@ -51,7 +59,34 @@ const flush = async () => {
   await Promise.resolve()
 }
 
-test("resolves an uncached session", async () => {
+test("starts metadata and messages in parallel once the route has a session ID", async () => {
+  await createRoot(async (dispose) => {
+    const fixture = createFixture()
+    const [id, setId] = createSignal<string>()
+    const current = createSessionResolution(id, () => fixture.sessions)
+
+    expect(current()).toBeUndefined()
+    await flush()
+    expect(fixture.resolves).toEqual([])
+    expect(fixture.messages.syncs).toEqual([])
+
+    setId("ses_a")
+    expect(fixture.resolves).toEqual(["ses_a"])
+    expect(fixture.messages.syncs).toEqual(["ses_a"])
+
+    fixture.messages.resolve(undefined)
+    await flush()
+    expect(current()).toBeUndefined()
+
+    fixture.settle("ses_a")
+    await flush()
+    expect(current()?.id).toBe("ses_a")
+
+    dispose()
+  })
+})
+
+test("message failure does not fail metadata resolution", async () => {
   await createRoot(async (dispose) => {
     const fixture = createFixture()
     const current = createSessionResolution(
@@ -59,9 +94,10 @@ test("resolves an uncached session", async () => {
       () => fixture.sessions,
     )
 
-    expect(current()).toBeUndefined()
     await flush()
-    expect(fixture.resolves).toEqual(["ses_a"])
+    fixture.messages.reject(new Error("message sync failed"))
+    await flush()
+    expect(current()).toBeUndefined()
 
     fixture.settle("ses_a")
     await flush()
@@ -82,12 +118,15 @@ test("re-resolves when navigating to an uncached session without a remount", asy
 
     await flush()
     expect(current()?.id).toBe("ses_a")
+    expect(fixture.resolves).toEqual([])
+    expect(fixture.messages.syncs).toEqual(["ses_a"])
 
     expect(() => {
       setId("ses_b")
       current()
     }).not.toThrow()
     expect(fixture.resolves).toEqual(["ses_b"])
+    expect(fixture.messages.syncs).toEqual(["ses_a", "ses_b"])
 
     fixture.settle("ses_b")
     await flush()
@@ -139,6 +178,7 @@ test("returning to a pruned session re-resolves instead of throwing not found",
       current()
     }).not.toThrow()
     expect(fixture.resolves).toEqual(["ses_a", "ses_b", "ses_a"])
+    expect(fixture.messages.syncs).toEqual(["ses_a", "ses_b", "ses_a"])
 
     fixture.settle("ses_a")
     await flush()
@@ -167,6 +207,7 @@ test("revisiting a session whose resolution failed while unfocused retries clean
       current()
     }).not.toThrow()
     expect(fixture.resolves).toEqual(["ses_a", "ses_b", "ses_a"])
+    expect(fixture.messages.syncs).toEqual(["ses_a", "ses_b", "ses_a"])
 
     fixture.settle("ses_a")
     await flush()
@@ -197,6 +238,8 @@ test("re-resolves against a replaced session store", async () => {
     }).not.toThrow()
     await flush()
     expect(second.resolves).toEqual(["ses_a"])
+    expect(first.messages.syncs).toEqual(["ses_a"])
+    expect(second.messages.syncs).toEqual(["ses_a"])
 
     second.settle("ses_a")
     await flush()

packages/app/test-browser/solid-virtual.test.ts

@@ -198,3 +198,41 @@ test("stale pinned indexes do not produce missing virtual items after count shri
     dispose()
   })
 })
+
+test("snapshots materialize only measured rows and restore their current geometry", () => {
+  const options = {
+    count: 100,
+    getItemKey: (index: number) => `row-${index}`,
+    estimateSize: () => 60,
+    getScrollElement: () => null,
+    scrollToFn: () => {},
+    observeElementRect: () => {},
+    observeElementOffset: () => {},
+  }
+  const virtualizer = new Virtualizer<HTMLDivElement, HTMLDivElement>(options)
+  expect(virtualizer.getTotalSize()).toBe(6000)
+  virtualizer.resizeItem(4, 100)
+  virtualizer.resizeItem(99, 140)
+  const measurements = virtualizer.getMeasurements()
+  const reads: number[] = []
+  virtualizer.getMeasurements = () =>
+    new Proxy(measurements, {
+      get(target, key, receiver) {
+        if (typeof key === "string" && /^\d+$/.test(key)) reads.push(Number(key))
+        return Reflect.get(target, key, receiver)
+      },
+    })
+
+  const snapshot = virtualizer.takeSnapshot()
+  expect(reads).toEqual([4, 99])
+  expect(snapshot).toEqual([
+    { index: 4, key: "row-4", start: 240, size: 100, end: 340, lane: 0 },
+    { index: 99, key: "row-99", start: 5980, size: 140, end: 6120, lane: 0 },
+  ])
+  const restored = new Virtualizer<HTMLDivElement, HTMLDivElement>({ ...options, initialMeasurementsCache: snapshot })
+  expect(restored.getTotalSize()).toBe(6120)
+  expect(restored.takeSnapshot()).toEqual(snapshot)
+  restored.setOptions({ ...options, count: 10 })
+  restored.resizeItem(4, 80)
+  expect(restored.takeSnapshot()).toEqual([{ index: 4, key: "row-4", start: 240, size: 80, end: 320, lane: 0 }])
+})

packages/client/src/effect/api/api.ts

@@ -1950,6 +1950,12 @@ export type VcsGetInput = {
 export type VcsGetOutput = { readonly location: Location.Info; readonly data: Vcs.Info }
 export type VcsGetOperation<E = never> = (input?: VcsGetInput) => Effect.Effect<VcsGetOutput, E>
 
+export type VcsBaseInput = {
+  readonly location?: { readonly directory?: string | undefined; readonly workspace?: string | undefined } | undefined
+}
+export type VcsBaseOutput = { readonly location: Location.Info; readonly data: Vcs.Base | null }
+export type VcsBaseOperation<E = never> = (input?: VcsBaseInput) => Effect.Effect<VcsBaseOutput, E>
+
 export type VcsStatusInput = {
   readonly location?: { readonly directory?: string | undefined; readonly workspace?: string | undefined } | undefined
 }
@@ -1967,6 +1973,7 @@ export type VcsBranchesOperation<E = never> = (input?: VcsBranchesInput) => Effe
 export type VcsDiffInput = {
   readonly location?: { readonly directory?: string | undefined; readonly workspace?: string | undefined } | undefined
   readonly mode: Vcs.Mode
+  readonly base?: string | undefined
   readonly context?: number | undefined
 }
 export type VcsDiffOutput = { readonly location: Location.Info; readonly data: ReadonlyArray<FileDiff.Info> }
@@ -1974,6 +1981,7 @@ export type VcsDiffOperation<E = never> = (input: VcsDiffInput) => Effect.Effect
 
 export interface VcsApi<E = never> {
   readonly get: VcsGetOperation<E>
+  readonly base: VcsBaseOperation<E>
   readonly status: VcsStatusOperation<E>
   readonly branches: VcsBranchesOperation<E>
   readonly diff: VcsDiffOperation<E>

packages/client/src/effect/generated/client.ts

@@ -244,6 +244,8 @@ import type {
   WorkspaceDestroyOutput,
   VcsGetInput,
   VcsGetOutput,
+  VcsBaseInput,
+  VcsBaseOutput,
   VcsStatusInput,
   VcsStatusOutput,
   VcsBranchesInput,
@@ -1468,6 +1470,11 @@ const EndpointVcsGet = (raw: RawClient["server.vcs"]) => (input?: VcsGetInput) =
     raw["vcs.get"]({ query: { location: input?.["location"] } }).pipe(Effect.mapError(mapClientError)),
   )
 
+const EndpointVcsBase = (raw: RawClient["server.vcs"]) => (input?: VcsBaseInput) =>
+  preserveEffect<VcsBaseOutput>()(
+    raw["vcs.base"]({ query: { location: input?.["location"] } }).pipe(Effect.mapError(mapClientError)),
+  )
+
 const EndpointVcsStatus = (raw: RawClient["server.vcs"]) => (input?: VcsStatusInput) =>
   preserveEffect<VcsStatusOutput>()(
     raw["vcs.status"]({ query: { location: input?.["location"] } }).pipe(Effect.mapError(mapClientError)),
@@ -1482,13 +1489,14 @@ const EndpointVcsBranches = (raw: RawClient["server.vcs"]) => (input?: VcsBranch
 
 const EndpointVcsDiff = (raw: RawClient["server.vcs"]) => (input: VcsDiffInput) =>
   preserveEffect<VcsDiffOutput>()(
-    raw["vcs.diff"]({ query: { location: input["location"], mode: input["mode"], context: input["context"] } }).pipe(
-      Effect.mapError(mapClientError),
-    ),
+    raw["vcs.diff"]({
+      query: { location: input["location"], mode: input["mode"], base: input["base"], context: input["context"] },
+    }).pipe(Effect.mapError(mapClientError)),
   )
 
 const adaptGroupVcs = (raw: RawClient["server.vcs"]) => ({
   get: EndpointVcsGet(raw),
+  base: EndpointVcsBase(raw),
   status: EndpointVcsStatus(raw),
   branches: EndpointVcsBranches(raw),
   diff: EndpointVcsDiff(raw),

packages/client/src/effect/index.ts

@@ -34,6 +34,7 @@ export { Permission } from "@opencode-ai/schema/permission"
 export { PermissionSaved } from "@opencode-ai/schema/permission-saved"
 export { Project } from "@opencode-ai/schema/project"
 export { Worktree } from "@opencode-ai/schema/worktree"
+export { Vcs } from "@opencode-ai/schema/vcs"
 export { Provider } from "@opencode-ai/schema/provider"
 export { Pty } from "@opencode-ai/schema/pty"
 export { Question } from "@opencode-ai/schema/question"

packages/client/src/promise/generated/client.ts

@@ -240,6 +240,8 @@ import type {
   WorkspaceDestroyOutput,
   VcsGetInput,
   VcsGetOutput,
+  VcsBaseInput,
+  VcsBaseOutput,
   VcsStatusInput,
   VcsStatusOutput,
   VcsBranchesInput,
@@ -1996,6 +1998,18 @@ export function make(options: ClientOptions) {
           },
           requestOptions,
         ),
+      base: (input?: VcsBaseInput, requestOptions?: RequestOptions) =>
+        request<VcsBaseOutput>(
+          {
+            method: "GET",
+            path: `/api/vcs/base`,
+            query: { location: input?.["location"] },
+            successStatus: 200,
+            declaredStatuses: [503, 401, 400],
+            empty: false,
+          },
+          requestOptions,
+        ),
       status: (input?: VcsStatusInput, requestOptions?: RequestOptions) =>
         request<VcsStatusOutput>(
           {
@@ -2025,9 +2039,9 @@ export function make(options: ClientOptions) {
           {
             method: "GET",
             path: `/api/vcs/diff`,
-            query: { location: input["location"], mode: input["mode"], context: input["context"] },
+            query: { location: input["location"], mode: input["mode"], base: input["base"], context: input["context"] },
             successStatus: 200,
-            declaredStatuses: [401, 400],
+            declaredStatuses: [503, 401, 400],
             empty: false,
           },
           requestOptions,

packages/client/src/promise/generated/types.ts

@@ -419,6 +419,8 @@ export type WorkspaceDestroyResult = { destroyed: boolean }
 
 export type VcsBranch = { current?: string; default?: string }
 
+export type VcsBase = { name: string; ref: string; source: "reflog" | "default" }
+
 export type VcsFileStatus = {
   file: string
   additions: number
@@ -6073,6 +6075,17 @@ export type VcsGetOutput = {
   data: VcsInfo
 }
 
+export type VcsBaseInput = {
+  readonly location?: {
+    readonly location?: { readonly directory?: string | undefined; readonly workspace?: string | undefined } | undefined
+  }["location"]
+}
+
+export type VcsBaseOutput = {
+  location: { directory: string; workspaceID?: string; project: { id: string; directory: string; canonical: string } }
+  data: VcsBase | null
+}
+
 export type VcsStatusInput = {
   readonly location?: {
     readonly location?: { readonly directory?: string | undefined; readonly workspace?: string | undefined } | undefined
@@ -6110,17 +6123,26 @@ export type VcsBranchesOutput = {
 export type VcsDiffInput = {
   readonly location?: {
     readonly location?: { readonly directory?: string | undefined; readonly workspace?: string | undefined } | undefined
-    readonly mode: "working" | "branch"
+    readonly mode: "working" | "branch" | "committed"
+    readonly base?: string | undefined
     readonly context?: number | undefined
   }["location"]
   readonly mode: {
     readonly location?: { readonly directory?: string | undefined; readonly workspace?: string | undefined } | undefined
-    readonly mode: "working" | "branch"
+    readonly mode: "working" | "branch" | "committed"
+    readonly base?: string | undefined
     readonly context?: number | undefined
   }["mode"]
+  readonly base?: {
+    readonly location?: { readonly directory?: string | undefined; readonly workspace?: string | undefined } | undefined
+    readonly mode: "working" | "branch" | "committed"
+    readonly base?: string | undefined
+    readonly context?: number | undefined
+  }["base"]
   readonly context?: {
     readonly location?: { readonly directory?: string | undefined; readonly workspace?: string | undefined } | undefined
-    readonly mode: "working" | "branch"
+    readonly mode: "working" | "branch" | "committed"
+    readonly base?: string | undefined
     readonly context?: number | undefined
   }["context"]
 }

packages/client/src/solid/data.ts

@@ -750,7 +750,8 @@ export function createData(config: CreateDataInput) {
             command: event.data.shell.command,
             status: event.data.shell.status,
             exit: event.data.shell.exit,
-            metadata: event.metadata,
+            metadata:
+              event.data.shell.metadata.background === true ? { ...event.metadata, background: true } : event.metadata,
             time: { created: event.created },
           })
         })

packages/client/test/contract-identity.test.ts

@@ -6,6 +6,7 @@ import { Model } from "@opencode-ai/schema/model"
 import { Prompt } from "@opencode-ai/schema/prompt"
 import { Session } from "@opencode-ai/schema/session"
 import { SessionMessage } from "@opencode-ai/schema/session-message"
+import { Vcs } from "@opencode-ai/schema/vcs"
 
 const Client = await import("../src/effect")
 
@@ -14,6 +15,7 @@ test("effect entrypoint exposes canonical Schema contracts", () => {
   expect(Client.Config).toBe(Config)
   expect(Client.Model).toBe(Model)
   expect(Client.Session).toBe(Session)
+  expect(Client.Vcs.Base).toBe(Vcs.Base)
 })
 
 test("generated Effect API names canonical and composed outputs", async () => {

packages/client/test/effect.test.ts

@@ -27,6 +27,26 @@ test("health.get decodes the readiness response", async () => {
   expect(result).toEqual({ healthy: true, version: "old", pid: 123 })
 })
 
+test("vcs.base decodes nullable review-base metadata", async () => {
+  const location = { directory: "/repo", project: { id: "global", directory: "/repo", canonical: "/repo" } }
+  const base = {
+    name: "release",
+    ref: "refs/remotes/origin/release",
+    source: "reflog",
+  }
+  for (const data of [base, null]) {
+    const httpClient = HttpClient.make((request) =>
+      Effect.succeed(HttpClientResponse.fromWeb(request, Response.json({ location, data }))),
+    )
+    const result = await Effect.gen(function* () {
+      const client = yield* OpenCode.make({ baseUrl: "http://localhost:3000" })
+      return yield* client.vcs.base({ location: { directory: AbsolutePath.make("/repo") } })
+    }).pipe(Effect.provideService(HttpClient.HttpClient, httpClient), Effect.runPromise)
+    expect(result.data).toEqual(data)
+    expect(result.location.directory).toBe("/repo")
+  }
+})
+
 test("session.get returns the decoded Effect projection", async () => {
   const httpClient = HttpClient.make((request) =>
     Effect.succeed(HttpClientResponse.fromWeb(request, Response.json(session))),

packages/client/test/promise.test.ts

@@ -47,7 +47,7 @@ test("exposes every standard HTTP API group", () => {
   expect(Object.keys(client.integration.command)).toEqual(["connect", "status", "cancel"])
   expect(Object.keys(client.websearch)).toEqual(["providers", "query"])
   expect(Object.keys(client.file)).toEqual(["read", "list", "find"])
-  expect(Object.keys(client.vcs)).toEqual(["get", "status", "branches", "diff"])
+  expect(Object.keys(client.vcs)).toEqual(["get", "base", "status", "branches", "diff"])
   expect(Object.keys(client.pty)).toEqual(["list", "create", "get", "update", "remove", "connect"])
   expect(Object.keys(client.pty.connect)).toEqual(["token"])
   expect(Object.keys(client.experimental)).toEqual(["persistentPty"])
@@ -84,6 +84,46 @@ test("config.get returns ordered config entries for a location", async () => {
   expect(request?.url).toBe("http://localhost:3000/api/config?location%5Bdirectory%5D=%2Ftmp%2Fproject")
 })
 
+test("vcs.base and committed diffs preserve location and explicit base on the wire", async () => {
+  const requests: Request[] = []
+  const location = { directory: "/repo", project: { id: "global", directory: "/repo", canonical: "/repo" } }
+  const base = { name: "release", ref: "refs/remotes/origin/release", source: "reflog" }
+  const client = OpenCode.make({
+    baseUrl: "http://localhost:3000",
+    fetch: async (input, init) => {
+      const request = input instanceof Request ? input : new Request(input, init)
+      requests.push(request)
+      return Response.json({ location, data: new URL(request.url).pathname.endsWith("/base") ? base : [] })
+    },
+  })
+  expect(await client.vcs.base({ location: { directory: "/repo" } })).toEqual({ location, data: base })
+  expect(
+    await client.vcs.diff({ location: { directory: "/repo" }, mode: "committed", base: base.ref, context: 1 }),
+  ).toEqual({ location, data: [] })
+  expect(new URL(requests[0].url).pathname).toBe("/api/vcs/base")
+  const query = new URL(requests[1].url).searchParams
+  expect(query.get("location[directory]")).toBe("/repo")
+  expect(query.get("mode")).toBe("committed")
+  expect(query.get("base")).toBe(base.ref)
+  expect(query.get("context")).toBe("1")
+})
+
+test("vcs.diff exposes unavailable comparisons as errors, not empty diffs", async () => {
+  const client = OpenCode.make({
+    baseUrl: "http://localhost:3000",
+    fetch: async () =>
+      Response.json(
+        { _tag: "ServiceUnavailableError", service: "vcs", message: "No review base available" },
+        { status: 503 },
+      ),
+  })
+  await expect(client.vcs.diff({ mode: "committed" })).rejects.toMatchObject({
+    _tag: "ServiceUnavailableError",
+    service: "vcs",
+    message: "No review base available",
+  })
+})
+
 test("project.update uses the global project contract", async () => {
   let request: Request | undefined
   const project = {

packages/client/test/solid-data.test.ts

@@ -666,6 +666,36 @@ test("ignores activity snapshots from an older connection", async () => {
   }
 })
 
+test("projects background user shell metadata from durable shell data", () => {
+  const setup = activityFixture(() => Response.json({ data: {} }))
+  try {
+    setup.emit({
+      id: "evt_user_shell",
+      created: 1,
+      type: "session.shell.started",
+      durable: { aggregateID: "ses_refresh", seq: 1, version: 1 },
+      data: {
+        sessionID: "ses_refresh",
+        shell: {
+          id: "sh_user",
+          status: "running",
+          command: "pwd",
+          cwd: "/project",
+          shell: "/bin/sh",
+          file: "/project/shell.out",
+          metadata: { sessionID: "ses_refresh", background: true },
+          time: { started: 1 },
+        },
+      },
+    })
+    expect(setup.data.session.message.list("ses_refresh")).toMatchObject([
+      { type: "shell", shellID: "sh_user", status: "running", metadata: { background: true } },
+    ])
+  } finally {
+    setup.dispose()
+  }
+})
+
 function activityFixture(read: () => Response | Promise<Response>) {
   const listeners = new Set<Parameters<CreateDataInput["event"]["listen"]>[0]>()
   const api = OpenCode.make({

packages/core/src/config/plugin/mcp.ts

@@ -46,12 +46,12 @@ export const register = Effect.fn("ConfigMCPPlugin.register")(function* (
     const servers = new Map<string, ServerConfig>()
     for (const document of documents) {
       for (const [name, server] of Object.entries(document.info.mcp?.servers ?? {})) {
-        servers.set(name, { ...server, timeout: { ...timeout, ...server.timeout } })
+        servers.set(name, server)
       }
     }
     for (const [name, server] of servers) {
       if (draft.get(name)) continue
-      draft.set(name, server)
+      draft.set(name, { ...server, timeout: { ...timeout, ...server.timeout } })
     }
   })
 })

packages/core/src/github-copilot/responses/openai-responses-language-model.ts

@@ -4,7 +4,6 @@ import {
   type LanguageModelV3,
   type LanguageModelV3CallOptions,
   type LanguageModelV3Content,
-  type LanguageModelV3ProviderTool,
   type LanguageModelV3StreamPart,
   type SharedV3ProviderMetadata,
   type SharedV3Warning,
@@ -27,7 +26,7 @@ import { imageGenerationOutputSchema } from "./tool/image-generation.js"
 import { convertToOpenAIResponsesInput } from "./convert-to-openai-responses-input.js"
 import { mapOpenAIResponseFinishReason } from "./map-openai-responses-finish-reason.js"
 import type { OpenAIResponsesIncludeOptions, OpenAIResponsesIncludeValue } from "./openai-responses-api-types.js"
-import { prepareResponsesTools } from "./openai-responses-prepare-tools.js"
+import { prepareResponsesTools, type ResponsesHostedTool } from "./openai-responses-prepare-tools.js"
 import type { OpenAIResponsesModelId } from "./openai-responses-settings.js"
 
 const webSearchCallItem = z.object({
@@ -221,15 +220,23 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
       addInclude("message.output_text.logprobs")
     }
 
-    // when a web search tool is present, automatically include the sources:
-    const webSearchToolName = (
-      tools?.find(
-        (tool) =>
-          tool.type === "provider" && (tool.id === "openai.web_search" || tool.id === "openai.web_search_preview"),
-      ) as LanguageModelV3ProviderTool | undefined
-    )?.name
+    const {
+      tools: openaiTools,
+      toolChoice: openaiToolChoice,
+      hostedTools,
+      selectedHostedTool,
+      toolWarnings,
+    } = prepareResponsesTools({
+      tools,
+      toolChoice,
+      strictJsonSchema,
+    })
+    const getHostedToolName = (responseType: ResponsesHostedTool["responseType"]) => {
+      if (selectedHostedTool?.responseType === responseType) return selectedHostedTool.name
+      return hostedTools.find((tool) => tool.responseType === responseType)?.name ?? responseType
+    }
 
-    if (webSearchToolName) {
+    if (hostedTools.some((tool) => tool.responseType === "web_search")) {
       addInclude("web_search_call.action.sources")
     }
 
@@ -357,18 +364,8 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
       baseArgs.service_tier = undefined
     }
 
-    const {
-      tools: openaiTools,
-      toolChoice: openaiToolChoice,
-      toolWarnings,
-    } = prepareResponsesTools({
-      tools,
-      toolChoice,
-      strictJsonSchema,
-    })
-
     return {
-      webSearchToolName,
+      getHostedToolName,
       args: {
         ...baseArgs,
         tools: openaiTools,
@@ -379,7 +376,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
   }
 
   async doGenerate(options: LanguageModelV3CallOptions) {
-    const { args: body, warnings, webSearchToolName } = await this.getArgs(options)
+    const { args: body, warnings, getHostedToolName } = await this.getArgs(options)
     const url = this.config.url({
       path: "/responses",
       modelId: this.modelId,
@@ -526,7 +523,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
           content.push({
             type: "tool-call",
             toolCallId: part.id,
-            toolName: "image_generation",
+            toolName: getHostedToolName("image_generation"),
             input: "{}",
             providerExecuted: true,
           })
@@ -534,7 +531,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
           content.push({
             type: "tool-result",
             toolCallId: part.id,
-            toolName: "image_generation",
+            toolName: getHostedToolName("image_generation"),
             result: {
               result: part.result,
             } satisfies z.infer<typeof imageGenerationOutputSchema>,
@@ -605,7 +602,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
           content.push({
             type: "tool-call",
             toolCallId: part.id,
-            toolName: webSearchToolName ?? "web_search",
+            toolName: getHostedToolName("web_search"),
             input: JSON.stringify({ action: part.action }),
             providerExecuted: true,
           })
@@ -613,7 +610,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
           content.push({
             type: "tool-result",
             toolCallId: part.id,
-            toolName: webSearchToolName ?? "web_search",
+            toolName: getHostedToolName("web_search"),
             result: { status: part.status },
           })
 
@@ -645,7 +642,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
           content.push({
             type: "tool-call",
             toolCallId: part.id,
-            toolName: "file_search",
+            toolName: getHostedToolName("file_search"),
             input: "{}",
             providerExecuted: true,
           })
@@ -653,7 +650,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
           content.push({
             type: "tool-result",
             toolCallId: part.id,
-            toolName: "file_search",
+            toolName: getHostedToolName("file_search"),
             result: {
               queries: part.queries,
               results:
@@ -673,7 +670,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
           content.push({
             type: "tool-call",
             toolCallId: part.id,
-            toolName: "code_interpreter",
+            toolName: getHostedToolName("code_interpreter"),
             input: JSON.stringify({
               code: part.code,
               containerId: part.container_id,
@@ -684,7 +681,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
           content.push({
             type: "tool-result",
             toolCallId: part.id,
-            toolName: "code_interpreter",
+            toolName: getHostedToolName("code_interpreter"),
             result: {
               outputs: part.outputs,
             } satisfies z.infer<typeof codeInterpreterOutputSchema>,
@@ -746,7 +743,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
   }
 
   async doStream(options: LanguageModelV3CallOptions) {
-    const { args: body, warnings, webSearchToolName } = await this.getArgs(options)
+    const { args: body, warnings, getHostedToolName } = await this.getArgs(options)
 
     const { responseHeaders, value: response } = await postJsonToApi({
       url: this.config.url({
@@ -866,7 +863,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
                 controller.enqueue({
                   type: "tool-input-start",
                   id: value.item.id,
-                  toolName: webSearchToolName ?? "web_search",
+                  toolName: getHostedToolName("web_search"),
                 })
               } else if (value.item.type === "computer_call") {
                 ongoingToolCalls[value.output_index] = {
@@ -889,7 +886,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
                 controller.enqueue({
                   type: "tool-input-start",
                   id: value.item.id,
-                  toolName: "code_interpreter",
+                  toolName: getHostedToolName("code_interpreter"),
                 })
 
                 controller.enqueue({
@@ -901,7 +898,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
                 controller.enqueue({
                   type: "tool-call",
                   toolCallId: value.item.id,
-                  toolName: "file_search",
+                  toolName: getHostedToolName("file_search"),
                   input: "{}",
                   providerExecuted: true,
                 })
@@ -909,7 +906,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
                 controller.enqueue({
                   type: "tool-call",
                   toolCallId: value.item.id,
-                  toolName: "image_generation",
+                  toolName: getHostedToolName("image_generation"),
                   input: "{}",
                   providerExecuted: true,
                 })
@@ -980,7 +977,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
                 controller.enqueue({
                   type: "tool-call",
                   toolCallId: value.item.id,
-                  toolName: "web_search",
+                  toolName: getHostedToolName("web_search"),
                   input: JSON.stringify({ action: value.item.action }),
                   providerExecuted: true,
                 })
@@ -988,7 +985,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
                 controller.enqueue({
                   type: "tool-result",
                   toolCallId: value.item.id,
-                  toolName: "web_search",
+                  toolName: getHostedToolName("web_search"),
                   result: { status: value.item.status },
                 })
               } else if (value.item.type === "computer_call") {
@@ -1022,7 +1019,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
                 controller.enqueue({
                   type: "tool-result",
                   toolCallId: value.item.id,
-                  toolName: "file_search",
+                  toolName: getHostedToolName("file_search"),
                   result: {
                     queries: value.item.queries,
                     results:
@@ -1041,7 +1038,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
                 controller.enqueue({
                   type: "tool-result",
                   toolCallId: value.item.id,
-                  toolName: "code_interpreter",
+                  toolName: getHostedToolName("code_interpreter"),
                   result: {
                     outputs: value.item.outputs,
                   } satisfies z.infer<typeof codeInterpreterOutputSchema>,
@@ -1050,7 +1047,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
                 controller.enqueue({
                   type: "tool-result",
                   toolCallId: value.item.id,
-                  toolName: "image_generation",
+                  toolName: getHostedToolName("image_generation"),
                   result: {
                     result: value.item.result,
                   } satisfies z.infer<typeof imageGenerationOutputSchema>,
@@ -1099,7 +1096,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
               controller.enqueue({
                 type: "tool-result",
                 toolCallId: value.item_id,
-                toolName: "image_generation",
+                toolName: getHostedToolName("image_generation"),
                 result: {
                   result: value.partial_image_b64,
                 } satisfies z.infer<typeof imageGenerationOutputSchema>,
@@ -1135,7 +1132,7 @@ export class OpenAIResponsesLanguageModel implements LanguageModelV3 {
                 controller.enqueue({
                   type: "tool-call",
                   toolCallId: toolCall.toolCallId,
-                  toolName: "code_interpreter",
+                  toolName: getHostedToolName("code_interpreter"),
                   input: JSON.stringify({
                     code: value.code,
                     containerId: toolCall.codeInterpreter!.containerId,

packages/core/src/github-copilot/responses/openai-responses-prepare-tools.ts

@@ -1,4 +1,9 @@
-import { type LanguageModelV3CallOptions, type SharedV3Warning, UnsupportedFunctionalityError } from "@ai-sdk/provider"
+import {
+  type LanguageModelV3CallOptions,
+  type LanguageModelV3ProviderTool,
+  type SharedV3Warning,
+  UnsupportedFunctionalityError,
+} from "@ai-sdk/provider"
 import { codeInterpreterArgsSchema } from "./tool/code-interpreter.js"
 import { fileSearchArgsSchema } from "./tool/file-search.js"
 import { webSearchArgsSchema } from "./tool/web-search.js"
@@ -6,6 +11,28 @@ import { webSearchPreviewArgsSchema } from "./tool/web-search-preview.js"
 import { imageGenerationArgsSchema } from "./tool/image-generation.js"
 import type { OpenAIResponsesTool } from "./openai-responses-api-types.js"
 
+export type ResponsesHostedTool = {
+  name: string
+  type: "file_search" | "web_search_preview" | "web_search" | "code_interpreter" | "image_generation"
+  responseType: "file_search" | "web_search" | "code_interpreter" | "image_generation"
+}
+
+export function getResponsesHostedTool(tool: LanguageModelV3ProviderTool): ResponsesHostedTool | undefined {
+  switch (tool.id) {
+    case "openai.file_search":
+      return { name: tool.name, type: "file_search", responseType: "file_search" }
+    case "openai.web_search_preview":
+      return { name: tool.name, type: "web_search_preview", responseType: "web_search" }
+    case "openai.web_search":
+      return { name: tool.name, type: "web_search", responseType: "web_search" }
+    case "openai.code_interpreter":
+      return { name: tool.name, type: "code_interpreter", responseType: "code_interpreter" }
+    case "openai.image_generation":
+      return { name: tool.name, type: "image_generation", responseType: "image_generation" }
+  }
+  return undefined
+}
+
 export function prepareResponsesTools({
   tools,
   toolChoice,
@@ -26,6 +53,8 @@ export function prepareResponsesTools({
     | { type: "function"; name: string }
     | { type: "code_interpreter" }
     | { type: "image_generation" }
+  hostedTools: ResponsesHostedTool[]
+  selectedHostedTool?: ResponsesHostedTool
   toolWarnings: SharedV3Warning[]
 } {
   // when the tools array is empty, change it to undefined to prevent errors:
@@ -34,7 +63,49 @@ export function prepareResponsesTools({
   const toolWarnings: SharedV3Warning[] = []
 
   if (tools == null) {
-    return { tools: undefined, toolChoice: undefined, toolWarnings }
+    return { tools: undefined, toolChoice: undefined, hostedTools: [], toolWarnings }
+  }
+
+  const hostedTools = tools.flatMap((tool) => {
+    if (tool.type !== "provider") return []
+    const hostedTool = getResponsesHostedTool(tool)
+    return hostedTool ? [hostedTool] : []
+  })
+  const selectedToolName = toolChoice?.type === "tool" ? toolChoice.toolName : undefined
+  const selectedTools = selectedToolName === undefined ? [] : tools.filter((tool) => tool.name === selectedToolName)
+  if (selectedTools.length > 1) {
+    throw new UnsupportedFunctionalityError({
+      functionality: `ambiguous tool choice '${selectedToolName}': multiple tool definitions share this name`,
+    })
+  }
+  const selectedHostedTool =
+    selectedTools[0]?.type === "provider" ? getResponsesHostedTool(selectedTools[0]) : undefined
+
+  const ambiguousHostedResponse =
+    toolChoice?.type === "none" || toolChoice?.type === "tool"
+      ? undefined
+      : hostedTools.find(
+          (tool) =>
+            new Set(
+              hostedTools.filter((candidate) => candidate.responseType === tool.responseType).map((item) => item.name),
+            ).size > 1,
+        )
+  if (ambiguousHostedResponse) {
+    const names = new Set(
+      hostedTools.filter((tool) => tool.responseType === ambiguousHostedResponse.responseType).map((tool) => tool.name),
+    )
+    throw new UnsupportedFunctionalityError({
+      functionality: `ambiguous ${ambiguousHostedResponse.responseType} response for hosted tools: ${[...names].join(", ")}`,
+    })
+  }
+
+  if (selectedHostedTool) {
+    const names = new Set(hostedTools.filter((tool) => tool.type === selectedHostedTool.type).map((tool) => tool.name))
+    if (names.size > 1) {
+      throw new UnsupportedFunctionalityError({
+        functionality: `ambiguous ${selectedHostedTool.type} tool choice for hosted tools: ${[...names].join(", ")}`,
+      })
+    }
   }
 
   const openaiTools: Array<OpenAIResponsesTool> = []
@@ -134,7 +205,7 @@ export function prepareResponsesTools({
   }
 
   if (toolChoice == null) {
-    return { tools: openaiTools, toolChoice: undefined, toolWarnings }
+    return { tools: openaiTools, toolChoice: undefined, hostedTools, selectedHostedTool, toolWarnings }
   }
 
   const type = toolChoice.type
@@ -143,20 +214,18 @@ export function prepareResponsesTools({
     case "auto":
     case "none":
     case "required":
-      return { tools: openaiTools, toolChoice: type, toolWarnings }
-    case "tool":
+      return { tools: openaiTools, toolChoice: type, hostedTools, selectedHostedTool, toolWarnings }
+    case "tool": {
       return {
         tools: openaiTools,
-        toolChoice:
-          toolChoice.toolName === "code_interpreter" ||
-          toolChoice.toolName === "file_search" ||
-          toolChoice.toolName === "image_generation" ||
-          toolChoice.toolName === "web_search_preview" ||
-          toolChoice.toolName === "web_search"
-            ? { type: toolChoice.toolName }
-            : { type: "function", name: toolChoice.toolName },
+        toolChoice: selectedHostedTool
+          ? { type: selectedHostedTool.type }
+          : { type: "function", name: toolChoice.toolName },
+        hostedTools,
+        selectedHostedTool,
         toolWarnings,
       }
+    }
     default: {
       const _exhaustiveCheck: never = type
       throw new UnsupportedFunctionalityError({

packages/core/src/image/photon.ts

@@ -78,9 +78,15 @@ export const make = Effect.gen(function* () {
             ...JPEG_QUALITIES.map((quality) => ["image/jpeg", () => resized.get_bytes_jpeg(quality)] as const),
           ]
           for (const [mime, encode] of encoders) {
-            const candidate = Buffer.from(encode()).toString("base64")
-            if (Buffer.byteLength(candidate, "utf-8") <= limits.maxBase64Bytes)
-              return { ...content, content: candidate, encoding: "base64" as const, mime }
+            const candidate = encode()
+            // Base64 uses four bytes per three input bytes, including padding.
+            if (Math.ceil(candidate.length / 3) * 4 <= limits.maxBase64Bytes)
+              return {
+                ...content,
+                content: Buffer.from(candidate).toString("base64"),
+                encoding: "base64" as const,
+                mime,
+              }
           }
         } finally {
           resized.free()

packages/core/src/instance.ts

@@ -45,6 +45,8 @@ import { InstructionBuiltIns } from "./instructions/builtins.js"
 import { InstructionEntry } from "./session/instruction-entry.js"
 import { SessionInstructions } from "./session/instructions.js"
 import { SessionGenerateNode } from "./session/generate-node.js"
+import { SessionPromptNode } from "./session/prompt-node.js"
+import { SessionRevertNode } from "./session/revert-node.js"
 import { McpTool } from "./tool/mcp.js"
 import { ReadToolFileSystem } from "./tool/read-filesystem.js"
 import { Tool } from "./tool.js"
@@ -92,6 +94,8 @@ const nodes = [
   Form.node,
   Generate.node,
   SessionGenerateNode.node,
+  SessionPromptNode.node,
+  SessionRevertNode.node,
   ReadToolFileSystem.node,
   McpTool.node,
   SessionInstructions.node,

packages/core/src/models-dev.ts

@@ -636,8 +636,8 @@ export const layer = (options?: Options) =>
       // population. The payload has outgrown some KV backends' per-value
       // limits (Durable Object SQLite caps values at 2 MB and api.json
       // passed it in Aug 2026); a boot without a cache hit just refetches.
-      const writeCache = Effect.fn("ModelsDev.writeCache")(function* (text: string) {
-        yield* kv.set(key, { updatedAt: Date.now(), digest: bodyDigest(text), body: text }).pipe(
+      const writeCache = Effect.fn("ModelsDev.writeCache")(function* (text: string, digest = bodyDigest(text)) {
+        yield* kv.set(key, { updatedAt: Date.now(), digest, body: text }).pipe(
           Effect.catchCauseIf(
             (cause) => !Cause.hasInterruptsOnly(cause),
             (cause) => Effect.logWarning("Failed to cache models.dev catalog", { cause }),
@@ -681,12 +681,13 @@ export const layer = (options?: Options) =>
               const stored = yield* loadFromCache()
               if (!force && stored && Date.now() - stored.updatedAt < Duration.toMillis(ttl)) return
               const text = yield* fetchApi()
+              const digest = bodyDigest(text)
               // models.dev rarely changes between polls; skip the cache write,
               // invalidation, and Refreshed event for a byte-identical body so
               // downstream catalog.updated listeners stay quiet.
-              if (!force && stored?.digest === bodyDigest(text)) return
+              if (!force && stored?.digest === digest) return
               yield* decodeCatalog(text)
-              yield* writeCache(text)
+              yield* writeCache(text, digest)
               yield* invalidate
               yield* bus.publish(ModelsDev.Event.Refreshed, {})
             }),

packages/core/src/plugin/host.ts

@@ -369,9 +369,10 @@ export const make = Effect.fn("PluginHost.make")(function* (plugin: Interface, p
     },
     vcs: {
       get: () => response(vcs.info()),
+      base: () => response(vcs.base()),
       branches: (input) => response(vcs.branches({ search: input?.search, limit: input?.limit })),
       status: () => response(vcs.status()),
-      diff: (input) => response(vcs.diff(input.mode, { context: input.context })),
+      diff: (input) => response(vcs.diff(input.mode, { context: input.context, base: input.base })),
       transform: vcs.transform,
       reload: vcs.reload,
     },

packages/core/src/plugin/vcs/git.ts

@@ -4,10 +4,11 @@ import { define } from "@opencode-ai/plugin/effect/plugin"
 import { Effect } from "effect"
 import { ChildProcess } from "effect/unstable/process"
 import { FileDiff } from "@opencode-ai/schema/file-diff"
-import { BranchList, FileStatus, Info, Mode } from "@opencode-ai/schema/vcs"
+import { Base, BranchList, FileStatus, Info, Mode } from "@opencode-ai/schema/vcs"
 import { AppProcess } from "@opencode-ai/util/process"
 import { Location } from "../../location.js"
 import type { Adapter, BranchOptions, DiffOptions } from "../../vcs.js"
+import { DiffError } from "../../vcs.js"
 import {
   chunksByFile,
   emptyPatch,
@@ -35,9 +36,10 @@ export const Plugin = define({
         id: "git",
         name: "Git",
         info: () => adapter.info(),
+        base: () => adapter.base(),
         branches: (input) => adapter.branches({ search: input.search, limit: input.limit }),
         status: () => adapter.status(),
-        diff: (input) => adapter.diff(input.mode, { context: input.context }),
+        diff: (input) => adapter.diff(input.mode, { context: input.context, base: input.base }),
       })
     })
   }),
@@ -48,7 +50,7 @@ export const Plugin = define({
  * batched through one `git diff` invocation where possible and capped by
  * per-file and total byte budgets, falling back to empty patches when capped.
  */
-function make(proc: AppProcess.Interface, input: { directory: string; worktree: string }): Adapter {
+function make(proc: AppProcess.Interface, input: { directory: string; worktree: string }) {
   // Listing commands scope pathspecs to the requested directory; per-file
   // commands run from the worktree root because git lists root-relative paths.
   const ctx: Ctx = { git: makeGit(proc), directory: input.directory, worktree: input.worktree }
@@ -60,6 +62,7 @@ function make(proc: AppProcess.Interface, input: { directory: string; worktree:
       })
       return { branch: { current, default: root?.name } } satisfies Info
     }),
+    base: () => ctx.git.base(ctx.directory),
     branches: Effect.fn("VcsGit.branches")(function* (options?: BranchOptions) {
       return yield* ctx.git.branches(ctx.directory, options)
     }),
@@ -93,25 +96,23 @@ function make(proc: AppProcess.Interface, input: { directory: string; worktree:
         return yield* track(ctx, (yield* git.hasHead(ctx.directory)) ? "HEAD" : undefined, options)
       }
 
-      const [current, root] = yield* Effect.all([git.branch(ctx.directory), git.defaultBranch(ctx.directory)], {
-        concurrency: 2,
-      })
-      if (!root) return []
-      if (current && current === root.name) return []
-      const ref = yield* git.mergeBase(ctx.directory, root.ref)
-      if (!ref) return []
-      return yield* diffAgainstRef(ctx, ref, options)
+      if (!(yield* git.hasHead(ctx.directory))) {
+        return mode === "committed" ? [] : yield* track(ctx, undefined, options)
+      }
+      const base = options?.base ?? (yield* git.defaultBranch(ctx.directory))?.ref
+      const ref = base ? yield* git.mergeBase(ctx.directory, base) : undefined
+      if (!ref) {
+        return yield* new DiffError({
+          message: base ? `No merge base available for ${base}` : "No review base available",
+        })
+      }
+      return yield* diffAgainstRef(ctx, ref, { ...options, target: mode === "committed" ? "HEAD" : undefined })
     }),
-  }
+  } satisfies Adapter
 }
 
 type Kind = FileStatus["status"]
 
-interface Base {
-  readonly name: string
-  readonly ref: string
-}
-
 interface Item {
   readonly file: string
   readonly code: string
@@ -124,8 +125,11 @@ interface Stat {
   readonly deletions: number
 }
 
-interface PatchOptions {
-  readonly context?: number
+interface GitDiffOptions extends DiffOptions {
+  readonly target?: "HEAD"
+}
+
+interface PatchOptions extends GitDiffOptions {
   readonly maxOutputBytes?: number
 }
 
@@ -196,7 +200,7 @@ function makeGit(proc: AppProcess.Interface) {
     const result = yield* run(["config", "init.defaultBranch"], { cwd })
     const name = result.text().trim()
     if (!name || !list.includes(name)) return
-    return { name, ref: name } satisfies Base
+    return { name, ref: name }
   })
 
   const primary = Effect.fnUntraced(function* (cwd: string) {
@@ -239,15 +243,70 @@ function makeGit(proc: AppProcess.Interface) {
           .trim()
           .replace(/^refs\/remotes\//, "")
         const name = ref.startsWith(`${remote}/`) ? ref.slice(`${remote}/`.length) : ""
-        if (name) return { name, ref } satisfies Base
+        if (name) return { name, ref }
       }
     }
 
     const list = yield* lines(["for-each-ref", "--format=%(refname:short)", "refs/heads"], { cwd })
     const next = yield* configured(cwd, list)
     if (next) return next
-    if (list.includes("main")) return { name: "main", ref: "main" } satisfies Base
-    if (list.includes("master")) return { name: "master", ref: "master" } satisfies Base
+    if (list.includes("main")) return { name: "main", ref: "main" }
+    if (list.includes("master")) return { name: "master", ref: "master" }
+  })
+
+  const resolve = Effect.fnUntraced(function* (cwd: string, ref: string) {
+    const result = yield* run(["rev-parse", "--verify", "--end-of-options", `${ref}^{commit}`], { cwd })
+    if (result.exitCode !== 0) return
+    return result.text().trim() || undefined
+  })
+
+  const ancestor = Effect.fnUntraced(function* (cwd: string, commit: string, ref: string) {
+    if (!/^[a-f0-9]{40,64}$/.test(commit)) return false
+    return (yield* run(["merge-base", "--is-ancestor", commit, ref], { cwd })).exitCode === 0
+  })
+
+  const namedRef = Effect.fnUntraced(function* (cwd: string, input: string) {
+    // Creation hints must identify a branch, not HEAD, an object ID, or a revision expression.
+    if (input === "HEAD" || input.endsWith("/HEAD") || /[~^:@{}\s]/.test(input)) return
+    const ref = (yield* text(["rev-parse", "--symbolic-full-name", "--verify", "--end-of-options", input], {
+      cwd,
+    })).trim()
+    if (!/^refs\/(heads|remotes)\/.+/.test(ref) || ref.endsWith("/HEAD") || !(yield* resolve(cwd, ref))) return
+    return { name: ref.replace(/^refs\/heads\//, "").replace(/^refs\/remotes\/[^/]+\//, ""), ref }
+  })
+
+  const base = Effect.fn("VcsGit.base")(function* (cwd: string) {
+    if (!(yield* hasHead(cwd))) return null
+    const current = yield* branch(cwd)
+    if (!current) return yield* new DiffError({ message: "Choose a review base" })
+    const history = (yield* lines(
+      ["reflog", "show", "--max-count=256", "--format=%H%x00%gs", `refs/heads/${current}`],
+      {
+        cwd,
+      },
+    )).flatMap((line) => {
+      const match = /^([a-f0-9]+)\0(.+)$/.exec(line)
+      return match ? [{ commit: match[1], message: match[2] }] : []
+    })
+    const renamed = history.some((entry) => entry.message.startsWith("Branch: renamed "))
+    const creation = renamed ? undefined : history.find((entry) => entry.message.startsWith("branch: Created from "))
+    const origin = creation?.message.slice("branch: Created from ".length)
+    if (creation && origin) {
+      const candidate = yield* namedRef(cwd, origin)
+      if (
+        candidate &&
+        candidate.name !== current &&
+        (yield* ancestor(cwd, creation.commit, "HEAD")) &&
+        (yield* ancestor(cwd, creation.commit, candidate.ref))
+      ) {
+        return { ...candidate, source: "reflog" } satisfies Base
+      }
+    }
+    const root = yield* defaultBranch(cwd)
+    if (!root || current !== root.name) return yield* new DiffError({ message: "Choose a review base" })
+    const candidate = yield* namedRef(cwd, root.ref)
+    if (!candidate) return yield* new DiffError({ message: "The default review base is unavailable" })
+    return { name: root.name, ref: candidate.ref, source: "default" } satisfies Base
   })
 
   const hasHead = Effect.fn("VcsGit.hasHead")(function* (cwd: string) {
@@ -256,7 +315,9 @@ function makeGit(proc: AppProcess.Interface) {
   })
 
   const mergeBase = Effect.fn("VcsGit.mergeBase")(function* (cwd: string, base: string) {
-    const result = yield* run(["merge-base", base, "HEAD"], { cwd })
+    const ref = yield* resolve(cwd, base)
+    if (!ref) return
+    const result = yield* run(["merge-base", ref, "HEAD"], { cwd })
     if (result.exitCode !== 0) return
     return result.text().trim() || undefined
   })
@@ -272,10 +333,13 @@ function makeGit(proc: AppProcess.Interface) {
     })
   })
 
-  const diff = Effect.fn("VcsGit.diffNames")(function* (cwd: string, ref: string) {
-    const list = nuls(
-      yield* text(["diff", "--no-ext-diff", "--no-renames", "--name-status", "-z", ref, "--", "."], { cwd }),
+  const diff = Effect.fn("VcsGit.diffNames")(function* (cwd: string, ref: string, target?: string) {
+    const result = yield* run(
+      ["diff", "--no-ext-diff", "--no-renames", "--name-status", "-z", ref, ...(target ? [target] : []), "--", "."],
+      { cwd },
     )
+    if (result.exitCode !== 0) return yield* new DiffError({ message: "Unable to list Git changes" })
+    const list = nuls(result.text())
     return list.flatMap((code, idx) => {
       if (idx % 2 !== 0) return []
       const file = list[idx + 1]
@@ -284,9 +348,12 @@ function makeGit(proc: AppProcess.Interface) {
     })
   })
 
-  const stats = Effect.fn("VcsGit.stats")(function* (cwd: string, ref: string) {
+  const stats = Effect.fn("VcsGit.stats")(function* (cwd: string, ref: string, target?: string) {
     return nuls(
-      yield* text(["diff", "--no-ext-diff", "--no-renames", "--numstat", "-z", ref, "--", "."], { cwd }),
+      yield* text(
+        ["diff", "--no-ext-diff", "--no-renames", "--numstat", "-z", ref, ...(target ? [target] : []), "--", "."],
+        { cwd },
+      ),
     ).flatMap((item) => {
       const a = item.indexOf("\t")
       const b = item.indexOf("\t", a + 1)
@@ -309,7 +376,17 @@ function makeGit(proc: AppProcess.Interface) {
 
   const patch = Effect.fn("VcsGit.patch")(function* (cwd: string, ref: string, file: string, options?: PatchOptions) {
     const result = yield* run(
-      ["diff", "--patch", "--no-ext-diff", "--no-renames", `--unified=${options?.context ?? 3}`, ref, "--", file],
+      [
+        "diff",
+        "--patch",
+        "--no-ext-diff",
+        "--no-renames",
+        `--unified=${options?.context ?? 3}`,
+        ref,
+        ...(options?.target ? [options.target] : []),
+        "--",
+        file,
+      ],
       { cwd, maxOutputBytes: options?.maxOutputBytes },
     )
     return { text: result.truncated ? "" : result.text(), truncated: result.truncated } satisfies Patch
@@ -317,7 +394,17 @@ function makeGit(proc: AppProcess.Interface) {
 
   const patchAll = Effect.fn("VcsGit.patchAll")(function* (cwd: string, ref: string, options?: PatchOptions) {
     const result = yield* run(
-      ["diff", "--patch", "--no-ext-diff", "--no-renames", `--unified=${options?.context ?? 3}`, ref, "--", "."],
+      [
+        "diff",
+        "--patch",
+        "--no-ext-diff",
+        "--no-renames",
+        `--unified=${options?.context ?? 3}`,
+        ref,
+        ...(options?.target ? [options.target] : []),
+        "--",
+        ".",
+      ],
       { cwd, maxOutputBytes: options?.maxOutputBytes },
     )
     return { text: result.text(), truncated: result.truncated } satisfies Patch
@@ -367,6 +454,7 @@ function makeGit(proc: AppProcess.Interface) {
   return {
     branch,
     branches,
+    base,
     defaultBranch,
     hasHead,
     mergeBase,
@@ -393,10 +481,11 @@ const merge = (...lists: Item[][]) => {
 
 const emptyBatch = () => ({ patches: new Map<string, string>(), capped: false })
 
-const batchPatches = Effect.fnUntraced(function* (ctx: Ctx, ref: string, list: Item[], options?: DiffOptions) {
+const batchPatches = Effect.fnUntraced(function* (ctx: Ctx, ref: string, list: Item[], options?: GitDiffOptions) {
   if (list.length === 0) return emptyBatch()
 
   const result = yield* ctx.git.patchAll(ctx.directory, ref, {
+    target: options?.target,
     context: options?.context ?? PATCH_CONTEXT_LINES,
     maxOutputBytes: MAX_TOTAL_PATCH_BYTES,
   })
@@ -407,7 +496,12 @@ const batchPatches = Effect.fnUntraced(function* (ctx: Ctx, ref: string, list: I
   }
 })
 
-const nativePatch = Effect.fnUntraced(function* (ctx: Ctx, ref: string | undefined, item: Item, options?: DiffOptions) {
+const nativePatch = Effect.fnUntraced(function* (
+  ctx: Ctx,
+  ref: string | undefined,
+  item: Item,
+  options?: GitDiffOptions,
+) {
   const result =
     item.code === "??" || !ref
       ? yield* ctx.git.patchUntracked(ctx.worktree, item.file, {
@@ -415,6 +509,7 @@ const nativePatch = Effect.fnUntraced(function* (ctx: Ctx, ref: string | undefin
           maxOutputBytes: MAX_PATCH_BYTES,
         })
       : yield* ctx.git.patch(ctx.worktree, ref, item.file, {
+          target: options?.target,
           context: options?.context ?? PATCH_CONTEXT_LINES,
           maxOutputBytes: MAX_PATCH_BYTES,
         })
@@ -434,7 +529,7 @@ const patchForItem = Effect.fnUntraced(function* (
   item: Item,
   batch: { patches: Map<string, string>; capped: boolean },
   capped: boolean,
-  options?: DiffOptions,
+  options?: GitDiffOptions,
 ) {
   if (capped) return emptyPatch(item.file)
 
@@ -450,7 +545,7 @@ const files = Effect.fnUntraced(function* (
   list: Item[],
   map: Map<string, { additions: number; deletions: number }>,
   batch: { patches: Map<string, string>; capped: boolean },
-  options?: DiffOptions,
+  options?: GitDiffOptions,
 ) {
   const next: FileDiff.Info[] = []
   let total = 0
@@ -459,7 +554,7 @@ const files = Effect.fnUntraced(function* (
   for (const item of list.toSorted((a, b) => a.file.localeCompare(b.file))) {
     const stat =
       map.get(item.file) ??
-      (item.status === "added" ? yield* ctx.git.statUntracked(ctx.worktree, item.file) : undefined)
+      (!options?.target && item.status === "added" ? yield* ctx.git.statUntracked(ctx.worktree, item.file) : undefined)
     const patch = yield* patchForItem(ctx, ref, item, batch, capped, options)
     const result: { patch: string; capped: boolean } = capped
       ? { patch, capped: true }
@@ -481,9 +576,13 @@ const files = Effect.fnUntraced(function* (
   return next
 })
 
-const diffAgainstRef = Effect.fnUntraced(function* (ctx: Ctx, ref: string, options?: DiffOptions) {
+const diffAgainstRef = Effect.fnUntraced(function* (ctx: Ctx, ref: string, options?: GitDiffOptions) {
   const [list, stats, extra] = yield* Effect.all(
-    [ctx.git.diff(ctx.directory, ref), ctx.git.stats(ctx.directory, ref), ctx.git.status(ctx.directory)],
+    [
+      ctx.git.diff(ctx.directory, ref, options?.target),
+      ctx.git.stats(ctx.directory, ref, options?.target),
+      options?.target ? Effect.succeed([]) : ctx.git.status(ctx.directory),
+    ],
     { concurrency: 3 },
   )
   return yield* files(

packages/core/src/plugin/vcs/hg.ts

@@ -10,6 +10,7 @@ import { FSUtil } from "@opencode-ai/util/fs-util"
 import { AppProcess } from "@opencode-ai/util/process"
 import { Location } from "../../location.js"
 import type { Adapter, DiffOptions } from "../../vcs.js"
+import { DiffError } from "../../vcs.js"
 import {
   addPatch,
   chunksByFile,
@@ -42,7 +43,7 @@ export const Plugin = define({
         info: () => adapter.info(),
         branches: (input) => adapter.branches({ search: input.search, limit: input.limit }),
         status: () => adapter.status(),
-        diff: (input) => adapter.diff(input.mode, { context: input.context }),
+        diff: (input) => adapter.diff(input.mode, { context: input.context, base: input.base }),
       })
     })
   }),
@@ -121,6 +122,11 @@ function make(
     }),
     diff: Effect.fn("VcsHg.diff")(function* (mode: Mode, options?: DiffOptions) {
       if (mode === "working") return yield* diffAgainst(undefined, options)
+      if (mode === "committed" || options?.base !== undefined) {
+        return yield* new DiffError({
+          message: "The Mercurial provider does not support committed reviews or explicit bases",
+        })
+      }
 
       const branch = yield* hg.branch()
       if (!branch || branch === "default") return []

packages/core/src/project.ts

@@ -62,6 +62,7 @@ export const root = Effect.fn("Project.root")(function* (
 export interface Interface {
   readonly list: () => Effect.Effect<ReadonlyArray<Info>>
   readonly update: (input: UpdateInput) => Effect.Effect<Info, NotFoundError>
+  /** Resolves and persists the owning Project. */
   readonly resolve: (input: AbsolutePath, options?: { readonly discovery?: boolean }) => Effect.Effect<Resolved>
 }
 

packages/core/src/session/compaction.ts

@@ -164,7 +164,9 @@ const serialize = (message: SessionMessage.Info) => {
   if (message.type === "synthetic") return `[Synthetic context]: ${message.text}`
   if (message.type === "skill") return `[Skill activated: ${message.name}]\n${message.text}`
   if (message.type === "shell")
-    return `[Shell]: ${message.command}\n${truncateToolOutput(message.output?.output ?? "")}`
+    return message.metadata?.background === true
+      ? ""
+      : `[Shell]: ${message.command}\n${truncateToolOutput(message.output?.output ?? "")}`
   return ""
 }
 

packages/core/src/session/error.ts

@@ -2,6 +2,7 @@ export * as SessionErrors from "./error.js"
 
 import { Schema } from "effect"
 import { Agent } from "@opencode-ai/schema/agent"
+import { Skill } from "@opencode-ai/schema/skill"
 import { SessionMessage } from "./message.js"
 import { SessionSchema } from "./schema.js"
 import { SessionError } from "@opencode-ai/schema/session-error"
@@ -10,6 +11,35 @@ export class NotFoundError extends Schema.TaggedError<NotFoundError>()("Session.
   sessionID: SessionSchema.ID,
 }) {}
 
+export class MessageNotFoundError extends Schema.TaggedError<MessageNotFoundError>()("Session.MessageNotFoundError", {
+  sessionID: SessionSchema.ID,
+  messageID: SessionMessage.ID,
+}) {}
+
+export class MessageNotAssistantError extends Schema.TaggedError<MessageNotAssistantError>()(
+  "Session.MessageNotAssistantError",
+  {
+    sessionID: SessionSchema.ID,
+    messageID: SessionMessage.ID,
+  },
+) {}
+
+export class MessageIncompleteError extends Schema.TaggedError<MessageIncompleteError>()(
+  "Session.MessageIncompleteError",
+  {
+    sessionID: SessionSchema.ID,
+    messageID: SessionMessage.ID,
+  },
+) {}
+
+export class MessageToolIncompleteError extends Schema.TaggedError<MessageToolIncompleteError>()(
+  "Session.MessageToolIncompleteError",
+  {
+    sessionID: SessionSchema.ID,
+    messageID: SessionMessage.ID,
+  },
+) {}
+
 export class ForkEmptyError extends Schema.TaggedError<ForkEmptyError>()("Session.ForkEmptyError", {
   sessionID: SessionSchema.ID,
 }) {
@@ -52,3 +82,42 @@ export class UserInterruptedError extends Schema.TaggedError<UserInterruptedErro
     return "Session interrupted by user"
   }
 }
+
+export class PromptConflictError extends Schema.TaggedError<PromptConflictError>()("Session.PromptConflictError", {
+  sessionID: SessionSchema.ID,
+  messageID: SessionMessage.ID,
+}) {}
+
+export class SyntheticConflictError extends Schema.TaggedError<SyntheticConflictError>()(
+  "Session.SyntheticConflictError",
+  {
+    sessionID: SessionSchema.ID,
+    inputID: SessionMessage.ID,
+  },
+) {}
+
+export class AttachmentError extends Schema.TaggedError<AttachmentError>()("Session.AttachmentError", {
+  uri: Schema.String,
+  message: Schema.String,
+}) {}
+
+export class CompactionConflictError extends Schema.TaggedError<CompactionConflictError>()(
+  "Session.CompactionConflictError",
+  {
+    sessionID: SessionSchema.ID,
+    inputID: SessionMessage.ID,
+  },
+) {}
+
+export class BusyError extends Schema.TaggedError<BusyError>()("Session.BusyError", {
+  sessionID: SessionSchema.ID,
+}) {}
+
+export class InboxConflictError extends Schema.TaggedError<InboxConflictError>()("Session.InboxConflictError", {
+  sessionID: SessionSchema.ID,
+  inboxID: SessionMessage.ID,
+}) {}
+
+export class SkillNotFoundError extends Schema.TaggedError<SkillNotFoundError>()("Session.SkillNotFoundError", {
+  skill: Skill.ID,
+}) {}

packages/core/src/session/execution.ts

@@ -18,6 +18,8 @@ import { SessionInbox } from "./inbox.js"
 export interface Interface {
   /** Snapshots active execution owned by this process. */
   readonly active: Effect.Effect<ReadonlySet<SessionSchema.ID>>
+  /** Checks process-local ownership, including interruption cleanup and terminal settlement. */
+  readonly isActive: (sessionID: SessionSchema.ID) => Effect.Effect<boolean>
   /** Starts execution while idle or joins the active execution. */
   readonly resume: (sessionID: SessionSchema.ID) => Effect.Effect<void, SessionRunner.RunError>
   /** Registers newly recorded work. Repeated wakeups may coalesce. */
@@ -142,6 +144,7 @@ export const layer = Layer.effect(
 
     return Service.of({
       active: coordinator.active,
+      isActive: coordinator.isActive,
       interrupt: (sessionID, options) =>
         Effect.gen(function* () {
           const interrupted = yield* coordinator.interrupt(sessionID, "user")
@@ -178,6 +181,7 @@ export const noopLayer = Layer.succeed(
   Service,
   Service.of({
     active: Effect.succeed(new Set()),
+    isActive: () => Effect.succeed(false),
     resume: () => Effect.void,
     wake: () => Effect.void,
     interrupt: () => Effect.succeed(false),

packages/core/src/session/execution/restart.ts

@@ -9,6 +9,7 @@ import { SessionEvent } from "../event.js"
 import { SessionExecution } from "../execution.js"
 import { SessionSchema } from "../schema.js"
 import { SessionStore } from "../store.js"
+import { ShellResult } from "../../shell/result.js"
 import { SubagentCompletion } from "../subagent-completion.js"
 
 const CONTINUE_AFTER_SERVER_RESTART =
@@ -116,13 +117,13 @@ export const layer = (options?: Options) =>
             id: background.notificationID,
             sessionID: recovery.sessionID,
             description: recovery.command,
-            text: `<shell id="${background.id}" state="${state}" command="${recovery.command}">\n${text}\n</shell>`,
-            metadata: {
-              source: "shell",
+            ...ShellResult.notification({
               jobID: background.id,
               shellID: recovery.shellID,
+              command: recovery.command,
               state,
-            },
+              text,
+            }),
             ...(suspended.has(recovery.sessionID) ? { resume: false } : {}),
           })
           .pipe(
@@ -156,7 +157,7 @@ export const layer = (options?: Options) =>
           yield* notify(background)
           return
         }
-        if ((yield* execution.active).has(recovery.childSessionID)) return
+        if (yield* execution.isActive(recovery.childSessionID)) return
         if (!(yield* prepareResume(recovery.childSessionID))) {
           yield* notify({ status: "error", error: RESUME_EXHAUSTED.message })
           return

packages/core/src/session/inbox.ts

@@ -1,7 +1,8 @@
 export * as SessionInbox from "./inbox.js"
 
 import { and, asc, eq, or } from "drizzle-orm"
-import { DateTime, Effect, Schema } from "effect"
+import { Context, DateTime, Effect, Layer, Schema } from "effect"
+import { makeGlobalNode } from "@opencode-ai/util/effect/app-node"
 import {
   Compaction,
   CompactionPayload,
@@ -15,7 +16,7 @@ import {
   User,
   UserPayload,
 } from "@opencode-ai/schema/session-inbox"
-import type { Database } from "../database/database.js"
+import { Database } from "../database/database.js"
 import { Bus } from "../bus.js"
 import { KeyedMutex } from "../effect/keyed-mutex.js"
 import { SessionEvent } from "./event.js"
@@ -65,6 +66,13 @@ export class LifecycleConflict extends Schema.TaggedError<LifecycleConflict>()("
   id: SessionMessage.ID,
 }) {}
 
+function matches<Type extends Item["type"]>(
+  stored: Info,
+  request: PendingRef & { readonly type: Type },
+): stored is Extract<Info, { readonly type: Type }> {
+  return stored.sessionID === request.sessionID && stored.type === request.type
+}
+
 const fromRow = (row: typeof SessionInboxTable.$inferSelect): Info => {
   const base = {
     id: SessionMessage.ID.make(row.id),
@@ -116,7 +124,7 @@ const promotedFromMessage = Effect.fn("SessionInbox.promotedFromMessage")(functi
     .pipe(Effect.orDie)
   if (row === undefined) return undefined
   if (row.session_id !== sessionID || (row.type !== "user" && row.type !== "synthetic"))
-    return yield* Effect.die(new LifecycleConflict({ id }))
+    return yield* new LifecycleConflict({ id })
   const message = decodeMessage({ ...row.data, id: row.id, type: row.type })
   const base = { id, sessionID, timeCreated: message.time.created, delivery }
   if (message.type === "user")
@@ -131,89 +139,140 @@ const promotedFromMessage = Effect.fn("SessionInbox.promotedFromMessage")(functi
       type: "synthetic",
       payload: decodeSynthetic(message),
     })
-  return yield* Effect.die(new LifecycleConflict({ id }))
+  return yield* new LifecycleConflict({ id })
 })
 
-/** Reconciles pending or delivered work without preparing a new admission payload. */
-export const reconcile = Effect.fn("SessionInbox.reconcile")(function* (
-  db: DatabaseService,
-  request: {
+export type Interface = Effect.Success<ReturnType<typeof make>>
+
+export class Service extends Context.Service<Service, Interface>()("@opencode/SessionInbox") {}
+
+export const make = Effect.fn("SessionInbox.make")(function* () {
+  const database = yield* Database.Service
+  const db = database.db
+  const bus = yield* Bus.Service
+
+  /** First admission wins for matching Session and type, without preparing a new payload. */
+  const reconcile = Effect.fn("SessionInbox.reconcile")(function* <Type extends Item["type"]>(request: {
+    readonly id: SessionMessage.ID
+    readonly sessionID: SessionSchema.ID
+    readonly type: Type
+    readonly delivery: Delivery
+  }) {
+    const existing =
+      (yield* find(db, request.id)) ?? (yield* promotedFromMessage(db, request.sessionID, request.id, request.delivery))
+    if (existing === undefined) return undefined
+    if (existing.type === "compaction" || !matches(existing, request))
+      return yield* new LifecycleConflict({ id: request.id })
+    return existing
+  })
+
+  const admit = Effect.fn("SessionInbox.admit")(function* <Type extends Item["type"]>(request: {
+    readonly id: SessionMessage.ID
+    readonly sessionID: SessionSchema.ID
+    readonly item: Item & { readonly type: Type }
+  }) {
+    const existing = yield* reconcile({ ...request, type: request.item.type, delivery: request.item.delivery })
+    if (existing !== undefined) return existing
+    const admitted = yield* bus
+      .publish(SessionEvent.InboxEnqueued, {
+        inboxID: request.id,
+        sessionID: request.sessionID,
+        item: request.item,
+      })
+      .pipe(
+        Effect.map((event) =>
+          Info.make({
+            id: request.id,
+            sessionID: request.sessionID,
+            timeCreated: DateTime.makeUnsafe(event.created),
+            ...request.item,
+          }),
+        ),
+        Effect.catchDefect((defect) =>
+          defect instanceof LifecycleConflict
+            ? find(db, request.id).pipe(
+                Effect.flatMap((stored) => (stored === undefined ? Effect.fail(defect) : Effect.succeed(stored))),
+              )
+            : Effect.die(defect),
+        ),
+      )
+    if (!matches(admitted, { ...request, type: request.item.type }))
+      return yield* new LifecycleConflict({ id: request.id })
+    return admitted
+  })
+
+  const admitCompaction = Effect.fn("SessionInbox.admitCompaction")(function* (input: {
     readonly id: SessionMessage.ID
     readonly sessionID: SessionSchema.ID
     readonly delivery: Delivery
-  },
-) {
-  const existing = yield* find(db, request.id)
-  if (existing !== undefined) {
-    if (existing.type === "compaction") return yield* Effect.die(new LifecycleConflict({ id: request.id }))
-    return existing
-  }
-  return yield* promotedFromMessage(db, request.sessionID, request.id, request.delivery)
-})
-
-export const admit = Effect.fn("SessionInbox.admit")(function* (
-  db: DatabaseService,
-  bus: Bus.Interface,
-  request: {
-    readonly id: SessionMessage.ID
-    readonly sessionID: SessionSchema.ID
-    readonly item: Item
-  },
-) {
-  const existing = yield* reconcile(db, { ...request, delivery: request.item.delivery })
-  if (existing !== undefined) return existing
-  return yield* bus
-    .publish(SessionEvent.InboxEnqueued, {
-      inboxID: request.id,
-      sessionID: request.sessionID,
-      item: request.item,
-    })
-    .pipe(
-      Effect.map((event) =>
-        Info.make({
-          id: request.id,
-          sessionID: request.sessionID,
-          timeCreated: DateTime.makeUnsafe(event.created),
-          ...request.item,
-        }),
-      ),
-      Effect.catchDefect((defect) =>
-        find(db, request.id).pipe(
-          Effect.flatMap((stored) =>
-            stored?.type === request.item.type ? Effect.succeed(stored) : Effect.die(defect),
-          ),
-        ),
-      ),
+  }) {
+    return yield* serialized(
+      input.sessionID,
+      Effect.gen(function* () {
+        const exact = yield* find(db, input.id)
+        if (exact) {
+          if (exact.type === "compaction" && exact.sessionID === input.sessionID) return exact
+          return yield* new LifecycleConflict({ id: input.id })
+        }
+        if (yield* promotedFromMessage(db, input.sessionID, input.id, input.delivery))
+          return yield* new LifecycleConflict({ id: input.id })
+        const pending = (yield* list(db, input.sessionID)).find((item) => item.type === "compaction")
+        if (pending) return pending
+        return yield* admit({
+          id: input.id,
+          sessionID: input.sessionID,
+          item: { type: "compaction", payload: {}, delivery: Delivery.make(input.delivery) },
+        })
+      }),
     )
+  })
+
+  const cancel = Effect.fn("SessionInbox.cancel")((input: PendingRef) =>
+    publishMutation(
+      input,
+      bus.publish(SessionEvent.InboxCancelled, {
+        sessionID: input.sessionID,
+        inboxID: input.id,
+      }),
+    ),
+  )
+
+  const steer = Effect.fn("SessionInbox.steer")((input: PendingRef) =>
+    publishMutation(
+      input,
+      bus.publish(SessionEvent.InboxDeliveryChanged, {
+        sessionID: input.sessionID,
+        inboxID: input.id,
+        delivery: "steer",
+      }),
+    ),
+  )
+
+  const queue = Effect.fn("SessionInbox.queue")((input: PendingRef) =>
+    publishMutation(
+      input,
+      bus.publish(SessionEvent.InboxDeliveryChanged, {
+        sessionID: input.sessionID,
+        inboxID: input.id,
+        delivery: "queue",
+      }),
+    ),
+  )
+
+  return {
+    list: (sessionID: SessionSchema.ID) => list(db, sessionID),
+    reconcile,
+    admit,
+    admitCompaction,
+    cancel,
+    steer,
+    queue,
+  }
 })
 
-export const admitCompaction = Effect.fn("SessionInbox.admitCompaction")(function* (
-  db: DatabaseService,
-  bus: Bus.Interface,
-  input: { readonly id: SessionMessage.ID; readonly sessionID: SessionSchema.ID; readonly delivery: Delivery },
-) {
-  return yield* serialized(
-    input.sessionID,
-    Effect.gen(function* () {
-      const exact = yield* find(db, input.id)
-      if (exact) {
-        if (exact.type === "compaction" && exact.sessionID === input.sessionID) return exact
-        return yield* Effect.die(new LifecycleConflict({ id: input.id }))
-      }
-      if (yield* promotedFromMessage(db, input.sessionID, input.id, input.delivery))
-        return yield* Effect.die(new LifecycleConflict({ id: input.id }))
-      const pending = (yield* list(db, input.sessionID)).find((item) => item.type === "compaction")
-      if (pending) return pending
-      const admitted = yield* admit(db, bus, {
-        id: input.id,
-        sessionID: input.sessionID,
-        item: Item.make({ type: "compaction", payload: {}, delivery: input.delivery }),
-      })
-      if (admitted.type === "compaction") return admitted
-      return yield* Effect.die(new LifecycleConflict({ id: input.id }))
-    }),
-  )
-})
+export const layer = Layer.effect(Service, make())
+
+export const node = makeGlobalNode({ service: Service, layer, deps: [Database.node, Bus.node] })
 
 export const projectAdmitted = Effect.fn("SessionInbox.projectAdmitted")(function* (
   db: DatabaseService,
@@ -392,39 +451,11 @@ export const has = Effect.fn("SessionInbox.has")(function* (
 })
 
 const publishMutation = <A, E, R>(input: PendingRef, effect: Effect.Effect<A, E, R>) =>
-  serialized(input.sessionID, effect).pipe(Effect.asVoid)
-
-export const cancel = Effect.fn("SessionInbox.cancel")((bus: Bus.Interface, input: PendingRef) =>
-  publishMutation(
-    input,
-    bus.publish(SessionEvent.InboxCancelled, {
-      sessionID: input.sessionID,
-      inboxID: input.id,
-    }),
-  ),
-)
-
-export const steer = Effect.fn("SessionInbox.steer")((bus: Bus.Interface, input: PendingRef) =>
-  publishMutation(
-    input,
-    bus.publish(SessionEvent.InboxDeliveryChanged, {
-      sessionID: input.sessionID,
-      inboxID: input.id,
-      delivery: "steer",
-    }),
-  ),
-)
-
-export const queue = Effect.fn("SessionInbox.queue")((bus: Bus.Interface, input: PendingRef) =>
-  publishMutation(
-    input,
-    bus.publish(SessionEvent.InboxDeliveryChanged, {
-      sessionID: input.sessionID,
-      inboxID: input.id,
-      delivery: "queue",
-    }),
-  ),
-)
+  serialized(input.sessionID, effect).pipe(
+    Effect.asVoid,
+    // Bus projectors abort their transaction through the defect channel.
+    Effect.catchDefect((defect) => (defect instanceof LifecycleConflict ? Effect.fail(defect) : Effect.die(defect))),
+  )
 
 const publish = Effect.fn("SessionInbox.publish")(function* (
   db: DatabaseService,
@@ -447,6 +478,7 @@ const publish = Effect.fn("SessionInbox.publish")(function* (
             defect instanceof LifecycleConflict
               ? promotedFromMessage(db, sessionID, entry.id, entry.delivery).pipe(
                   Effect.flatMap((stored) => (stored !== undefined ? Effect.void : Effect.die(defect))),
+                  Effect.orDie,
                 )
               : Effect.die(defect),
           ),

packages/core/src/session/message-updater.ts

@@ -169,7 +169,8 @@ export function update(adapter: Adapter, event: SessionEvent.DurableEvent) {
           SessionMessage.Shell.make({
             id: SessionMessage.ID.fromEvent(event.id),
             type: "shell",
-            metadata: event.metadata,
+            metadata:
+              event.data.shell.metadata.background === true ? { ...event.metadata, background: true } : event.metadata,
             shellID: event.data.shell.id,
             command: event.data.shell.command,
             status: event.data.shell.status,

packages/core/src/session/prompt-node.ts

@@ -0,0 +1,16 @@
+export * as SessionPromptNode from "./prompt-node.js"
+
+import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
+import { FSUtil } from "@opencode-ai/util/fs-util"
+import { Image } from "../image.js"
+import { PluginHooks } from "../plugin/hooks.js"
+import { PluginSupervisor } from "../plugin/supervisor.js"
+import { Skill } from "../skill.js"
+import { SessionPrompt } from "./prompt.js"
+
+// Keep the supervisor implementation out of the global Session import path.
+export const node = makeLocationNode({
+  service: SessionPrompt.Service,
+  layer: SessionPrompt.layer,
+  deps: [FSUtil.node, PluginSupervisor.node, PluginHooks.node, Image.node, Skill.node],
+})

packages/core/src/session/prompt.ts

@@ -0,0 +1,231 @@
+export * as SessionPrompt from "./prompt.js"
+
+import { Base64, FileAttachment, Prompt } from "@opencode-ai/schema/prompt"
+import { PromptInput } from "@opencode-ai/schema/prompt-input"
+import { SessionInbox } from "@opencode-ai/schema/session-inbox"
+import type { Session } from "@opencode-ai/schema/session"
+import type { SessionMessage } from "@opencode-ai/schema/session-message"
+import { FSUtil } from "@opencode-ai/util/fs-util"
+import { Context, Effect, Layer } from "effect"
+import path from "path"
+import { fileURLToPath } from "url"
+import { Image } from "../image.js"
+import { Mime } from "../mime.js"
+import { PluginHooks } from "../plugin/hooks.js"
+import { PluginSupervisor } from "../plugin/supervisor-service.js"
+import { Skill } from "../skill.js"
+import { AttachmentError, SkillNotFoundError } from "./error.js"
+
+export type Input = {
+  text: string
+  files?: PromptInput.Prompt["files"]
+  agents?: PromptInput.Prompt["agents"]
+  skills?: PromptInput.Prompt["skills"]
+  metadata?: Record<string, unknown>
+  delivery?: SessionInbox.Delivery
+}
+
+export const make = Effect.fn("SessionPrompt.make")(function* () {
+  const fs = yield* FSUtil.Service
+  const plugins = yield* PluginSupervisor.Service
+  const hooks = yield* PluginHooks.Service
+  const image = yield* Image.Service
+  const skillService = yield* Skill.Service
+
+  const prepare = Effect.fn("SessionPrompt.prepare")(function* (request: {
+    sessionID: Session.ID
+    messageID: SessionMessage.ID
+    input: Input
+  }) {
+    yield* plugins.flush
+    const event = yield* hooks.trigger("session", "prompt", {
+      sessionID: request.sessionID,
+      messageID: request.messageID,
+      prompt: structuredClone({
+        text: request.input.text,
+        files: request.input.files?.slice(),
+        agents: request.input.agents?.slice(),
+        skills: request.input.skills?.slice(),
+      }),
+      metadata: structuredClone(request.input.metadata),
+      delivery: request.input.delivery ?? "steer",
+    })
+    const input = event.prompt
+    const files = input.files
+      ? yield* Effect.forEach(input.files, materializeAttachment, { concurrency: 8 })
+      : undefined
+    const requested = input.skills
+    const selected = yield* Effect.gen(function* () {
+      if (!requested?.length) return undefined
+      const prepared = new Map<Skill.ID, Skill.Name>()
+      return yield* Effect.forEach(requested, (attachment) =>
+        Effect.gen(function* () {
+          const name = prepared.get(attachment.id)
+          if (name !== undefined) return { id: attachment.id, name, mention: attachment.mention }
+          const skill = yield* skillService.get(attachment.id)
+          if (!skill) return yield* new SkillNotFoundError({ skill: attachment.id })
+          prepared.set(skill.id, skill.name)
+          return {
+            id: skill.id,
+            name: skill.name,
+            text: (yield* Skill.prepare(fs, skill).pipe(Effect.orDie)).output,
+            mention: attachment.mention,
+          }
+        }),
+      )
+    })
+    return {
+      type: "user",
+      payload: SessionInbox.UserPayload.make({
+        ...Prompt.make({
+          text: input.text,
+          agents: input.agents,
+          files,
+          skills: selected?.length ? selected : undefined,
+        }),
+        metadata: event.metadata,
+      }),
+      delivery: SessionInbox.Delivery.make(event.delivery),
+    } satisfies SessionInbox.Item
+  })
+
+  const materializeAttachment = Effect.fn("SessionPrompt.materializeAttachment")(function* (
+    input: PromptInput.FileAttachment,
+  ) {
+    const resolved = input.uri.startsWith("data:")
+      ? {
+          bytes: yield* decodeDataURL(input.uri),
+          source: { type: "inline" as const },
+          start: undefined,
+          end: undefined,
+          name: undefined,
+          mime: undefined,
+        }
+      : yield* readFileAttachment(input.uri)
+    if (resolved.bytes.byteLength > MAX_ATTACHMENT_BYTES)
+      return yield* new AttachmentError({
+        uri: input.uri,
+        message: `Attachment exceeds the ${MAX_ATTACHMENT_BYTES} byte limit: ${input.uri}`,
+      })
+
+    const mime = resolved.mime ?? Mime.detect(resolved.bytes)
+    const content =
+      mime === "text/plain" && resolved.start !== undefined
+        ? Buffer.from(
+            Buffer.from(resolved.bytes)
+              .toString("utf8")
+              .split("\n")
+              .slice(resolved.start - 1, resolved.end)
+              .join("\n"),
+          )
+        : resolved.bytes
+    const normalized = yield* normalizeImageAttachment(input, Buffer.from(content).toString("base64"), mime)
+    return FileAttachment.create({
+      data: normalized.data,
+      mime: normalized.mime,
+      source: resolved.source,
+      name: input.name ?? resolved.name,
+      description: input.description,
+      mention: input.mention,
+    })
+  })
+
+  const normalizeImageAttachment = Effect.fn("SessionPrompt.normalizeImageAttachment")(function* (
+    input: PromptInput.FileAttachment,
+    data: string,
+    mime: string,
+  ) {
+    if (!mime.startsWith("image/")) return { data: Base64.make(data), mime }
+    const label = input.name ?? (input.uri.startsWith("data:") ? "inline attachment" : input.uri)
+    const content = { uri: label, content: data, encoding: "base64" as const, mime }
+    const normalized = yield* image.normalize(label, content).pipe(
+      Effect.catchTag("Image.ResizerUnavailableError", () => Effect.succeed(content)),
+      Effect.mapError((error) => new AttachmentError({ uri: label, message: error.message })),
+    )
+    return { data: Base64.make(normalized.content), mime: normalized.mime }
+  })
+
+  const readFileAttachment = Effect.fn("SessionPrompt.readFileAttachment")(function* (uri: string) {
+    const url = yield* Effect.try({
+      try: () => new URL(uri),
+      catch: () => new AttachmentError({ uri, message: `Invalid attachment URI: ${uri}` }),
+    })
+    if (url.protocol !== "file:")
+      return yield* new AttachmentError({ uri, message: `Unsupported attachment URI: ${uri}` })
+    const start = positiveInt(url.searchParams.get("start"))
+    const end = positiveInt(url.searchParams.get("end"))
+    const target = yield* Effect.try({
+      try: () => {
+        url.search = ""
+        url.hash = ""
+        return fileURLToPath(url)
+      },
+      catch: () => new AttachmentError({ uri, message: `Invalid file URI: ${uri}` }),
+    })
+    const info = yield* fs
+      .stat(target)
+      .pipe(Effect.mapError(() => new AttachmentError({ uri, message: `Unable to read attachment: ${uri}` })))
+    if (info.type === "Directory") {
+      const entries = yield* fs
+        .readDirectoryEntries(target)
+        .pipe(Effect.mapError(() => new AttachmentError({ uri, message: `Unable to read attachment: ${uri}` })))
+      return {
+        bytes: Buffer.from(
+          entries
+            .filter((entry) => entry.type === "file" || entry.type === "directory")
+            .sort((a, b) => (a.type === b.type ? a.name.localeCompare(b.name) : a.type === "directory" ? -1 : 1))
+            .map((entry) => entry.name + (entry.type === "directory" ? path.sep : ""))
+            .join("\n"),
+        ),
+        source: { type: "uri" as const, uri },
+        start: undefined,
+        end: undefined,
+        name: path.basename(target),
+        mime: "application/x-directory",
+      }
+    }
+    if (info.type !== "File") return yield* new AttachmentError({ uri, message: `Attachment is not a file: ${uri}` })
+    if (Number(info.size) > MAX_ATTACHMENT_BYTES)
+      return yield* new AttachmentError({
+        uri,
+        message: `Attachment exceeds the ${MAX_ATTACHMENT_BYTES} byte limit: ${uri}`,
+      })
+    const bytes = yield* fs
+      .readFile(target)
+      .pipe(Effect.mapError(() => new AttachmentError({ uri, message: `Unable to read attachment: ${uri}` })))
+    return { bytes, source: { type: "uri" as const, uri }, start, end, name: path.basename(target), mime: undefined }
+  })
+
+  return { prepare }
+})
+
+export type Interface = Effect.Success<ReturnType<typeof make>>
+
+export class Service extends Context.Service<Service, Interface>()("@opencode/SessionPrompt") {}
+
+export const layer = Layer.effect(Service, make())
+
+const MAX_ATTACHMENT_BYTES = 20 * 1024 * 1024
+
+function decodeDataURL(uri: string) {
+  return Effect.try({
+    try: () => {
+      const comma = uri.indexOf(",")
+      if (comma === -1) throw new Error("Invalid data URL")
+      const metadata = uri.slice(5, comma)
+      const payload = uri.slice(comma + 1)
+      if (!metadata.split(";").some((part) => part.toLowerCase() === "base64"))
+        return Buffer.from(decodeURIComponent(payload))
+      const bytes = Buffer.from(payload, "base64")
+      if (bytes.toString("base64") !== payload) throw new Error("Non-canonical base64")
+      return bytes
+    },
+    catch: () => new AttachmentError({ uri, message: "Invalid attachment data URL" }),
+  })
+}
+
+function positiveInt(value: string | null) {
+  if (value === null) return
+  const parsed = Number(value)
+  return Number.isInteger(parsed) && parsed > 0 ? parsed : undefined
+}

packages/core/src/session/revert-node.ts

@@ -0,0 +1,15 @@
+export * as SessionRevertNode from "./revert-node.js"
+
+import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
+import { Bus } from "../bus.js"
+import { Database } from "../database/database.js"
+import { PluginSupervisor } from "../plugin/supervisor.js"
+import { Snapshot } from "../snapshot.js"
+import { SessionRevert } from "./revert.js"
+
+// Keep the supervisor implementation out of the global Session import path.
+export const node = makeLocationNode({
+  service: SessionRevert.Service,
+  layer: SessionRevert.layer,
+  deps: [Database.node, Bus.node, PluginSupervisor.node, Snapshot.node],
+})

packages/core/src/session/revert.ts

@@ -1,28 +1,97 @@
 export * as SessionRevert from "./revert.js"
 
 import { and, asc, eq, gt } from "drizzle-orm"
-import { Effect, Schema } from "effect"
+import { Context, Effect, Layer, Schema } from "effect"
 import { Database } from "../database/database.js"
 import { Bus } from "../bus.js"
+import { PluginSupervisor } from "../plugin/supervisor-service.js"
 import { RelativePath } from "../schema.js"
 import { Snapshot } from "../snapshot.js"
 import { SessionEvent } from "./event.js"
+import { MessageNotFoundError } from "./error.js"
 import { SessionMessage } from "./message.js"
 import { SessionSchema } from "./schema.js"
 import { SessionMessageTable } from "./sql.js"
 
-export class MessageNotFoundError extends Schema.TaggedError<MessageNotFoundError>()("Session.MessageNotFoundError", {
-  sessionID: SessionSchema.ID,
-  messageID: SessionMessage.ID,
-}) {}
+export { MessageNotFoundError }
 
 interface BoundaryInput {
   readonly sessionID: SessionSchema.ID
   readonly messageID: SessionMessage.ID
 }
 
-const plan = Effect.fn("SessionRevert.plan")(function* (input: BoundaryInput) {
-  const db = (yield* Database.Service).db
+export interface Interface {
+  readonly stage: (input: {
+    readonly session: SessionSchema.Info
+    readonly messageID: SessionMessage.ID
+    readonly files?: boolean
+  }) => Effect.Effect<SessionSchema.Revert, MessageNotFoundError | Snapshot.Error>
+  readonly clear: (session: SessionSchema.Info) => Effect.Effect<void, Snapshot.Error>
+}
+
+export class Service extends Context.Service<Service, Interface>()("@opencode/SessionRevert") {}
+
+export const make = Effect.fn("SessionRevert.make")(function* () {
+  const database = yield* Database.Service
+  const bus = yield* Bus.Service
+  const plugins = yield* PluginSupervisor.Service
+  const snapshot = yield* Snapshot.Service
+
+  const stage: Interface["stage"] = Effect.fn("SessionRevert.stage")(function* (input) {
+    yield* plugins.flush
+    const original = input.session.revert?.snapshot
+      ? Snapshot.ID.make(input.session.revert.snapshot)
+      : yield* snapshot.capture()
+    const next = yield* plan(database.db, { sessionID: input.session.id, messageID: input.messageID })
+    const restore = new Map<RelativePath, Snapshot.ID>()
+    if (original) {
+      for (const file of input.session.revert?.files ?? []) restore.set(RelativePath.make(file.file), original)
+    }
+    if (input.files !== false) for (const [file, tree] of next) restore.set(file, tree)
+    if (restore.size) yield* snapshot.restore({ files: restore })
+    const paths = input.files === false ? [] : Array.from(next.keys())
+    const files = original
+      ? yield* snapshot.diff({ from: original, to: (yield* snapshot.capture()) ?? original, paths })
+      : []
+    const revert = {
+      messageID: input.messageID,
+      snapshot: original,
+      files,
+    } satisfies SessionSchema.Info["revert"]
+    yield* bus.publish(SessionEvent.RevertEvent.Staged, {
+      sessionID: input.session.id,
+      revert,
+    })
+    return revert
+  })
+
+  const clear: Interface["clear"] = Effect.fn("SessionRevert.clear")(function* (session) {
+    yield* plugins.flush
+    if (!session.revert) return
+    const original = session.revert.snapshot ? Snapshot.ID.make(session.revert.snapshot) : undefined
+    if (original)
+      yield* snapshot.restore({
+        files: new Map((session.revert.files ?? []).map((file) => [RelativePath.make(file.file), original])),
+      })
+    yield* bus.publish(SessionEvent.RevertEvent.Cleared, {
+      sessionID: session.id,
+    })
+  })
+
+  return { stage, clear }
+})
+
+export const layer = Layer.effect(Service, make())
+
+export const commit = Effect.fn("SessionRevert.commit")(function* (bus: Bus.Interface, session: SessionSchema.Info) {
+  if (!session.revert) return
+  yield* bus.publish(SessionEvent.RevertEvent.Committed, {
+    sessionID: session.id,
+    to: session.revert.messageID,
+  })
+})
+
+const plan = Effect.fn("SessionRevert.plan")(function* (db: Database.Interface["db"], input: BoundaryInput) {
   const boundary = yield* db
     .select({ seq: SessionMessageTable.seq })
     .from(SessionMessageTable)
@@ -53,59 +122,3 @@ const plan = Effect.fn("SessionRevert.plan")(function* (input: BoundaryInput) {
   }
   return files
 })
-
-export const stage = Effect.fn("SessionRevert.stage")(function* (input: {
-  readonly session: SessionSchema.Info
-  readonly messageID: SessionMessage.ID
-  readonly files?: boolean
-}) {
-  const snapshot = yield* Snapshot.Service
-  const bus = yield* Bus.Service
-  const original = input.session.revert?.snapshot
-    ? Snapshot.ID.make(input.session.revert.snapshot)
-    : yield* snapshot.capture()
-  const next = yield* plan({ sessionID: input.session.id, messageID: input.messageID })
-  const restore = new Map<RelativePath, Snapshot.ID>()
-  if (original) {
-    for (const file of input.session.revert?.files ?? []) restore.set(RelativePath.make(file.file), original)
-  }
-  if (input.files !== false) for (const [file, tree] of next) restore.set(file, tree)
-  if (restore.size) yield* snapshot.restore({ files: restore })
-  const paths = input.files === false ? [] : Array.from(next.keys())
-  const files = original
-    ? yield* snapshot.diff({ from: original, to: (yield* snapshot.capture()) ?? original, paths })
-    : []
-  const revert = {
-    messageID: input.messageID,
-    snapshot: original,
-    files,
-  } satisfies SessionSchema.Info["revert"]
-  yield* bus.publish(SessionEvent.RevertEvent.Staged, {
-    sessionID: input.session.id,
-    revert,
-  })
-  return revert
-})
-
-export const clear = Effect.fn("SessionRevert.clear")(function* (session: SessionSchema.Info) {
-  if (!session.revert) return
-  const snapshot = yield* Snapshot.Service
-  const original = session.revert.snapshot ? Snapshot.ID.make(session.revert.snapshot) : undefined
-  if (original)
-    yield* snapshot.restore({
-      files: new Map((session.revert.files ?? []).map((file) => [RelativePath.make(file.file), original])),
-    })
-  const bus = yield* Bus.Service
-  yield* bus.publish(SessionEvent.RevertEvent.Cleared, {
-    sessionID: session.id,
-  })
-})
-
-export const commit = Effect.fn("SessionRevert.commit")(function* (session: SessionSchema.Info) {
-  if (!session.revert) return
-  const bus = yield* Bus.Service
-  yield* bus.publish(SessionEvent.RevertEvent.Committed, {
-    sessionID: session.id,
-    to: session.revert.messageID,
-  })
-})

packages/core/src/session/run-coordinator.ts

@@ -7,6 +7,8 @@ import type { Promotable } from "./inbox.js"
 export interface Coordinator<Key, E, Reason = never> {
   /** Snapshots keys with an execution owned by this coordinator. */
   readonly active: Effect.Effect<ReadonlySet<Key>>
+  /** Checks ownership for one key, including cleanup and terminal settlement. */
+  readonly isActive: (key: Key) => Effect.Effect<boolean>
   /** Starts an execution while idle, or joins the active execution and returns its exit. */
   readonly run: (key: Key) => Effect.Effect<void, E>
   /** Rings the doorbell: an idle key starts an execution; an active one drains again before settling. */
@@ -112,6 +114,8 @@ export const make = <Key, E, Reason = never>(options: {
       Deferred.doneUnsafe(execution.done, exit)
     }
 
+    const isActive = (key: Key) => Effect.sync(() => executions.has(key))
+
     const run = (key: Key): Effect.Effect<void, E> =>
       Effect.suspend(() => {
         const execution = executions.get(key)
@@ -166,5 +170,5 @@ export const make = <Key, E, Reason = never>(options: {
         return Deferred.await(execution.done).pipe(Effect.ignoreCause, Effect.andThen(awaitIdle(key)))
       })
 
-    return { active: Effect.sync(() => new Set(executions.keys())), run, wake, interrupt, awaitIdle }
+    return { active: Effect.sync(() => new Set(executions.keys())), isActive, run, wake, interrupt, awaitIdle }
   })

packages/core/src/session/runner/to-llm-message.ts

@@ -260,6 +260,8 @@ function toLLMMessage(message: SessionMessage.Info, model: Model.Ref, providerMe
     case "system":
       return [Message.system(message.text)]
     case "shell":
+      // Background shell results enter context once, through their completion inbox item.
+      if (message.metadata?.background === true) return []
       return [
         Message.make({
           id: message.id,

packages/core/src/session/session.ts

@@ -0,0 +1,416 @@
+export * as Session from "./session.js"
+
+import { DateTime, Effect, Fiber, Layer, Schema, Scope } from "effect"
+import type { Agent } from "@opencode-ai/schema/agent"
+import type { Model } from "@opencode-ai/schema/model"
+import { Event } from "@opencode-ai/schema/event"
+import { Bus } from "../bus.js"
+import { Location } from "../location.js"
+import { PluginSupervisor } from "../plugin/supervisor-service.js"
+import { Shell } from "../shell.js"
+import { ShellResult } from "../shell/result.js"
+import {
+  BusyError,
+  CompactionConflictError,
+  InboxConflictError,
+  MessageIncompleteError,
+  MessageNotAssistantError,
+  MessageNotFoundError,
+  MessageToolIncompleteError,
+  NotFoundError,
+  PromptConflictError,
+  SyntheticConflictError,
+} from "./error.js"
+import { SessionEvent } from "./event.js"
+import { SessionExecution } from "./execution.js"
+import { SessionInbox } from "./inbox.js"
+import { SessionMessage } from "./message.js"
+import { SessionPrompt } from "./prompt.js"
+import { SessionRevert } from "./revert.js"
+import { SessionSchema } from "./schema.js"
+import { SessionStore } from "./store.js"
+
+export type Services = PluginSupervisor.Service | SessionPrompt.Service | SessionRevert.Service | Shell.Service
+
+type PromptRequest = SessionPrompt.Input & {
+  id?: SessionMessage.ID
+  resume?: boolean
+}
+
+/**
+ * Build once in the host Scope: `const sessions = yield* Session.make(servicesFor)`.
+ * Use `sessions.forSession(id)` for handles that share host services and reload current state.
+ */
+export const make = Effect.fn("Session.make")(function* (servicesFor: (ref: Location.Ref) => Layer.Layer<Services>) {
+  const bus = yield* Bus.Service
+  const store = yield* SessionStore.Service
+  const execution = yield* SessionExecution.Service
+  const admission = yield* SessionInbox.Service
+  const scope = yield* Scope.Scope
+
+  const get = Effect.fn("Session.get")(function* (sessionID: SessionSchema.ID) {
+    const session = yield* store.get(sessionID)
+    if (!session) return yield* new NotFoundError({ sessionID })
+    return session
+  })
+  const message = Effect.fn("Session.message")(function* (sessionID: SessionSchema.ID, messageID: SessionMessage.ID) {
+    const stored = yield* store.message(messageID)
+    return stored?.sessionID === sessionID ? stored.message : undefined
+  })
+  const updateMessage = Effect.fn("Session.updateMessage")(function* (
+    sessionID: SessionSchema.ID,
+    input: { readonly messageID: SessionMessage.ID; readonly content: readonly SessionMessage.AssistantContent[] },
+  ) {
+    const ref = { sessionID, messageID: input.messageID }
+    yield* get(sessionID)
+    if (yield* execution.isActive(sessionID)) return yield* new BusyError({ sessionID })
+    const current = yield* message(sessionID, input.messageID)
+    if (!current) return yield* new MessageNotFoundError(ref)
+    if (current.type !== "assistant") return yield* new MessageNotAssistantError(ref)
+    if (!current.time.completed) return yield* new MessageIncompleteError(ref)
+    if (input.content.some(isUnfinishedTool)) return yield* new MessageToolIncompleteError(ref)
+    yield* bus.publish(SessionEvent.MessageContentUpdated, {
+      ...ref,
+      content: Schema.encodeSync(Schema.Array(SessionMessage.AssistantContent))(input.content),
+    })
+    const updated = yield* message(sessionID, input.messageID)
+    if (updated?.type !== "assistant") return yield* new MessageNotFoundError(ref)
+    return updated
+  })
+  const view = Effect.fn("Session.view")(function* (sessionID: SessionSchema.ID, input: { idle: number }) {
+    const session = yield* get(sessionID)
+    if (
+      session.time.idle === undefined ||
+      input.idle > DateTime.toEpochMillis(session.time.idle) ||
+      (session.time.viewed !== undefined && DateTime.toEpochMillis(session.time.viewed) >= input.idle)
+    )
+      return
+    yield* bus.publish(SessionEvent.Viewed, { sessionID, idle: input.idle })
+  })
+  const rename = Effect.fn("Session.rename")(function* (sessionID: SessionSchema.ID, input: { title: string }) {
+    yield* get(sessionID)
+    yield* bus.publish(SessionEvent.Renamed, { sessionID, title: input.title })
+  })
+  const switchAgent = Effect.fn("Session.switchAgent")(function* (
+    sessionID: SessionSchema.ID,
+    input: { agent: Agent.ID },
+  ) {
+    const session = yield* get(sessionID)
+    yield* bus.publish(SessionEvent.AgentSelected, { sessionID, agent: input.agent, previous: session.agent })
+  })
+  const switchModel = Effect.fn("Session.switchModel")(function* (
+    sessionID: SessionSchema.ID,
+    input: { model: Model.Ref },
+  ) {
+    const session = yield* get(sessionID)
+    if (
+      session.model?.providerID === input.model.providerID &&
+      session.model.id === input.model.id &&
+      (session.model.variant ?? "default") === (input.model.variant ?? "default")
+    )
+      return
+    yield* bus.publish(SessionEvent.ModelSelected, { sessionID, model: input.model, previous: session.model })
+  })
+  const mutatePending = (
+    sessionID: SessionSchema.ID,
+    inboxID: SessionMessage.ID,
+    mutation: (input: {
+      readonly id: SessionMessage.ID
+      readonly sessionID: SessionSchema.ID
+    }) => Effect.Effect<void, SessionInbox.LifecycleConflict>,
+  ) =>
+    mutation({ sessionID, id: inboxID }).pipe(
+      Effect.catchTag("SessionInbox.LifecycleConflict", () =>
+        Effect.gen(function* () {
+          yield* get(sessionID)
+          return yield* new InboxConflictError({ sessionID, inboxID })
+        }),
+      ),
+    )
+
+  const inbox = Effect.fn("Session.inbox")(function* (sessionID: SessionSchema.ID) {
+    yield* get(sessionID)
+    return yield* admission.list(sessionID)
+  })
+  const cancelInbox = Effect.fn("Session.cancelInbox")(
+    (sessionID: SessionSchema.ID, inboxID: SessionMessage.ID) => mutatePending(sessionID, inboxID, admission.cancel),
+    Effect.uninterruptible,
+  )
+  const steerInbox = Effect.fn("Session.steerInbox")(function* (
+    sessionID: SessionSchema.ID,
+    inboxID: SessionMessage.ID,
+  ) {
+    yield* mutatePending(sessionID, inboxID, admission.steer)
+    yield* execution.wake(sessionID)
+  }, Effect.uninterruptible)
+  const queueInbox = Effect.fn("Session.queueInbox")(
+    (sessionID: SessionSchema.ID, inboxID: SessionMessage.ID) => mutatePending(sessionID, inboxID, admission.queue),
+    Effect.uninterruptible,
+  )
+  const prompt = Effect.fn("Session.prompt")((sessionID: SessionSchema.ID, input: PromptRequest) =>
+    Effect.uninterruptibleMask((restore) =>
+      Effect.gen(function* () {
+        const session = yield* get(sessionID)
+        const messageID = input.id ?? SessionMessage.ID.create()
+        const admitted = yield* Effect.gen(function* () {
+          const existing = yield* admission.reconcile({
+            id: messageID,
+            sessionID: session.id,
+            type: "user",
+            delivery: input.delivery ?? "steer",
+          })
+          if (existing) return existing
+          const item = yield* restore(
+            SessionPrompt.Service.use((preparation) => preparation.prepare({ sessionID, messageID, input })).pipe(
+              Effect.provide(servicesFor(session.location)),
+            ),
+          )
+          // Commit a staged revert only after preparation succeeds, before admitting new work.
+          if (session.revert) yield* SessionRevert.commit(bus, session)
+          return yield* admission.admit({
+            id: messageID,
+            sessionID: session.id,
+            item,
+          })
+        }).pipe(
+          Effect.catchTag("SessionInbox.LifecycleConflict", () => new PromptConflictError({ sessionID, messageID })),
+        )
+        if (input.resume !== false) yield* execution.wake(sessionID)
+        return admitted
+      }),
+    ),
+  )
+  const shell = Effect.fn("Session.shell")(function* (
+    sessionID: SessionSchema.ID,
+    input: { id?: Event.ID; command: string },
+  ) {
+    const session = yield* get(sessionID)
+    // The server owns completion recording even if the submitting client disconnects.
+    const running = yield* Effect.gen(function* () {
+      // Resolve shell services here without pinning Session events to this Location after a move.
+      const shell = yield* Effect.gen(function* () {
+        const plugins = yield* PluginSupervisor.Service
+        yield* plugins.flush
+        return yield* Shell.Service
+      }).pipe(Effect.provide(servicesFor(session.location)))
+      const started = yield* shell
+        .create({
+          command: input.command,
+          cwd: session.location.directory,
+          timeout: 0,
+          metadata: { sessionID, background: true },
+        })
+        .pipe(
+          Effect.tapError((error) =>
+            synthetic(sessionID, {
+              text: `User shell command failed to start:\n${input.command}\n\n${error.message}`,
+              description: input.command,
+              metadata: { source: "shell", state: "error" },
+              resume: false,
+            }),
+          ),
+          Effect.orDie,
+        )
+      yield* bus.publish(
+        SessionEvent.Shell.Started,
+        {
+          sessionID,
+          shell: started,
+        },
+        { id: input.id },
+      )
+      const terminal = yield* shell.result(started)
+      const preview = yield* shell
+        .output(started.id, { limit: SHELL_MAX_CAPTURE_BYTES })
+        .pipe(Effect.catchTag("Shell.NotFoundError", () => Effect.succeed(ShellResult.unavailable)))
+      yield* bus.publish(SessionEvent.Shell.Ended, {
+        sessionID,
+        shell: terminal.info,
+        output: preview,
+      })
+      yield* synthetic(sessionID, {
+        ...ShellResult.userNotification(terminal),
+        resume: false,
+      }).pipe(
+        Effect.catchTag("Session.NotFoundError", () => Effect.void),
+        Effect.orDie,
+      )
+    }).pipe(Effect.forkIn(scope, { startImmediately: true }))
+    yield* Fiber.join(running)
+  })
+  const compact = Effect.fn("Session.compact")(function* (
+    sessionID: SessionSchema.ID,
+    input: { id?: SessionMessage.ID; delivery?: SessionInbox.Delivery },
+  ) {
+    yield* get(sessionID)
+    const inputID = input.id ?? SessionMessage.ID.create()
+    const admitted = yield* admission
+      .admitCompaction({
+        id: inputID,
+        sessionID,
+        delivery: input.delivery ?? "steer",
+      })
+      .pipe(
+        Effect.catchTag("SessionInbox.LifecycleConflict", () => new CompactionConflictError({ sessionID, inputID })),
+      )
+    yield* execution.wake(sessionID)
+    return admitted
+  })
+  const wait = Effect.fn("Session.wait")(function* (sessionID: SessionSchema.ID) {
+    yield* get(sessionID)
+    yield* execution.awaitIdle(sessionID)
+  })
+  const resume = Effect.fn("Session.resume")(function* (sessionID: SessionSchema.ID) {
+    yield* get(sessionID)
+    yield* execution.resume(sessionID)
+  })
+  const synthetic = Effect.fn("Session.synthetic")(
+    (
+      sessionID: SessionSchema.ID,
+      input: {
+        id?: SessionMessage.ID
+        text: string
+        description?: string
+        metadata?: Record<string, unknown>
+        delivery?: SessionInbox.Delivery
+        resume?: boolean
+      },
+    ) =>
+      Effect.uninterruptible(
+        Effect.gen(function* () {
+          yield* get(sessionID)
+          const inputID = input.id ?? SessionMessage.ID.create()
+          const admittedInput = {
+            type: "synthetic",
+            payload: SessionInbox.SyntheticPayload.make({
+              text: input.text,
+              description: input.description,
+              metadata: input.metadata,
+            }),
+            delivery: SessionInbox.Delivery.make(input.delivery ?? "steer"),
+          } satisfies SessionInbox.Item
+          const admitted = yield* admission
+            .admit({
+              id: inputID,
+              sessionID,
+              item: admittedInput,
+            })
+            .pipe(
+              Effect.catchTag(
+                "SessionInbox.LifecycleConflict",
+                () => new SyntheticConflictError({ sessionID, inputID }),
+              ),
+            )
+          if (input.resume !== false && !(yield* get(sessionID)).revert) yield* execution.wake(sessionID)
+          return admitted
+        }),
+      ),
+  )
+  const interrupt = Effect.fn("Session.interrupt")(
+    (sessionID: SessionSchema.ID, options?: { readonly continue?: boolean }) =>
+      Effect.uninterruptible(execution.interrupt(sessionID, options)),
+  )
+  const stage = Effect.fn("Session.revert.stage")(function* (
+    sessionID: SessionSchema.ID,
+    input: { messageID: SessionMessage.ID; files?: boolean },
+  ) {
+    const session = yield* get(sessionID)
+    if (yield* execution.isActive(sessionID)) return yield* new BusyError({ sessionID })
+    return yield* SessionRevert.Service.use((revert) =>
+      revert.stage({ session, messageID: input.messageID, files: input.files }),
+    ).pipe(Effect.provide(servicesFor(session.location)))
+  })
+  const clear = Effect.fn("Session.revert.clear")(function* (sessionID: SessionSchema.ID) {
+    const session = yield* get(sessionID)
+    if (yield* execution.isActive(sessionID)) return yield* new BusyError({ sessionID })
+    yield* SessionRevert.Service.use((revert) => revert.clear(session)).pipe(
+      Effect.provide(servicesFor(session.location)),
+    )
+    return yield* execution.wake(sessionID)
+  })
+  const commit = Effect.fn("Session.revert.commit")(function* (sessionID: SessionSchema.ID) {
+    const session = yield* get(sessionID)
+    if (yield* execution.isActive(sessionID)) return yield* new BusyError({ sessionID })
+    return yield* SessionRevert.commit(bus, session)
+  })
+  const revert = { stage, clear, commit }
+  const operations = {
+    get,
+    message,
+    updateMessage,
+    view,
+    rename,
+    switchAgent,
+    switchModel,
+    inbox,
+    prompt,
+    synthetic,
+    shell,
+    compact,
+    wait,
+    resume,
+    interrupt,
+    cancelInbox,
+    steerInbox,
+    queueInbox,
+    revert,
+  }
+
+  const forSession = (sessionID: SessionSchema.ID) => {
+    const get = operations.get.bind(undefined, sessionID)
+    const message = operations.message.bind(undefined, sessionID)
+    const updateMessage = operations.updateMessage.bind(undefined, sessionID)
+    const view = operations.view.bind(undefined, sessionID)
+    const rename = operations.rename.bind(undefined, sessionID)
+    const switchAgent = operations.switchAgent.bind(undefined, sessionID)
+    const switchModel = operations.switchModel.bind(undefined, sessionID)
+    const inbox = operations.inbox.bind(undefined, sessionID)
+    const prompt = operations.prompt.bind(undefined, sessionID)
+    const synthetic = operations.synthetic.bind(undefined, sessionID)
+    const shell = operations.shell.bind(undefined, sessionID)
+    const compact = operations.compact.bind(undefined, sessionID)
+    const wait = operations.wait.bind(undefined, sessionID)
+    const resume = operations.resume.bind(undefined, sessionID)
+    const interrupt = operations.interrupt.bind(undefined, sessionID)
+    const cancelInbox = operations.cancelInbox.bind(undefined, sessionID)
+    const steerInbox = operations.steerInbox.bind(undefined, sessionID)
+    const queueInbox = operations.queueInbox.bind(undefined, sessionID)
+    const stage = operations.revert.stage.bind(undefined, sessionID)
+    const clear = operations.revert.clear.bind(undefined, sessionID)
+    const commit = operations.revert.commit.bind(undefined, sessionID)
+    const revert = { stage, clear, commit }
+
+    return {
+      id: sessionID,
+      get,
+      message,
+      updateMessage,
+      view,
+      rename,
+      switchAgent,
+      switchModel,
+      inbox,
+      prompt,
+      synthetic,
+      shell,
+      compact,
+      wait,
+      resume,
+      interrupt,
+      cancelInbox,
+      steerInbox,
+      queueInbox,
+      revert,
+    }
+  }
+  return { forSession }
+})
+
+export type Handle = ReturnType<Effect.Success<ReturnType<typeof make>>["forSession"]>
+
+function isUnfinishedTool(content: SessionMessage.AssistantContent) {
+  return content.type === "tool" && (content.state.status === "streaming" || content.state.status === "running")
+}
+
+// Mirrors the shell tool's in-memory preview safety limit.
+const SHELL_MAX_CAPTURE_BYTES = 1024 * 1024

packages/core/src/session/store.ts

@@ -1,7 +1,10 @@
 export * as SessionStore from "./store.js"
 
-import { and, eq, isNotNull, isNull, notInArray, sql } from "drizzle-orm"
-import { Context, Effect, Layer } from "effect"
+import { and, asc, desc, eq, gt, isNotNull, isNull, like, lt, notInArray, or, sql, type SQL } from "drizzle-orm"
+import { Context, Effect, Layer, Schema } from "effect"
+import { Project } from "@opencode-ai/schema/project"
+import { Workspace } from "@opencode-ai/schema/workspace"
+import { AbsolutePath, PositiveInt, RelativePath } from "@opencode-ai/schema/schema"
 import { Database } from "../database/database.js"
 import { makeGlobalNode } from "@opencode-ai/util/effect/app-node"
 import { SessionHistory } from "./history.js"
@@ -11,8 +14,45 @@ import { Session } from "@opencode-ai/schema/session"
 import { SessionMessageTable, SessionTable } from "./sql.js"
 import { fromRow } from "./info.js"
 
+const ListInputBase = {
+  workspaceID: Workspace.ID.pipe(Schema.optional),
+  search: Schema.String.pipe(Schema.optional),
+  limit: PositiveInt.pipe(Schema.optional),
+  order: Schema.Literals(["asc", "desc"]).pipe(Schema.optional),
+  parentID: Schema.NullOr(Session.ID).pipe(Schema.optional),
+  anchor: Session.ListAnchor.pipe(Schema.optional),
+}
+
+const ListDirectoryInput = Schema.Struct({
+  ...ListInputBase,
+  directory: AbsolutePath,
+})
+
+const ListProjectInput = Schema.Struct({
+  ...ListInputBase,
+  project: Project.ID,
+  subpath: RelativePath.pipe(Schema.optional),
+})
+
+const ListAllInput = Schema.Struct(ListInputBase)
+
+export const ListInput = Schema.Union([ListDirectoryInput, ListProjectInput, ListAllInput])
+export type ListInput = typeof ListInput.Type
+
+export type MessagesInput = {
+  sessionID: Session.ID
+  limit?: number
+  order?: "asc" | "desc"
+  cursor?: {
+    id: SessionMessage.ID
+    direction: "previous" | "next"
+  }
+}
+
 export interface Interface {
   readonly get: (sessionID: Session.ID) => Effect.Effect<Session.Info | undefined>
+  readonly list: (input?: ListInput) => Effect.Effect<Session.Info[]>
+  readonly messages: (input: MessagesInput) => Effect.Effect<SessionMessage.Info[], MessageDecodeError>
   readonly context: (sessionID: Session.ID) => Effect.Effect<SessionMessage.Info[], MessageDecodeError>
   readonly message: (
     messageID: SessionMessage.ID,
@@ -55,6 +95,83 @@ const layer = Layer.effect(
         const row = yield* db.select().from(SessionTable).where(eq(SessionTable.id, sessionID)).get().pipe(Effect.orDie)
         return row ? fromRow(row) : undefined
       }),
+      list: Effect.fn("SessionStore.list")(function* (input = {}) {
+        const direction = input.anchor?.direction ?? "next"
+        const requestedOrder = input.order ?? "desc"
+        const order = direction === "previous" ? (requestedOrder === "asc" ? "desc" : "asc") : requestedOrder
+        const sortColumn = SessionTable.time_updated
+        const conditions: SQL[] = []
+        if ("directory" in input) conditions.push(eq(SessionTable.directory, input.directory))
+        if (input.workspaceID) conditions.push(eq(SessionTable.workspace_id, input.workspaceID))
+        if ("project" in input) conditions.push(eq(SessionTable.project_id, input.project))
+        if ("project" in input && input.subpath !== undefined) conditions.push(eq(SessionTable.path, input.subpath))
+        if (input.search) conditions.push(like(SessionTable.title, `%${input.search}%`))
+        if (input.parentID !== undefined)
+          conditions.push(
+            input.parentID === null ? isNull(SessionTable.parent_id) : eq(SessionTable.parent_id, input.parentID),
+          )
+        if (input.anchor) {
+          conditions.push(
+            order === "asc"
+              ? or(
+                  gt(sortColumn, input.anchor.time),
+                  and(eq(sortColumn, input.anchor.time), gt(SessionTable.id, input.anchor.id)),
+                )!
+              : or(
+                  lt(sortColumn, input.anchor.time),
+                  and(eq(sortColumn, input.anchor.time), lt(SessionTable.id, input.anchor.id)),
+                )!,
+          )
+        }
+        const query = db
+          .select()
+          .from(SessionTable)
+          .where(conditions.length > 0 ? and(...conditions) : undefined)
+          .orderBy(
+            order === "asc" ? asc(sortColumn) : desc(sortColumn),
+            order === "asc" ? asc(SessionTable.id) : desc(SessionTable.id),
+          )
+        const rows = yield* (input.limit === undefined ? query.all() : query.limit(input.limit).all()).pipe(
+          Effect.orDie,
+        )
+        return (direction === "previous" ? rows.toReversed() : rows).map((row) => fromRow(row))
+      }),
+      messages: Effect.fn("SessionStore.messages")(function* (input) {
+        const direction = input.cursor?.direction ?? "next"
+        const requestedOrder = input.order ?? "desc"
+        const order = direction === "previous" ? (requestedOrder === "asc" ? "desc" : "asc") : requestedOrder
+        const anchor = input.cursor
+          ? yield* db
+              .select({ seq: SessionMessageTable.seq })
+              .from(SessionMessageTable)
+              .where(
+                and(eq(SessionMessageTable.session_id, input.sessionID), eq(SessionMessageTable.id, input.cursor.id)),
+              )
+              .get()
+              .pipe(Effect.orDie)
+          : undefined
+        if (input.cursor && !anchor) return []
+        const boundary = anchor
+          ? order === "asc"
+            ? gt(SessionMessageTable.seq, anchor.seq)
+            : lt(SessionMessageTable.seq, anchor.seq)
+          : undefined
+        const where = boundary
+          ? and(eq(SessionMessageTable.session_id, input.sessionID), boundary)
+          : eq(SessionMessageTable.session_id, input.sessionID)
+        const query = db
+          .select()
+          .from(SessionMessageTable)
+          .where(where)
+          .orderBy(order === "asc" ? asc(SessionMessageTable.seq) : desc(SessionMessageTable.seq))
+        const rows = yield* (input.limit === undefined ? query.all() : query.limit(input.limit).all()).pipe(
+          Effect.orDie,
+        )
+        return yield* Effect.forEach(
+          direction === "previous" ? rows.toReversed() : rows,
+          SessionHistory.decodeMessageRow,
+        )
+      }),
       context: Effect.fn("SessionStore.context")((sessionID) => SessionHistory.load(db, sessionID)),
       message: Effect.fn("SessionStore.message")(function* (messageID) {
         const row = yield* db

packages/core/src/shell.ts

@@ -18,6 +18,9 @@ import type { ShellCreateBefore } from "@opencode-ai/plugin/effect/shell"
 import { PluginHooks } from "./plugin/hooks.js"
 import { SessionEnvironment } from "./session/environment.js"
 import { SessionSchema } from "./session/schema.js"
+import { Config } from "./config.js"
+import { ToolOutput } from "./tool-output.js"
+import { ShellResult } from "./shell/result.js"
 
 export class NotFoundError extends Schema.TaggedError<NotFoundError>()("Shell.NotFoundError", {
   id: Shell.ID,
@@ -65,6 +68,8 @@ export interface Interface {
   // Resolves once the command reaches a terminal status, returning its final Info. Fails with
   // NotFoundError if the command is unknown or is removed before it terminates.
   readonly wait: (id: Shell.ID) => Effect.Effect<Shell.Info, NotFoundError>
+  // A known shell's terminal state and bounded tail. Missing capture remains distinct from its exit status.
+  readonly result: (started: Shell.Info) => Effect.Effect<ShellResult.Result>
   // Replaces the running command's timeout from now; zero clears it.
   readonly timeout: (id: Shell.ID, duration: number) => Effect.Effect<Shell.Info, NotFoundError>
   readonly output: (id: Shell.ID, input?: Shell.OutputInput) => Effect.Effect<Shell.Output, NotFoundError>
@@ -120,6 +125,7 @@ const layer = () =>
       const environment = yield* Environment.Service
       const hooks = yield* PluginHooks.Service
       const environments = yield* SessionEnvironment.Service
+      const config = yield* Config.Service
       const context = yield* Effect.context()
       const runFork = Effect.runForkWith(context)
       const commands = new Map<Shell.ID, Active>()
@@ -217,6 +223,28 @@ const layer = () =>
         }
       })
 
+      const result = Effect.fn("Shell.result")(function* (started: Shell.Info) {
+        const info = yield* wait(started.id).pipe(
+          Effect.catchTag("Shell.NotFoundError", () =>
+            Effect.succeed({ ...started, status: "killed" as const, time: { ...started.time, completed: Date.now() } }),
+          ),
+        )
+        const capture = yield* Effect.gen(function* () {
+          const limits = Config.latest(yield* config.entries(), "tool_output")
+          const maxLines = limits?.max_lines ?? ToolOutput.MAX_LINES
+          const maxBytes = limits?.max_bytes ?? ToolOutput.MAX_BYTES
+          const latest = yield* output(info.id, { cursor: Number.MAX_SAFE_INTEGER })
+          const page = yield* output(info.id, { cursor: Math.max(0, latest.size - maxBytes), limit: maxBytes })
+          const lines = page.output.split("\n")
+          if (page.output.endsWith("\n")) lines.pop()
+          const truncated = latest.size > maxBytes || lines.length > maxLines
+          const text = lines.length > maxLines ? lines.slice(-maxLines).join("\n") : page.output
+          const notice = truncated ? `\n\n[output truncated; full output saved to: ${info.file}]` : ""
+          return { output: `${text || "(no output)"}${notice}`, truncated }
+        }).pipe(Effect.catchTag("Shell.NotFoundError", () => Effect.succeed(undefined)))
+        return { info, capture }
+      })
+
       const create = Effect.fn("Shell.create")(function* <E = never, R = never>(
         input: CreateInput,
         before?: (input: ShellCreateBefore) => Effect.Effect<void, E, R>,
@@ -341,9 +369,11 @@ const layer = () =>
                     if (!oldest) break
                     yield* removeCommand(oldest)
                   }
-                  // Cancel a pending timeout once the command exits on its own. Interrupting last avoids
-                  // aborting finish when finish itself runs on the timeout fiber.
-                  if (command.timeoutFiber) yield* Fiber.interrupt(command.timeoutFiber)
+                  // Keep exited history data-only. Interrupt last because finish may run on the timeout fiber.
+                  const timeoutFiber = command.timeoutFiber
+                  command.timeout = undefined
+                  command.timeoutFiber = undefined
+                  if (timeoutFiber) yield* Fiber.interrupt(timeoutFiber)
                 })
 
               command.timeout = (duration) =>
@@ -382,7 +412,7 @@ const layer = () =>
         return command.info
       })
 
-      return Service.of({ create, list, get, wait, timeout, output, remove })
+      return Service.of({ create, list, get, wait, result, timeout, output, remove })
     }),
   )
 
@@ -397,6 +427,7 @@ export const node = makeLocationNode({
     Environment.node,
     PluginHooks.node,
     SessionEnvironment.node,
+    Config.node,
     cleanupNode,
   ],
 })

packages/core/src/shell/result.ts

@@ -0,0 +1,74 @@
+export * as ShellResult from "./result.js"
+
+import type { Shell } from "@opencode-ai/schema/shell"
+
+export type Result = {
+  info: Shell.Info
+  capture: { output: string; truncated: boolean } | undefined
+}
+
+type Output = { output: string; truncated: boolean; exit?: number; timeout?: boolean }
+
+const missing = "Shell command output is no longer available."
+export const unavailable: Shell.Output = {
+  output: missing,
+  cursor: Buffer.byteLength(missing),
+  size: Buffer.byteLength(missing),
+  truncated: false,
+}
+
+export function output(result: Result): Output {
+  return {
+    output: result.capture?.output ?? unavailable.output,
+    truncated: result.capture?.truncated ?? false,
+    ...(result.info.exit !== undefined ? { exit: result.info.exit } : {}),
+    ...(result.info.status === "timeout" ? { timeout: true } : {}),
+  }
+}
+
+export function notice(output: Pick<Output, "exit" | "timeout">) {
+  if (output.timeout) return "Command timed out before completion."
+  if (output.exit !== undefined) return `Command exited with code ${output.exit}.`
+}
+
+export function metadata(output: Output) {
+  return {
+    truncated: output.truncated,
+    ...(output.exit !== undefined ? { exit: output.exit } : {}),
+    ...(output.timeout !== undefined ? { timeout: output.timeout } : {}),
+  }
+}
+
+export function notification(input: {
+  shellID: string
+  jobID?: string
+  command: string
+  state: "completed" | "cancelled" | "error"
+  text: string
+  output?: Output
+}) {
+  return {
+    text: `<shell id="${input.jobID ?? input.shellID}" state="${input.state}" command="${input.command}">\n${input.text}\n</shell>`,
+    metadata: {
+      source: "shell",
+      shellID: input.shellID,
+      ...(input.jobID !== undefined ? { jobID: input.jobID } : {}),
+      state: input.state,
+      ...(input.output ? metadata(input.output) : {}),
+    },
+  }
+}
+
+export function userNotification(result: Result) {
+  const captured = output(result)
+  const status =
+    result.info.status === "killed" ? "Command cancelled." : (notice(captured) ?? "Command exited with code unknown.")
+  const message = notification({
+    shellID: result.info.id,
+    command: result.info.command,
+    state: result.info.status === "killed" ? "cancelled" : "completed",
+    text: `${captured.output}\n\n${status}`,
+    output: captured,
+  })
+  return { ...message, text: `The following shell command was executed by the user:\n${message.text}` }
+}

packages/core/src/tool/plugin/shell.ts

@@ -2,6 +2,8 @@ export * as ShellTool from "./shell.js"
 
 import { ToolFailure } from "@opencode-ai/ai"
 import type { Context } from "@opencode-ai/plugin/effect/plugin"
+import type { ShellCreateBefore } from "@opencode-ai/plugin/effect/shell"
+import type { Tool } from "@opencode-ai/schema/tool"
 import { Deferred, Effect, Schema, Scope } from "effect"
 import { Config } from "../../config.js"
 import { Environment } from "../../environment/index.js"
@@ -13,7 +15,7 @@ import { SessionSchema } from "../../session/schema.js"
 import { Shell } from "../../shell.js"
 import { ShellParse } from "../../shell/parse.js"
 import { ShellSelect } from "../../shell/select.js"
-import { ToolOutput } from "../../tool-output.js"
+import { ShellResult } from "../../shell/result.js"
 
 export const name = "shell"
 export const DEFAULT_TIMEOUT_MS = 2 * 60 * 1_000
@@ -71,11 +73,7 @@ const Output = Schema.Struct({
 type Output = typeof Output.Type
 
 const resultMessages = (output: Output) => {
-  const notice = (() => {
-    if (output.status === "running") return BACKGROUND_INSTRUCTION
-    if (output.timeout) return "Command timed out before completion."
-    if (output.exit !== undefined) return `Command exited with code ${output.exit}.`
-  })()
+  const notice = output.status === "running" ? BACKGROUND_INSTRUCTION : ShellResult.notice(output)
   return [output.output, ...(notice ? [notice] : [])]
 }
 
@@ -85,10 +83,8 @@ const toolResult = (output: Output) => {
     content: resultMessages(output).map((text) => ({ type: "text" as const, text })),
     metadata: {
       status: output.status,
-      truncated: output.truncated,
-      ...(output.exit !== undefined ? { exit: output.exit } : {}),
+      ...ShellResult.metadata(output),
       ...(output.shellID !== undefined ? { shellID: output.shellID } : {}),
-      ...(output.timeout !== undefined ? { timeout: output.timeout } : {}),
     },
   }
 }
@@ -113,6 +109,56 @@ export const Plugin = {
     const permission = yield* Permission.Service
     const config = yield* Config.Service
 
+    const prepare = Effect.fn("ShellTool.prepare")(function* (invocation: ShellCreateBefore, context: Tool.Context) {
+      const source = {
+        type: "tool" as const,
+        messageID: context.messageID,
+        id: context.id,
+      }
+      const target = yield* mutation.resolve({ path: invocation.cwd, kind: "directory" })
+      invocation.cwd = target.absolute
+      const timeout = invocation.timeout
+      const portable = Config.latest(yield* config.entries(), "experimental")?.portable_shell_scanner === true
+      const parsed = yield* ShellParse.scan(invocation.command, invocation.shell, target.absolute, { portable })
+      const directories = yield* Effect.forEach(parsed.directories, (directory) =>
+        mutation.resolve({
+          path: LocationMutation.resolvePath(target.absolute, directory),
+          kind: "directory",
+        }),
+      )
+      const external = [target, ...directories]
+        .map((item) => item.externalDirectory)
+        .filter((item) => item !== undefined)
+        .filter((item, index, items) => items.findIndex((other) => other.resource === item.resource) === index)
+      if (external.length > 0)
+        yield* permission.assert({
+          action: "external_directory",
+          resources: external.map((item) => item.resource),
+          save: external.map((item) => item.save),
+          sessionID: context.sessionID,
+          agent: context.agent,
+          source,
+        })
+      if (parsed.commands.length > 0)
+        yield* permission.assert({
+          action: name,
+          resources: parsed.commands.map((command) => command.resource),
+          save: parsed.commands.map((command) => command.save),
+          sessionID: context.sessionID,
+          agent: context.agent,
+          source,
+        })
+      // Approval can outlive the directory, so validate immediately before spawning.
+      const workdir = yield* Environment.typeFollowing(environment.files, target.absolute).pipe(
+        Effect.catchTag("Environment.NotFound", () =>
+          Effect.fail(new Error(`Working directory does not exist: ${target.absolute}`)),
+        ),
+      )
+      if (workdir !== "directory")
+        return yield* Effect.fail(new Error(`Working directory is not a directory: ${target.absolute}`))
+      return timeout
+    })
+
     const notifyWhenDone = Effect.fn("ShellTool.notifyWhenDone")(
       function* (
         sessionID: SessionSchema.ID,
@@ -132,21 +178,15 @@ export const Plugin = {
         yield* runtime.session.synthetic({
           ...(info.notificationID ? { id: info.notificationID } : {}),
           sessionID,
-          text: `<shell id="${id}" state="${info.status}" command="${command}">\n${text}\n</shell>`,
           description: command,
-          metadata: {
-            source: "shell",
+          ...ShellResult.notification({
             jobID: id,
             shellID,
+            command,
             state: info.status,
-            ...(output
-              ? {
-                  truncated: output.truncated,
-                  ...(output.exit !== undefined ? { exit: output.exit } : {}),
-                  ...(output.timeout !== undefined ? { timeout: output.timeout } : {}),
-                }
-              : {}),
-          },
+            text,
+            output,
+          }),
         })
         if (info.notificationID) yield* runtime.job.completeBackground(info.notificationID)
       },
@@ -163,11 +203,6 @@ export const Plugin = {
           output: Output,
           execute: (input, context) =>
             Effect.gen(function* () {
-              const source = {
-                type: "tool" as const,
-                messageID: context.messageID,
-                id: context.id,
-              }
               const timeout = input.background === true ? (input.timeout ?? 0) : (input.timeout ?? DEFAULT_TIMEOUT_MS)
               let finalTimeout = timeout
               const info = yield* shell.create(
@@ -180,101 +215,24 @@ export const Plugin = {
                 },
                 (invocation) =>
                   Effect.gen(function* () {
-                    const target = yield* mutation.resolve({ path: invocation.cwd, kind: "directory" })
-                    invocation.cwd = target.absolute
-                    finalTimeout = invocation.timeout
-                    const portable =
-                      Config.latest(yield* config.entries(), "experimental")?.portable_shell_scanner === true
-                    const parsed = yield* ShellParse.scan(invocation.command, invocation.shell, target.absolute, {
-                      portable,
-                    })
-                    const directories = yield* Effect.forEach(parsed.directories, (directory) =>
-                      mutation.resolve({
-                        path: LocationMutation.resolvePath(target.absolute, directory),
-                        kind: "directory",
-                      }),
-                    )
-                    const external = [target, ...directories]
-                      .map((item) => item.externalDirectory)
-                      .filter((item) => item !== undefined)
-                      .filter(
-                        (item, index, items) => items.findIndex((other) => other.resource === item.resource) === index,
-                      )
-                    if (external.length > 0)
-                      yield* permission.assert({
-                        action: "external_directory",
-                        resources: external.map((item) => item.resource),
-                        save: external.map((item) => item.save),
-                        sessionID: context.sessionID,
-                        agent: context.agent,
-                        source,
-                      })
-                    if (parsed.commands.length > 0)
-                      yield* permission.assert({
-                        action: name,
-                        resources: parsed.commands.map((command) => command.resource),
-                        save: parsed.commands.map((command) => command.save),
-                        sessionID: context.sessionID,
-                        agent: context.agent,
-                        source,
-                      })
-                    const workdir = yield* Environment.typeFollowing(environment.files, target.absolute).pipe(
-                      Effect.catchTag("Environment.NotFound", () =>
-                        Effect.fail(new Error(`Working directory does not exist: ${target.absolute}`)),
-                      ),
-                    )
-                    if (workdir !== "directory")
-                      return yield* Effect.fail(new Error(`Working directory is not a directory: ${target.absolute}`))
+                    finalTimeout = yield* prepare(invocation, context)
                   }),
               )
               yield* context.progress({ shellID: info.id })
 
-              const captureShell = Effect.fnUntraced(function* () {
-                const configured = Config.latest(yield* config.entries(), "tool_output")
-                const maxLines = configured?.max_lines ?? ToolOutput.MAX_LINES
-                const maxBytes = configured?.max_bytes ?? ToolOutput.MAX_BYTES
-                const latest = yield* shell.output(info.id, { cursor: Number.MAX_SAFE_INTEGER })
-                const page = yield* shell.output(info.id, {
-                  cursor: Math.max(0, latest.size - maxBytes),
-                  limit: maxBytes,
-                })
-                const lines = page.output.split("\n")
-                if (page.output.endsWith("\n")) lines.pop()
-                const truncated = latest.size > maxBytes || lines.length > maxLines
-                const output = lines.length > maxLines ? lines.slice(-maxLines).join("\n") : page.output
-                const notice = truncated ? `\n\n[output truncated; full output saved to: ${info.file}]` : ""
+              const settled = yield* Deferred.make<Output>()
+              const run = Effect.gen(function* () {
+                const result = yield* shell.result(info)
+                if (!result.capture) return yield* new Shell.NotFoundError({ id: info.id })
+                const output = ShellResult.output(result)
                 return {
-                  output: `${output || "(no output)"}${notice}`,
-                  truncated,
-                }
-              })
-
-              const settleShell = Effect.fnUntraced(function* () {
-                const final = yield* shell.wait(info.id)
-                const capture = yield* captureShell()
-
-                // `exit` is optionalKey in the Output schema; a present-but-undefined key
-                // fails output encoding, so omit it when the process has no exit code.
-                if (final.status === "timeout") {
-                  return {
-                    ...(final.exit !== undefined ? { exit: final.exit } : {}),
-                    output: `${capture.output}\n\nCommand exceeded timeout of ${finalTimeout} ms. Retry with a larger timeout if the command is expected to take longer.`,
-                    truncated: capture.truncated,
-                    timeout: true,
-                    status: "completed" as const,
-                  }
-                }
-
-                return {
-                  ...(final.exit !== undefined ? { exit: final.exit } : {}),
-                  output: capture.output,
-                  truncated: capture.truncated,
+                  ...output,
+                  output: output.timeout
+                    ? `${output.output}\n\nCommand exceeded timeout of ${finalTimeout} ms. Retry with a larger timeout if the command is expected to take longer.`
+                    : output.output,
                   status: "completed" as const,
                 }
-              })
-
-              const settled = yield* Deferred.make<Output>()
-              const run = settleShell().pipe(
+              }).pipe(
                 Effect.tap((output) => Deferred.succeed(settled, output)),
                 Effect.map((output) => resultMessages(output).join("\n\n")),
                 Effect.onInterrupt(() => shell.remove(info.id).pipe(Effect.ignore)),

packages/core/src/vcs.ts

@@ -5,7 +5,7 @@ import { Cause, Context, Effect, Layer, Schema, Stream } from "effect"
 import type { VcsDefinition, VcsDraft } from "@opencode-ai/plugin/effect/vcs"
 import { FileDiff } from "@opencode-ai/schema/file-diff"
 import { FileSystem } from "@opencode-ai/schema/filesystem"
-import { BranchList, FileStatus, Info, Mode } from "@opencode-ai/schema/vcs"
+import { Base, BranchList, FileStatus, Info, Mode } from "@opencode-ai/schema/vcs"
 import { VcsEvent } from "@opencode-ai/schema/vcs-event"
 import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
 import { FSUtil } from "@opencode-ai/util/fs-util"
@@ -14,10 +14,15 @@ import { Bus } from "./bus.js"
 import { State } from "./state.js"
 import { emptyPatch, MAX_TOTAL_PATCH_BYTES, PATCH_CONTEXT_LINES } from "./vcs/patch.js"
 
-export { BranchList, FileStatus, Info, Mode }
+export { Base, BranchList, FileStatus, Info, Mode }
+
+export class DiffError extends Schema.TaggedError<DiffError>()("Vcs.DiffError", {
+  message: Schema.String,
+}) {}
 
 export interface DiffOptions {
   readonly context?: number
+  readonly base?: string
 }
 
 export interface BranchOptions {
@@ -27,12 +32,15 @@ export interface BranchOptions {
 
 export interface Adapter {
   readonly info: () => Effect.Effect<Info>
+  readonly base?: () => Effect.Effect<Base | null, DiffError>
   readonly branches: (options?: BranchOptions) => Effect.Effect<BranchList>
   readonly status: () => Effect.Effect<FileStatus[]>
-  readonly diff: (mode: Mode, options?: DiffOptions) => Effect.Effect<FileDiff.Info[]>
+  readonly diff: (mode: Mode, options?: DiffOptions) => Effect.Effect<FileDiff.Info[], DiffError>
 }
 
-export interface Interface extends Adapter, State.Transformable<VcsDraft> {}
+export interface Interface extends Adapter, State.Transformable<VcsDraft> {
+  readonly base: () => Effect.Effect<Base | null, DiffError>
+}
 
 interface Data {
   readonly providers: Map<string, VcsDefinition>
@@ -56,6 +64,7 @@ const layer = Layer.effect(
       ...(vcs ? { store: vcs.store } : {}),
     }
     const decodeInfo = Schema.decodeUnknownEffect(Schema.toType(Info))
+    const decodeBase = Schema.decodeUnknownEffect(Schema.NullOr(Base))
     const decodeBranches = Schema.decodeUnknownEffect(BranchList)
     const decodeStatus = Schema.decodeUnknownEffect(Schema.Array(FileStatus))
     const decodeDiff = Schema.decodeUnknownEffect(Schema.Array(FileDiff.Info))
@@ -86,6 +95,27 @@ const layer = Layer.effect(
               ),
         ),
       )
+    const review = <A>(provider: VcsDefinition, operation: "base" | "diff", effect: Effect.Effect<A, unknown>) =>
+      effect.pipe(
+        Effect.catchCause((cause) => {
+          if (Cause.hasInterrupts(cause)) return Effect.failCause(cause).pipe(Effect.orDie)
+          const error = Cause.squash(cause)
+          return Effect.logWarning("vcs provider failed", { provider: provider.id, operation, cause }).pipe(
+            Effect.andThen(
+              Effect.fail(
+                error instanceof DiffError
+                  ? error
+                  : new DiffError({
+                      message:
+                        operation === "base"
+                          ? "VCS provider could not resolve a review base"
+                          : "VCS provider could not produce a diff",
+                    }),
+              ),
+            ),
+          )
+        }),
+      )
     const refresh = Effect.fn("Vcs.refresh")(function* () {
       const provider = selected()
       const next: Info = provider
@@ -117,6 +147,11 @@ const layer = Layer.effect(
       info: Effect.fn("Vcs.info")(function* () {
         return current.info
       }),
+      base: Effect.fn("Vcs.base")(function* () {
+        const provider = selected()
+        if (!provider?.base) return null
+        return yield* review(provider, "base", provider.base(scope).pipe(Effect.flatMap(decodeBase)))
+      }),
       branches: Effect.fn("Vcs.branches")(function* (options?: BranchOptions) {
         const provider = selected()
         if (provider)
@@ -145,18 +180,18 @@ const layer = Layer.effect(
       diff: Effect.fn("Vcs.diff")(function* (mode: Mode, options?: DiffOptions) {
         const provider = selected()
         if (!provider) return []
-        const rows = yield* protect(
+        const rows = yield* review(
           provider,
           "diff",
           provider
             .diff({
               ...scope,
               mode,
+              ...(options?.base !== undefined ? { base: options.base } : {}),
               context: options?.context ?? PATCH_CONTEXT_LINES,
               maxOutputBytes: MAX_TOTAL_PATCH_BYTES,
             })
             .pipe(Effect.flatMap(decodeDiff)),
-          [],
         )
         let total = 0
         return rows.map((row) => {

packages/core/test/fixture/prompt-location.ts

@@ -1,18 +1,40 @@
+import { Bus } from "@opencode-ai/core/bus"
+import { Image } from "@opencode-ai/core/image"
 import { LocationServiceMap } from "@opencode-ai/core/location-service-map"
 import type { LocationServices } from "@opencode-ai/core/location-services"
 import { PluginHooks } from "@opencode-ai/core/plugin/hooks"
 import { PluginSupervisor } from "@opencode-ai/core/plugin/supervisor-service"
+import { SessionPrompt } from "@opencode-ai/core/session/prompt"
+import { Skill } from "@opencode-ai/core/skill"
+import type { Location } from "@opencode-ai/schema/location"
+import { makeGlobalNode } from "@opencode-ai/util/effect/app-node"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
+import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Effect, Layer, LayerMap } from "effect"
 
-// Plain-prompt unit fixtures use virtual directories and need only the admission hook services.
-export const promptLocationLayer = Layer.effect(
-  LocationServiceMap.Service,
-  LayerMap.make(
-    () =>
-      Layer.merge(
-        LayerNode.compile(PluginHooks.node),
-        Layer.succeed(PluginSupervisor.Service, { flush: Effect.void }),
-      ) as Layer.Layer<LocationServices>,
+// Plain-prompt unit fixtures use virtual directories and need only prompt preparation services.
+export const promptLocationNode = makeGlobalNode({
+  service: LocationServiceMap.Service,
+  layer: Layer.effect(
+    LocationServiceMap.Service,
+    Effect.gen(function* () {
+      const bus = yield* Bus.Service
+      const fs = yield* FSUtil.Service
+      return yield* LayerMap.make(
+        (_ref: Location.Ref) =>
+          SessionPrompt.layer.pipe(
+            Layer.provideMerge(
+              Layer.mergeAll(
+                LayerNode.compile(LayerNode.group([PluginHooks.node, Image.node, Skill.node]), [
+                  [Bus.node, Layer.succeed(Bus.Service, bus)],
+                ]),
+                Layer.succeed(FSUtil.Service, fs),
+                Layer.succeed(PluginSupervisor.Service, { flush: Effect.void }),
+              ),
+            ),
+          ) as Layer.Layer<LocationServices>,
+      )
+    }),
   ),
-)
+  deps: [Bus.node, FSUtil.node],
+})

packages/core/test/github-copilot/openai-responses-language-model.test.ts

@@ -1,10 +1,197 @@
 import { OpenAIResponsesLanguageModel } from "@opencode-ai/core/github-copilot/responses/openai-responses-language-model"
 import { convertToOpenAIResponsesInput } from "@opencode-ai/core/github-copilot/responses/convert-to-openai-responses-input"
 import { describe, test, expect, mock } from "bun:test"
-import type { LanguageModelV3Prompt, LanguageModelV3StreamPart } from "@ai-sdk/provider"
+import type { LanguageModelV3Prompt, LanguageModelV3ProviderTool, LanguageModelV3StreamPart } from "@ai-sdk/provider"
 
 const TEST_PROMPT: LanguageModelV3Prompt = [{ role: "user", content: [{ type: "text", text: "Hello" }] }]
 
+const HOSTED_TOOL_CASES = [
+  {
+    id: "openai.web_search",
+    name: "current_web",
+    args: {},
+    wireType: "web_search",
+    output: {
+      type: "web_search_call",
+      id: "web_1",
+      status: "completed",
+      action: { type: "search", query: "news" },
+    },
+    stream: [
+      {
+        type: "response.output_item.added",
+        output_index: 0,
+        item: {
+          type: "web_search_call",
+          id: "web_1",
+          status: "in_progress",
+          action: { type: "search", query: "news" },
+        },
+      },
+      {
+        type: "response.output_item.done",
+        output_index: 0,
+        item: {
+          type: "web_search_call",
+          id: "web_1",
+          status: "completed",
+          action: { type: "search", query: "news" },
+        },
+      },
+    ],
+    streamEventTypes: ["tool-input-start", "tool-input-end", "tool-call", "tool-result"],
+    eventTypes: ["tool-input-start", "tool-call", "tool-result"],
+  },
+  {
+    id: "openai.web_search_preview",
+    name: "preview_web",
+    args: {},
+    wireType: "web_search_preview",
+    output: {
+      type: "web_search_call",
+      id: "preview_1",
+      status: "completed",
+      action: { type: "search", query: "news" },
+    },
+    stream: [
+      {
+        type: "response.output_item.added",
+        output_index: 0,
+        item: {
+          type: "web_search_call",
+          id: "preview_1",
+          status: "in_progress",
+          action: { type: "search", query: "news" },
+        },
+      },
+      {
+        type: "response.output_item.done",
+        output_index: 0,
+        item: {
+          type: "web_search_call",
+          id: "preview_1",
+          status: "completed",
+          action: { type: "search", query: "news" },
+        },
+      },
+    ],
+    streamEventTypes: ["tool-input-start", "tool-input-end", "tool-call", "tool-result"],
+    eventTypes: ["tool-input-start", "tool-call", "tool-result"],
+  },
+  {
+    id: "openai.file_search",
+    name: "documents",
+    args: { vectorStoreIds: ["store_1"] },
+    wireType: "file_search",
+    output: { type: "file_search_call", id: "file_1", queries: ["news"], results: null },
+    stream: [
+      {
+        type: "response.output_item.added",
+        output_index: 0,
+        item: { type: "file_search_call", id: "file_1" },
+      },
+      {
+        type: "response.output_item.done",
+        output_index: 0,
+        item: { type: "file_search_call", id: "file_1", queries: ["news"], results: null },
+      },
+    ],
+    streamEventTypes: ["tool-call", "tool-result"],
+    eventTypes: ["tool-call", "tool-result"],
+  },
+  {
+    id: "openai.code_interpreter",
+    name: "python",
+    args: {},
+    wireType: "code_interpreter",
+    output: {
+      type: "code_interpreter_call",
+      id: "code_1",
+      code: "print(1)",
+      container_id: "container_1",
+      outputs: null,
+    },
+    stream: [
+      {
+        type: "response.output_item.added",
+        output_index: 0,
+        item: {
+          type: "code_interpreter_call",
+          id: "code_1",
+          code: null,
+          container_id: "container_1",
+          outputs: null,
+          status: "in_progress",
+        },
+      },
+      {
+        type: "response.code_interpreter_call_code.delta",
+        item_id: "code_1",
+        output_index: 0,
+        delta: "print(",
+      },
+      {
+        type: "response.code_interpreter_call_code.done",
+        item_id: "code_1",
+        output_index: 0,
+        code: "print(1)",
+      },
+      {
+        type: "response.output_item.done",
+        output_index: 0,
+        item: {
+          type: "code_interpreter_call",
+          id: "code_1",
+          code: "print(1)",
+          container_id: "container_1",
+          outputs: null,
+        },
+      },
+    ],
+    streamEventTypes: [
+      "tool-input-start",
+      "tool-input-delta",
+      "tool-input-delta",
+      "tool-input-delta",
+      "tool-input-end",
+      "tool-call",
+      "tool-result",
+    ],
+    eventTypes: ["tool-input-start", "tool-call", "tool-result"],
+  },
+  {
+    id: "openai.image_generation",
+    name: "illustrate",
+    args: {},
+    wireType: "image_generation",
+    output: { type: "image_generation_call", id: "image_1", result: "final-image" },
+    stream: [
+      {
+        type: "response.output_item.added",
+        output_index: 0,
+        item: { type: "image_generation_call", id: "image_1" },
+      },
+      {
+        type: "response.image_generation_call.partial_image",
+        item_id: "image_1",
+        output_index: 0,
+        partial_image_b64: "partial-image",
+      },
+      {
+        type: "response.output_item.done",
+        output_index: 0,
+        item: { type: "image_generation_call", id: "image_1", result: "final-image" },
+      },
+    ],
+    streamEventTypes: ["tool-call", "tool-result", "tool-result"],
+    eventTypes: ["tool-call", "tool-result", "tool-result"],
+  },
+] as const
+
+function hostedTool(testCase: (typeof HOSTED_TOOL_CASES)[number]): LanguageModelV3ProviderTool {
+  return { type: "provider", id: testCase.id, name: testCase.name, args: testCase.args }
+}
+
 function createMockFetch(body: unknown) {
   return mock(
     async () => new Response(JSON.stringify(body), { status: 200, headers: { "Content-Type": "application/json" } }),
@@ -30,12 +217,144 @@ function createModel(fetchFn: ReturnType<typeof mock>) {
   })
 }
 
+async function readStream(stream: ReadableStream<LanguageModelV3StreamPart>) {
+  const reader = stream.getReader()
+  const events: LanguageModelV3StreamPart[] = []
+  while (true) {
+    const item = await reader.read()
+    if (item.done) return events
+    events.push(item.value)
+  }
+}
+
 // GitHub Copilot's Responses model echoes item metadata (itemId, reasoningEncryptedContent,
 // responseId, ...) under the "copilot" providerOptions/providerMetadata namespace, matching the
 // namespace request options already use. It used to echo this metadata under "openai" (a leftover
 // from forking the OpenAI Responses model), which left it unreachable by anything reading the
 // "copilot" namespace and let stale itemIds slip past stripping meant for that namespace.
 describe("doGenerate", () => {
+  test.each([...HOSTED_TOOL_CASES])("forces $id by its declared logical name", async (testCase) => {
+    const requests: unknown[] = []
+    const model = createModel(
+      mock(async (_input: Parameters<typeof fetch>[0], init?: RequestInit) => {
+        requests.push(await new Response(init?.body).json())
+        return new Response(
+          JSON.stringify({
+            id: "resp_1",
+            created_at: 0,
+            model: "test-model",
+            output: [],
+            usage: { input_tokens: 1, output_tokens: 1 },
+          }),
+          { status: 200, headers: { "Content-Type": "application/json" } },
+        )
+      }),
+    )
+
+    await model.doGenerate({
+      prompt: TEST_PROMPT,
+      tools: [hostedTool(testCase)],
+      toolChoice: { type: "tool", toolName: testCase.name },
+    })
+
+    expect(requests[0]).toMatchObject({ tool_choice: { type: testCase.wireType } })
+  })
+
+  test("does not mistake a colliding function name for a hosted tool", async () => {
+    const requests: unknown[] = []
+    const model = createModel(
+      mock(async (_input: Parameters<typeof fetch>[0], init?: RequestInit) => {
+        requests.push(await new Response(init?.body).json())
+        return new Response(
+          JSON.stringify({
+            id: "resp_1",
+            created_at: 0,
+            model: "test-model",
+            output: [],
+            usage: { input_tokens: 1, output_tokens: 1 },
+          }),
+          { status: 200, headers: { "Content-Type": "application/json" } },
+        )
+      }),
+    )
+    await model.doGenerate({
+      prompt: TEST_PROMPT,
+      tools: [
+        { type: "provider", id: "openai.web_search", name: "lookup", args: {} },
+        { type: "function", name: "web_search", inputSchema: { type: "object" } },
+      ],
+      toolChoice: { type: "tool", toolName: "web_search" },
+    })
+
+    expect(requests[0]).toMatchObject({ tool_choice: { type: "function", name: "web_search" } })
+  })
+
+  test.each([...HOSTED_TOOL_CASES])("uses $name for generated $id calls and results", async (testCase) => {
+    const model = createModel(
+      createMockFetch({
+        id: "resp_1",
+        created_at: 0,
+        model: "test-model",
+        output: [testCase.output],
+        usage: { input_tokens: 1, output_tokens: 1 },
+      }),
+    )
+
+    const result = await model.doGenerate({ prompt: TEST_PROMPT, tools: [hostedTool(testCase)] })
+
+    expect(result.content.filter((part) => part.type === "tool-call" || part.type === "tool-result")).toMatchObject([
+      { type: "tool-call", toolName: testCase.name },
+      { type: "tool-result", toolName: testCase.name },
+    ])
+  })
+
+  test("uses canonical names only when no hosted declaration matches", async () => {
+    const model = createModel(
+      createMockFetch({
+        id: "resp_1",
+        created_at: 0,
+        model: "test-model",
+        output: [
+          HOSTED_TOOL_CASES[0].output,
+          HOSTED_TOOL_CASES[2].output,
+          HOSTED_TOOL_CASES[3].output,
+          HOSTED_TOOL_CASES[4].output,
+          { type: "computer_call", id: "computer_1", status: "completed" },
+        ],
+        usage: { input_tokens: 1, output_tokens: 1 },
+      }),
+    )
+
+    const result = await model.doGenerate({ prompt: TEST_PROMPT })
+
+    expect(result.content.filter((part) => part.type === "tool-call").map((part) => part.toolName)).toEqual([
+      "web_search",
+      "file_search",
+      "code_interpreter",
+      "image_generation",
+      "computer_use",
+    ])
+  })
+
+  test("rejects an automatic web response when both variants have different logical names", async () => {
+    const model = createModel(
+      createMockFetch({
+        id: "resp_1",
+        created_at: 0,
+        model: "test-model",
+        output: [HOSTED_TOOL_CASES[0].output],
+        usage: { input_tokens: 1, output_tokens: 1 },
+      }),
+    )
+
+    await expect(
+      model.doGenerate({
+        prompt: TEST_PROMPT,
+        tools: [hostedTool(HOSTED_TOOL_CASES[0]), hostedTool(HOSTED_TOOL_CASES[1])],
+      }),
+    ).rejects.toThrow("ambiguous web_search response for hosted tools: current_web, preview_web")
+  })
+
   test("attaches item metadata under the copilot namespace, not openai", async () => {
     const mockFetch = createMockFetch({
       id: "resp_1",
@@ -129,6 +448,105 @@ describe("doGenerate", () => {
 })
 
 describe("doStream", () => {
+  test.each([...HOSTED_TOOL_CASES])("uses $name for every streamed $id identity event", async (testCase) => {
+    const model = createModel(createStreamFetch(testCase.stream))
+    const result = await model.doStream({
+      prompt: TEST_PROMPT,
+      tools: [hostedTool(testCase)],
+    })
+    const streamEvents = (await readStream(result.stream)).filter(
+      (event) => event.type !== "stream-start" && event.type !== "finish",
+    )
+    const events = streamEvents.filter((event) => "toolName" in event)
+
+    expect(streamEvents.map((event) => event.type)).toEqual([...testCase.streamEventTypes])
+    expect(events.map((event) => event.type)).toEqual([...testCase.eventTypes])
+    expect(events.map((event) => event.toolName)).toEqual(testCase.eventTypes.map(() => testCase.name))
+  })
+
+  test("uses the forced web variant's logical name when both variants are declared", async () => {
+    const model = createModel(createStreamFetch(HOSTED_TOOL_CASES[1].stream))
+
+    const result = await model.doStream({
+      prompt: TEST_PROMPT,
+      tools: [hostedTool(HOSTED_TOOL_CASES[0]), hostedTool(HOSTED_TOOL_CASES[1])],
+      toolChoice: { type: "tool", toolName: "preview_web" },
+    })
+    const events = (await readStream(result.stream)).filter((event) => "toolName" in event)
+
+    expect(events.map((event) => event.toolName)).toEqual(["preview_web", "preview_web", "preview_web"])
+  })
+
+  test("rejects ambiguous web variants before fetching or exposing a stream", async () => {
+    const fetchFn = createStreamFetch(HOSTED_TOOL_CASES[0].stream)
+    const model = createModel(fetchFn)
+
+    await expect(
+      model.doStream({
+        prompt: TEST_PROMPT,
+        tools: [hostedTool(HOSTED_TOOL_CASES[0]), hostedTool(HOSTED_TOOL_CASES[1])],
+      }),
+    ).rejects.toThrow("ambiguous web_search response for hosted tools")
+    expect(fetchFn).not.toHaveBeenCalled()
+  })
+
+  test("rejects an ambiguous forced wire choice before fetching or exposing a stream", async () => {
+    const fetchFn = createStreamFetch(HOSTED_TOOL_CASES[0].stream)
+    const model = createModel(fetchFn)
+
+    await expect(
+      model.doStream({
+        prompt: TEST_PROMPT,
+        tools: [hostedTool(HOSTED_TOOL_CASES[0]), { ...hostedTool(HOSTED_TOOL_CASES[0]), name: "backup_web" }],
+        toolChoice: { type: "tool", toolName: HOSTED_TOOL_CASES[0].name },
+      }),
+    ).rejects.toThrow("ambiguous web_search tool choice for hosted tools")
+    expect(fetchFn).not.toHaveBeenCalled()
+  })
+
+  test("streams a shared logical name for both web variants", async () => {
+    const model = createModel(createStreamFetch(HOSTED_TOOL_CASES[0].stream))
+    const tools = [hostedTool(HOSTED_TOOL_CASES[0]), hostedTool(HOSTED_TOOL_CASES[1])].map((tool) => ({
+      ...tool,
+      name: "web",
+    }))
+
+    const result = await model.doStream({ prompt: TEST_PROMPT, tools })
+    const events = (await readStream(result.stream)).filter((event) => "toolName" in event)
+
+    expect(events.map((event) => event.toolName)).toEqual(["web", "web", "web"])
+  })
+
+  test("uses canonical names for undeclared streamed web and computer calls", async () => {
+    const model = createModel(
+      createStreamFetch([
+        ...HOSTED_TOOL_CASES[0].stream,
+        {
+          type: "response.output_item.added",
+          output_index: 1,
+          item: { type: "computer_call", id: "computer_1", status: "in_progress" },
+        },
+        {
+          type: "response.output_item.done",
+          output_index: 1,
+          item: { type: "computer_call", id: "computer_1", status: "completed" },
+        },
+      ]),
+    )
+
+    const result = await model.doStream({ prompt: TEST_PROMPT })
+    const events = (await readStream(result.stream)).filter((event) => "toolName" in event)
+
+    expect(events.map((event) => event.toolName)).toEqual([
+      "web_search",
+      "web_search",
+      "web_search",
+      "computer_use",
+      "computer_use",
+      "computer_use",
+    ])
+  })
+
   test("streams sequential Copilot reasoning summary blocks", async () => {
     const model = createModel(
       createStreamFetch([

packages/core/test/github-copilot/openai-responses-prepare-tools.test.ts

@@ -1,5 +1,9 @@
 import { expect, test } from "bun:test"
-import type { LanguageModelV3FunctionTool } from "@ai-sdk/provider"
+import type {
+  LanguageModelV3CallOptions,
+  LanguageModelV3FunctionTool,
+  LanguageModelV3ProviderTool,
+} from "@ai-sdk/provider"
 import { prepareResponsesTools } from "@opencode-ai/core/github-copilot/responses/openai-responses-prepare-tools"
 
 function prepare(strict: boolean | undefined, strictJsonSchema: boolean) {
@@ -18,3 +22,198 @@ test("function tools prefer explicit strictness over the global fallback", () =>
   expect(prepare(undefined, true)).toMatchObject({ type: "function", strict: true })
   expect(prepare(undefined, false)).toMatchObject({ type: "function", strict: false })
 })
+
+const webTools: LanguageModelV3ProviderTool[] = [
+  { type: "provider", id: "openai.web_search", name: "current_web", args: {} },
+  { type: "provider", id: "openai.web_search_preview", name: "preview_web", args: {} },
+]
+
+test.each([
+  { order: webTools, toolChoice: undefined },
+  { order: webTools.toReversed(), toolChoice: undefined },
+  { order: webTools, toolChoice: { type: "auto" as const } },
+  { order: webTools.toReversed(), toolChoice: { type: "auto" as const } },
+  { order: webTools, toolChoice: { type: "required" as const } },
+  { order: webTools.toReversed(), toolChoice: { type: "required" as const } },
+])("rejects differently named web variants before automatic or required selection", ({ order, toolChoice }) => {
+  expect(() => prepareResponsesTools({ tools: order, toolChoice, strictJsonSchema: false })).toThrow(
+    "ambiguous web_search response for hosted tools",
+  )
+})
+
+test.each([
+  { order: webTools, name: "current_web", wireType: "web_search" },
+  { order: webTools.toReversed(), name: "current_web", wireType: "web_search" },
+  { order: webTools, name: "preview_web", wireType: "web_search_preview" },
+  { order: webTools.toReversed(), name: "preview_web", wireType: "web_search_preview" },
+])("uses the uniquely forced web variant independent of declaration order", ({ order, name, wireType }) => {
+  const result = prepareResponsesTools({
+    tools: order,
+    toolChoice: { type: "tool", toolName: name },
+    strictJsonSchema: false,
+  })
+
+  expect(result.toolChoice).toEqual({ type: wireType })
+  expect(result.selectedHostedTool).toMatchObject({ name, type: wireType, responseType: "web_search" })
+})
+
+test.each([{ order: webTools }, { order: webTools.toReversed() }])(
+  "allows indistinguishable web variants when they share one logical name",
+  ({ order }) => {
+    const tools = order.map((tool) => ({ ...tool, name: "web" }))
+    const result = prepareResponsesTools({ tools, toolChoice: { type: "required" }, strictJsonSchema: false })
+
+    expect(result.hostedTools.map((tool) => tool.name)).toEqual(["web", "web"])
+  },
+)
+
+const duplicateToolCases = [
+  [
+    { type: "function", name: "lookup", inputSchema: { type: "object" } },
+    { type: "provider", id: "openai.web_search", name: "lookup", args: {} },
+  ],
+  [
+    { type: "provider", id: "other.unsupported", name: "lookup", args: {} },
+    { type: "provider", id: "openai.web_search", name: "lookup", args: {} },
+  ],
+  [
+    { type: "provider", id: "openai.web_search", name: "lookup", args: {} },
+    { type: "provider", id: "openai.web_search_preview", name: "lookup", args: {} },
+  ],
+] satisfies Array<NonNullable<LanguageModelV3CallOptions["tools"]>>
+
+test.each(duplicateToolCases.flatMap((tools) => [{ tools }, { tools: tools.toReversed() }]))(
+  "rejects duplicate forced definitions independent of type and order",
+  ({ tools }) => {
+    expect(() =>
+      prepareResponsesTools({
+        tools,
+        toolChoice: { type: "tool", toolName: "lookup" },
+        strictJsonSchema: false,
+      }),
+    ).toThrow("multiple tool definitions share this name")
+  },
+)
+
+const duplicateHostedToolCases = [
+  { id: "openai.web_search", responseType: "web_search", args: {} },
+  { id: "openai.web_search_preview", responseType: "web_search", args: {} },
+  { id: "openai.file_search", responseType: "file_search", args: { vectorStoreIds: ["store_1"] } },
+  { id: "openai.code_interpreter", responseType: "code_interpreter", args: {} },
+  { id: "openai.image_generation", responseType: "image_generation", args: {} },
+] as const
+
+function duplicateHostedTools(testCase: (typeof duplicateHostedToolCases)[number], sameName = false) {
+  return [
+    { type: "provider" as const, id: testCase.id, name: `${testCase.responseType}_one`, args: testCase.args },
+    {
+      type: "provider" as const,
+      id: testCase.id,
+      name: sameName ? `${testCase.responseType}_one` : `${testCase.responseType}_two`,
+      args: testCase.args,
+    },
+  ]
+}
+
+test.each(
+  duplicateHostedToolCases.flatMap((testCase) =>
+    [undefined, { type: "auto" as const }, { type: "required" as const }].flatMap((toolChoice) => {
+      const tools = duplicateHostedTools(testCase)
+      return [
+        { testCase, tools, toolChoice, selection: toolChoice?.type ?? "default" },
+        { testCase, tools: tools.toReversed(), toolChoice, selection: toolChoice?.type ?? "default" },
+      ]
+    }),
+  ),
+)(
+  "rejects differently named duplicate $testCase.id responses for $selection selection",
+  ({ testCase, tools, toolChoice }) => {
+    expect(() => prepareResponsesTools({ tools, toolChoice, strictJsonSchema: false })).toThrow(
+      `ambiguous ${testCase.responseType} response for hosted tools`,
+    )
+  },
+)
+
+test.each(
+  duplicateHostedToolCases.flatMap((testCase) => {
+    const tools = duplicateHostedTools(testCase, true)
+    return [
+      { testCase, tools },
+      { testCase, tools: tools.toReversed() },
+    ]
+  }),
+)("allows duplicate $testCase.id responses with the same logical name", ({ tools }) => {
+  expect(
+    prepareResponsesTools({ tools, toolChoice: { type: "required" }, strictJsonSchema: false }).hostedTools.map(
+      (tool) => tool.name,
+    ),
+  ).toEqual([tools[0].name, tools[0].name])
+})
+
+test.each(
+  duplicateHostedToolCases.flatMap((testCase) => {
+    const tools = duplicateHostedTools(testCase)
+    return [
+      { testCase, tools },
+      { testCase, tools: tools.toReversed() },
+    ]
+  }),
+)("rejects a forced $testCase.id wire choice with multiple logical identities", ({ testCase, tools }) => {
+  expect(() =>
+    prepareResponsesTools({
+      tools,
+      toolChoice: { type: "tool", toolName: `${testCase.responseType}_one` },
+      strictJsonSchema: false,
+    }),
+  ).toThrow(`ambiguous ${tools[0].id.replace("openai.", "")} tool choice for hosted tools`)
+})
+
+test.each(
+  duplicateHostedToolCases.flatMap((testCase) => {
+    const tools = duplicateHostedTools(testCase, true)
+    return [{ tools }, { tools: tools.toReversed() }]
+  }),
+)("rejects a forced logical name shared by duplicate same-wire definitions", ({ tools }) => {
+  expect(() =>
+    prepareResponsesTools({
+      tools,
+      toolChoice: { type: "tool", toolName: tools[0].name },
+      strictJsonSchema: false,
+    }),
+  ).toThrow("multiple tool definitions share this name")
+})
+
+test.each([...duplicateHostedToolCases])("skips ambiguous $id responses when tool choice is none", (testCase) => {
+  expect(
+    prepareResponsesTools({
+      tools: duplicateHostedTools(testCase),
+      toolChoice: { type: "none" },
+      strictJsonSchema: false,
+    }).toolChoice,
+  ).toBe("none")
+})
+
+test.each([...duplicateHostedToolCases])("skips ambiguous $id responses for a uniquely forced function", (testCase) => {
+  expect(
+    prepareResponsesTools({
+      tools: [...duplicateHostedTools(testCase), { type: "function", name: "local", inputSchema: { type: "object" } }],
+      toolChoice: { type: "tool", toolName: "local" },
+      strictJsonSchema: false,
+    }).toolChoice,
+  ).toEqual({ type: "function", name: "local" })
+})
+
+test.each([{ ambiguousWebTools: duplicateHostedTools(duplicateHostedToolCases[0]) }, { ambiguousWebTools: webTools }])(
+  "validates only the selected wire choice for a forced unrelated hosted tool",
+  ({ ambiguousWebTools }) => {
+    const selected = duplicateHostedTools(duplicateHostedToolCases[2], true)[0]
+    const result = prepareResponsesTools({
+      tools: [...ambiguousWebTools, selected],
+      toolChoice: { type: "tool", toolName: selected.name },
+      strictJsonSchema: false,
+    })
+
+    expect(result.toolChoice).toEqual({ type: "file_search" })
+    expect(result.selectedHostedTool).toMatchObject({ name: selected.name, type: "file_search" })
+  },
+)

packages/core/test/lib/project.ts

@@ -1,11 +1,24 @@
+import { Database } from "@opencode-ai/core/database/database"
 import { Project } from "@opencode-ai/core/project"
+import { upsertProject } from "@opencode-ai/core/project/sql"
+import { makeGlobalNode } from "@opencode-ai/util/effect/app-node"
 import { Effect, Layer } from "effect"
 
-export const globalProjectLayer = Layer.succeed(
-  Project.Service,
-  Project.Service.of({
-    list: () => Effect.succeed([]),
-    update: () => Effect.die("not implemented"),
-    resolve: (directory) => Effect.succeed({ id: Project.ID.global, directory, canonical: directory }),
-  }),
-)
+export const globalProjectNode = makeGlobalNode({
+  service: Project.Service,
+  layer: Layer.effect(
+    Project.Service,
+    Effect.gen(function* () {
+      const database = yield* Database.Service
+      return Project.Service.of({
+        list: () => Effect.succeed([]),
+        update: () => Effect.die("not implemented"),
+        resolve: (directory) => {
+          const project = { id: Project.ID.global, directory, canonical: directory }
+          return upsertProject(database.db, project).pipe(Effect.orDie, Effect.as(project))
+        },
+      })
+    }),
+  ),
+  deps: [Database.node],
+})

packages/core/test/mcp.test.ts

@@ -1207,6 +1207,68 @@ test("adds, disconnects, and reconnects MCP servers at runtime", async () => {
   )
 })
 
+testEffect(Layer.empty).live(
+  "merges MCP defaults into the winning configured server without changing runtime overrides",
+  () =>
+    Effect.gen(function* () {
+      const entries = [
+        new Document({
+          type: "document",
+          info: new Info({
+            mcp: new ConfigMCP.Info({
+              timeout: { startup: 10, catalog: 20, execution: 30 },
+              servers: {
+                resources: { type: "local", command: ["earlier"], disabled: true, timeout: { execution: 90 } },
+              },
+            }),
+          }),
+        }),
+        new Document({
+          type: "document",
+          info: new Info({
+            mcp: new ConfigMCP.Info({
+              timeout: { catalog: 40 },
+              servers: {
+                resources: { type: "local", command: ["later"], disabled: true, timeout: { startup: 50 } },
+              },
+            }),
+          }),
+        }),
+      ]
+      const original = JSON.stringify(entries)
+      yield* Effect.gen(function* () {
+        const service = yield* Mcp.Service
+        const check = yield* service.transform((draft) => {
+          expect(draft.get("resources")).toEqual({
+            type: "local",
+            command: ["later"],
+            disabled: true,
+            timeout: { startup: 50, catalog: 40, execution: 30 },
+          })
+        })
+        yield* check.dispose
+        const runtime = {
+          type: "local",
+          command: ["runtime"],
+          disabled: true,
+          timeout: { catalog: 60 },
+        } satisfies ConfigMCP.Local
+        yield* service.add("resources", runtime)
+        yield* service.reload()
+        yield* service.transform((draft) => {
+          expect(draft.get("resources")).toEqual(runtime)
+        })
+      }).pipe(
+        Effect.provide(
+          resourceMcpLayer("https://unused.example", undefined, undefined, {
+            entries: () => Effect.succeed(entries),
+          }),
+        ),
+      )
+      expect(JSON.stringify(entries)).toBe(original)
+    }),
+)
+
 testEffect(resourceMcpLayer(new ConfigMCP.Local({ type: "local", command: ["unused"], disabled: true }))).live(
   "manages live MCP servers entirely through scoped transforms",
   () =>

packages/core/test/models.test.ts

@@ -297,7 +297,10 @@ describe("ModelsDev Service", () => {
       const context = yield* Layer.build(buildLayer(state, cache, { fetch: true, snapshot: false }))
       const result = yield* ModelsDev.Service.use((s) => s.get()).pipe(Effect.provide(context))
       expect(result).toEqual(fixture2Snapshot)
-      expect(cache.values.get(cacheKey)).toMatchObject({ body: JSON.stringify(fixture2) })
+      expect(cache.values.get(cacheKey)).toMatchObject({
+        body: JSON.stringify(fixture2),
+        digest: bodyDigest(JSON.stringify(fixture2)),
+      })
       const final = yield* Ref.get(state)
       expect(final.calls.length).toBe(1)
     }),
@@ -387,7 +390,10 @@ describe("ModelsDev Service", () => {
       )
       expect(result.before).toEqual(fixtureSnapshot)
       expect(result.after).toEqual(fixture2Snapshot)
-      expect(cache.values.get(cacheKey)).toMatchObject({ body: JSON.stringify(fixture2) })
+      expect(cache.values.get(cacheKey)).toMatchObject({
+        body: JSON.stringify(fixture2),
+        digest: bodyDigest(JSON.stringify(fixture2)),
+      })
       const final = yield* Ref.get(state)
       expect(final.calls.length).toBe(1)
       expect(final.calls[0].url).toContain("/api.json")
@@ -440,6 +446,10 @@ describe("ModelsDev Service", () => {
       const final = yield* Ref.get(state)
       expect(final.calls.length).toBe(1)
       expect(after).toEqual(fixture2Snapshot)
+      expect(cache.values.get(cacheKey)).toMatchObject({
+        body: JSON.stringify(fixture2),
+        digest: bodyDigest(JSON.stringify(fixture2)),
+      })
     }),
   )
 

packages/core/test/plugin/host.ts

@@ -129,6 +129,7 @@ export function host(overrides: Overrides = {}): Plugin.Context {
       hook: () => Effect.die("unused tool.hook"),
     },
     vcs: overrides.vcs ?? {
+      base: () => Effect.die("unused vcs.base"),
       get: () => Effect.die("unused vcs.get"),
       branches: () => Effect.die("unused vcs.branches"),
       status: () => Effect.die("unused vcs.status"),

packages/core/test/plugin/promise.test.ts

@@ -567,7 +567,7 @@ describe("fromPromise", () => {
     }),
   )
 
-  it.effect("registers a Promise VCS provider and forwards client reads", () =>
+  it.effect("registers a Promise VCS provider and preserves its receiver when forwarding client reads", () =>
     Effect.gen(function* () {
       const vcs = yield* Vcs.Service
       const plugin = yield* Plugin.Service
@@ -584,6 +584,11 @@ describe("fromPromise", () => {
                 signals.push(request.signal)
                 return { branch: { current: "feature", default: "main" } }
               },
+              async base(_input, request) {
+                expect(this.id).toBe("custom")
+                signals.push(request.signal)
+                return { name: "main", ref: "refs/heads/main", source: "default" }
+              },
               branches: async (input, request) => {
                 signals.push(request.signal)
                 expect(input.search).toBe("feat")
@@ -604,6 +609,7 @@ describe("fromPromise", () => {
           })
 
           expect((await ctx.vcs.get()).data.branch.current).toBe("feature")
+          expect((await ctx.vcs.base()).data).toEqual({ name: "main", ref: "refs/heads/main", source: "default" })
           expect((await ctx.vcs.branches({ search: "feat" })).data).toEqual(["feature"])
           expect((await ctx.vcs.status()).data).toHaveLength(1)
           expect((await ctx.vcs.diff({ mode: "working", context: 2 })).data[0].patch).toBe("+hello")
@@ -612,7 +618,7 @@ describe("fromPromise", () => {
 
       yield* PluginPromise.fromPromise(promisePlugin).effect(host)
       expect((yield* vcs.info()).branch.current).toBe("feature")
-      expect(signals).toHaveLength(4)
+      expect(signals).toHaveLength(5)
       expect(signals.every((signal) => signal instanceof AbortSignal)).toBeTrue()
     }),
   )

packages/core/test/session-compact.test.ts

@@ -21,7 +21,7 @@ import { SessionRunnerModel } from "@opencode-ai/core/session/runner/model"
 import { SessionStore } from "@opencode-ai/core/session/store"
 import { Effect, Layer, LayerMap, Stream } from "effect"
 import { testEffect } from "./lib/effect"
-import { globalProjectLayer } from "./lib/project"
+import { globalProjectNode } from "./lib/project"
 
 const location = Location.Ref.make({ directory: AbsolutePath.make("/project") })
 const model = LanguageModel.make({
@@ -66,7 +66,7 @@ const it = testEffect(
     LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node, Session.node]),
     [
       [LocationServiceMap.node, locations],
-      [Project.node, globalProjectLayer],
+      [Project.node, globalProjectNode],
       [SessionExecution.node, SessionExecution.noopLayer],
     ],
   ),