Merge branch 'v2' into background-button

Co-authored-by: Brendonovich <14191578+Brendonovich@users.noreply.github.com>

.github/workflows/publish.yml

@@ -91,7 +91,7 @@ jobs:
 
       - uses: ./.github/actions/setup-bun
         with:
-          bun-version: 1.4.0
+          bun-version: 1.4.1
 
       - name: Setup git committer
         id: committer
@@ -113,7 +113,7 @@ jobs:
         id: build
         run: ./packages/cli/script/build.ts ${{ (github.ref_name == 'beta' && '--sourcemaps') || '' }}
         env:
-          BUN_COMPILE_RELEASE: bun-v1.4.0
+          BUN_COMPILE_RELEASE: bun-v1.4.1
           OPENCODE_VERSION: ${{ needs.version.outputs.version }}
           OPENCODE_RELEASE: ${{ needs.version.outputs.release }}
           GH_REPO: ${{ needs.version.outputs.repo }}

bun.lock

@@ -1065,6 +1065,7 @@
     "@opentui/solid": "catalog:",
     "@types/bun": "catalog:",
     "@types/node": "catalog:",
+    "bun-types": "1.4.1",
     "effect": "catalog:",
     "solid-js": "catalog:",
   },
@@ -1102,7 +1103,7 @@
     "@tanstack/solid-virtual": "3.13.37",
     "@tsconfig/bun": "1.0.9",
     "@tsconfig/node22": "22.0.2",
-    "@types/bun": "1.3.13",
+    "@types/bun": "1.4.0",
     "@types/cross-spawn": "6.0.6",
     "@types/luxon": "3.7.1",
     "@types/node": "24.12.2",
@@ -3032,7 +3033,7 @@
 
     "@types/braces": ["@types/braces@3.0.5", "", {}, "sha512-SQFof9H+LXeWNz8wDe7oN5zu7ket0qwMu5vZubW4GCJ8Kkeh6nBWUz87+KTz/G3Kqsrp0j/W253XJb3KMEeg3w=="],
 
-    "@types/bun": ["@types/bun@1.3.13", "", { "dependencies": { "bun-types": "1.3.13" } }, "sha512-9fqXWk5YIHGGnUau9TEi+qdlTYDAnOj+xLCmSTwXfAIqXr2x4tytJb43E9uCvt09zJURKXwAtkoH4nLQfzeTXw=="],
+    "@types/bun": ["@types/bun@1.4.0", "", { "dependencies": { "bun-types": "1.4.0" } }, "sha512-K+lZULY23vRgK/CfTjFIV+tyifaNdSMlPh9j+6mQ/cLfpOznLyAuzgV/JQysyECpkBQLVMSyvjlr2fBUSA9wFQ=="],
 
     "@types/cacache": ["@types/cacache@20.0.1", "", { "dependencies": { "@types/node": "*", "minipass": "*" } }, "sha512-QlKW3AFoFr/hvPHwFHMIVUH/ZCYeetBNou3PCmxu5LaNDvrtBlPJtIA6uhmU9JRt9oxj7IYoqoLcpxtzpPiTcw=="],
 
@@ -3484,7 +3485,7 @@
 
     "bun-pty": ["bun-pty@0.4.8", "", {}, "sha512-rO70Mrbr13+jxHHHu2YBkk2pNqrJE5cJn29WE++PUr+GFA0hq/VgtQPZANJ8dJo6d7XImvBk37Innt8GM7O28w=="],
 
-    "bun-types": ["bun-types@1.3.13", "", { "dependencies": { "@types/node": "*" } }, "sha512-QXKeHLlOLqQX9LgYaHJfzdBaV21T63HhFJnvuRCcjZiaUDpbs5ED1MgxbMra71CsryN/1dAoXuJJJwIv/2drVA=="],
+    "bun-types": ["bun-types@1.4.1", "", { "dependencies": { "@types/node": "*" } }, "sha512-loKuVrAFZKfEv+JvWkHRS9GW5IqLuLRjVXN9p+vZvBN86O5hf/pBZQ5hSoyipsrMmWObZBDvWnlmKvjKTM0PdA=="],
 
     "bundle-name": ["bundle-name@4.1.0", "", { "dependencies": { "run-applescript": "^7.0.0" } }, "sha512-tjwM5exMg6BGRI+kNmTntNsvdZS1X8BFYS6tnJ2hdH0kVxM6/eVZ2xy+FqStSWvYmtfFMDLIxurorHwDKfDz5Q=="],
 
@@ -6340,10 +6341,6 @@
 
     "@solidjs/start/vite": ["vite@7.1.10", "", { "dependencies": { "esbuild": "^0.25.0", "fdir": "^6.5.0", "picomatch": "^4.0.3", "postcss": "^8.5.6", "rollup": "^4.43.0", "tinyglobby": "^0.2.15" }, "optionalDependencies": { "fsevents": "~2.3.3" }, "peerDependencies": { "@types/node": "^20.19.0 || >=22.12.0", "jiti": ">=1.21.0", "less": "^4.0.0", "lightningcss": "^1.21.0", "sass": "^1.70.0", "sass-embedded": "^1.70.0", "stylus": ">=0.54.8", "sugarss": "^5.0.0", "terser": "^5.16.0", "tsx": "^4.8.1", "yaml": "^2.4.2" }, "optionalPeers": ["@types/node", "jiti", "less", "lightningcss", "sass", "sass-embedded", "stylus", "sugarss", "terser", "tsx", "yaml"], "bin": { "vite": "bin/vite.js" } }, "sha512-CmuvUBzVJ/e3HGxhg6cYk88NGgTnBoOo7ogtfJJ0fefUWAxN/WDSUa50o+oVBxuIhO8FoEZW0j2eW7sfjs5EtA=="],
 
-    "@standard-community/standard-json/effect": ["effect@4.0.0-rc.111", "", { "dependencies": { "@standard-schema/spec": "^1.1.0", "fast-check": "^4.9.0", "msgpackr": "^2.0.5" } }, "sha512-ASd5L58EIR0CUNueZNKKjSsyOCd+2alxOAIaTcHaqkJkPsaYSsw5Cg/cfANk5K4Jr2YsX756xvX11shzqsreWA=="],
-
-    "@standard-community/standard-openapi/effect": ["effect@4.0.0-rc.111", "", { "dependencies": { "@standard-schema/spec": "^1.1.0", "fast-check": "^4.9.0", "msgpackr": "^2.0.5" } }, "sha512-ASd5L58EIR0CUNueZNKKjSsyOCd+2alxOAIaTcHaqkJkPsaYSsw5Cg/cfANk5K4Jr2YsX756xvX11shzqsreWA=="],
-
     "@tailwindcss/node/lightningcss": ["lightningcss@1.32.0", "", { "dependencies": { "detect-libc": "^2.0.3" }, "optionalDependencies": { "lightningcss-android-arm64": "1.32.0", "lightningcss-darwin-arm64": "1.32.0", "lightningcss-darwin-x64": "1.32.0", "lightningcss-freebsd-x64": "1.32.0", "lightningcss-linux-arm-gnueabihf": "1.32.0", "lightningcss-linux-arm64-gnu": "1.32.0", "lightningcss-linux-arm64-musl": "1.32.0", "lightningcss-linux-x64-gnu": "1.32.0", "lightningcss-linux-x64-musl": "1.32.0", "lightningcss-win32-arm64-msvc": "1.32.0", "lightningcss-win32-x64-msvc": "1.32.0" } }, "sha512-NXYBzinNrblfraPGyrbPoD19C1h9lfI/1mzgWYvXUTe414Gz/X1FD2XBZSZM7rRTrMA8JL3OtAaGifrIKhQ5yQ=="],
 
     "@tailwindcss/oxide-wasm32-wasi/@emnapi/core": ["@emnapi/core@1.11.3", "", { "dependencies": { "@emnapi/wasi-threads": "1.2.3", "tslib": "^2.4.0" }, "bundled": true }, "sha512-zLpS5asjEb7lq8jYLq37N6XKaE41DIexlY1rF/z4/tIl3wo13Sqm28fRyfIsKZD+NZ8mM5RoKkpW/rBcuoSZSg=="],
@@ -6922,8 +6919,6 @@
 
     "@brendonovich/vite-plugin-opencode/@opencode-ai/client/@opencode-ai/schema": ["@opencode-ai/schema@0.0.0-beta-18050", "", { "dependencies": { "@standard-schema/spec": "1.1.0", "effect": "4.0.0-rc.111" } }, "sha512-/D6VXaWlytTXR3IOiMLIKuPcfp7FQNUzRPm9z3K7UBFd1Bw4q/WZksaf5RVcBGz+0YRxYMc1V4D7MFlceSgtyg=="],
 
-    "@brendonovich/vite-plugin-opencode/@opencode-ai/client/effect": ["effect@4.0.0-rc.111", "", { "dependencies": { "@standard-schema/spec": "^1.1.0", "fast-check": "^4.9.0", "msgpackr": "^2.0.5" } }, "sha512-ASd5L58EIR0CUNueZNKKjSsyOCd+2alxOAIaTcHaqkJkPsaYSsw5Cg/cfANk5K4Jr2YsX756xvX11shzqsreWA=="],
-
     "@bruits/satteri-wasm32-wasi/@emnapi/core/@emnapi/wasi-threads": ["@emnapi/wasi-threads@1.2.2", "", { "dependencies": { "tslib": "^2.4.0" } }, "sha512-c95qOXkHdydNKhscBTebqEC1CVAZpyqOfVfBzQ1qgzyl3gfeldUjIggDbIZgDKsHLgnsM+igH7TJ/eAasaVuMA=="],
 
     "@electron/asar/minimatch/brace-expansion": ["brace-expansion@1.1.18", "", { "dependencies": { "balanced-match": "^1.0.0", "concat-map": "0.0.1" } }, "sha512-Edep/X9fGqVNmzKBVsDYIOtD+z1tuezV70LBjdCst9Tqu76lsnvRiZ6oTic1n+/BIwX6QDGAO94PN4N2SADvtw=="],

nix/hashes.json

@@ -1,8 +1,8 @@
 {
   "nodeModules": {
-    "x86_64-linux": "sha256-I2sHU46Bdp1DmW/ygNKKxF6U53oNIeVeAS8TmMdtvzw=",
-    "aarch64-linux": "sha256-aQUEBmfHhaR/YdsRyw0u6hsEo0TEmXHBMyiGnOFRCeI=",
-    "aarch64-darwin": "sha256-40Y3HYSjs8S0M3SFNUrU8lMYaHy7vpmiW+7b6Y9pKzs=",
-    "x86_64-darwin": "sha256-7iGegI/1pXcR5W0UBX0wAWAga+F34fhj9lbAHotVwEo="
+    "x86_64-linux": "sha256-J7xJ1+x+f13zso+UMP1YYzkjFM0LiHZURmf8HhO3X4M=",
+    "aarch64-linux": "sha256-CF7BiObbwjFT4BV5FUqB535fqoPuXuExKpERcev/Re0=",
+    "aarch64-darwin": "sha256-ts3zgHiPeQcrehST1ikr+BNwlF+3JDn0/IUeJSAOB3o=",
+    "x86_64-darwin": "sha256-awKiMBuDMrapw3Lrm39TbE+ILJZ1P8R8sqYJEWapSf8="
   }
 }

package.json

@@ -5,7 +5,7 @@
   "version": "0.0.0",
   "private": true,
   "type": "module",
-  "packageManager": "bun@1.4.0",
+  "packageManager": "bun@1.4.1",
   "scripts": {
     "dev": "bun run --cwd packages/cli --conditions=browser src/index.ts",
     "dev:live": "sh -c 'OPENCODE_TUI_CHANNEL=dev OPENCODE_PASSWORD=\"$(opencode2 service get password)\" exec bun run dev \"$@\" --server \"$(opencode2 service status)\"' --",
@@ -43,7 +43,7 @@
       "@effect/platform-node-shared": "4.0.0-rc.112",
       "@effect/sql-sqlite-bun": "4.0.0-rc.112",
       "@npmcli/arborist": "9.4.0",
-      "@types/bun": "1.3.13",
+      "@types/bun": "1.4.0",
       "@types/cross-spawn": "6.0.6",
       "@octokit/rest": "22.0.0",
       "@hono/standard-validator": "0.2.0",
@@ -159,6 +159,7 @@
     "@effect/platform-node-shared": "catalog:",
     "@types/bun": "catalog:",
     "@types/node": "catalog:",
+    "bun-types": "1.4.1",
     "effect": "catalog:",
     "solid-js": "catalog:"
   },

packages/ai/README.md

@@ -247,6 +247,8 @@ it does not repair or truncate them.
 
 For explicit compaction, script a `CompactionResponse` through `push`, `always`, or `serve`. Its `replacement` contains the next context window, including retained user messages. The client returns that result and usage directly, with the same lazy request recording and gates. Generation and compaction reject fixtures for the wrong operation instead of converting between response shapes.
 
+For `compact(request, { mechanism: "trigger" })`, script a `CompactionCheckpointResponse` instead. It carries `checkpoint`, `responseID`, and optional `usage`. Endpoint and trigger calls reject each other's fixtures; both share the same queue, gates, lazy recording, and fallback controls.
+
 The published legacy `Service`, `layer`, `clientLayer`, and module-level controls remain available as adapters
 over the same implementation, including the legacy live `requests` array. New tests should use `Test` and
 `testLayer`.
@@ -259,7 +261,7 @@ This is different from prompt caching, server-side history storage, or truncatio
 
 ### Explicit compaction
 
-`LLMClient.compact(request)` is the caller-controlled operation for OpenAI, Azure, and xAI Responses. It performs exactly one HTTP call to `/responses/compact`, using the selected route's endpoint, credentials, query, and HTTP middleware. It returns a `CompactionResponse` with `replacement: Message[]` and optional `usage`, not a normal generation response.
+`LLMClient.compact(request)` (equivalently, `{ mechanism: "endpoint" }`) is the caller-controlled operation for OpenAI, Azure, and xAI Responses. It performs exactly one HTTP call to `/responses/compact`, using the selected route's endpoint, credentials, query, and HTTP middleware. It returns a `CompactionResponse` with `replacement: Message[]` and optional `usage`, not a normal generation response. This mechanism does not accept a WebSocket executor.
 
 Prefer this operation, where supported, when the application owns compaction policy and durable context updates.
 
@@ -279,6 +281,41 @@ Generation-only body overlays such as `stream` and `store` are not sent to the c
 
 The input must still fit the model's context window. Explicit compaction is not an overflow-recovery operation. Anthropic does not expose this operation in this package; its in-band compaction remains available below. Compatible routes do not inherit an explicit compact endpoint simply because they use a Responses protocol.
 
+### Streamed checkpoint compaction
+
+OpenAI Responses also exposes a separate, explicitly selected mechanism:
+
+```ts
+const result =
+  yield *
+  LLMClient.compact(request, {
+    mechanism: "trigger",
+    webSocket, // Optional: without it, the request uses HTTP/SSE.
+  })
+
+result.checkpoint // Successful encrypted CompactionPart.
+result.responseID
+result.usage
+```
+
+This appends a native `compaction_trigger` control item to the full input and sends a normal Responses request. It follows the [Codex V2 request shape](https://github.com/openai/codex/blob/728cb12/codex-rs/core/src/compact_remote_v2_attempt.rs), with tools and instructions retained, `stream: true`, `store: false`, and parallel tool calls enabled. It removes normal-answer text/output-format controls, forced tool choices, output-token/tool-call limits, and automatic `context_management`. Body overlays cannot replace `input` or supply `previous_response_id`/`conversation`; the complete canonical history is required for safe stateless replay. Session/cache identifiers, auth, headers, query parameters, service tier, and supported prompt-cache settings are preserved.
+
+Only a successful `response.completed` with a response ID and exactly one logical encrypted checkpoint succeeds. Repeated item events are correlated by ID/output slot, including ID-less checkpoints. Other output is ignored, not returned as assistant text or dispatched as tools. Failed, incomplete, malformed, and interrupted responses return errors rather than partial checkpoints.
+
+The result is **not a replacement window**. The caller selects retained history, combines it with `result.checkpoint`, and durably installs it before continuing. The operation does not choose a retention budget, prune messages, or modify the original request.
+
+The supplied WebSocket executor can reuse a compatible append baseline for the compaction request. On completion the protocol supplies no continuation checkpoint, clearing the old baseline so the next generation sends the newly installed window in full. Validation occurs before transport completion is acknowledged. There is no operation-level retry or fallback to `/responses/compact`; existing safe transport fallback may use SSE, with full history and no connection-local response ID.
+
+Trigger support is separate from endpoint support. Only the OpenAI Responses route advertises it; Azure, xAI, Chat, and compatible Responses routes do not inherit it. Untyped calls still fail before sending: missing route capabilities return `UnsupportedOperation`, while unknown mechanism names and invalid inputs return `InvalidRequest`. Dynamic callers must narrow for the selected mechanism:
+
+```ts
+if (LLMClient.canCompact(request, { mechanism: "trigger" })) {
+  const result = yield * LLMClient.compact(request, { mechanism: "trigger" })
+}
+```
+
+This capability describes protocol implementation, **not universal availability on OpenAI API deployments**. The host application owns subscription/deployment eligibility, OAuth, endpoint selection, and deployment-specific headers. Local protocol/socket tests do not establish live provider support.
+
 ### Advanced: in-band compaction
 
 `providerOptions.contextManagement` lets the provider decide when to compact during an ordinary `generate` or `stream` call. This is an advanced option for callers that own persistence and recovery: persist the complete assistant message, including its checkpoint, before continuing. Enabling the option does not provide durable checkpoint storage, interruption recovery, or model-switch policy. Keep the prior context until a successful checkpoint has been persisted.

packages/ai/src/cache-policy.ts

@@ -11,7 +11,7 @@
 // Manual `cache: CacheHint` placements on individual parts are preserved and
 // count against the four-breakpoint budget; auto only fills remaining slots.
 import { CacheHint, type CachePolicy, type CachePolicyObject } from "./schema/options.js"
-import { LLMRequest, Message, ToolDefinition, type ContentPart } from "./schema/messages.js"
+import { LLMRequest, Message, ToolDefinition, type ContentPart, type ToolEntry } from "./schema/messages.js"
 
 const AUTO: CachePolicyObject = {
   tools: true,
@@ -50,18 +50,24 @@ interface Budget {
   remaining: number
 }
 
-const markLastTool = (
-  tools: ReadonlyArray<ToolDefinition>,
-  hint: CacheHint,
-  budget: Budget,
-): ReadonlyArray<ToolDefinition> => {
-  if (tools.length === 0) return tools
-  const last = tools.length - 1
-  if (tools[last]!.cache || budget.remaining === 0) return tools
+const markLastTool = (tools: ReadonlyArray<ToolEntry>, hint: CacheHint, budget: Budget): ReadonlyArray<ToolEntry> => {
+  const target = tools.at(-1)
+  if (target === undefined) return tools
+  if (target.type === "namespace") {
+    const nested = markLastTool(target.tools, hint, budget)
+    return nested === target.tools ? tools : [...tools.slice(0, -1), { ...target, tools: nested }]
+  }
+  if (target.cache || budget.remaining === 0) return tools
   budget.remaining -= 1
-  return tools.map((tool, i) => (i === last ? new ToolDefinition({ ...tool, cache: hint }) : tool))
+  return [...tools.slice(0, -1), new ToolDefinition({ ...target, cache: hint })]
 }
 
+const countToolHints = (tools: ReadonlyArray<ToolEntry>): number =>
+  tools.reduce(
+    (count, tool) => count + (tool.type === "tool" ? (tool.cache === undefined ? 0 : 1) : countToolHints(tool.tools)),
+    0,
+  )
+
 const markSystemBoundaries = (system: LLMRequest["system"], hint: CacheHint, budget: Budget): LLMRequest["system"] => {
   if (system.length === 0) return system
   let changed = false
@@ -122,7 +128,7 @@ const markMessages = (
 }
 
 const countHints = (request: LLMRequest) =>
-  request.tools.reduce((count, tool) => count + (tool.cache === undefined ? 0 : 1), 0) +
+  countToolHints(request.tools) +
   request.system.reduce((count, part) => count + (part.cache === undefined ? 0 : 1), 0) +
   request.messages.reduce(
     (count, message) =>

packages/ai/src/llm.ts

@@ -12,9 +12,10 @@ import {
   LanguageModel,
   SystemPart,
   ToolChoice,
-  ToolDefinition,
+  ToolEntry,
   type ContentPart,
   type LanguageModelProviderOptions,
+  type ToolEntryInput,
 } from "./schema/index.js"
 import { make as makeTool, toDefinitions, type ToolSchema } from "./tool.js"
 
@@ -27,7 +28,7 @@ export type RequestInput<SelectedLanguageModel extends LanguageModel = LanguageM
   readonly system?: string | SystemPart | ReadonlyArray<SystemPart>
   readonly prompt?: string | ContentPart | ReadonlyArray<ContentPart>
   readonly messages?: ReadonlyArray<Message | Message.Input>
-  readonly tools?: ReadonlyArray<ToolDefinition.Input>
+  readonly tools?: ReadonlyArray<ToolEntryInput>
   readonly toolChoice?: ToolChoice.Input
   readonly generation?: GenerationOptions.Input
   readonly providerOptions?: NoInfer<LanguageModelProviderOptions<SelectedLanguageModel>>
@@ -56,7 +57,7 @@ export const request = <const SelectedLanguageModel extends LanguageModel>(
     ...rest,
     system: SystemPart.content(requestSystem),
     messages: [...(messages?.map(Message.make) ?? []), ...(prompt === undefined ? [] : [Message.user(prompt)])],
-    tools: tools?.map(ToolDefinition.make) ?? [],
+    tools: tools?.map(ToolEntry.make) ?? [],
     toolChoice: requestToolChoice ? ToolChoice.make(requestToolChoice) : undefined,
     generation: requestGeneration === undefined ? undefined : GenerationOptions.make(requestGeneration),
     providerOptions: requestProviderOptions,

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

@@ -1067,10 +1067,11 @@ const fromRequest = Effect.fn("AnthropicMessages.fromRequest")(function* (reques
   // messages. Tools live highest in the cache hierarchy, so when callers
   // over-mark we keep their tool hints and shed the message-tail ones first.
   const breakpoints = Cache.newBreakpoints(ANTHROPIC_BREAKPOINT_CAP)
+  const flattened = ProviderShared.flattenToolRequest(request)
   const tools =
-    request.tools.length === 0
+    flattened.tools.length === 0
       ? undefined
-      : request.tools.map((tool) =>
+      : flattened.tools.map((tool) =>
           lowerTool(
             breakpoints,
             tool,
@@ -1088,7 +1089,7 @@ const fromRequest = Effect.fn("AnthropicMessages.fromRequest")(function* (reques
           text: part.text,
           cache_control: cacheControl(breakpoints, part.cache),
         }))
-  const messages = yield* lowerMessages(request, breakpoints)
+  const messages = yield* lowerMessages(flattened.request, breakpoints)
   if (breakpoints.dropped > 0) {
     yield* Effect.logWarning(
       `Anthropic Messages: dropped ${breakpoints.dropped} cache breakpoint(s); the API allows at most ${ANTHROPIC_BREAKPOINT_CAP} per request.`,

packages/ai/src/protocols/bedrock-converse.ts

@@ -415,7 +415,10 @@ const lowerMessages = Effect.fn("BedrockConverse.lowerMessages")(function* (
 
 // System prompts share the cache-point convention: emit the text block, then
 // optionally a positional `cachePoint` marker.
-const lowerSystem = (breakpoints: BedrockCache.Breakpoints, system: ReadonlyArray<LLMRequest["system"][number]>) => {
+const lowerSystem = (
+  breakpoints: BedrockCache.Breakpoints,
+  system: ReadonlyArray<LLMRequest["system"][number]>,
+) => {
   const content = system
     .filter((part) => part.text.length > 0)
     .flatMap((part) => textWithCache(breakpoints, part.text, part.cache))
@@ -424,21 +427,22 @@ const lowerSystem = (breakpoints: BedrockCache.Breakpoints, system: ReadonlyArra
 
 const fromRequest = Effect.fn("BedrockConverse.fromRequest")(function* (request: LLMRequest) {
   const toolChoice = request.toolChoice ? yield* lowerToolChoice(request.toolChoice) : undefined
+  const flattened = ProviderShared.flattenToolRequest(request)
   const generation = request.generation
   // Bedrock-Claude shares Anthropic's 4-breakpoint cap. Spend the budget in
   // tools → system → messages order to favour the highest-impact prefixes.
   const breakpoints = BedrockCache.breakpoints()
   const toolConfig = (() => {
-    if (request.tools.length === 0) return undefined
+    if (flattened.tools.length === 0) return undefined
     return {
-      tools: lowerTools(request.model.compatibility?.toolSchema, breakpoints, request.tools),
+      tools: lowerTools(request.model.compatibility?.toolSchema, breakpoints, flattened.tools),
       // Converse has no native "none". Keep definitions stable for prompt
       // caching and omit only the unsupported choice.
       toolChoice,
     }
   })()
   const system = lowerSystem(breakpoints, request.system)
-  const messages = yield* lowerMessages(request, breakpoints)
+  const messages = yield* lowerMessages(flattened.request, breakpoints)
   if (breakpoints.dropped > 0) {
     yield* Effect.logWarning(
       `Bedrock Converse: dropped ${breakpoints.dropped} cache breakpoint(s); the API allows at most ${BedrockCache.BEDROCK_BREAKPOINT_CAP} per request.`,

packages/ai/src/protocols/gemini.ts

@@ -465,7 +465,8 @@ function mapSafetySettings(value: unknown) {
 }
 
 const fromRequest = Effect.fn("Gemini.fromRequest")(function* (request: LLMRequest) {
-  const hasTools = request.tools.length > 0
+  const flattened = ProviderShared.flattenToolRequest(request)
+  const hasTools = flattened.tools.length > 0
   const generation = request.generation
   const options = resolveOptions(request)
   const toolSchemaCompatibility = request.model.compatibility?.toolSchema
@@ -483,7 +484,7 @@ const fromRequest = Effect.fn("Gemini.fromRequest")(function* (request: LLMReque
 
   return {
     cachedContent: options.cachedContent,
-    contents: yield* lowerMessages(request),
+    contents: yield* lowerMessages(flattened.request),
     safetySettings: options.safetySettings,
     serviceTier: options.serviceTier,
     systemInstruction:
@@ -491,7 +492,7 @@ const fromRequest = Effect.fn("Gemini.fromRequest")(function* (request: LLMReque
     tools: hasTools
       ? [
           {
-            functionDeclarations: request.tools.map((tool) =>
+            functionDeclarations: flattened.tools.map((tool) =>
               lowerTool(tool, ToolSchemaProjection.modelCompatibility(tool.inputSchema, toolSchemaCompatibility)),
             ),
           },

packages/ai/src/protocols/mistral-chat.ts

@@ -414,10 +414,11 @@ export const fromRequest = Effect.fn("MistralChat.fromRequest")(function* (reque
         tool: (name) => ({ type: "function" as const, function: { name } }),
       })
     : undefined
+  const flattened = ProviderShared.flattenToolRequest(request)
   return {
     model: request.model.id,
-    messages: yield* lowerMessages(request),
-    tools: request.tools.length > 0 ? request.tools.map(lowerTool) : undefined,
+    messages: yield* lowerMessages(flattened.request),
+    tools: flattened.tools.length > 0 ? flattened.tools.map(lowerTool) : undefined,
     tool_choice: toolChoice,
     stream: true as const,
     max_tokens: request.generation?.maxTokens,

packages/ai/src/protocols/open-responses-continuation.ts

@@ -42,6 +42,7 @@ const canonical = (value: unknown): string => {
   if (Array.isArray(value)) return `[${value.map(canonical).join(",")}]`
   if (!ProviderShared.isRecord(value)) return ProviderShared.encodeJson(value)
   return `{${Object.keys(value)
+    .filter((key) => value[key] !== undefined)
     .sort()
     .map((key) => `${ProviderShared.encodeJson(key)}:${canonical(value[key])}`)
     .join(",")}}`
@@ -57,7 +58,12 @@ const comparable = (value: unknown) => {
   if (value.type === "message" && value.role === "assistant")
     return {
       role: "assistant",
-      content: value.content,
+      // Annotations and logprobs describe the response, not the text replayed in model input.
+      content: Array.isArray(value.content)
+        ? value.content.map((part) =>
+            ProviderShared.isRecord(part) && part.type === "output_text" ? { type: part.type, text: part.text } : part,
+          )
+        : value.content,
       ...(value.phase === undefined ? {} : { phase: value.phase }),
     }
   if (value.type === "function_call")
@@ -121,7 +127,7 @@ const rejected = (
 
 export const driver = (input: DriverInput): WebSocketChannelDriver => {
   const { previous_response_id: _previousResponseID, ...request } = input.request
-  let output: unknown[] = []
+  let output: OpenResponses.StreamItem[] = []
   return {
     create: (checkpoint) =>
       Effect.sync(() => {
@@ -149,6 +155,12 @@ export const driver = (input: DriverInput): WebSocketChannelDriver => {
           if (rejection === "websocket_connection_limit_reached") return rejected(observation, "rotate-and-retry-full")
         }
         if (observation.type !== "completed") return observation
+        // A trigger installs a different context window. Clear the append baseline, retaining the socket.
+        if (
+          Array.isArray(request.input) &&
+          request.input.some((item) => ProviderShared.isRecord(item) && item.type === "compaction_trigger")
+        )
+          return observation
         const responseID = event.response?.id
         if (!responseID || responseID.trim().length === 0) return observation
         return {
@@ -159,7 +171,14 @@ export const driver = (input: DriverInput): WebSocketChannelDriver => {
               version: VERSION,
               responseID,
               request,
-              output: event.response?.output ? [...event.response.output] : output.slice(),
+              // Completion can re-encrypt reasoning. Callers replay the item already emitted by output_item.done.
+              output: event.response?.output
+                ? event.response.output.map((item) =>
+                    item.type === "reasoning" && item.id !== undefined
+                      ? (output.find((done) => done.type === item.type && done.id === item.id) ?? item)
+                      : item,
+                  )
+                : output.slice(),
             } satisfies CheckpointValue,
           },
         }

packages/ai/src/protocols/open-responses.ts

@@ -189,6 +189,7 @@ export const InputItem = Schema.Union([
     id: Schema.optionalKey(Schema.String),
     call_id: Schema.String,
     name: Schema.String,
+    namespace: Schema.optional(Schema.String),
     arguments: Schema.String,
   }),
   Schema.Struct({
@@ -315,6 +316,7 @@ export const StreamItem = Schema.StructWithRest(
     id: Schema.optional(Schema.String),
     call_id: Schema.optional(Schema.String),
     name: Schema.optional(Schema.String),
+    namespace: Schema.optional(Schema.String),
     arguments: Schema.optional(Schema.String),
     encrypted_content: optionalNull(Schema.String),
   }),
@@ -488,6 +490,7 @@ const lowerToolCall = (part: ToolCallPart, providerMetadataKey: string): OpenRes
     ...(id === undefined ? {} : { id }),
     call_id: part.id,
     name: part.name,
+    namespace: part.namespace,
     arguments: ProviderShared.encodeJson(part.input),
   }
 }
@@ -807,14 +810,15 @@ export const fromRequestWithAdapter = Effect.fn("OpenResponses.fromRequestWithAd
   request: LLMRequest,
   adapter: ProviderAdapter,
 ) {
+  const projected = ProviderShared.flattenToolRequest(request)
   const toolSchemaCompatibility = request.model.compatibility?.toolSchema
   return {
-    ...(yield* lowerConversation(request, adapter)),
+    ...(yield* lowerConversation(projected.request, adapter)),
     ...lowerGeneration(request),
     tools:
-      request.tools.length === 0
+      projected.tools.length === 0
         ? undefined
-        : yield* Effect.forEach(request.tools, (tool) =>
+        : yield* Effect.forEach(projected.tools, (tool) =>
             lowerTool(
               adapter.name,
               tool,
@@ -919,7 +923,7 @@ const joinReasoningText = (parts: ReadonlyArray<string | undefined>) => {
   return parts.filter((part) => part !== undefined).join("\n\n")
 }
 
-const outputItemID = (state: ParserState, event: Event) =>
+const outputItemID = (state: Pick<ParserState, "outputItems">, event: Event) =>
   event.output_index === undefined ? event.item_id : (state.outputItems[event.output_index] ?? event.item_id)
 
 const ITEM_ID_PREFIX: Readonly<Record<string, string>> = {
@@ -931,7 +935,11 @@ const ITEM_ID_PREFIX: Readonly<Record<string, string>> = {
 
 // An item without an id adopts the id already open in its output slot,
 // otherwise it gets a locally minted one.
-const resolveItem = (state: ParserState, item: StreamItem, index: number | undefined): OutputItem => ({
+const resolveItem = (
+  state: Pick<ParserState, "outputItems">,
+  item: StreamItem,
+  index: number | undefined,
+): OutputItem => ({
   ...item,
   id:
     item.id ??
@@ -941,7 +949,7 @@ const resolveItem = (state: ParserState, item: StreamItem, index: number | undef
 
 // Registered output slots are authoritative for `item_id` routing, and items
 // are resolved here so everything downstream can rely on `item.id`.
-export const normalize = (state: ParserState, input: Event): NormalizedEvent => ({
+export const normalize = (state: Pick<ParserState, "outputItems">, input: Event): NormalizedEvent => ({
   ...input,
   item_id: input.item_id === undefined ? undefined : outputItemID(state, input),
   item: input.item ? resolveItem(state, input.item, input.output_index) : input.item,
@@ -1094,11 +1102,20 @@ const onOutputItemAdded = (state: ParserState, event: NormalizedEvent): StepResu
       tools: ToolStream.start(state.tools, item.id, {
         id: item.call_id,
         name: item.name ?? "",
+        namespace: item.namespace,
         input: item.arguments ?? "",
         providerMetadata: metadata,
       }),
     },
-    [...events, LLMEvent.toolInputStart({ id: item.call_id, name: item.name ?? "", providerMetadata: metadata })],
+    [
+      ...events,
+      LLMEvent.toolInputStart({
+        id: item.call_id,
+        name: item.name ?? "",
+        namespace: item.namespace,
+        providerMetadata: metadata,
+      }),
+    ],
   ]
 }
 
@@ -1217,7 +1234,12 @@ const onOutputItemDone = Effect.fn("OpenResponses.onOutputItemDone")(function* (
     const registered = state.tools[item.id] !== undefined
     const tools = registered
       ? state.tools
-      : ToolStream.start(state.tools, item.id, { id: item.call_id, name: item.name, providerMetadata: metadata })
+      : ToolStream.start(state.tools, item.id, {
+          id: item.call_id,
+          name: item.name,
+          namespace: item.namespace,
+          providerMetadata: metadata,
+        })
     const result =
       item.arguments === undefined
         ? yield* ToolStream.finish(state.id, tools, item.id)
@@ -1228,7 +1250,15 @@ const onOutputItemDone = Effect.fn("OpenResponses.onOutputItemDone")(function* (
     const resultEvents =
       registered || finished.length === 0
         ? finished
-        : [LLMEvent.toolInputStart({ id: item.call_id, name: item.name, providerMetadata: metadata }), ...finished]
+        : [
+            LLMEvent.toolInputStart({
+              id: item.call_id,
+              name: item.name,
+              namespace: item.namespace,
+              providerMetadata: metadata,
+            }),
+            ...finished,
+          ]
     const lifecycle = resultEvents.length ? Lifecycle.stepStart(state.lifecycle, events) : state.lifecycle
     events.push(...resultEvents)
     return [

packages/ai/src/protocols/openai-chat.ts

@@ -736,6 +736,7 @@ export const fromRequest = Effect.fn("OpenAIChat.fromRequest")(function* (
     )
   const generation = request.generation
   const toolSchemaCompatibility = request.model.compatibility?.toolSchema
+  const flattened = ProviderShared.flattenToolRequest(request)
   const provider = String(request.model.provider)
   const baseURL = request.model.route.endpoint.baseURL
   const detectedMaxTokensField = detectMaxTokensField(provider, baseURL)
@@ -748,16 +749,16 @@ export const fromRequest = Effect.fn("OpenAIChat.fromRequest")(function* (
   const zaiToolStream =
     request.model.compatibility?.zaiToolStream ?? detectZaiToolStream(provider, baseURL, request.model.id)
   const hasHistory = hasToolHistory(request.messages)
-  const hasActiveTools = request.tools.length > 0
+  const hasActiveTools = flattened.tools.length > 0
   return {
     model: request.model.id,
-    messages: yield* lowerMessages(request, options),
+    messages: yield* lowerMessages(flattened.request, options),
     tools:
-      request.tools.length === 0
+      flattened.tools.length === 0
         ? hasHistory
           ? []
           : undefined
-        : request.tools.map((tool) =>
+        : flattened.tools.map((tool) =>
             lowerTool(
               tool,
               ToolSchemaProjection.modelCompatibility(tool.inputSchema, toolSchemaCompatibility),

packages/ai/src/protocols/openai-responses.ts

@@ -5,7 +5,7 @@ import { Auth } from "../route/auth.js"
 import { Endpoint } from "../route/endpoint.js"
 import { Protocol } from "../route/protocol.js"
 import { HttpTransport } from "../route/transport/index.js"
-import type { LLMRequest, JsonSchema, ToolDefinition } from "../schema/index.js"
+import { LLMRequest, mergeJsonRecords, type JsonSchema, type ToolDefinition, type ToolEntry } from "../schema/index.js"
 import { OpenResponses } from "./open-responses.js"
 import { JsonObject, optionalArray, optionalNull, ProviderShared } from "./shared.js"
 import { OpenAIImage } from "./utils/openai-image.js"
@@ -13,6 +13,7 @@ import { ResponsesHostedTools } from "./utils/responses-hosted-tools.js"
 import { ToolSchemaProjection } from "./utils/tool-schema.js"
 import { OpenResponsesChannel } from "./open-responses-channel.js"
 import { ResponsesCompaction } from "./utils/responses-compaction.js"
+import { ResponsesCheckpoint } from "./utils/responses-checkpoint.js"
 
 const ADAPTER = "openai-responses"
 const NAME = "OpenAI Responses"
@@ -75,7 +76,18 @@ const OpenAIResponsesHostedToolItem = Schema.Union([
   ),
 ])
 
-const OpenAIResponsesTools = Schema.Union([OpenResponses.Tool, OpenAIResponsesImageGenerationTool])
+const OpenAIResponsesNamespace = Schema.Struct({
+  type: Schema.tag("namespace"),
+  name: Schema.String,
+  description: Schema.String,
+  tools: Schema.Array(OpenResponses.Tool),
+})
+
+const OpenAIResponsesTools = Schema.Union([
+  OpenResponses.Tool,
+  OpenAIResponsesNamespace,
+  OpenAIResponsesImageGenerationTool,
+])
 
 const OpenAIResponsesToolChoice = Schema.Union([
   OpenResponses.ToolChoice,
@@ -103,6 +115,18 @@ const OpenAIResponsesBody = Schema.Struct({
 })
 export type OpenAIResponsesBody = Schema.Schema.Type<typeof OpenAIResponsesBody>
 
+/** Request control, never conversation content. */
+export const CompactionTrigger = Schema.Struct({ type: Schema.Literal("compaction_trigger") })
+const CheckpointBody = Schema.Struct({
+  ...OpenAIResponsesBody.fields,
+  input: Schema.Array(Schema.Union([OpenResponses.InputItem, OpenAIResponsesHostedToolItem, CompactionTrigger])),
+  store: Schema.Literal(false),
+  prompt_cache_retention: optionalNull(Schema.String),
+  prompt_cache_options: optionalNull(
+    Schema.Struct({ mode: Schema.optional(Schema.String), ttl: Schema.optional(Schema.String) }),
+  ),
+})
+
 const adapter = {
   id: ADAPTER,
   name: NAME,
@@ -128,13 +152,33 @@ const lowerTool = Effect.fn("OpenAIResponses.lowerTool")(function* (tool: ToolDe
   return yield* OpenResponses.lowerTool(NAME, tool, inputSchema)
 })
 
-const lowerToolChoice = (toolChoice: NonNullable<LLMRequest["toolChoice"]>, tools: ReadonlyArray<ToolDefinition>) =>
+// Native namespaces hold only function tools, so deeper levels flatten into
+// the leaf names the same way non-native protocols flatten the whole tree.
+const lowerToolEntry = Effect.fn("OpenAIResponses.lowerToolEntry")(function* (
+  tool: ToolEntry,
+  compatibility: Parameters<typeof ToolSchemaProjection.modelCompatibility>[1],
+) {
+  if (tool.type === "tool")
+    return yield* lowerTool(tool, ToolSchemaProjection.modelCompatibility(tool.inputSchema, compatibility))
+  // OpenAI requires a namespace description; fall back to a generic one so a
+  // missing description never blocks the request.
+  return {
+    type: "namespace" as const,
+    name: tool.name,
+    description: tool.description ?? `Tools in the ${tool.name} namespace.`,
+    tools: yield* Effect.forEach(ProviderShared.flattenTools(tool.tools), (leaf) =>
+      OpenResponses.lowerTool(NAME, leaf, ToolSchemaProjection.modelCompatibility(leaf.inputSchema, compatibility)),
+    ),
+  }
+})
+
+const lowerToolChoice = (toolChoice: NonNullable<LLMRequest["toolChoice"]>, tools: ReadonlyArray<ToolEntry>) =>
   ProviderShared.matchToolChoice(NAME, toolChoice, {
     auto: () => "auto" as const,
     none: () => "none" as const,
     required: () => "required" as const,
     tool: (name) =>
-      tools.some((tool) => tool.name === name && nativeImageTool(tool) !== undefined)
+      tools.some((tool) => tool.type === "tool" && tool.name === name && nativeImageTool(tool) !== undefined)
         ? ({ type: "image_generation" } as const)
         : { type: "function" as const, name },
   })
@@ -153,15 +197,42 @@ const fromRequest = Effect.fn("OpenAIResponses.fromRequest")(function* (request:
     tools:
       request.tools.length === 0
         ? undefined
-        : yield* Effect.forEach(request.tools, (tool) =>
-            lowerTool(tool, ToolSchemaProjection.modelCompatibility(tool.inputSchema, toolSchemaCompatibility)),
-          ),
+        : yield* Effect.forEach(request.tools, (tool) => lowerToolEntry(tool, toolSchemaCompatibility)),
     tool_choice:
       OpenResponses.allowedToolChoice(request) ??
       (request.toolChoice ? yield* lowerToolChoice(request.toolChoice, request.tools) : undefined),
   })
 })
 
+const checkpointBody = {
+  schema: CheckpointBody,
+  from: Effect.fn("OpenAIResponses.checkpointBody")(function* (request: LLMRequest) {
+    const native = yield* fromRequest(LLMRequest.update(request, { toolChoice: undefined }))
+    const overlay = request.http?.body
+    // Complete history is required for stateless replay and SSE recovery. Raw input overrides bypass that contract.
+    if (
+      overlay?.input !== undefined ||
+      overlay?.previous_response_id !== undefined ||
+      overlay?.conversation !== undefined
+    )
+      return yield* ProviderShared.invalidRequest(
+        "Trigger compaction requires complete canonical history, not an input or continuation override",
+      )
+    return yield* ProviderShared.validateWith(Schema.decodeUnknownEffect(CheckpointBody))({
+      ...mergeJsonRecords(native, overlay),
+      input: [...native.input, { type: "compaction_trigger" }],
+      stream: true,
+      store: false,
+      parallel_tool_calls: true,
+      tool_choice: undefined,
+      context_management: undefined,
+      text: undefined,
+      max_output_tokens: undefined,
+      max_tool_calls: undefined,
+    })
+  }),
+}
+
 const hostedToolResult = Effect.fn("OpenAIResponses.hostedToolResult")(function* (item: ResponsesHostedTools.Item) {
   const isError = item.error !== undefined && item.error !== null
   if (item.type === "image_generation_call" && item.result) {
@@ -239,7 +310,7 @@ export const transport = channelTransport({
 })
 
 export const route = Route.make({
-  compact: ResponsesCompaction.make(adapter),
+  compact: { endpoint: ResponsesCompaction.make(adapter), trigger: ResponsesCheckpoint.make(checkpointBody) },
   id: ADAPTER,
   provider: "openai",
   providerMetadataKey: "openai",

packages/ai/src/protocols/shared.ts

@@ -9,11 +9,14 @@ import {
   UnsupportedOperationError,
   AIError,
   HttpContext,
+  LLMRequest,
+  Message,
+  ToolDefinition,
   type ContentPart,
-  type LLMRequest,
   type MediaPart,
   type ProviderID,
   type TextPart,
+  type ToolEntry,
   type ToolResultPart,
 } from "../schema/index.js"
 import { isRecord } from "../utils/record.js"
@@ -46,6 +49,7 @@ export const promptCacheKey = (request: LLMRequest): string | undefined => {
 export interface ToolAccumulator {
   readonly id: string
   readonly name: string
+  readonly namespace?: string
   readonly input: string
 }
 
@@ -279,6 +283,38 @@ export const unsupportedOperation = (input: {
     }),
   })
 
+/**
+ * Lower namespaces to flat definitions for protocols without a native
+ * namespace construct. Leaf names join their namespace path with `_` because
+ * `.` is not broadly accepted in provider tool names.
+ */
+export const flattenTools = (tools: ReadonlyArray<ToolEntry>, path: ReadonlyArray<string> = []) => {
+  const flat = tools.flatMap((tool): ReadonlyArray<ToolDefinition> => {
+    if (tool.type === "namespace") return flattenTools(tool.tools, [...path, tool.name])
+    if (path.length === 0) return [tool]
+    return [new ToolDefinition({ ...tool, name: [...path, tool.name].join("_") })]
+  })
+  return [...new Map(flat.map((tool) => [tool.name, tool])).values()]
+}
+
+export const flattenToolRequest = (request: LLMRequest) => {
+  const messages = request.messages.map((message) => {
+    const content = message.content.map((part) => {
+      if ((part.type !== "tool-call" && part.type !== "tool-result") || part.namespace === undefined) return part
+      return { ...part, name: `${part.namespace}_${part.name}`, namespace: undefined }
+    })
+    return content.every((part, index) => part === message.content[index])
+      ? message
+      : new Message({ ...message, content })
+  })
+  return {
+    tools: flattenTools(request.tools),
+    request: messages.every((message, index) => message === request.messages[index])
+      ? request
+      : LLMRequest.update(request, { messages }),
+  }
+}
+
 export const imageResponse = Effect.fn("ProviderShared.imageResponse")(function* (
   route: string,
   name: string,

packages/ai/src/protocols/utils/responses-checkpoint.ts

@@ -0,0 +1,122 @@
+import { Effect, Schema, Stream } from "effect"
+import { Route, type RouteBody, type TriggerCompactOperation } from "../../route/client.js"
+import { Protocol } from "../../route/protocol.js"
+import { CompactionCheckpointResponse, HttpOptions, LLMEvent, LLMRequest } from "../../schema/index.js"
+import { OpenResponses } from "../open-responses.js"
+import { ProviderShared } from "../shared.js"
+
+interface State {
+  readonly parser: Pick<OpenResponses.ParserState, "id" | "provider" | "outputItems">
+  readonly checkpoints: Readonly<Record<string, CompactionCheckpointResponse["checkpoint"]>>
+  readonly responseID?: string
+}
+
+const onOutputItem = Effect.fn("ResponsesCheckpoint.onOutputItem")(function* (
+  state: State,
+  input: OpenResponses.Event,
+) {
+  const event = OpenResponses.normalize(state.parser, input)
+  const item = event.item
+  if (!item) return state
+  const parser =
+    event.output_index === undefined || state.parser.outputItems[event.output_index] === item.id
+      ? state.parser
+      : { ...state.parser, outputItems: { ...state.parser.outputItems, [event.output_index]: item.id } }
+  const next = parser === state.parser ? state : { ...state, parser }
+  if (event.type === "response.output_item.added" || item.type !== "compaction") return next
+  if (
+    event.output_index !== undefined &&
+    Object.entries(state.parser.outputItems).some(
+      ([index, id]) => id === item.id && Number(index) !== event.output_index,
+    )
+  )
+    return yield* ProviderShared.eventError(parser.id, "Compaction checkpoint appeared in multiple output slots")
+  if (!item.encrypted_content)
+    return yield* ProviderShared.eventError(parser.id, "Compaction output is missing its encrypted content")
+  const previous = state.checkpoints[item.id]
+  if (previous && previous.encrypted !== item.encrypted_content)
+    return yield* ProviderShared.eventError(parser.id, "Compaction output changed after completion")
+  if (previous) return next
+  return {
+    ...next,
+    checkpoints: {
+      ...state.checkpoints,
+      [item.id]: { type: "compaction", provider: parser.provider, id: item.id, encrypted: item.encrypted_content },
+    },
+  } satisfies State
+})
+
+/** Collect a trigger response before acknowledging transport completion. No generation output escapes. */
+export const make = <Body>(body: RouteBody<Body>): TriggerCompactOperation =>
+  Effect.fn("ResponsesCheckpoint.execute")(function* (request, executor, options) {
+    const source = request.model.route
+    let result: CompactionCheckpointResponse | undefined
+    // Route registries erase the frame type. The codec validates that boundary before parsing.
+    const event: Schema.Codec<OpenResponses.Event, unknown> = OpenResponses.protocol.stream.event
+    const protocol = Protocol.make({
+      id: source.protocol,
+      body,
+      stream: {
+        event,
+        initial: (request: LLMRequest): State => ({
+          parser: { id: source.id, provider: request.model.provider, outputItems: {} },
+          checkpoints: {},
+        }),
+        terminal: OpenResponses.terminal,
+        step: Effect.fn("ResponsesCheckpoint.step")(function* (state: State, event: OpenResponses.Event) {
+          if (event.response?.id && state.responseID && event.response.id !== state.responseID)
+            return yield* ProviderShared.eventError(source.id, "Compaction response ID changed during execution")
+          if (event.type === "response.created") return [{ ...state, responseID: event.response?.id }, []] as const
+          if (event.type === "error" || event.type === "response.failed")
+            return yield* OpenResponses.providerFailure(event, "Compaction request failed")
+          if (event.type === "response.incomplete")
+            return yield* ProviderShared.eventError(source.id, "Compaction response was incomplete")
+          if (event.type === "response.output_item.added" || event.type === "response.output_item.done")
+            return [yield* onOutputItem(state, event), []] as const
+          if (event.type !== "response.completed") return [state, []] as const
+          const responseID = event.response?.id
+          if (!responseID?.trim())
+            return yield* ProviderShared.eventError(source.id, "Compaction response is missing its response ID")
+          if (event.response?.status !== undefined && event.response.status !== "completed")
+            return yield* ProviderShared.eventError(source.id, "Compaction response did not complete successfully")
+          let next = state
+          for (const [index, item] of (event.response?.output ?? []).entries()) {
+            next = yield* onOutputItem(next, { type: "response.output_item.done", output_index: index, item })
+          }
+          const checkpoints = Object.values(next.checkpoints)
+          const checkpoint = checkpoints[0]
+          if (checkpoints.length !== 1 || !checkpoint)
+            return yield* ProviderShared.eventError(
+              source.id,
+              "Compaction response must contain exactly one checkpoint",
+            )
+          result = new CompactionCheckpointResponse({
+            checkpoint,
+            responseID,
+            usage: OpenResponses.mapUsage(event.response?.usage, OpenResponses.metadataKey(request.model)),
+          })
+          return [next, [LLMEvent.finish({ reason: { normalized: "stop" } })]] as const
+        }),
+      },
+    })
+    const route = Route.make({
+      id: source.id,
+      provider: source.provider,
+      providerMetadataKey: source.providerMetadataKey,
+      protocol,
+      endpoint: source.endpoint,
+      auth: source.auth,
+      transport: source.transport,
+    })
+    const native = yield* body.from(request)
+    // The body builder already applied and validated overlays. Do not let transport reapply them.
+    const preparedRequest = LLMRequest.update(request, {
+      http: request.http === undefined ? undefined : new HttpOptions({ ...request.http, body: undefined }),
+    })
+    const prepared = yield* route.prepareTransport(native, preparedRequest, options)
+    yield* route.streamPrepared(prepared, preparedRequest, { http: executor }, options).pipe(Stream.runDrain)
+    if (!result) return yield* ProviderShared.eventError(source.id, "Compaction response ended without a checkpoint")
+    return result
+  })
+
+export * as ResponsesCheckpoint from "./responses-checkpoint.js"

packages/ai/src/protocols/utils/tool-stream.ts

@@ -55,6 +55,7 @@ const inputStart = (tool: PendingTool) =>
   LLMEvent.toolInputStart({
     id: tool.id,
     name: tool.name,
+    namespace: tool.namespace,
     providerExecuted: tool.providerExecuted ? true : undefined,
     providerMetadata: tool.providerMetadata,
   })
@@ -63,6 +64,7 @@ const inputDelta = (tool: PendingTool, text: string) =>
   LLMEvent.toolInputDelta({
     id: tool.id,
     name: tool.name,
+    namespace: tool.namespace,
     text,
     input: Option.getOrElse(parsePartialInput(tool.input), () => ({})),
   })
@@ -85,6 +87,7 @@ const toolCall = (route: string, tool: PendingTool, inputOverride?: string) => {
         LLMEvent.toolCall({
           id: tool.id,
           name: tool.name,
+          namespace: tool.namespace,
           input,
           providerExecuted: tool.providerExecuted ? true : undefined,
           providerMetadata: tool.providerMetadata,
@@ -94,7 +97,12 @@ const toolCall = (route: string, tool: PendingTool, inputOverride?: string) => {
 }
 
 const finishEvents = (tool: PendingTool, event: ToolCall): ReadonlyArray<LLMEvent> => [
-  LLMEvent.toolInputEnd({ id: tool.id, name: tool.name, providerMetadata: tool.providerMetadata }),
+  LLMEvent.toolInputEnd({
+    id: tool.id,
+    name: tool.name,
+    namespace: tool.namespace,
+    providerMetadata: tool.providerMetadata,
+  }),
   event,
 ]
 
@@ -150,6 +158,7 @@ export const appendOrStart = <K extends StreamKey>(
   const tool = {
     id,
     name,
+    namespace: current?.namespace,
     input: `${current?.input ?? ""}${delta.text}`,
     providerExecuted: current?.providerExecuted,
     providerMetadata: current?.providerMetadata,

packages/ai/src/provider-package.ts

@@ -1,5 +1,5 @@
 import type { LanguageModel, ProviderOptions } from "./schema/index.js"
-import type { CompactOperation } from "./route/client.js"
+import type { CompactionOperations } from "./route/client.js"
 
 export interface Settings extends Readonly<Record<string, unknown>> {
   readonly baseURL?: string
@@ -10,7 +10,7 @@ export interface Settings extends Readonly<Record<string, unknown>> {
 export interface Definition<
   ProviderSettings extends Settings = Settings,
   Options extends ProviderOptions = ProviderOptions,
-  Compact extends CompactOperation | undefined = CompactOperation | undefined,
+  Compact extends CompactionOperations | undefined = CompactionOperations | undefined,
 > {
   readonly model: (modelID: string, settings: ProviderSettings) => LanguageModel<Options, Compact>
 }

packages/ai/src/providers/azure.ts

@@ -1,7 +1,7 @@
 import { Headers } from "effect/unstable/http"
 import { Auth } from "../route/auth.js"
 import { type AtLeastOne, type ProviderAuthOption } from "../route/auth-options.js"
-import type { Route, RouteDefaultsInput, CompactOperation } from "../route/client.js"
+import type { Route, RouteDefaultsInput, CompactionOperations } from "../route/client.js"
 import type { ProviderPackage } from "../provider-package.js"
 import { ProviderID, type ModelID } from "../schema/index.js"
 import * as OpenAIChat from "../protocols/openai-chat.js"
@@ -39,6 +39,7 @@ export type Settings = ProviderPackage.Settings &
 const resourceBaseURL = (resourceName: string) => `https://${resourceName.trim()}.openai.azure.com/openai`
 
 const responsesRoute = OpenAIResponses.route.with({
+  compact: { endpoint: OpenAIResponses.route.compact.endpoint },
   id: "azure-openai-responses",
   provider: id,
   auth: routeAuth,
@@ -102,7 +103,7 @@ const auth = (input: Config) => {
   )
 }
 
-const configuredRoute = <Body, Prepared, Compact extends CompactOperation | undefined>(
+const configuredRoute = <Body, Prepared, Compact extends CompactionOperations | undefined>(
   route: Route<Body, Prepared, Compact>,
   input: Config,
   modelID: string | ModelID,
@@ -168,7 +169,7 @@ const config = (settings: Settings): Config => {
 export const responsesModel: ProviderPackage.Definition<
   Settings,
   OpenAIProviderOptionsInput,
-  CompactOperation
+  typeof responsesRoute.compact
 >["model"] = (modelID, settings) => configure(config(settings)).responses(modelID)
 export const chatModel: ProviderPackage.Definition<Settings, OpenAIProviderOptionsInput>["model"] = (
   modelID,

packages/ai/src/providers/openai.ts

@@ -1,5 +1,5 @@
 import { AuthOptions, type ProviderAuthOption } from "../route/auth-options.js"
-import type { Route, RouteDefaultsInput, CompactOperation } from "../route/client.js"
+import type { Route, RouteDefaultsInput, CompactionOperations } from "../route/client.js"
 import type { ProviderPackage } from "../provider-package.js"
 import { HttpOptions, ProviderID, ToolDefinition, mergeHttpOptions, type ModelID } from "../schema/index.js"
 import * as OpenAIChat from "../protocols/openai-chat.js"
@@ -73,7 +73,7 @@ const defaults = (input: Config) => {
   return rest
 }
 
-const configuredRoute = <Body, Prepared, Compact extends CompactOperation | undefined>(
+const configuredRoute = <Body, Prepared, Compact extends CompactionOperations | undefined>(
   route: Route<Body, Prepared, Compact>,
   input: Config,
 ) =>
@@ -132,10 +132,11 @@ const config = (settings: Settings): Config => {
   }
 }
 
-export const model: ProviderPackage.Definition<Settings, OpenAIProviderOptionsInput, CompactOperation>["model"] = (
-  modelID,
-  settings,
-) => {
+export const model: ProviderPackage.Definition<
+  Settings,
+  OpenAIProviderOptionsInput,
+  typeof OpenAIResponses.route.compact
+>["model"] = (modelID, settings) => {
   return configure(config(settings)).responses(modelID)
 }
 

packages/ai/src/providers/xai.ts

@@ -1,5 +1,5 @@
 import { AuthOptions, type ProviderAuthOption } from "../route/auth-options.js"
-import { Route, type RouteDefaultsInput, type CompactOperation } from "../route/client.js"
+import { Route, type RouteDefaultsInput } from "../route/client.js"
 import { Endpoint } from "../route/endpoint.js"
 import { HttpOptions, ProviderID, type ModelID } from "../schema/index.js"
 import * as OpenAICompatibleProfiles from "./openai-compatible-profile.js"
@@ -32,7 +32,7 @@ export type { XAIImageOptions } from "../protocols/xai-images.js"
 const RESPONSES_WEBSOCKET_ROTATE_AFTER_MS = 24 * 60 * 1000
 
 const responsesRoute = Route.make({
-  compact: XAIResponses.compact,
+  compact: { endpoint: XAIResponses.compact },
   id: "openai-responses",
   provider: id,
   providerMetadataKey: "xai",
@@ -103,10 +103,11 @@ export const configure = (input: LanguageModelOptions = {}) => {
 }
 
 export const provider = configure()
-export const model: ProviderPackage.Definition<Settings, XAIProviderOptionsInput, CompactOperation>["model"] = (
-  modelID,
-  settings,
-) =>
+export const model: ProviderPackage.Definition<
+  Settings,
+  XAIProviderOptionsInput,
+  typeof responsesRoute.compact
+>["model"] = (modelID, settings) =>
   configure({
     apiKey: settings.apiKey,
     baseURL: settings.baseURL,

packages/ai/src/route/client.ts

@@ -14,6 +14,7 @@ import type { ProtocolID, ProviderOptions } from "../schema/index.js"
 import {
   AIError,
   CompactionResponse,
+  CompactionCheckpointResponse,
   AIErrorReason,
   GenerationOptions,
   HttpOptions,
@@ -38,7 +39,7 @@ export interface RouteBody<Body> {
 export interface Route<
   Body,
   Prepared = unknown,
-  Compact extends CompactOperation | undefined = CompactOperation | undefined,
+  Compact extends CompactionOperations | undefined = CompactionOperations | undefined,
 > {
   readonly compact: Compact
   readonly id: string
@@ -53,7 +54,15 @@ export interface Route<
   readonly transport: Transport<Body, Prepared, unknown>
   readonly defaults: RouteDefaults
   readonly body: RouteBody<Body>
-  readonly with: (patch: RoutePatch<Body, Prepared>) => Route<Body, Prepared, Compact>
+  readonly with: {
+    <Next extends CompactionOperations | undefined>(
+      patch: RoutePatch<Body, Prepared> & { readonly compact: Next },
+    ): Route<Body, Prepared, Next>
+    (
+      patch: Omit<RoutePatch<Body, Prepared>, "compact"> & { readonly compact?: undefined },
+    ): Route<Body, Prepared, Compact>
+    (patch: RoutePatch<Body, Prepared>): Route<Body, Prepared>
+  }
   readonly model: <Options extends ProviderOptions = ProviderOptions>(
     input: RouteMappedLanguageModelInput,
   ) => LanguageModel<Options, Compact>
@@ -74,7 +83,7 @@ export interface Route<
 // Normal call sites use `OpenAIChat.route`; callers only need body types
 // when preparing a request with a protocol-specific type assertion.
 // oxlint-disable-next-line typescript-eslint/no-explicit-any
-export type AnyRoute<Compact extends CompactOperation | undefined = CompactOperation | undefined> = Route<
+export type AnyRoute<Compact extends CompactionOperations | undefined = CompactionOperations | undefined> = Route<
   any,
   any,
   Compact
@@ -101,6 +110,7 @@ export interface RouteDefaultsInput {
 }
 
 export interface RoutePatch<Body, Prepared> extends RouteDefaultsInput {
+  readonly compact?: CompactionOperations
   readonly id?: string
   readonly provider?: string | ProviderID
   readonly providerMetadataKey?: string
@@ -111,7 +121,7 @@ export interface RoutePatch<Body, Prepared> extends RouteDefaultsInput {
 
 type RouteMappedLanguageModelInput = RouteLanguageModelInput | RouteRoutedLanguageModelInput
 
-const makeRouteLanguageModel = <Options extends ProviderOptions, Compact extends CompactOperation | undefined>(
+const makeRouteLanguageModel = <Options extends ProviderOptions, Compact extends CompactionOperations | undefined>(
   route: AnyRoute<Compact>,
   mapped: RouteMappedLanguageModelInput,
 ) => {
@@ -162,10 +172,7 @@ export const httpOptions = (input: HttpOptionsInput | undefined) => {
 }
 
 export interface Interface {
-  readonly compact: (
-    request: CompactionRequest,
-    options?: Pick<StreamOptions, "http">,
-  ) => Effect.Effect<CompactionResponse, AIError>
+  readonly compact: CompactMethod
   readonly stream: StreamMethod
   readonly generate: GenerateMethod
 }
@@ -189,12 +196,64 @@ export type CompactOperation = (
   options?: Pick<StreamOptions, "http">,
 ) => Effect.Effect<CompactionResponse, AIError>
 
-export type CompactionRequest = LLMRequest & {
-  readonly model: LanguageModel<ProviderOptions, CompactOperation>
+export type TriggerCompactOperation = (
+  request: LLMRequest,
+  executor: RequestExecutor.Interface,
+  options: TriggerCompactOptions,
+) => Effect.Effect<CompactionCheckpointResponse, AIError>
+
+/** Protocol capabilities, not deployment/model eligibility. */
+export interface CompactionOperations {
+  readonly endpoint?: CompactOperation
+  readonly trigger?: TriggerCompactOperation
 }
 
-export const canCompact = (request: LLMRequest): request is CompactionRequest =>
-  request.model.route.compact !== undefined
+export interface EndpointCompactOptions extends Pick<StreamOptions, "http"> {
+  readonly mechanism?: "endpoint"
+  readonly webSocket?: never
+}
+
+export interface TriggerCompactOptions extends StreamOptions {
+  readonly mechanism: "trigger"
+}
+
+// Keep the required route shape explicit: the schema class's self type erases its model parameter in assignability.
+export type CompactionRequest = LLMRequest & {
+  readonly model: LanguageModel<ProviderOptions, { readonly endpoint: CompactOperation }>
+}
+export type CheckpointRequest = LLMRequest & {
+  readonly model: LanguageModel<ProviderOptions, { readonly trigger: TriggerCompactOperation }>
+}
+
+export interface CompactMethod<R = never> {
+  (request: CheckpointRequest, options: TriggerCompactOptions): Effect.Effect<CompactionCheckpointResponse, AIError, R>
+  (request: CompactionRequest, options?: EndpointCompactOptions): Effect.Effect<CompactionResponse, AIError, R>
+}
+
+export function canCompact(
+  request: LLMRequest,
+  options?: { readonly mechanism?: "endpoint" },
+): request is CompactionRequest
+export function canCompact(
+  request: LLMRequest,
+  options: { readonly mechanism: "trigger" },
+): request is CheckpointRequest
+export function canCompact(request: LLMRequest, options?: { readonly mechanism?: string }) {
+  if (options?.mechanism === "trigger") return request.model.route.compact?.trigger !== undefined
+  if (options?.mechanism !== undefined && options.mechanism !== "endpoint") return false
+  return request.model.route.compact?.endpoint !== undefined
+}
+
+const unsupportedCompaction = (request: LLMRequest, mechanism: string | undefined) => {
+  if (mechanism !== undefined && mechanism !== "endpoint" && mechanism !== "trigger")
+    return ProviderShared.invalidRequest(`Unknown compaction mechanism: ${mechanism}`)
+  return ProviderShared.unsupportedOperation({
+    operation: mechanism === "trigger" ? "compact.trigger" : "compact",
+    provider: request.model.provider,
+    route: request.model.route.id,
+    message: `${request.model.provider}/${request.model.route.id} does not support ${mechanism === "trigger" ? "trigger" : "explicit"} compaction`,
+  })
+}
 
 export class Service extends Context.Service<Service, Interface>()("@opencode/LLMClient") {}
 
@@ -216,7 +275,7 @@ const resolveRequestOptions = (request: LLMRequest) => {
 }
 
 export interface MakeInput<Body, Frame, Event, State> {
-  readonly compact?: CompactOperation
+  readonly compact?: CompactionOperations
   /** Route id used in diagnostics and prepared request metadata. */
   readonly id: string
   /** Provider identity for route-owned model construction. */
@@ -238,7 +297,7 @@ export interface MakeInput<Body, Frame, Event, State> {
 }
 
 export interface MakeTransportInput<Body, Prepared, Frame, Event, State> {
-  readonly compact?: CompactOperation
+  readonly compact?: CompactionOperations
   /** Route id used in diagnostics and prepared request metadata. */
   readonly id: string
   /** Provider identity for route-owned model construction. */
@@ -326,9 +385,10 @@ function makeFromTransport<Body, Prepared, Frame, Event, State>(
       defaults: routeInput.defaults ?? {},
       body: protocol.body,
       with: (patch: RoutePatch<Body, Prepared>) => {
-        const { id, provider, providerMetadataKey, auth, transport, endpoint, ...defaults } = patch
+        const { compact, id, provider, providerMetadataKey, auth, transport, endpoint, ...defaults } = patch
         return build({
           ...routeInput,
+          compact: "compact" in patch ? compact : routeInput.compact,
           id: id ?? routeInput.id,
           provider: provider ?? routeInput.provider,
           providerMetadataKey:
@@ -343,7 +403,7 @@ function makeFromTransport<Body, Prepared, Frame, Event, State>(
         })
       },
       model: <Options extends ProviderOptions = ProviderOptions>(input: RouteMappedLanguageModelInput) =>
-        makeRouteLanguageModel<Options, CompactOperation | undefined>(route, input),
+        makeRouteLanguageModel<Options, CompactionOperations | undefined>(route, input),
       prepareTransport: (body, request, options) =>
         routeInput.transport.prepare({
           body,
@@ -440,12 +500,12 @@ function makeFromTransport<Body, Prepared, Frame, Event, State>(
   return build({ ...input, defaults: mergeRouteDefaults(undefined, input.defaults ?? {}) })
 }
 
-export function make<Body, Prepared, Frame, Event, State>(
-  input: MakeTransportInput<Body, Prepared, Frame, Event, State> & { readonly compact: CompactOperation },
-): Route<Body, Prepared, CompactOperation>
-export function make<Body, Frame, Event, State>(
-  input: MakeInput<Body, Frame, Event, State> & { readonly compact: CompactOperation },
-): Route<Body, HttpTransport.HttpPrepared<Frame>, CompactOperation>
+export function make<Body, Prepared, Frame, Event, State, Compact extends CompactionOperations>(
+  input: MakeTransportInput<Body, Prepared, Frame, Event, State> & { readonly compact: Compact },
+): Route<Body, Prepared, Compact>
+export function make<Body, Frame, Event, State, Compact extends CompactionOperations>(
+  input: MakeInput<Body, Frame, Event, State> & { readonly compact: Compact },
+): Route<Body, HttpTransport.HttpPrepared<Frame>, Compact>
 export function make<Body, Prepared, Frame, Event, State>(
   input: MakeTransportInput<Body, Prepared, Frame, Event, State>,
 ): Route<Body, Prepared>
@@ -487,10 +547,14 @@ export function make<Body, Prepared, Frame, Event, State>(
 }
 
 const prepareRequest = (request: LLMRequest) => {
-  const original = applyCachePolicy(resolveRequestOptions(request))
+  const original = resolveRequestOptions(request)
   const sanitized = LLMRequest.update(original, sanitizeSurrogates({ ...LLMRequest.input(original), model: undefined }))
-  const tools = [...new Map(sanitized.tools.map((tool) => [tool.name, tool])).values()]
-  const resolved = tools.length === sanitized.tools.length ? sanitized : LLMRequest.update(sanitized, { tools })
+  // Deduplicate per sibling level; a tool and a namespace may share a name.
+  const dedupe = (tools: LLMRequest["tools"]): LLMRequest["tools"] =>
+    [...new Map(tools.map((tool) => [`${tool.type}:${tool.name}`, tool])).values()].map((tool) =>
+      tool.type === "tool" ? tool : { ...tool, tools: dedupe(tool.tools) },
+    )
+  const resolved = applyCachePolicy(LLMRequest.update(sanitized, { tools: dedupe(sanitized.tools) }))
   const headers = resolved.model.route.headers?.({ request: resolved })
   return headers === undefined
     ? resolved
@@ -557,14 +621,23 @@ export function generate(request: LLMRequest, options?: StreamOptions): Effect.E
   })
 }
 
-export const compact = (
+export function compact(
+  request: CheckpointRequest,
+  options: TriggerCompactOptions,
+): Effect.Effect<CompactionCheckpointResponse, AIError, Service>
+export function compact(
   request: CompactionRequest,
-  options?: Pick<StreamOptions, "http">,
-): Effect.Effect<CompactionResponse, AIError, Service> =>
-  Effect.gen(function* () {
+  options?: EndpointCompactOptions,
+): Effect.Effect<CompactionResponse, AIError, Service>
+export function compact(request: LLMRequest, options?: EndpointCompactOptions | TriggerCompactOptions) {
+  return Effect.gen(function* () {
     const client = yield* Service
-    return yield* client.compact(request, options)
+    if (options?.mechanism === "trigger" && canCompact(request, options)) return yield* client.compact(request, options)
+    if ((options?.mechanism === undefined || options.mechanism === "endpoint") && canCompact(request))
+      return yield* client.compact(request, options)
+    return yield* unsupportedCompaction(request, options?.mechanism)
   })
+}
 
 export const streamRequest = (request: LLMRequest, options?: StreamOptions) =>
   Stream.unwrap(
@@ -578,21 +651,27 @@ export const layer: Layer.Layer<Service, never, RequestExecutor.Service> = Layer
   Effect.gen(function* () {
     const executor = yield* RequestExecutor.Service
     const stream = streamRequestWith({ http: executor })
+    function compact(
+      request: CompactionRequest,
+      options?: EndpointCompactOptions,
+    ): Effect.Effect<CompactionResponse, AIError>
+    function compact(
+      request: CheckpointRequest,
+      options: TriggerCompactOptions,
+    ): Effect.Effect<CompactionCheckpointResponse, AIError>
+    function compact(request: LLMRequest, options?: EndpointCompactOptions | TriggerCompactOptions) {
+      return Effect.suspend((): Effect.Effect<CompactionResponse | CompactionCheckpointResponse, AIError> => {
+        if (options?.mechanism === "trigger" && canCompact(request, options))
+          return request.model.route.compact.trigger(prepareRequest(request), executor, options)
+        if ((options?.mechanism === undefined || options.mechanism === "endpoint") && canCompact(request))
+          return request.model.route.compact.endpoint(prepareRequest(request), executor, options)
+        return unsupportedCompaction(request, options?.mechanism)
+      })
+    }
     return Service.of({
       stream,
       generate: generateWith(stream),
-      compact: (request, options) =>
-        Effect.suspend(() => {
-          const operation = request.model.route.compact
-          if (!operation)
-            return ProviderShared.unsupportedOperation({
-              operation: "compact",
-              provider: request.model.provider,
-              route: request.model.route.id,
-              message: `${request.model.provider}/${request.model.route.id} does not support explicit compaction`,
-            })
-          return operation(prepareRequest(request), executor, options)
-        }),
+      compact,
     })
   }),
 )

packages/ai/src/route/index.ts

@@ -9,6 +9,12 @@ export type {
   Interface as LLMClientShape,
   Service as LLMClientService,
   StreamOptions,
+  CompactMethod,
+  CompactionOperations,
+  CompactionRequest,
+  CheckpointRequest,
+  EndpointCompactOptions,
+  TriggerCompactOptions,
 } from "./client.js"
 export * from "./executor.js"
 export { Auth } from "./auth.js"

packages/ai/src/schema/events.ts

@@ -97,6 +97,21 @@ export class CompactionResponse extends Schema.Class<CompactionResponse>("LLM.Co
   usage: Schema.optional(Usage),
 }) {}
 
+/** A checkpoint only; retained history and replacement-window construction belong to the caller. */
+export class CompactionCheckpointResponse extends Schema.Class<CompactionCheckpointResponse>(
+  "LLM.CompactionCheckpointResponse",
+)({
+  checkpoint: CompactionPart.pipe(
+    Schema.refine(
+      (part): part is CompactionPart & { readonly encrypted: string; readonly text?: never } =>
+        part.encrypted !== undefined && part.encrypted.length > 0,
+      { message: "A checkpoint response requires encrypted compaction content" },
+    ),
+  ),
+  responseID: Schema.String.check(Schema.isPattern(/\S/)),
+  usage: Schema.optional(Usage),
+}) {}
+
 export const StepStart = Schema.Struct({
   type: Schema.tag("step-start"),
   index: Schema.Number,
@@ -155,6 +170,7 @@ export const ToolInputStart = Schema.Struct({
   type: Schema.tag("tool-input-start"),
   id: ToolCallID,
   name: Schema.String,
+  namespace: Schema.optional(Schema.String),
   providerExecuted: Schema.optional(Schema.Boolean),
   providerMetadata: Schema.optional(ProviderMetadata),
 }).annotate({ identifier: "LLM.Event.ToolInputStart" })
@@ -164,6 +180,7 @@ export const ToolInputDelta = Schema.Struct({
   type: Schema.tag("tool-input-delta"),
   id: ToolCallID,
   name: Schema.String,
+  namespace: Schema.optional(Schema.String),
   text: Schema.String,
   /** Best-effort parse of all input fragments received through this delta. */
   input: Schema.optional(Schema.Unknown),
@@ -174,6 +191,7 @@ export const ToolInputEnd = Schema.Struct({
   type: Schema.tag("tool-input-end"),
   id: ToolCallID,
   name: Schema.String,
+  namespace: Schema.optional(Schema.String),
   providerMetadata: Schema.optional(ProviderMetadata),
 }).annotate({ identifier: "LLM.Event.ToolInputEnd" })
 export type ToolInputEnd = Schema.Schema.Type<typeof ToolInputEnd>
@@ -183,6 +201,7 @@ export const ToolInputError = Schema.Struct({
   type: Schema.tag("tool-input-error"),
   id: ToolCallID,
   name: Schema.String,
+  namespace: Schema.optional(Schema.String),
   raw: Schema.String,
 }).annotate({ identifier: "LLM.Event.ToolInputError" })
 export type ToolInputError = Schema.Schema.Type<typeof ToolInputError>
@@ -191,6 +210,7 @@ export const ToolCall = Schema.Struct({
   type: Schema.tag("tool-call"),
   id: ToolCallID,
   name: Schema.String,
+  namespace: Schema.optional(Schema.String),
   input: Schema.Unknown,
   providerExecuted: Schema.optional(Schema.Boolean),
   providerMetadata: Schema.optional(ProviderMetadata),
@@ -201,6 +221,7 @@ export const ToolResult = Schema.Struct({
   type: Schema.tag("tool-result"),
   id: ToolCallID,
   name: Schema.String,
+  namespace: Schema.optional(Schema.String),
   result: ToolResultValue,
   output: Schema.optional(ToolOutput),
   providerExecuted: Schema.optional(Schema.Boolean),
@@ -212,6 +233,7 @@ export const ToolError = Schema.Struct({
   type: Schema.tag("tool-error"),
   id: ToolCallID,
   name: Schema.String,
+  namespace: Schema.optional(Schema.String),
   message: Schema.String,
   error: Schema.optional(Schema.Defect()),
   providerMetadata: Schema.optional(ProviderMetadata),
@@ -385,6 +407,7 @@ interface ContentAssembly {
 
 interface ToolInputAssembly {
   readonly name: string
+  readonly namespace?: string
   readonly text: string
   readonly providerMetadata?: ProviderMetadata
 }
@@ -522,12 +545,17 @@ const reduceToolInputStart = (state: ResponseState, event: ToolInputStart): Resp
   ...state,
   toolInputs: {
     ...state.toolInputs,
-    [event.id]: { name: event.name, text: "", providerMetadata: event.providerMetadata },
+    [event.id]: {
+      name: event.name,
+      namespace: event.namespace,
+      text: "",
+      providerMetadata: event.providerMetadata,
+    },
   },
 })
 
 const reduceToolInputDelta = (state: ResponseState, event: ToolInputDelta): ResponseState => {
-  const current = state.toolInputs[event.id] ?? { name: event.name, text: "" }
+  const current = state.toolInputs[event.id] ?? { name: event.name, namespace: event.namespace, text: "" }
   return {
     ...state,
     toolInputs: { ...state.toolInputs, [event.id]: { ...current, text: current.text + event.text } },
@@ -535,7 +563,7 @@ const reduceToolInputDelta = (state: ResponseState, event: ToolInputDelta): Resp
 }
 
 const reduceToolInputEnd = (state: ResponseState, event: ToolInputEnd): ResponseState => {
-  const current = state.toolInputs[event.id] ?? { name: event.name, text: "" }
+  const current = state.toolInputs[event.id] ?? { name: event.name, namespace: event.namespace, text: "" }
   return {
     ...state,
     toolInputs: {
@@ -543,6 +571,7 @@ const reduceToolInputEnd = (state: ResponseState, event: ToolInputEnd): Response
       [event.id]: {
         ...current,
         name: event.name,
+        namespace: event.namespace,
         providerMetadata: event.providerMetadata ?? current.providerMetadata,
       },
     },
@@ -553,6 +582,7 @@ const toolCallContent = (event: ToolCall): ContentPart =>
   ToolCallPart.make({
     id: event.id,
     name: event.name,
+    namespace: event.namespace,
     input: event.input,
     ...(event.providerExecuted === undefined ? {} : { providerExecuted: event.providerExecuted }),
     ...(event.providerMetadata === undefined ? {} : { providerMetadata: event.providerMetadata }),
@@ -562,6 +592,7 @@ const toolResultContent = (event: ToolResult): ContentPart =>
   ToolResultPart.make({
     id: event.id,
     name: event.name,
+    namespace: event.namespace,
     result: event.result,
     ...(event.providerExecuted === undefined ? {} : { providerExecuted: event.providerExecuted }),
     ...(event.providerMetadata === undefined ? {} : { providerMetadata: event.providerMetadata }),

packages/ai/src/schema/messages.ts

@@ -135,6 +135,7 @@ export const ToolCallPart = Object.assign(
     type: Schema.Literal("tool-call"),
     id: Schema.String,
     name: Schema.String,
+    namespace: Schema.optional(Schema.String),
     input: Schema.Unknown,
     providerExecuted: Schema.optional(Schema.Boolean),
     cache: Schema.optional(CacheHint),
@@ -152,6 +153,7 @@ export const ToolResultPart = Object.assign(
     type: Schema.Literal("tool-result"),
     id: Schema.String,
     name: Schema.String,
+    namespace: Schema.optional(Schema.String),
     result: ToolResultValue,
     providerExecuted: Schema.optional(Schema.Boolean),
     cache: Schema.optional(CacheHint),
@@ -168,6 +170,7 @@ export const ToolResultPart = Object.assign(
       type: "tool-result",
       id: input.id,
       name: input.name,
+      namespace: input.namespace,
       result: ToolResultValue.make(input.result, input.resultType),
       providerExecuted: input.providerExecuted,
       cache: input.cache,
@@ -266,7 +269,7 @@ export namespace Message {
     make({ role: "tool", content: ["type" in result ? result : ToolResultPart.make(result)] })
 }
 
-export class ToolDefinition extends Schema.Class<ToolDefinition>("LLM.ToolDefinition")({
+const toolDefinitionFields = {
   name: Schema.String,
   description: Schema.String,
   inputSchema: JsonSchema,
@@ -274,15 +277,71 @@ export class ToolDefinition extends Schema.Class<ToolDefinition>("LLM.ToolDefini
   cache: Schema.optional(CacheHint),
   metadata: Schema.optional(Schema.Record(Schema.String, Schema.Unknown)),
   native: Schema.optional(Schema.Record(Schema.String, Schema.Unknown)),
-}) {}
+}
+
+export type ToolDefinitionInput = Schema.Struct.Type<typeof toolDefinitionFields>
+
+export class ToolDefinition extends Schema.Class<ToolDefinition>("LLM.ToolDefinition")({
+  type: Schema.Literal("tool"),
+  ...toolDefinitionFields,
+}) {
+  constructor(input: ToolDefinitionInput) {
+    super({ ...input, type: "tool" })
+  }
+}
 
 export namespace ToolDefinition {
-  export type Input = ToolDefinition | ConstructorParameters<typeof ToolDefinition>[0]
+  export type Input = ToolDefinition | ToolDefinitionInput
 
   /** Normalize tool definition input into the canonical `ToolDefinition` class. */
   export const make = (input: Input) => (input instanceof ToolDefinition ? input : new ToolDefinition(input))
 }
 
+export type ToolNamespace = {
+  readonly type: "namespace"
+  readonly name: string
+  readonly description?: string
+  readonly tools: ReadonlyArray<ToolEntry>
+}
+
+export type ToolNamespaceInput = Omit<ToolNamespace, "type" | "tools"> & {
+  readonly tools: ReadonlyArray<ToolEntryInput>
+}
+export type ToolNamespaceEntryInput = ToolNamespaceInput & { readonly type: "namespace" }
+
+export const ToolNamespace: Schema.Codec<ToolNamespace> & {
+  readonly make: (input: ToolNamespace | ToolNamespaceInput) => ToolNamespace
+} = Object.assign(
+  Schema.Struct({
+    type: Schema.Literal("namespace"),
+    name: Schema.String,
+    description: Schema.optional(Schema.UndefinedOr(Schema.String)),
+    tools: Schema.Array(Schema.suspend((): Schema.Codec<ToolEntry> => ToolEntry)),
+  }).annotate({ identifier: "LLM.ToolNamespace" }),
+  {
+    make: (input: ToolNamespace | ToolNamespaceInput): ToolNamespace => ({
+      ...input,
+      type: "namespace",
+      tools: input.tools.map(ToolEntry.make),
+    }),
+  },
+)
+
+export type ToolEntry = ToolDefinition | ToolNamespace
+export type ToolEntryInput = ToolDefinition.Input | ToolNamespaceEntryInput
+export const ToolEntry: Schema.Codec<ToolEntry> & {
+  readonly make: (input: ToolEntryInput) => ToolEntry
+} = Object.assign(
+  Schema.Union([ToolDefinition, ToolNamespace]).pipe(
+    Schema.toTaggedUnion("type"),
+    Schema.annotate({ identifier: "LLM.ToolEntry" }),
+  ),
+  {
+    make: (input: ToolEntryInput): ToolEntry =>
+      "type" in input && input.type === "namespace" ? ToolNamespace.make(input) : ToolDefinition.make(input),
+  },
+)
+
 export class ToolChoice extends Schema.Class<ToolChoice>("LLM.ToolChoice")({
   type: Schema.Literals(["auto", "none", "required", "tool"]),
   name: Schema.optional(Schema.String),
@@ -312,7 +371,7 @@ const requestSchema = Schema.Struct({
   model: LanguageModelSchema,
   system: Schema.Array(SystemPart),
   messages: Schema.Array(Message),
-  tools: Schema.Array(ToolDefinition),
+  tools: Schema.Array(ToolEntry),
   toolChoice: Schema.optional(ToolChoice),
   generation: Schema.optional(GenerationOptions),
   providerOptions: Schema.optional(ProviderOptions),

packages/ai/src/schema/options.ts

@@ -1,6 +1,6 @@
 import { Schema } from "effect"
 import { ModelID, ProviderID } from "./ids.js"
-import type { AnyRoute, CompactOperation } from "../route/client.js"
+import type { AnyRoute, CompactionOperations } from "../route/client.js"
 import { isRecord } from "../utils/record.js"
 
 export const JsonSchema = Schema.Record(Schema.String, Schema.Unknown)
@@ -175,7 +175,7 @@ export namespace LanguageModelCompatibility {
 
 export class LanguageModel<
   Options extends ProviderOptions = ProviderOptions,
-  Compact extends CompactOperation | undefined = CompactOperation | undefined,
+  Compact extends CompactionOperations | undefined = CompactionOperations | undefined,
 > {
   declare protected readonly _ProviderOptions: Options
   readonly id: ModelID
@@ -194,7 +194,7 @@ export class LanguageModel<
 
   static make<
     Options extends ProviderOptions = ProviderOptions,
-    Compact extends CompactOperation | undefined = CompactOperation | undefined,
+    Compact extends CompactionOperations | undefined = CompactionOperations | undefined,
   >(input: LanguageModel.Input<Compact>) {
     return new LanguageModel<Options, Compact>({
       id: ModelID.make(input.id),
@@ -206,7 +206,7 @@ export class LanguageModel<
     })
   }
 
-  static input<Options extends ProviderOptions, Compact extends CompactOperation | undefined>(
+  static input<Options extends ProviderOptions, Compact extends CompactionOperations | undefined>(
     model: LanguageModel<Options, Compact>,
   ): LanguageModel.ConstructorInput<Compact> {
     return {
@@ -218,11 +218,11 @@ export class LanguageModel<
     }
   }
 
-  static update<Options extends ProviderOptions, Compact extends CompactOperation | undefined>(
+  static update<Options extends ProviderOptions, Compact extends CompactionOperations | undefined>(
     model: LanguageModel<Options>,
     patch: Partial<LanguageModel.Input<Compact>> & { readonly route: AnyRoute<Compact> },
   ): LanguageModel<Options, Compact>
-  static update<Options extends ProviderOptions, Compact extends CompactOperation | undefined>(
+  static update<Options extends ProviderOptions, Compact extends CompactionOperations | undefined>(
     model: LanguageModel<Options, Compact>,
     patch: Partial<Omit<LanguageModel.Input, "route">> & { readonly route?: undefined },
   ): LanguageModel<Options, Compact>
@@ -241,7 +241,7 @@ export class LanguageModel<
 }
 
 export namespace LanguageModel {
-  export type ConstructorInput<Compact extends CompactOperation | undefined = CompactOperation | undefined> = {
+  export type ConstructorInput<Compact extends CompactionOperations | undefined = CompactionOperations | undefined> = {
     readonly id: ModelID
     readonly provider: ProviderID
     readonly route: AnyRoute<Compact>
@@ -249,7 +249,7 @@ export namespace LanguageModel {
     readonly compatibility?: LanguageModelCompatibility
   }
 
-  export type Input<Compact extends CompactOperation | undefined = CompactOperation | undefined> = Omit<
+  export type Input<Compact extends CompactionOperations | undefined = CompactionOperations | undefined> = Omit<
     ConstructorInput<Compact>,
     "id" | "provider" | "defaults" | "compatibility"
   > & {

packages/ai/src/testing.ts

@@ -1,10 +1,17 @@
 export * as TestLLM from "./testing.js"
 
-import { LLMClient } from "./route/client.js"
+import {
+  LLMClient,
+  type CompactionRequest,
+  type CheckpointRequest,
+  type EndpointCompactOptions,
+  type TriggerCompactOptions,
+} from "./route/client.js"
 import {
   LLMEvent,
   LLMResponse,
   CompactionResponse,
+  CompactionCheckpointResponse,
   type FinishReasonDetails,
   type AIError,
   type LLMRequest,
@@ -13,7 +20,11 @@ import {
 } from "./schema/index.js"
 import { Context, Deferred, Effect, Latch, Layer, Queue, Scope, Stream } from "effect"
 
-export type Response = readonly LLMEvent[] | Stream.Stream<LLMEvent, AIError> | CompactionResponse
+export type Response =
+  | readonly LLMEvent[]
+  | Stream.Stream<LLMEvent, AIError>
+  | CompactionResponse
+  | CompactionCheckpointResponse
 
 export type Gate = Readonly<{ started: Effect.Effect<void>; release: Effect.Effect<void> }>
 
@@ -132,21 +143,38 @@ const make = (options: LayerOptions) =>
       Stream.unwrap(
         take(request).pipe(
           Effect.map((response) => {
-            if (response instanceof CompactionResponse)
+            if (response instanceof CompactionResponse || response instanceof CompactionCheckpointResponse)
               return Stream.die("TestLLM generation requires an event response")
             return Stream.isStream(response) ? response : Stream.fromIterable(response)
           }),
         ),
       )
-    const test = Test.of({
-      compact: (request) =>
-        take(request).pipe(
-          Effect.flatMap((response) =>
-            response instanceof CompactionResponse
+    function compact(
+      request: CompactionRequest,
+      options?: EndpointCompactOptions,
+    ): Effect.Effect<CompactionResponse, AIError>
+    function compact(
+      request: CheckpointRequest,
+      options: TriggerCompactOptions,
+    ): Effect.Effect<CompactionCheckpointResponse, AIError>
+    function compact(
+      request: LLMRequest,
+      options?: EndpointCompactOptions | TriggerCompactOptions,
+    ): Effect.Effect<CompactionResponse | CompactionCheckpointResponse, AIError> {
+      return take(request).pipe(
+        Effect.flatMap((response): Effect.Effect<CompactionResponse | CompactionCheckpointResponse> => {
+          if (options?.mechanism === "trigger")
+            return response instanceof CompactionCheckpointResponse
               ? Effect.succeed(response)
-              : Effect.die("TestLLM compaction requires a CompactionResponse"),
-          ),
-        ),
+              : Effect.die("TestLLM trigger compaction requires a CompactionCheckpointResponse")
+          return response instanceof CompactionResponse
+            ? Effect.succeed(response)
+            : Effect.die("TestLLM compaction requires a CompactionResponse")
+        }),
+      )
+    }
+    const test = Test.of({
+      compact,
       stream,
       generate: (request) =>
         stream(request).pipe(

packages/ai/src/tool-history.ts

@@ -37,7 +37,13 @@ function missingToolResults(calls: Iterable<ToolCallPart>) {
   return new Message({
     role: "tool",
     content: [...calls].map((call) =>
-      ToolResultPart.make({ id: call.id, name: call.name, result: MISSING_TOOL_RESULT, resultType: "error" }),
+      ToolResultPart.make({
+        id: call.id,
+        name: call.name,
+        namespace: call.namespace,
+        result: MISSING_TOOL_RESULT,
+        resultType: "error",
+      }),
     ),
   })
 }
@@ -47,7 +53,7 @@ function normalizeToolMessage(message: Message, pending: Map<string, ToolCallPar
     if (part.type !== "tool-result" || part.providerExecuted === true) return part
     const call = pending.get(part.id)
     if (call) pending.delete(part.id)
-    return normalizeToolResult(part, call?.name ?? part.name)
+    return normalizeToolResult(part, call)
   })
   if (content.length === 0) return undefined
   if (content.every((part, index) => part === message.content[index])) return message
@@ -61,8 +67,11 @@ function normalizeToolMessage(message: Message, pending: Map<string, ToolCallPar
   })
 }
 
-function normalizeToolResult(part: ToolResultPart, name: string): ToolResultPart {
-  const named = part.name === name ? part : { ...part, name }
+function normalizeToolResult(part: ToolResultPart, call: ToolCallPart | undefined): ToolResultPart {
+  const named =
+    call === undefined || (part.name === call.name && part.namespace === call.namespace)
+      ? part
+      : { ...part, name: call.name, namespace: call.namespace }
   if (named.result.type === "text" && named.result.value === "")
     return { ...named, result: { type: "text", value: EMPTY_TOOL_OUTPUT } }
   if (named.result.type === "error" && named.result.value === "")

packages/ai/src/tool-runtime.ts

@@ -21,10 +21,11 @@ export interface DispatchResult extends ToolSettlement {
 
 /** Execute one canonical tool call without owning provider IO or continuation. */
 export const dispatch = (tools: Tools, call: ToolCallPart): Effect.Effect<DispatchResult> => {
-  const tool = tools[call.name]
-  if (!tool) return Effect.succeed(result(call, { type: "error", value: `Unknown tool: ${call.name}` }))
+  const name = call.namespace === undefined ? call.name : `${call.namespace}.${call.name}`
+  const tool = tools[name]
+  if (!tool) return Effect.succeed(result(call, { type: "error", value: `Unknown tool: ${name}` }))
   if (!tool.execute)
-    return Effect.succeed(result(call, { type: "error", value: `Tool has no execute handler: ${call.name}` }))
+    return Effect.succeed(result(call, { type: "error", value: `Tool has no execute handler: ${name}` }))
 
   return decodeAndExecute(tool, call).pipe(
     Effect.map((value) => result(call, value)),
@@ -38,7 +39,11 @@ const decodeAndExecute = (tool: AnyTool, call: ToolCallPart): Effect.Effect<Tool
   tool._decode(call.input).pipe(
     Effect.mapError((error) => new ToolFailure({ message: `Invalid tool input: ${error.message}` })),
     Effect.flatMap((decoded) =>
-      tool.execute!(decoded, { id: call.id, name: call.name }).pipe(
+      tool.execute!(decoded, {
+        id: call.id,
+        name: call.name,
+        namespace: call.namespace,
+      }).pipe(
         Effect.flatMap((value) =>
           tool._encode(value).pipe(
             Effect.mapError(
@@ -71,6 +76,7 @@ const result = (call: ToolCallPart, value: ToolResultValueType | ToolSettlement,
             LLMEvent.toolError({
               id: call.id,
               name: call.name,
+              namespace: call.namespace,
               message: String(settlement.result.value),
               error,
               providerMetadata: call.providerMetadata,
@@ -78,6 +84,7 @@ const result = (call: ToolCallPart, value: ToolResultValueType | ToolSettlement,
             LLMEvent.toolResult({
               id: call.id,
               name: call.name,
+              namespace: call.namespace,
               result: settlement.result,
               providerMetadata: call.providerMetadata,
             }),
@@ -86,6 +93,7 @@ const result = (call: ToolCallPart, value: ToolResultValueType | ToolSettlement,
             LLMEvent.toolResult({
               id: call.id,
               name: call.name,
+              namespace: call.namespace,
               result: settlement.result,
               output: settlement.output,
               providerMetadata: call.providerMetadata,

packages/ai/src/tool.ts

@@ -16,6 +16,7 @@ export type ToolSchema<T> = Schema.Codec<T, any, never, never>
 export interface ToolExecuteContext {
   readonly id: ToolCallPart["id"]
   readonly name: ToolCallPart["name"]
+  readonly namespace?: ToolCallPart["namespace"]
 }
 
 export type ToolExecute<Parameters extends ToolSchema<any>, Success extends ToolSchema<any>> = (

packages/ai/test/cache-policy.test.ts

@@ -215,6 +215,35 @@ describe("applyCachePolicy", () => {
     }),
   )
 
+  it.effect("deduplicates tools before counting cache hints", () =>
+    Effect.gen(function* () {
+      const manual = new CacheHint({ type: "ephemeral" })
+      const duplicate = (description: string) => ({
+        name: "lookup",
+        description,
+        inputSchema: { type: "object" },
+        cache: manual,
+      })
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model: anthropicModel,
+          tools: [
+            duplicate("first"),
+            duplicate("second"),
+            duplicate("third"),
+            duplicate("fourth"),
+            { name: "lookup", description: "final", inputSchema: { type: "object" } },
+          ],
+          cache: { tools: true },
+        }),
+      )
+
+      expect(prepared.body.tools).toEqual([
+        expect.objectContaining({ name: "lookup", description: "final", cache_control: { type: "ephemeral" } }),
+      ])
+    }),
+  )
+
   it.effect("auto policy preserves manual CacheHints on other parts", () =>
     Effect.gen(function* () {
       const prepared = yield* compileRequest(
@@ -281,6 +310,30 @@ describe("applyCachePolicy", () => {
     }),
   )
 
+  test("marks the final leaf inside a tool namespace", () => {
+    const request = LLM.request({
+      model: anthropicModel,
+      tools: [
+        {
+          type: "namespace",
+          name: "crm",
+          tools: [
+            { name: "lookup", description: "lookup", inputSchema: {} },
+            { name: "orders", description: "orders", inputSchema: {} },
+          ],
+        },
+      ],
+      cache: { tools: true },
+    })
+    const applied = applyCachePolicy(request)
+    const namespace = applied.tools[0]
+
+    expect(namespace?.type).toBe("namespace")
+    if (namespace?.type !== "namespace") throw new Error("Expected namespace")
+    expect(namespace.tools[0]).not.toHaveProperty("cache")
+    expect(namespace.tools[1]).toHaveProperty("cache", { type: "ephemeral" })
+  })
+
   it.effect("ttlSeconds in the policy flows through to wire markers", () =>
     Effect.gen(function* () {
       const prepared = yield* compileRequest(

packages/ai/test/compile.test.ts

@@ -1,8 +1,16 @@
 import { describe, expect, test } from "bun:test"
 import { Effect, Ref, Schema } from "effect"
 import { HttpClientRequest, HttpClientResponse } from "effect/unstable/http"
-import { LLM, LLMRequest, Message, ToolCallPart, ToolDefinition, mergeProviderOptions } from "../src/index.js"
-import { AnthropicMessages, OpenAIChat } from "../src/protocols.js"
+import {
+  LLM,
+  LLMRequest,
+  Message,
+  ToolCallPart,
+  ToolDefinition,
+  ToolNamespace,
+  mergeProviderOptions,
+} from "../src/index.js"
+import { AnthropicMessages, OpenAIChat, OpenAIResponses } from "../src/protocols.js"
 import { Auth, LLMClient } from "../src/route.js"
 import { compileRequest } from "../src/route/client.js"
 import { it } from "./lib/effect.js"
@@ -106,6 +114,58 @@ describe("request option precedence", () => {
     }),
   )
 
+  it.effect("deduplicates tools within each namespace", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model: OpenAIResponses.route.model({ id: "gpt-5.4" }),
+          tools: [
+            ToolDefinition.make({ name: "crm", description: "Top-level CRM tool", inputSchema: {} }),
+            ToolNamespace.make({
+              name: "crm",
+              description: "CRM tools",
+              tools: [
+                ToolDefinition.make({ name: "lookup", description: "old", inputSchema: {} }),
+                ToolDefinition.make({ name: "search", description: "search", inputSchema: {} }),
+                ToolDefinition.make({ name: "lookup", description: "new", inputSchema: {} }),
+              ],
+            }),
+            ToolNamespace.make({
+              name: "support",
+              description: "Support tools",
+              tools: [ToolDefinition.make({ name: "lookup", description: "support", inputSchema: {} })],
+            }),
+          ],
+        }),
+      )
+
+      expect(prepared.body.tools).toEqual([
+        {
+          type: "function",
+          name: "crm",
+          description: "Top-level CRM tool",
+          parameters: {},
+          strict: false,
+        },
+        {
+          type: "namespace",
+          name: "crm",
+          description: "CRM tools",
+          tools: [
+            { type: "function", name: "lookup", description: "new", parameters: {}, strict: false },
+            { type: "function", name: "search", description: "search", parameters: {}, strict: false },
+          ],
+        },
+        {
+          type: "namespace",
+          name: "support",
+          description: "Support tools",
+          tools: [{ type: "function", name: "lookup", description: "support", parameters: {}, strict: false }],
+        },
+      ])
+    }),
+  )
+
   it.effect("normalizes tool history before protocol lowering", () =>
     Effect.gen(function* () {
       const prepared = yield* compileRequest(

packages/ai/test/llm.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, test } from "bun:test"
-import { CacheHint, LLM, LLMResponse } from "../src/index.js"
+import { Schema } from "effect"
+import { CacheHint, LLM, LLMResponse, ToolEntry, ToolNamespace } from "../src/index.js"
 import * as OpenAIChat from "../src/protocols/openai-chat.js"
 import * as OpenAIResponses from "../src/protocols/openai-responses.js"
 import {
@@ -17,6 +18,52 @@ const chatRoute = OpenAIChat.route
 const responsesRoute = OpenAIResponses.route
 
 describe("llm constructors", () => {
+  test("normalizes recursive tool namespaces", () => {
+    const request = LLM.request({
+      model: LanguageModel.make({ id: "fake-model", provider: "fake", route: responsesRoute }),
+      tools: [
+        {
+          type: "namespace",
+          name: "crm",
+          description: "Customer management",
+          tools: [
+            { name: "lookup", description: "Look up a customer", inputSchema: { type: "object" } },
+            {
+              type: "namespace",
+              name: "orders",
+              tools: [{ name: "list", description: "List orders", inputSchema: { type: "object" } }],
+            },
+          ],
+        },
+      ],
+    })
+
+    expect(request.tools[0]).toEqual({
+      type: "namespace",
+      name: "crm",
+      description: "Customer management",
+      tools: [
+        expect.objectContaining({ type: "tool", name: "lookup" }),
+        {
+          type: "namespace",
+          name: "orders",
+          description: undefined,
+          tools: [expect.objectContaining({ type: "tool", name: "list" })],
+        },
+      ],
+    })
+    expect(request.tools[0]).toEqual(
+      ToolNamespace.make({
+        name: "crm",
+        description: "Customer management",
+        tools: request.tools[0]!.type === "namespace" ? request.tools[0].tools : [],
+      }),
+    )
+    expect(Schema.decodeUnknownSync(ToolEntry)(Schema.encodeUnknownSync(ToolEntry)(request.tools[0]))).toEqual(
+      request.tools[0],
+    )
+  })
+
   test("builds canonical schema classes from ergonomic input", () => {
     const request = LLM.request({
       id: "req_1",

packages/ai/test/provider-options/checkpoint.types.ts

@@ -0,0 +1,129 @@
+import { Effect } from "effect"
+import {
+  CompactionCheckpointResponse,
+  CompactionResponse,
+  LanguageModel,
+  LLM,
+  LLMClient,
+  LLMRequest,
+} from "../../src/index.js"
+import {
+  Anthropic,
+  Azure,
+  AmazonBedrock,
+  AmazonBedrockMantle,
+  OpenAI,
+  OpenAICompatibleResponses,
+  XAI,
+} from "../../src/providers.js"
+import type { WebSocketChannelExecutor } from "../../src/route.js"
+import type { RoutePatch } from "../../src/route/client.js"
+import type { OpenAIResponsesBody } from "../../src/protocols/openai-responses.js"
+import type { Prepared } from "../../src/protocols/open-responses-channel.js"
+
+declare const webSocket: WebSocketChannelExecutor
+const model = OpenAI.configure().responses("fixture")
+const request = LLM.request({ model, prompt: "hello" })
+LLMClient.compact(request, { mechanism: "endpoint" }).pipe(Effect.map((result) => result satisfies CompactionResponse))
+LLMClient.compact(request, { mechanism: "trigger", webSocket }).pipe(
+  Effect.map((result) => {
+    result satisfies CompactionCheckpointResponse
+    result.checkpoint.encrypted satisfies string
+    result.responseID satisfies string
+    // @ts-expect-error A trigger does not return replacement history.
+    result.replacement
+  }),
+)
+// @ts-expect-error Endpoint compaction does not accept a WebSocket executor.
+LLMClient.compact(request, { mechanism: "endpoint", webSocket })
+// @ts-expect-error Omitting mechanism selects the HTTP endpoint.
+LLMClient.compact(request, { webSocket })
+// @ts-expect-error Unknown mechanisms do not have a permissive fallback overload.
+LLMClient.compact(request, { mechanism: "other" })
+
+for (const selected of [
+  model,
+  OpenAI.model("fixture", {}),
+  model.route.with({ headers: { fixture: "test" } }).model({ id: "fixture" }),
+  LanguageModel.make(LanguageModel.input(model)),
+  LanguageModel.update(model, { defaults: { generation: { maxTokens: 100 } } }),
+]) {
+  LLMClient.compact(LLM.request({ model: selected }), { mechanism: "trigger" })
+}
+LLMClient.compact(new LLMRequest(LLMRequest.input(request)), { mechanism: "trigger" })
+LLMClient.compact(LLMRequest.update(request, { messages: [] }), { mechanism: "trigger" })
+
+const azure = Azure.configure({ resourceName: "fixture" }).responses("fixture")
+const xai = XAI.configure().responses("fixture")
+// @ts-expect-error Azure must not inherit OpenAI's trigger operation.
+LLMClient.compact(LLM.request({ model: azure }), { mechanism: "trigger" })
+LLMClient.compact(LLM.request({ model: Azure.responsesModel("fixture", { resourceName: "fixture" }) }), {
+  // @ts-expect-error Azure's package entrypoint must preserve its narrower capability.
+  mechanism: "trigger",
+})
+// @ts-expect-error xAI endpoint support does not imply trigger support.
+LLMClient.compact(LLM.request({ model: xai }), { mechanism: "trigger" })
+// @ts-expect-error xAI's package entrypoint must preserve its narrower capability.
+LLMClient.compact(LLM.request({ model: XAI.model("fixture", {}) }), { mechanism: "trigger" })
+
+const unsupported = {
+  bedrock: LLM.request({ model: AmazonBedrock.configure().model("fixture") }),
+  mantle: LLM.request({ model: AmazonBedrockMantle.configure().responses("fixture") }),
+  anthropic: LLM.request({ model: Anthropic.configure().model("fixture") }),
+  openai: LLM.request({ model: OpenAI.configure().chat("fixture") }),
+  azure: LLM.request({ model: Azure.configure({ resourceName: "fixture" }).chat("fixture") }),
+  xai: LLM.request({ model: XAI.configure().chat("fixture") }),
+  compatible: LLM.request({
+    model: OpenAICompatibleResponses.configure({ baseURL: "https://example.com" }).model("fixture"),
+  }),
+}
+// @ts-expect-error Bedrock does not expose trigger compaction.
+LLMClient.compact(unsupported.bedrock, { mechanism: "trigger" })
+// @ts-expect-error Mantle must not inherit trigger support from OpenAI's protocol.
+LLMClient.compact(unsupported.mantle, { mechanism: "trigger" })
+// @ts-expect-error Anthropic does not expose trigger compaction.
+LLMClient.compact(unsupported.anthropic, { mechanism: "trigger" })
+// @ts-expect-error OpenAI Chat does not expose trigger compaction.
+LLMClient.compact(unsupported.openai, { mechanism: "trigger" })
+// @ts-expect-error Azure Chat does not expose trigger compaction.
+LLMClient.compact(unsupported.azure, { mechanism: "trigger" })
+// @ts-expect-error xAI Chat does not expose trigger compaction.
+LLMClient.compact(unsupported.xai, { mechanism: "trigger" })
+// @ts-expect-error Generic protocol compatibility does not grant trigger support.
+LLMClient.compact(unsupported.compatible, { mechanism: "trigger" })
+// @ts-expect-error Changing the model replaces its capability.
+LLMClient.compact(LLMRequest.update(request, { model: azure }), { mechanism: "trigger" })
+// @ts-expect-error Changing the route replaces its capability.
+LLMClient.compact(LLM.request({ model: LanguageModel.update(model, { route: azure.route }) }), { mechanism: "trigger" })
+LLMClient.compact(
+  LLM.request({
+    model: model.route.with({ compact: { endpoint: model.route.compact.endpoint } }).model({ id: "fixture" }),
+  }),
+  // @ts-expect-error Replacing route operations does not retain the old trigger capability.
+  { mechanism: "trigger" },
+)
+
+declare const dynamic: LLMRequest
+declare const patch: Partial<LLMRequest.Input>
+declare const routePatch: RoutePatch<OpenAIResponsesBody, Prepared>
+// @ts-expect-error A dynamic operation override cannot preserve trigger support.
+LLMClient.compact(LLM.request({ model: model.route.with(routePatch).model({ id: "fixture" }) }), {
+  mechanism: "trigger",
+})
+// @ts-expect-error Explicitly removing operations removes trigger support.
+LLMClient.compact(LLM.request({ model: model.route.with({ compact: undefined }).model({ id: "fixture" }) }), {
+  mechanism: "trigger",
+})
+// @ts-expect-error Dynamic models must be narrowed.
+LLMClient.compact(dynamic, { mechanism: "trigger" })
+if (LLMClient.canCompact(dynamic, { mechanism: "trigger" })) {
+  LLMClient.compact(dynamic, { mechanism: "trigger" })
+  LLMClient.Service.use((client) => client.compact(dynamic, { mechanism: "trigger" }))
+}
+if (LLMClient.canCompact(dynamic)) {
+  LLMClient.compact(dynamic)
+  // @ts-expect-error Endpoint narrowing does not grant trigger support.
+  LLMClient.compact(dynamic, { mechanism: "trigger" })
+}
+// @ts-expect-error A dynamic model override cannot preserve trigger support.
+LLMClient.compact(LLMRequest.update(request, patch), { mechanism: "trigger" })

packages/ai/test/provider/checkpoint.test.ts

@@ -0,0 +1,243 @@
+import { expect } from "bun:test"
+import { Effect, Stream } from "effect"
+import { LLM, LLMClient, LLMRequest } from "../../src/index.js"
+import { Azure, OpenAI } from "../../src/providers.js"
+import { testEffect } from "../lib/effect.js"
+import { dynamicResponse, fixedResponse } from "../lib/http.js"
+import { sseEvents } from "../lib/sse.js"
+
+const checkpoint = { type: "compaction", id: "cmp_1", encrypted_content: "opaque" }
+const request = LLM.request({ model: OpenAI.configure({ apiKey: "fixture" }).responses("fixture"), prompt: "hello" })
+const trigger = { mechanism: "trigger" } as const
+
+testEffect(
+  dynamicResponse(({ request, text, respond }) =>
+    Effect.sync(() => {
+      expect(new URL(request.url).pathname).toBe("/v1/responses")
+      expect(new URL(request.url).searchParams.get("trace")).toBe("request")
+      expect(request.headers.authorization).toBe("Bearer fixture")
+      expect(request.headers["chatgpt-account-id"]).toBe("fixture-account")
+      expect(request.headers["x-codex-beta-features"]).toBe("remote_compaction_v2")
+      const body = JSON.parse(text)
+      expect(body).toMatchObject({
+        model: "fixture",
+        stream: true,
+        store: false,
+        instructions: "Keep the context",
+        parallel_tool_calls: true,
+        prompt_cache_key: "session-key",
+        service_tier: "priority",
+        reasoning: { effort: "high", summary: "auto" },
+        prompt_cache_retention: "24h",
+        prompt_cache_options: { mode: "session", ttl: "1h" },
+        input: [{ role: "user", content: [{ type: "input_text", text: "hello" }] }, { type: "compaction_trigger" }],
+      })
+      expect(body.tools).toHaveLength(1)
+      expect(body.tools[0].name).toBe("lookup")
+      expect(body.tool_choice).toBeUndefined()
+      expect(body.context_management).toBeUndefined()
+      expect(body.text).toBeUndefined()
+      expect(body.max_output_tokens).toBeUndefined()
+      expect(body.previous_response_id).toBeUndefined()
+      return respond(
+        sseEvents({
+          type: "response.completed",
+          response: {
+            id: "resp_1",
+            output: [checkpoint],
+            usage: {
+              input_tokens: 100,
+              input_tokens_details: { cached_tokens: 40 },
+              output_tokens: 5,
+              total_tokens: 105,
+            },
+          },
+        }),
+        { headers: { "content-type": "text/event-stream" } },
+      )
+    }),
+  ),
+).effect("trigger uses normal request preparation, configured deployment, and supplied subscription headers", () =>
+  Effect.gen(function* () {
+    const calls: string[] = []
+    const input = LLM.request({
+      model: request.model,
+      system: "Keep the context",
+      prompt: "hello",
+      promptCacheKey: "session-key",
+      tools: [{ name: "lookup", description: "Lookup", inputSchema: { type: "object", properties: {} } }],
+      toolChoice: { type: "tool", name: "lookup" },
+      generation: { maxTokens: 1 },
+      providerOptions: {
+        store: true,
+        reasoningEffort: "high",
+        reasoningSummary: "auto",
+        contextManagement: [{ type: "compaction" }],
+      },
+      http: {
+        headers: { "chatgpt-account-id": "fixture-account", "x-codex-beta-features": "remote_compaction_v2" },
+        query: { trace: "request" },
+        body: {
+          service_tier: "priority",
+          prompt_cache_retention: "24h",
+          prompt_cache_options: { mode: "session", ttl: "1h" },
+          store: true,
+          stream: false,
+          text: { format: { type: "json_object" } },
+          tool_choice: "required",
+        },
+      },
+    })
+    const original = LLMRequest.input(input)
+    const result = yield* LLMClient.compact(input, {
+      ...trigger,
+      http: (request, next) => {
+        calls.push("http")
+        return next(request)
+      },
+    })
+    expect(result.checkpoint).toMatchObject({
+      type: "compaction",
+      provider: "openai",
+      id: "cmp_1",
+      encrypted: "opaque",
+    })
+    expect(result.responseID).toBe("resp_1")
+    expect(result.usage).toMatchObject({
+      inputTokens: 100,
+      outputTokens: 5,
+      totalTokens: 105,
+      cacheReadInputTokens: 40,
+    })
+    expect(LLMRequest.input(input)).toEqual(original)
+    expect(calls).toEqual(["http"])
+  }),
+)
+
+const idless = { type: "compaction", encrypted_content: "opaque" }
+testEffect(
+  fixedResponse(
+    sseEvents(
+      {
+        type: "response.output_item.done",
+        output_index: 0,
+        item: { type: "function_call", id: "fc_1", name: "unexpected", arguments: "not JSON" },
+      },
+      { type: "response.output_text.delta", delta: "do not expose this" },
+      { type: "response.output_item.added", output_index: 1, item: { type: "compaction" } },
+      { type: "response.output_item.done", output_index: 1, item: idless },
+      { type: "response.output_item.done", output_index: 1, item: idless },
+      {
+        type: "response.completed",
+        response: {
+          id: "resp_1",
+          output: [{ type: "function_call", id: "fc_1", name: "unexpected", arguments: "not JSON" }, idless],
+        },
+      },
+    ),
+  ),
+).effect("correlates an ID-less checkpoint across repeated events and ignores other output", () =>
+  Effect.gen(function* () {
+    const result = yield* LLMClient.compact(request, trigger)
+    expect(result.checkpoint.encrypted).toBe("opaque")
+    expect(result.checkpoint.id).toBeString()
+    expect("message" in result).toBe(false)
+  }),
+)
+
+for (const [name, events] of Object.entries({
+  missing: [{ type: "response.completed", response: { id: "resp_1", output: [] } }],
+  multiple: [
+    { type: "response.completed", response: { id: "resp_1", output: [checkpoint, { ...checkpoint, id: "cmp_2" }] } },
+  ],
+  duplicateSlots: [{ type: "response.completed", response: { id: "resp_1", output: [checkpoint, checkpoint] } }],
+  malformed: [
+    { type: "response.completed", response: { id: "resp_1", output: [{ type: "compaction", id: "cmp_1" }] } },
+  ],
+  noResponseID: [{ type: "response.completed", response: { output: [checkpoint] } }],
+  incomplete: [
+    { type: "response.output_item.done", item: checkpoint },
+    { type: "response.incomplete", response: { id: "resp_1", incomplete_details: { reason: "max_output_tokens" } } },
+  ],
+  failed: [
+    { type: "response.output_item.done", item: checkpoint },
+    { type: "response.failed", response: { id: "resp_1", error: { code: "server_error", message: "failed" } } },
+  ],
+})) {
+  const wire = events.map((event) => ({ ...event, fixture_extra: "preserved" }))
+  testEffect(
+    fixedResponse(sseEvents(...wire), { headers: { "content-type": "text/event-stream", "x-fixture": "preserved" } }),
+  ).effect(`rejects ${name} checkpoint response and preserves original error context`, () =>
+    Effect.gen(function* () {
+      const error = yield* LLMClient.compact(request, trigger).pipe(Effect.flip)
+      expect(error.reason.body).toBe(JSON.stringify(wire.at(-1)))
+      expect(error.reason.http).toMatchObject({ status: 200, headers: { "x-fixture": "preserved" } })
+    }),
+  )
+}
+
+testEffect(fixedResponse(sseEvents({ type: "response.output_item.done", item: checkpoint }))).effect(
+  "rejects clean EOF without response.completed",
+  () =>
+    Effect.gen(function* () {
+      const error = yield* LLMClient.compact(request, trigger).pipe(Effect.flip)
+      expect(error.reason._tag).toBe("InvalidProviderOutput")
+    }),
+)
+for (const body of [{ input: [] }, { previous_response_id: "stale" }]) {
+  testEffect(dynamicResponse(() => Effect.die("Must reject before sending"))).effect(
+    `rejects caller-supplied ${Object.keys(body)[0]} before sending trigger`,
+    () =>
+      Effect.gen(function* () {
+        const error = yield* LLMClient.compact(LLMRequest.update(request, { http: { body } }), trigger).pipe(
+          Effect.flip,
+        )
+        expect(error.reason._tag).toBe("InvalidRequest")
+      }),
+  )
+}
+
+testEffect(dynamicResponse(() => Effect.die("Must reject before sending"))).effect(
+  "endpoint support does not grant trigger support, including for untyped callers",
+  () =>
+    Effect.gen(function* () {
+      const client = yield* LLMClient.Service
+      const unsupported = LLM.request({ model: Azure.configure({ resourceName: "fixture" }).responses("fixture") })
+      expect(LLMClient.canCompact(unsupported)).toBe(true)
+      expect(LLMClient.canCompact(unsupported, trigger)).toBe(false)
+      // @ts-expect-error Exercise untyped consumers; the service must reject before sending.
+      const serviceError = yield* client.compact(unsupported, trigger).pipe(Effect.flip)
+      expect(serviceError.reason._tag).toBe("UnsupportedOperation")
+      // @ts-expect-error Exercise an unknown mechanism supplied by JavaScript.
+      const error = yield* LLMClient.compact(request, { mechanism: "other" }).pipe(Effect.flip)
+      expect(error.reason._tag).toBe("InvalidRequest")
+    }),
+)
+
+testEffect(fixedResponse("must not use HTTP")).effect(
+  "invalid checkpoint output is rejected before acknowledging channel completion",
+  () =>
+    Effect.gen(function* () {
+      let completed = 0
+      const operation = LLMClient.compact(request, {
+        mechanism: "trigger",
+        webSocket: {
+          execute: () =>
+            Effect.succeed({
+              frames: Stream.make(
+                JSON.stringify({
+                  type: "response.completed",
+                  response: { id: "resp_1", output: [] },
+                }),
+              ),
+              complete: Effect.sync(() => {
+                completed++
+              }),
+            }),
+        },
+      })
+      const error = yield* operation.pipe(Effect.flip)
+      expect(error.reason._tag).toBe("InvalidProviderOutput")
+      expect(completed).toBe(0)
+    }),
+)

packages/ai/test/provider/explicit-compaction.test.ts

@@ -1,6 +1,6 @@
 import { expect } from "bun:test"
 import { Effect, Schema } from "effect"
-import { LLM, LLMRequest, Message } from "../../src/index.js"
+import { LLM, LLMRequest, Message, ToolDefinition } from "../../src/index.js"
 import { LLMClient, Route } from "../../src/route/client.js"
 import { Auth } from "../../src/route/auth.js"
 import { Endpoint } from "../../src/route/endpoint.js"
@@ -134,7 +134,12 @@ for (const model of [
         [
           LLMRequest.update(request, {
             tools: [
-              { name: "unsupported", description: "Generation only", inputSchema: {}, native: { unsupported: {} } },
+              ToolDefinition.make({
+                name: "unsupported",
+                description: "Generation only",
+                inputSchema: {},
+                native: { unsupported: {} },
+              }),
             ],
           }),
           "InvalidRequest",

packages/ai/test/provider/open-responses-lifecycle.test.ts

@@ -326,7 +326,6 @@ describe("Open Responses basic-item lifecycles", () => {
       ])
     }),
   )
-
   it.effect("mints an id for a done-only tool that never had one", () =>
     Effect.gen(function* () {
       const events = yield* collect(
@@ -357,9 +356,16 @@ describe("Open Responses basic-item lifecycles", () => {
       const events = yield* collect({ type: "response.output_item.done", item }, completed)
       const providerMetadata = { "openai-compatible": { itemId: "fc_1" } }
       expect(events.filter((event) => event.type.startsWith("tool-"))).toEqual([
-        { type: "tool-input-start", id: "call_1", name: "lookup", providerMetadata },
-        { type: "tool-input-end", id: "call_1", name: "lookup", providerMetadata },
-        { type: "tool-call", id: "call_1", name: "lookup", input: { query: "weather" }, providerMetadata },
+        { type: "tool-input-start", id: "call_1", name: "lookup", namespace: undefined, providerMetadata },
+        { type: "tool-input-end", id: "call_1", name: "lookup", namespace: undefined, providerMetadata },
+        {
+          type: "tool-call",
+          id: "call_1",
+          name: "lookup",
+          namespace: undefined,
+          input: { query: "weather" },
+          providerMetadata,
+        },
       ])
       expect(events.filter(LLMEvent.is.finish)).toEqual([
         {

packages/ai/test/provider/openai-compatible-responses.test.ts

@@ -171,6 +171,66 @@ describe("Open Responses-compatible route", () => {
     }),
   )
 
+  it.effect("flattens tool namespaces", () =>
+    Effect.gen(function* () {
+      const model = configure({ apiKey: "test-key", baseURL: "https://responses.example.test/v1" }).model(
+        "example-model",
+      )
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model,
+          tools: [
+            {
+              type: "namespace",
+              name: "acme",
+              tools: [
+                {
+                  type: "namespace",
+                  name: "billing",
+                  tools: [ToolDefinition.make({ name: "lookup", description: "Lookup billing", inputSchema: {} })],
+                },
+                ToolDefinition.make({ name: "users", description: "Lookup users", inputSchema: {} }),
+              ],
+            },
+          ],
+        }),
+      )
+
+      expect(prepared.body.tools).toEqual([
+        {
+          type: "function",
+          name: "acme_billing_lookup",
+          description: "Lookup billing",
+          parameters: {},
+          strict: false,
+        },
+        { type: "function", name: "acme_users", description: "Lookup users", parameters: {}, strict: false },
+      ])
+    }),
+  )
+
+  it.effect("flattens tool namespaces in history", () =>
+    Effect.gen(function* () {
+      const model = configure({ apiKey: "test-key", baseURL: "https://responses.example.test/v1" }).model(
+        "example-model",
+      )
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model,
+          messages: [
+            Message.assistant({ type: "tool-call", id: "call_1", name: "lookup", namespace: "crm", input: {} }),
+            Message.tool({ id: "call_1", name: "lookup", namespace: "crm", result: "done", resultType: "text" }),
+          ],
+        }),
+      )
+
+      expect(prepared.body.input).toEqual([
+        { type: "function_call", call_id: "call_1", name: "crm_lookup", namespace: undefined, arguments: "{}" },
+        { type: "function_call_output", call_id: "call_1", output: "done" },
+      ])
+    }),
+  )
+
   it.effect("lowers canonical parallel tool control", () =>
     Effect.gen(function* () {
       const model = configure({

packages/ai/test/provider/openai-responses.test.ts

@@ -12,6 +12,7 @@ import {
   LanguageModel,
   ToolCallPart,
   ToolDefinition,
+  ToolNamespace,
   ToolResultPart,
   TransportError,
   Usage,
@@ -143,6 +144,94 @@ describe("OpenAI Responses route", () => {
     }),
   )
 
+  it.effect("lowers tool namespaces without flattening leaf names", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model,
+          prompt: "Find a customer and their orders.",
+          tools: [
+            ToolNamespace.make({
+              name: "crm",
+              description: "Customer management",
+              tools: [
+                ToolDefinition.make({ name: "lookup", description: "Look up a customer", inputSchema: {} }),
+                ToolDefinition.make({ name: "orders", description: "List customer orders", inputSchema: {} }),
+              ],
+            }),
+          ],
+        }),
+      )
+
+      expect(prepared.body.tools).toEqual([
+        {
+          type: "namespace",
+          name: "crm",
+          description: "Customer management",
+          tools: [
+            { type: "function", name: "lookup", description: "Look up a customer", parameters: {}, strict: false },
+            { type: "function", name: "orders", description: "List customer orders", parameters: {}, strict: false },
+          ],
+        },
+      ])
+    }),
+  )
+
+  it.effect("flattens nested levels within a native tool namespace", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model,
+          tools: [
+            {
+              type: "namespace",
+              name: "crm",
+              description: "Customer management",
+              tools: [
+                {
+                  type: "namespace",
+                  name: "orders",
+                  description: "Order management",
+                  tools: [ToolDefinition.make({ name: "list", description: "List orders", inputSchema: {} })],
+                },
+              ],
+            },
+          ],
+        }),
+      )
+
+      expect(prepared.body.tools).toEqual([
+        {
+          type: "namespace",
+          name: "crm",
+          description: "Customer management",
+          tools: [{ type: "function", name: "orders_list", description: "List orders", parameters: {}, strict: false }],
+        },
+      ])
+    }),
+  )
+
+  it.effect("defaults tool namespace descriptions", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model,
+          tools: [
+            {
+              type: "namespace",
+              name: "crm",
+              tools: [ToolDefinition.make({ name: "lookup", description: "Look up a customer", inputSchema: {} })],
+            },
+          ],
+        }),
+      )
+
+      expect(prepared.body.tools).toEqual([
+        expect.objectContaining({ type: "namespace", name: "crm", description: "Tools in the crm namespace." }),
+      ])
+    }),
+  )
+
   it.effect("rejects invalid hosted image generation options locally", () =>
     Effect.gen(function* () {
       const error = yield* compileRequest(
@@ -568,7 +657,7 @@ describe("OpenAI Responses route", () => {
     }),
   )
 
-  it.effect("continues a promoted steer after the completed assistant output", () =>
+  it.effect("continues a promoted steer after assistant output with response-only text metadata", () =>
     Effect.gen(function* () {
       const firstInput = [{ role: "user", content: [{ type: "input_text", text: "First" }] }]
       const first = continuationDriver({ type: "response.create", model: "gpt-5.2", store: false, input: firstInput })
@@ -582,7 +671,7 @@ describe("OpenAI Responses route", () => {
             id: "msg_1",
             status: "completed",
             role: "assistant",
-            content: [{ type: "output_text", text: "Hello" }],
+            content: [{ type: "output_text", text: "Hello", annotations: [], logprobs: [] }],
           },
         }),
       )
@@ -610,42 +699,37 @@ describe("OpenAI Responses route", () => {
     }),
   )
 
-  it.effect("continues store-false reasoning while retaining the output item ID", () =>
+  it.effect("continues streamed reasoning when completion re-encrypts the same item", () =>
     Effect.gen(function* () {
       const firstInput = [{ role: "user", content: [{ type: "input_text", text: "Think" }] }]
       const request = { type: "response.create", model: "gpt-5.2", store: false, input: firstInput }
+      const reasoning = {
+        type: "reasoning",
+        id: "rs_1",
+        summary: [{ type: "summary_text", text: "Thought" }],
+        encrypted_content: "encrypted",
+      }
       const first = continuationDriver(request)
       const create = yield* first.create(undefined)
       yield* first.observe(
         create,
         ProviderShared.encodeJson({
           type: "response.output_item.done",
-          item: {
-            type: "reasoning",
-            id: "rs_1",
-            summary: [{ type: "summary_text", text: "Thought" }],
-            encrypted_content: "encrypted",
-          },
+          item: reasoning,
         }),
       )
       const saved = checkpoint(
         yield* first.observe(
           create,
-          ProviderShared.encodeJson({ type: "response.completed", response: { id: "resp_1" } }),
+          ProviderShared.encodeJson({
+            type: "response.completed",
+            response: { id: "resp_1", output: [{ ...reasoning, encrypted_content: "terminal-encrypted" }] },
+          }),
         ),
       )
       const next = continuationDriver({
         ...request,
-        input: [
-          ...firstInput,
-          {
-            type: "reasoning",
-            id: "rs_1",
-            summary: [{ type: "summary_text", text: "Thought" }],
-            encrypted_content: "encrypted",
-          },
-          { role: "user", content: [{ type: "input_text", text: "Continue" }] },
-        ],
+        input: [...firstInput, reasoning, { role: "user", content: [{ type: "input_text", text: "Continue" }] }],
       })
 
       const continued = yield* next.create(saved)
@@ -655,6 +739,11 @@ describe("OpenAI Responses route", () => {
         previous_response_id: "resp_1",
         input: [{ role: "user", content: [{ type: "input_text", text: "Continue" }] }],
       })
+      const edited = yield* continuationDriver({
+        ...request,
+        input: [...firstInput, { ...reasoning, encrypted_content: "edited" }, { role: "user", content: "Continue" }],
+      }).create(saved)
+      expect(edited.mode).toBe("full")
     }),
   )
 
@@ -2130,6 +2219,71 @@ describe("OpenAI Responses route", () => {
     }),
   )
 
+  it.effect("preserves tool namespaces through streaming and history replay", () =>
+    Effect.gen(function* () {
+      const item = {
+        type: "function_call",
+        id: "fc_1",
+        call_id: "call_1",
+        namespace: "crm",
+        name: "lookup",
+        arguments: "",
+      }
+      const response = yield* LLMClient.generate(request).pipe(
+        Effect.provide(
+          fixedResponse(
+            sseEvents(
+              { type: "response.output_item.added", output_index: 0, item },
+              {
+                type: "response.function_call_arguments.delta",
+                output_index: 0,
+                item_id: "fc_1",
+                delta: '{"id":"123"}',
+              },
+              {
+                type: "response.output_item.done",
+                output_index: 0,
+                item: { ...item, arguments: '{"id":"123"}' },
+              },
+              { type: "response.completed", response: { id: "resp_1" } },
+            ),
+          ),
+        ),
+      )
+
+      const toolEvents = response.events.filter((event) => event.type.startsWith("tool-"))
+      expect(toolEvents).toEqual([
+        expect.objectContaining({ type: "tool-input-start", name: "lookup", namespace: "crm" }),
+        expect.objectContaining({ type: "tool-input-delta", name: "lookup", namespace: "crm" }),
+        expect.objectContaining({ type: "tool-input-end", name: "lookup", namespace: "crm" }),
+        expect.objectContaining({ type: "tool-call", name: "lookup", namespace: "crm", input: { id: "123" } }),
+      ])
+      expect(response.message.content).toEqual([
+        expect.objectContaining({ type: "tool-call", name: "lookup", namespace: "crm", input: { id: "123" } }),
+      ])
+
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model,
+          messages: [
+            response.message,
+            Message.tool({ id: "call_1", name: "lookup", namespace: "crm", result: { customer: "Ada" } }),
+          ],
+        }),
+      )
+      expect(prepared.body.input).toEqual([
+        {
+          type: "function_call",
+          id: "fc_1",
+          call_id: "call_1",
+          namespace: "crm",
+          name: "lookup",
+          arguments: '{"id":"123"}',
+        },
+        { type: "function_call_output", call_id: "call_1", output: '{"customer":"Ada"}' },
+      ])
+    }),
+  )
   it.effect("routes reasoning summary events by output index", () =>
     Effect.gen(function* () {
       const response = yield* LLMClient.generate(request).pipe(

packages/ai/test/testing.test.ts

@@ -3,6 +3,7 @@ import {
   AIError,
   CompactionPart,
   CompactionResponse,
+  CompactionCheckpointResponse,
   LanguageModel,
   LLM,
   LLMClient,
@@ -79,6 +80,31 @@ describe("TestLLM legacy client", () => {
 })
 
 describe("TestLLM first-class client", () => {
+  it.effect("returns scripted checkpoints only for trigger compaction", () =>
+    Effect.gen(function* () {
+      const client = yield* TestLLM.Test
+      const request = LLM.request({ model: OpenAI.configure().responses("fixture"), prompt: "hello" })
+      const checkpoint = new CompactionCheckpointResponse({
+        checkpoint: { type: "compaction", provider: ProviderID.make("openai"), encrypted: "opaque" },
+        responseID: "resp_fixture",
+      })
+      const endpoint = new CompactionResponse({ replacement: [] })
+      yield* client.push(checkpoint, endpoint, checkpoint, checkpoint)
+      const operation = LLMClient.compact(request, { mechanism: "trigger" })
+      expect(yield* client.requests()).toEqual([])
+      expect(yield* operation).toBe(checkpoint)
+      expect(yield* client.compact(request, { mechanism: "trigger" }).pipe(Effect.catchDefect(Effect.succeed))).toBe(
+        "TestLLM trigger compaction requires a CompactionCheckpointResponse",
+      )
+      expect(yield* client.compact(request).pipe(Effect.catchDefect(Effect.succeed))).toBe(
+        "TestLLM compaction requires a CompactionResponse",
+      )
+      expect(yield* client.generate(request).pipe(Effect.catchDefect(Effect.succeed))).toBe(
+        "TestLLM generation requires an event response",
+      )
+    }),
+  )
+
   it.effect("rejects response fixtures for the wrong operation", () =>
     Effect.gen(function* () {
       const client = yield* TestLLM.Test

packages/ai/test/tool-history.test.ts

@@ -15,13 +15,7 @@ describe("tool history normalization", () => {
       Message.assistant(toolCall("trailing")),
     ])
 
-    expect(normalized.map((message) => message.role)).toEqual([
-      "assistant",
-      "tool",
-      "tool",
-      "user",
-      "assistant",
-    ])
+    expect(normalized.map((message) => message.role)).toEqual(["assistant", "tool", "tool", "user", "assistant"])
     expect(normalized[1]?.content[0]).toMatchObject({ type: "tool-result", id: "first", name: "first" })
     expect(normalized[2]?.content).toEqual([
       { type: "tool-result", id: "second", name: "second", result: { type: "error", value: "Tool result missing" } },
@@ -74,4 +68,13 @@ describe("tool history normalization", () => {
 
     expect(normalizeToolHistory([orphan, hosted])).toEqual([orphan, hosted])
   })
+
+  test("uses a matching call as the complete tool identity", () => {
+    const normalized = normalizeToolHistory([
+      Message.assistant(ToolCallPart.make({ id: "call_1", name: "lookup", input: {} })),
+      Message.tool(ToolResultPart.make({ id: "call_1", name: "wrong", namespace: "stale", result: "done" })),
+    ])
+
+    expect(normalized[1]?.content[0]).toMatchObject({ name: "lookup", namespace: undefined })
+  })
 })

packages/ai/test/tool-runtime.test.ts

@@ -7,6 +7,7 @@ import {
   LLMEvent,
   LLMRequest,
   LLMResponse,
+  ToolCallPart,
   ToolChoice,
   ToolOutput,
   toDefinitions,
@@ -36,6 +37,27 @@ const baseRequest = LLM.request({
 })
 const weatherFailureCause = new Error("weather lookup denied")
 
+test("dispatches namespaced calls by qualified identity", async () => {
+  let context: ToolExecuteContext | undefined
+  const lookup = Tool.make({
+    description: "Look up a customer.",
+    parameters: Schema.Struct({}),
+    success: Schema.String,
+    execute: (_, value) => {
+      context = value
+      return Effect.succeed("customer")
+    },
+  })
+  const call = ToolCallPart.make({ id: "call_1", namespace: "crm", name: "lookup", input: {} })
+  const result = await Effect.runPromise(
+    ToolRuntime.dispatch({ "crm.lookup": lookup, lookup: schema_only_weather }, call),
+  )
+
+  expect(result.result).toEqual({ type: "text", value: "customer" })
+  expect(context).toEqual({ id: "call_1", namespace: "crm", name: "lookup" })
+  expect(result.events).toEqual([expect.objectContaining({ type: "tool-result", namespace: "crm", name: "lookup" })])
+})
+
 const get_weather = Tool.make({
   description: "Get current weather for a city.",
   parameters: Schema.Struct({ city: Schema.String }),

packages/ai/tsconfig.types.json

@@ -5,5 +5,5 @@
     "noEmit": true,
     "rootDir": "."
   },
-  "include": ["test/**/*.types.ts", "test/testing.test.ts"]
+  "include": ["test/**/*.types.ts", "test/testing.test.ts", "test/provider/checkpoint.test.ts"]
 }

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

@@ -88,27 +88,88 @@ story("renders a draft once and supports editing, caret restoration, and failure
   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 }) => {
+story("shows thinking on composer hover or when a non-default variant is selected", async ({ mount, page }) => {
   const component = await mount("opencode-composer-flow--model-and-variant")
   const composer = component.locator('[data-component="composer"]')
-  const input = composer.locator('[data-component="composer-editor"]')
+  const input = composer.getByRole("textbox", { name: "Prompt", exact: true })
   const control = composer.getByRole("button", { name: "Choose model variant" })
 
+  await component.getByRole("status").click()
   await page.mouse.move(0, 0)
-  await page.evaluate(() => (document.activeElement as HTMLElement | null)?.blur())
-  await expect(control).toBeVisible()
+  await expect(control).toHaveText("balanced")
+  await expect(control).toHaveCSS("opacity", "1")
 
+  await control.click()
+  await page.getByRole("menuitemradio", { name: "default", exact: true }).click()
+  await component.getByRole("status").click()
+  await expect(control).toHaveText("default")
+  await expect(control).toHaveCSS("opacity", "0")
+  await expect(control).toHaveCSS("pointer-events", "none")
+
+  await input.hover()
+  await expect(control).toHaveCSS("opacity", "1")
+  await expect(control).toHaveCSS("pointer-events", "auto")
+  await input.click()
+  await page.mouse.move(0, 0)
+  await expect(input).toBeFocused()
+  await expect(control).toHaveCSS("opacity", "0")
+
+  await input.hover()
   await control.click()
   const high = page.getByRole("menuitemradio", { name: "high" })
   await expect(high).toBeVisible()
   await page.mouse.move(0, 0)
-  await expect(control).toBeVisible()
+  await expect(control).toHaveAttribute("aria-expanded", "true")
+  await expect(control).toHaveCSS("opacity", "1")
   await expect(high).toBeVisible()
   await high.click()
+  await component.getByRole("status").click()
+  await expect(control).toHaveText("high")
+  await expect(control).toHaveCSS("opacity", "1")
 
-  await input.focus()
-  await expect(control).toBeVisible()
-  await input.blur()
-  await expect(control).toBeVisible()
+  await control.click()
+  await page.getByRole("menuitemradio", { name: "default", exact: true }).click()
+  await component.getByRole("status").click()
+  await expect(control).toHaveCSS("opacity", "0")
+})
+
+story("keeps default thinking accessible by keyboard without composer hover", async ({ mount, page }) => {
+  const component = await mount("opencode-composer-flow--model-and-variant")
+  const input = component.getByRole("textbox", { name: "Prompt", exact: true })
+  const control = component.getByRole("button", { name: "Choose model variant" })
+
+  await control.click()
+  await page.getByRole("menuitemradio", { name: "default", exact: true }).click()
+  await input.click()
+  await page.mouse.move(0, 0)
+  await expect(control).toHaveCSS("opacity", "0")
+
+  // Tab through Add, Agent, and Model to the visually hidden thinking trigger.
+  for (let count = 0; count < 4; count++) await page.keyboard.press("Tab")
+  await expect(control).toBeFocused()
+  await expect(control).toHaveCSS("opacity", "1")
+  await page.keyboard.press("Enter")
+  await expect(control).toHaveAttribute("aria-expanded", "true")
+  await expect(page.getByRole("menuitemradio", { name: "default", exact: true })).toBeFocused()
+  await expect(control).toHaveCSS("opacity", "1")
+  await page.keyboard.press("Escape")
+  await expect(control).toHaveAttribute("aria-expanded", "false")
+  await expect(control).toBeFocused()
+  await expect(control).toHaveCSS("opacity", "1")
+  await page.keyboard.press("Enter")
+  await expect(page.getByRole("menuitemradio", { name: "default", exact: true })).toBeFocused()
+  await page.keyboard.press("End")
+  await expect(page.getByRole("menuitemradio", { name: "high", exact: true })).toBeFocused()
+  await page.keyboard.press("Enter")
+  await expect(control).toHaveText("high")
+  await expect(control).toBeFocused()
+  await page.keyboard.press("Enter")
+  await expect(page.getByRole("menuitemradio", { name: "default", exact: true })).toBeFocused()
+  await page.keyboard.press("Enter")
+  await expect(control).toHaveText("default")
+  await expect(control).toBeFocused()
+  await expect(control).toHaveCSS("opacity", "1")
+  await page.keyboard.press("Tab")
+  await expect(control).not.toBeFocused()
+  await expect(control).toHaveCSS("opacity", "0")
 })

packages/app/e2e/regression/composer-slash-skill.spec.ts

@@ -0,0 +1,195 @@
+import { expect, test, type Page } from "@playwright/test"
+import { base64Encode } from "@opencode-ai/util/encode"
+import { mockOpenCodeServer } from "../utils/mock-server"
+
+const directory = "/repo/slash-skills"
+const projectID = "proj_slash_skills"
+const sessionID = "ses_slash_skills"
+const server = `http://${process.env.PLAYWRIGHT_SERVER_HOST ?? "127.0.0.1"}:${process.env.PLAYWRIGHT_SERVER_PORT ?? "4096"}`
+
+async function setup(page: Page, queued = false) {
+  const prompts: Record<string, unknown>[] = []
+  await mockOpenCodeServer(page, {
+    directory,
+    project: {
+      id: projectID,
+      worktree: directory,
+      vcs: "git",
+      name: "slash-skills",
+      time: { created: 1700000000000, updated: 1700000000000 },
+      sandboxes: [],
+    },
+    provider: {
+      all: [
+        {
+          id: "opencode",
+          name: "OpenCode",
+          models: { test: { id: "test", name: "Test", limit: { context: 200_000 } } },
+        },
+      ],
+      connected: ["opencode"],
+      default: { providerID: "opencode", modelID: "test" },
+    },
+    sessions: [
+      {
+        id: sessionID,
+        projectID,
+        directory,
+        title: "Slash skills",
+        version: "dev",
+        time: { created: 1700000000000, updated: 1700000000000 },
+      },
+    ],
+    pageMessages: () => ({ items: [] }),
+    sessionStatus: queued ? { [sessionID]: { type: "running" } } : {},
+    inbox: queued
+      ? [
+          {
+            id: "inb_slash_skill",
+            sessionID,
+            timeCreated: 1700000000000,
+            type: "user",
+            payload: { text: "Explain caching" },
+            delivery: "queue",
+          },
+        ]
+      : [],
+    findFiles: ({ query }) =>
+      query.includes("cache")
+        ? [
+            {
+              name: "cache.ts",
+              path: "src/cache.ts",
+              absolute: `${directory}/src/cache.ts`,
+              type: "file",
+              ignored: false,
+            },
+          ]
+        : [],
+    onPrompt: ({ body }) => prompts.push(body),
+  })
+  await page.route("**/api/skill?*", (route) =>
+    route.fulfill({
+      json: {
+        location: { directory, project: { id: projectID, directory, canonical: directory } },
+        data: [
+          { id: "show-me", slash: true, autoinvoke: false },
+          { id: "hidden", slash: false },
+          { id: "implicit" },
+          { id: "review", slash: true },
+          { id: "model", slash: true },
+        ].map((skill) => ({
+          name: skill.id === "show-me" ? "Show Me" : skill.id,
+          description: "Explain the current topic visually",
+          location: `/skills/${skill.id}/SKILL.md`,
+          content: "Explain visually",
+          ...skill,
+        })),
+      },
+      headers: { "access-control-allow-origin": "*" },
+    }),
+  )
+  await page.route("**/api/command?*", (route) =>
+    route.fulfill({
+      json: {
+        location: { directory, project: { id: projectID, directory, canonical: directory } },
+        data: [{ name: "review", description: "Review changes" }],
+      },
+      headers: { "access-control-allow-origin": "*" },
+    }),
+  )
+  await page.goto(`/server/${base64Encode(server)}/session/${sessionID}`)
+  const composer = page.locator('[data-component="composer"]')
+  const editor = composer.locator('[data-component="composer-editor"]')
+  await expect(editor).toBeEditable()
+  return { prompts, composer, editor }
+}
+
+for (const selection of ["keyboard", "pointer"]) {
+  test(`selects and submits a manual-only slash skill with ${selection}`, async ({ page }) => {
+    const { prompts, editor } = await setup(page)
+    await editor.fill("/show")
+    const skill = page.locator('[data-suggestion-id="skill:show-me"]')
+    await expect(skill).toContainText("/show-me")
+    await page.screenshot({ path: test.info().outputPath("slash-menu.png") })
+    if (selection === "keyboard") await editor.press("Enter")
+    if (selection === "pointer") await skill.click()
+    await expect(editor).toHaveText("/show-me ")
+    await expect(editor).toBeFocused()
+    await editor.pressSequentially("explain caching")
+    await editor.press("Enter")
+    await expect.poll(() => prompts.length).toBe(1)
+    expect(prompts[0]).toMatchObject({
+      text: "/show-me explain caching",
+      skills: [{ id: "show-me", mention: { start: 0, end: 8, text: "/show-me" } }],
+    })
+    await expect(editor).toBeEmpty()
+  })
+}
+
+test("respects slash flags and command precedence without hiding context skills", async ({ page }) => {
+  const { editor } = await setup(page)
+  await editor.fill("/")
+  await expect(page.locator('[data-suggestion-id="skill:show-me"]')).toBeVisible()
+  await expect(page.locator('[data-suggestion-id="custom.review"]')).toBeVisible()
+  await expect(page.locator('[data-suggestion-id="model.choose"]')).toBeVisible()
+  for (const id of ["hidden", "implicit", "review", "model"]) {
+    await expect(page.locator(`[data-suggestion-id="skill:${id}"]`)).toHaveCount(0)
+  }
+  await editor.press("Escape")
+  await expect(page.locator('[data-suggestion-id="skill:show-me"]')).toHaveCount(0)
+  await expect(editor).toBeFocused()
+  await editor.fill("@hidden")
+  const hidden = page.locator('[data-suggestion-id="skill:hidden"]')
+  await expect(hidden).toContainText("@hidden")
+  await hidden.click()
+  await expect(editor).toHaveText("@hidden ")
+  await expect(editor).toBeFocused()
+})
+
+test("preserves structured attachments when adding a slash skill from the command menu", async ({ page }) => {
+  const { prompts, composer, editor } = await setup(page)
+  await editor.fill("explain @cache")
+  const file = page.locator('[data-suggestion-id="file:src/cache.ts"]')
+  await expect(file).toBeVisible()
+  await file.click()
+  await expect(editor).toHaveText("explain @src/cache.ts ")
+  await composer.getByRole("button", { name: "Add images and files" }).click()
+  await page.getByRole("menuitem", { name: "Commands" }).click()
+  const skill = page.locator('[data-suggestion-id="skill:show-me"]')
+  await expect(skill).toBeVisible()
+  await skill.click()
+  await expect(editor).toHaveText("/show-me explain @src/cache.ts ")
+  await expect(editor).toBeFocused()
+  await editor.press("Enter")
+  await expect.poll(() => prompts.length).toBe(1)
+  expect(prompts[0]).toMatchObject({
+    skills: [{ id: "show-me", mention: { start: 0, end: 8, text: "/show-me" } }],
+    files: [{ name: "cache.ts", mention: { start: 17, end: 30, text: "@src/cache.ts" } }],
+  })
+})
+
+for (const select of [true, false]) {
+  test(`keeps slash skills in queued edits (${select ? "selected" : "typed"})`, async ({ page }) => {
+    const { prompts, editor } = await setup(page, true)
+    const row = page.locator('[data-component="session-queue-row"]')
+    await row.getByText("Explain caching", { exact: true }).click()
+    await expect(editor).toHaveText("Explain caching")
+    if (select) {
+      await editor.fill("/show")
+      const skill = page.locator('[data-suggestion-id="skill:show-me"]')
+      await expect(skill).toBeVisible()
+      await skill.click()
+      await expect(editor).toHaveText("/show-me ")
+      await editor.pressSequentially("explain caching")
+    }
+    if (!select) await editor.fill("/show-me explain caching")
+    await editor.press("Enter")
+    await expect.poll(() => prompts.length).toBe(1)
+    expect(prompts[0]).toMatchObject({
+      delivery: "queue",
+      text: "/show-me explain caching",
+      skills: [{ id: "show-me", mention: { start: 0, end: 8, text: "/show-me" } }],
+    })
+  })
+}

packages/app/e2e/regression/new-session-dropzone.spec.ts

@@ -0,0 +1,60 @@
+import { expect, test } from "@playwright/test"
+import { mockOpenCodeServer } from "../utils/mock-server"
+import { expectAppVisible } from "../utils/waits"
+
+const draftID = "draft_new_session_dropzone"
+const directory = "C:/OpenCode/NewSessionDropzone"
+const server = `http://${process.env.PLAYWRIGHT_SERVER_HOST ?? "127.0.0.1"}:${process.env.PLAYWRIGHT_SERVER_PORT ?? "4096"}`
+
+test("shows the dropzone and attaches a dropped file", async ({ page }) => {
+  await mockOpenCodeServer(page, {
+    directory,
+    project: {
+      id: "proj_new_session_dropzone",
+      worktree: directory,
+      vcs: "git",
+      name: "new-session-dropzone",
+      time: { created: 1700000000000, updated: 1700000000000 },
+      sandboxes: [],
+    },
+    provider: { all: [], connected: [], default: {} },
+    sessions: [],
+    pageMessages: () => ({ items: [] }),
+  })
+  await page.addInitScript(
+    ({ directory, draftID, server }) => {
+      localStorage.setItem(
+        "opencode.global.dat:server",
+        JSON.stringify({
+          projects: { local: [{ worktree: directory, expanded: true }] },
+          lastProject: { local: directory },
+        }),
+      )
+      localStorage.setItem(
+        "opencode.window.browser.dat:tabs",
+        JSON.stringify([{ type: "draft", draftID, server, directory }]),
+      )
+    },
+    { directory, draftID, server },
+  )
+
+  await page.goto(`/new-session?draftId=${draftID}`)
+  await expectAppVisible(page.locator('[data-component="composer-editor"]'))
+
+  const surface = page.locator('[data-component="new-session"]')
+  const dropzone = page.locator('[data-component="session-dropzone"]')
+  const transfer = await page.evaluateHandle(() => {
+    const value = new DataTransfer()
+    value.items.add(new File(["Dropzone fixture"], "dropzone.txt", { type: "text/plain" }))
+    return value
+  })
+
+  await expect(dropzone).toHaveCount(0)
+  await surface.dispatchEvent("dragover", { dataTransfer: transfer })
+  await expect(dropzone).toHaveAttribute("data-visible", "true")
+  await expect(dropzone).toContainText("Drop files to add")
+
+  await surface.dispatchEvent("drop", { dataTransfer: transfer })
+  await expect(page.locator('[data-component="composer-attachments"]')).toContainText("dropzone.txt")
+  await expect(dropzone).toHaveCount(0)
+})

packages/app/e2e/regression/new-session-workspace-pending.spec.ts

@@ -134,7 +134,7 @@ for (const viewport of [
       await expect(page).toHaveURL(pending.url)
       await expect(pending.message).toHaveAttribute("data-timeline-part-id", `${pending.messageID}:text:0`)
       await expect(pending.shimmer).toHaveAttribute("data-active", "true")
-      await expect(pending.title).toHaveText("New session")
+      await expect(pending.title).toHaveText("Session")
       await expect(editor).toHaveText(followUp)
       expect(mock.calls).toEqual(["worktree"])
 
@@ -238,7 +238,7 @@ for (const direction of ["ltr", "rtl"]) {
           !frame.message ||
           !frame.spinner ||
           frame.draft !== followUp ||
-          !["New session", "Created workspace session"].includes(frame.title ?? ""),
+          !["Session", "Created workspace session"].includes(frame.title ?? ""),
       ),
     ).toEqual([])
     const after = await title.boundingBox()
@@ -598,7 +598,7 @@ async function submitPending(page: Page, mock: Awaited<ReturnType<typeof openDra
   const shimmer = preparing.getByRole("status").locator('[data-component="text-shimmer"]')
   const title = preparing.getByRole("heading", { level: 1 })
   await expect(preparing).toBeVisible()
-  await expect(title).toHaveText("New session")
+  await expect(title).toHaveText("Session")
   await expect(page.locator('[data-component="composer-editor"]')).toBeEditable()
   await expect(page.locator('[data-action="composer-submit"]')).toBeDisabled()
   await expect(preparing.locator('[data-component="user-message"]')).toHaveCount(1)

packages/app/e2e/regression/prompt-thinking-level.spec.ts

@@ -1,4 +1,4 @@
-import { expect, test, type Page } from "@playwright/test"
+import { expect, test } from "@playwright/test"
 import { base64Encode } from "@opencode-ai/util/encode"
 import { mockOpenCodeServer } from "../utils/mock-server"
 import { expectAppVisible } from "../utils/waits"
@@ -8,7 +8,7 @@ const projectID = "proj_prompt_thinking_level_regression"
 const sessionID = "ses_prompt_thinking_level_regression"
 const server = `http://${process.env.PLAYWRIGHT_SERVER_HOST ?? "127.0.0.1"}:${process.env.PLAYWRIGHT_SERVER_PORT ?? "4096"}`
 
-test("shows the thinking level control while relevant", async ({ page }) => {
+test("shows thinking on hover or a non-default selection while preserving keyboard access", async ({ page }) => {
   await mockOpenCodeServer(page, {
     directory,
     project: {
@@ -52,30 +52,57 @@ test("shows the thinking level control while relevant", async ({ page }) => {
   })
   await page.goto(`/server/${base64Encode(server)}/session/${sessionID}`)
   const composer = page.locator('[data-component="composer"]')
-  const input = composer.locator('[data-component="composer-editor"]')
+  const input = composer.getByRole("textbox", { name: "Prompt", exact: true })
   const control = composer.getByRole("button", { name: "Choose model variant" })
   await expectAppVisible(composer)
 
-  await idleComposer(page)
-  await expect(control).toBeVisible()
+  await page.mouse.move(0, 0)
+  await expect(control).toHaveText("default")
+  await expect(control).toHaveCSS("opacity", "0")
+  await expect(control).toHaveCSS("pointer-events", "none")
 
+  await input.hover()
+  await expect(control).toHaveCSS("opacity", "1")
+  await input.click()
+  await page.mouse.move(0, 0)
+  await expect(input).toBeFocused()
+  await expect(control).toHaveCSS("opacity", "0")
+
+  await input.hover()
   await control.click()
   const high = page.getByRole("menuitemradio", { name: "high" })
   await expect(high).toBeVisible()
   await page.mouse.move(0, 0)
-  await expect(control).toBeVisible()
+  await expect(control).toHaveAttribute("aria-expanded", "true")
+  await expect(control).toHaveCSS("opacity", "1")
   await expect(high).toBeVisible()
   await high.click()
 
-  await idleComposer(page)
-  await input.focus()
-  await expect(control).toBeVisible()
-
-  await idleComposer(page)
-  await expect(control).toBeVisible()
-})
-
-async function idleComposer(page: Page) {
+  await input.click()
   await page.mouse.move(0, 0)
-  await page.evaluate(() => (document.activeElement as HTMLElement | null)?.blur())
-}
+  await expect(control).toHaveText("high")
+  await expect(control).toHaveCSS("opacity", "1")
+
+  await control.click()
+  await page.getByRole("menuitemradio", { name: "default", exact: true }).click()
+  await input.click()
+  await page.mouse.move(0, 0)
+  await expect(control).toHaveText("default")
+  await expect(control).toHaveCSS("opacity", "0")
+
+  // The single-agent fixture has only Add and Model before the thinking trigger.
+  await page.keyboard.press("Tab")
+  await expect(composer.getByRole("button", { name: "Add images and files" })).toBeFocused()
+  await page.keyboard.press("Tab")
+  await expect(composer.getByRole("button", { name: "Thinking Model" })).toBeFocused()
+  await page.keyboard.press("Tab")
+  await expect(control).toBeFocused()
+  await expect(control).toHaveCSS("opacity", "1")
+  await page.keyboard.press("Enter")
+  await expect(page.getByRole("menuitemradio", { name: "default", exact: true })).toBeFocused()
+  await expect(control).toHaveCSS("opacity", "1")
+  await page.keyboard.press("Escape")
+  await expect(control).toBeFocused()
+  await page.keyboard.press("Tab")
+  await expect(control).toHaveCSS("opacity", "0")
+})

packages/app/src/composer/attachments/attachments.ts

@@ -1,4 +1,4 @@
-import { onMount } from "solid-js"
+import { onCleanup, onMount } from "solid-js"
 import { makeEventListener } from "@solid-primitives/event-listener"
 import type { ComposerAttachment, ComposerPrompt } from "../types"
 
@@ -78,6 +78,7 @@ export type ComposerAttachmentConfig = {
   onError: (error: unknown) => void
   readClipboardImage?: () => Promise<File | null>
   getPathForFile?: (file: File) => string
+  onDragCancel?: (callback: () => void) => () => void
   store?: (file: File) => Promise<{ id: string; url: string }>
 }
 
@@ -90,6 +91,9 @@ export function createComposerAttachments(
     setDraggingType: (type: "image" | "@mention" | null) => void
   },
 ) {
+  const clearDrag = () => {
+    input.setDraggingType(null)
+  }
   const capture = () => {
     const prompt = input.capture()
     const editor = input.editor()
@@ -178,7 +182,7 @@ export function createComposerAttachments(
   const handleDrop = async (event: DragEvent) => {
     if (input.isDialogActive()) return
     event.preventDefault()
-    input.setDraggingType(null)
+    clearDrag()
     const plainText = event.dataTransfer?.getData("text/plain")
     if (plainText?.startsWith("file:")) {
       const path = plainText.slice("file:".length)
@@ -191,6 +195,8 @@ export function createComposerAttachments(
   }
 
   onMount(() => {
+    const cancel = input.onDragCancel?.(clearDrag)
+    if (cancel) onCleanup(cancel)
     makeEventListener(document, "dragover", (event) => {
       if (input.isDialogActive()) return
       event.preventDefault()
@@ -198,7 +204,10 @@ export function createComposerAttachments(
       else if (event.dataTransfer?.types.includes("text/plain")) input.setDraggingType("@mention")
     })
     makeEventListener(document, "dragleave", (event) => {
-      if (!input.isDialogActive() && !event.relatedTarget) input.setDraggingType(null)
+      if (!input.isDialogActive() && !event.relatedTarget) clearDrag()
+    })
+    makeEventListener(document, "keydown", (event) => {
+      if (event.key === "Escape") clearDrag()
     })
     makeEventListener(document, "drop", handleDrop)
   })

packages/app/src/composer/composer.stories.tsx

@@ -134,6 +134,7 @@ function ComposerStory(props: {
       },
       variant: {
         options: () => [
+          { id: "default", label: "default" },
           { id: "balanced", label: "balanced" },
           { id: "high", label: "high" },
         ],

packages/app/src/composer/dropzone.tsx

@@ -0,0 +1,87 @@
+import { Icon } from "@opencode-ai/ui/icon"
+import { Show, createMemo } from "solid-js"
+import { createStore } from "solid-js/store"
+import { useLanguage } from "@/runtime/i18n/language"
+import { createAnimatedPresence } from "@/runtime/animated-presence"
+
+export function ComposerDropzone(props: {
+  active: boolean
+  input?: { image?: boolean; pdf?: boolean }
+  identity?: () => unknown
+}) {
+  const language = useLanguage()
+  const [elements, setElements] = createStore<{ dropzone?: HTMLDivElement }>({})
+  const label = createMemo(() => {
+    if (!props.input?.image && !props.input?.pdf) return language.t("ui.promptInput.dropFiles")
+    if (!props.input.pdf) return language.t("ui.promptInput.dropFiles.image")
+    if (!props.input.image) return language.t("ui.promptInput.dropFiles.pdf")
+    return language.t("ui.promptInput.dropFiles.imagePdf")
+  })
+  const presence = createAnimatedPresence(
+    () => (props.active ? label() : undefined),
+    () => elements.dropzone ?? null,
+    props.identity,
+  )
+
+  return (
+    <>
+      <div
+        data-slot="session-dropzone-blur"
+        data-visible={props.active}
+        class="pointer-events-none absolute inset-0 z-[79] rounded-[inherit] opacity-[0.001] backdrop-blur-[1.5px] transition-opacity duration-200 ease-[cubic-bezier(0.215,0.61,0.355,1)] will-change-[opacity,backdrop-filter] data-[visible=true]:opacity-100 motion-reduce:transition-none"
+        style={{
+          "-webkit-mask-image":
+            "linear-gradient(to right, transparent 0%, black 25%, black 75%, transparent 100%), linear-gradient(to bottom, transparent 0%, black 28%, black 72%, transparent 100%)",
+          "-webkit-mask-composite": "source-in",
+          "mask-image":
+            "linear-gradient(to right, transparent 0%, black 25%, black 75%, transparent 100%), linear-gradient(to bottom, transparent 0%, black 28%, black 72%, transparent 100%)",
+          "mask-composite": "intersect",
+        }}
+      />
+      <Show when={presence.present()}>
+        <div
+          ref={(element) => setElements("dropzone", element)}
+          data-component="session-dropzone"
+          data-visible={props.active}
+          class="pointer-events-none absolute inset-0 z-[80] grid place-items-center overflow-hidden rounded-[inherit] bg-[color-mix(in_srgb,var(--v2-text-text-base)_var(--session-dropzone-wash),transparent)] opacity-100 transition-opacity duration-200 ease-[cubic-bezier(0.215,0.61,0.355,1)] data-[visible=false]:opacity-0 motion-reduce:transition-none"
+        >
+          <div class="absolute inset-0 bg-v2-background-bg-base/25" />
+          <div
+            class="absolute inset-y-0 left-1/2 w-full -translate-x-1/2 md:max-w-200 2xl:max-w-[1000px]"
+            style={{
+              "-webkit-mask-image": "linear-gradient(to right, transparent 0%, black 12%, black 88%, transparent 100%)",
+              "mask-image": "linear-gradient(to right, transparent 0%, black 12%, black 88%, transparent 100%)",
+            }}
+          >
+            <div
+              data-slot="session-dropzone-stripes"
+              class="absolute inset-0 opacity-60"
+              style={{
+                background:
+                  "repeating-linear-gradient(135deg, transparent 0px, transparent 12px, color-mix(in srgb, var(--v2-text-text-base) var(--session-dropzone-stripe), transparent) 12px, color-mix(in srgb, var(--v2-text-text-base) var(--session-dropzone-stripe), transparent) 24px)",
+                "-webkit-mask-image":
+                  "radial-gradient(ellipse 59% 40% at center, black 0%, rgba(0,0,0,0.72) 58%, transparent 100%)",
+                "mask-image":
+                  "radial-gradient(ellipse 59% 40% at center, black 0%, rgba(0,0,0,0.72) 58%, transparent 100%)",
+              }}
+            />
+          </div>
+          <div
+            data-slot="session-dropzone-content"
+            class="relative flex translate-y-0 flex-col items-center gap-5 opacity-100 transition-[opacity,transform] duration-200 ease-[cubic-bezier(0.215,0.61,0.355,1)] data-[visible=false]:translate-y-1 data-[visible=false]:opacity-0 motion-reduce:transition-none"
+            data-visible={props.active}
+          >
+            <div
+              data-slot="session-dropzone-upload"
+              class="flex size-10 items-center justify-center rounded-full bg-[var(--session-dropzone-card)] text-v2-icon-icon-muted shadow-[var(--v2-elevation-floating)]"
+              aria-hidden="true"
+            >
+              <Icon name="arrow-up" size="normal" class="text-v2-icon-icon-muted" />
+            </div>
+            <div class="text-[15px] font-[530] leading-6 text-v2-text-text-base">{presence.value()}</div>
+          </div>
+        </div>
+      </Show>
+    </>
+  )
+}

packages/app/src/composer/editor/actions.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, test } from "bun:test"
 import { createStore } from "solid-js/store"
+import { Skill } from "@opencode-ai/schema/skill"
 import type { ComposerPersistedState } from "../types"
 import { createComposerEditorActions } from "./actions"
 
@@ -97,4 +98,26 @@ describe("Composer store", () => {
 
     expect(prompt.state.prompt).toEqual([{ type: "text", content: "old", start: 0, end: 3 }])
   })
+
+  test("prepends a slash skill to an attachment-only draft without flattening it", () => {
+    const prompt = createPromptStore()
+    prompt.setPrompt([{ type: "file", path: "one", content: "@one", start: 0, end: 4 }], 4)
+    prompt.addMention(
+      {
+        type: "skill",
+        id: Skill.ID.make("show-me"),
+        name: Skill.Name.make("Show Me"),
+        content: "/show-me",
+        start: 0,
+        end: 0,
+      },
+      { start: 0, end: 0 },
+    )
+    expect(prompt.state.prompt).toMatchObject([
+      { type: "skill", id: "show-me", content: "/show-me", start: 0, end: 8 },
+      { type: "text", content: " ", start: 8, end: 9 },
+      { type: "file", path: "one", content: "@one", start: 9, end: 13 },
+    ])
+    expect(prompt.state.cursor).toBe(9)
+  })
 })

packages/app/src/composer/editor/actions.ts

@@ -69,12 +69,15 @@ export function createComposerEditorActions(input: ComposerStateStoreInput) {
       setStore()("context", "items", (items) => items.filter((item) => item.key !== key))
       clearRetry()
     },
-    addMention(mention: ComposerFilePart | ComposerAgentPart | ComposerSkillPart) {
+    addMention(
+      mention: ComposerFilePart | ComposerAgentPart | ComposerSkillPart,
+      range?: { start: number; end: number },
+    ) {
       const text = store()
         .prompt.map((part) => ("content" in part ? part.content : ""))
         .join("")
-      const end = store().cursor ?? text.length
-      const start = text.slice(0, end).lastIndexOf("@")
+      const end = range?.end ?? store().cursor ?? text.length
+      const start = range?.start ?? text.slice(0, end).lastIndexOf("@")
       setStore()("prompt", insertMention(store().prompt, start < 0 ? end : start, end, mention))
       setStore()("cursor", (start < 0 ? end : start) + mention.content.length + 1)
       clearRetry()
@@ -113,6 +116,9 @@ function insertMention(
   end: number,
   mention: ComposerFilePart | ComposerAgentPart | ComposerSkillPart,
 ): ComposerPrompt {
+  if (start === 0 && end === 0) {
+    return withOffsets([mention, { type: "text", content: " ", start: 0, end: 0 }, ...prompt])
+  }
   let position = 0
   const parts = prompt.flatMap<ComposerPrompt[number]>((part) => {
     if (part.type === "image") return [part]

packages/app/src/composer/editor/editor.css

@@ -2,6 +2,11 @@
   content: "\200B";
 }
 
+[data-component="composer"]:not(:hover) .composer-variant-default:not(:focus-visible, [data-expanded]) {
+  opacity: 0;
+  pointer-events: none;
+}
+
 [data-color-scheme="dark"] [data-component="composer"][data-dock-border-underlay="true"],
 [data-color-scheme="dark"] [data-component="new-session"] [data-component="composer"] {
   background: var(--v2-background-bg-layer-01);

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

@@ -118,7 +118,6 @@ export function ComposerEditor(props: ComposerEditorProps) {
         class="group/composer relative min-h-[96px] w-full overflow-clip rounded-xl bg-v2-background-bg-base"
         classList={{
           "shadow-[var(--v2-elevation-raised)]": !props.borderUnderlay,
-          "border border-v2-icon-icon-info border-dashed": state.drag === "active",
         }}
         onSubmit={(event) => {
           event.preventDefault()
@@ -129,12 +128,6 @@ export function ComposerEditor(props: ComposerEditorProps) {
         onDragLeave={props.controller.onDragLeave}
         onDrop={props.controller.onDrop}
       >
-        <Show when={state.drag === "active"}>
-          <div class="pointer-events-none absolute inset-0 z-20 grid place-items-center rounded-xl bg-v2-background-bg-base/90 text-v2-text-text-base">
-            {i18n.t("ui.promptInput.dropFiles")}
-          </div>
-        </Show>
-
         <Show when={state.mode === "normal"}>
           <ComposerAttachments
             attachments={props.controller.attachments()}
@@ -270,6 +263,7 @@ export function ComposerEditor(props: ComposerEditorProps) {
                       title={i18n.t("ui.promptInput.chooseVariant")}
                       keybind={["Shift", "Mod", "D"]}
                       control={control}
+                      class={control.current() === "default" ? "composer-variant-default" : undefined}
                     />
                   </Show>
                 )}
@@ -603,12 +597,14 @@ function ComposerEditorConfiguredSelect(props: {
   keybind?: string[]
   control: ComposerSelectControl
   model?: boolean
+  class?: string
 }) {
   const current = () => props.control.current()
   const providerID = () => props.control.options().find((option) => option.id === current())?.providerID
   return (
     <ComposerEditorSelect
       title={props.title}
+      class={props.class}
       keybind={props.control.keybind?.() ?? props.keybind}
       options={props.control.options()}
       current={current()}

packages/app/src/composer/editor/interaction.ts

@@ -145,7 +145,7 @@ export function createComposerEditor(input: {
       return
     }
     if (command.type === "mention.add") {
-      if (command.item.mention) draft.addMention(command.item.mention)
+      if (command.item.mention) draft.addMention(command.item.mention, command.range)
       return
     }
     if (command.type === "popover.filter") {

packages/app/src/composer/model.ts

@@ -21,7 +21,7 @@ import type { ImageAttachmentPart } from "./state"
 import type { PromptHistoryComment } from "./history/entry"
 import { createComposerHistory } from "./history/store"
 import { composerPlaceholder } from "./placeholder"
-import { createComposerSubmit } from "./submit"
+import { createComposerSubmit, withSlashSkill } from "./submit"
 
 export type ComposerModel = ComposerEditorModel & {
   readonly model: ComposerControls["model"]
@@ -42,9 +42,14 @@ export function createComposerModel(adapter: ComposerAdapter, options?: { queue?
 
   const interaction = createComposerEditorState(prompt.mode.current())
   createEffect(
-    on(adapter.ready, (ready) => {
-      if (ready) interaction[1]("mode", prompt.mode.current())
-    }),
+    on(
+      () => (adapter.ready() ? prompt.mode.current() : undefined),
+      (mode) => {
+        if (!mode) return
+        // Project external draft changes without another mode write clearing restored retry metadata.
+        interaction[1](mode === "shell" ? { mode, popover: { type: "closed" } } : { mode })
+      },
+    ),
   )
   const mode = () => interaction[0].mode
   const history = createComposerHistory()
@@ -236,22 +241,42 @@ export function createComposerModel(adapter: ComposerAdapter, options?: { queue?
         type: "builtin" as const,
       })),
   ])
-  const commands = createMemo<ComposerSuggestion[]>(() =>
-    slashCommands().map((item) => ({
+  const slashSkills = createMemo(() =>
+    skills().filter((skill) => skill.slash === true && !slashCommands().some((item) => item.trigger === skill.id)),
+  )
+  const commands = createMemo<ComposerSuggestion[]>(() => [
+    ...slashCommands().map((item) => ({
       id: item.id,
-      kind: "command",
+      kind: "command" as const,
       label: `/${item.trigger}`,
       trigger: item.trigger,
       title: item.title,
       description: item.description,
       keybind: command.keybindParts(item.id),
     })),
-  )
+    ...slashSkills().map((skill) => ({
+      id: `skill:${skill.id}`,
+      kind: "skill" as const,
+      label: `/${skill.id}`,
+      trigger: skill.id,
+      title: skill.name,
+      description: skill.description,
+      mention: {
+        type: "skill" as const,
+        id: Skill.ID.make(skill.id),
+        name: Skill.Name.make(skill.name),
+        content: `/${skill.id}`,
+        start: 0,
+        end: 0,
+      },
+    })),
+  ])
   const variants = createMemo(() => ["default", ...adapter.controls().model.selection.variant.list()])
   const submission = createComposerSubmit({
     adapter,
     mode,
     commands: () => data.location.command.list({ directory: sdk().directory }),
+    skills: slashSkills,
     editor: () => editor,
     queueScroll: () => requestAnimationFrame(() => editor?.scrollIntoView({ block: "nearest" })),
     addToHistory: (value, mode) => controller.addHistory(value, mode),
@@ -346,6 +371,7 @@ export function createComposerModel(adapter: ComposerAdapter, options?: { queue?
         }),
       readClipboardImage: platform.readClipboardImage,
       getPathForFile: platform.getPathForFile,
+      onDragCancel: platform.onDragCancel,
       store: platform.draftStore?.putBlob,
     },
     view: {
@@ -377,6 +403,7 @@ export function createComposerModel(adapter: ComposerAdapter, options?: { queue?
           // the composer value as a new prompt. Enter keeps it queued in
           // place; the alternate action sends it as a steer.
           if (queue?.editing()) {
+            prompt.set(withSlashSkill(prompt.current(), slashSkills()))
             queue.confirmEdit(submitOptions?.alternate ? "steer" : "queue")
             return
           }

packages/app/src/composer/submit.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, test } from "bun:test"
 import type { ModelSelection } from "@/providers/models/selection"
 import type { SessionMessageUser } from "@opencode-ai/client/promise"
 import { Skill } from "@opencode-ai/schema/skill"
+import { AbsolutePath } from "@opencode-ai/schema/schema"
 import type { ActiveComposerAdapter, ComposerControls, ComposerSession, NewSessionComposerAdapter } from "./adapter"
 import { createMemoryComposerState } from "./state"
 import { createComposerSubmit } from "./submit"
@@ -31,6 +32,16 @@ const selection = {
   },
 } satisfies ModelSelection
 
+const slashSkill = Skill.Info.make({
+  id: Skill.ID.make("show-me"),
+  name: Skill.Name.make("Show Me"),
+  description: "Explain visually",
+  slash: true,
+  autoinvoke: false,
+  location: AbsolutePath.make("/skills/show-me/SKILL.md"),
+  content: "Explain visually",
+})
+
 function controls(): ComposerControls {
   return {
     agents: {
@@ -53,11 +64,13 @@ function submitInput(
   notify = { missingSelection() {}, failed(_kind: "shell" | "command" | "prompt", _error: unknown) {} },
   mode: "normal" | "shell" = "normal",
   commands: () => readonly { name: string }[] | undefined = () => [],
+  skills: () => readonly Skill.Info[] | undefined = () => [],
 ) {
   return createComposerSubmit({
     adapter,
     mode: () => mode,
     commands,
+    skills,
     editor: () => undefined,
     queueScroll() {},
     addToHistory() {},
@@ -109,6 +122,107 @@ function session(input: {
 }
 
 describe("Composer submission", () => {
+  test("submits a slash skill with its trailing text and attachments", async () => {
+    const state = createMemoryComposerState({ prompt: "/show-me explain " }).capture()
+    state.set([
+      { type: "text", content: "/show-me explain ", start: 0, end: 17 },
+      { type: "file", path: "src/cache.ts", content: "@src/cache.ts", start: 17, end: 30 },
+    ])
+    const admitted = Promise.withResolvers<Parameters<ComposerSession["data"]["session"]["prompt"]>[0]>()
+    const target = session({ calls: [], prompt: async (value) => admitted.resolve(value) })
+    const adapter: ActiveComposerAdapter = {
+      kind: "active-session",
+      state,
+      ready: () => true,
+      controls,
+      working: () => false,
+      session: () => target,
+      interrupt: async () => undefined,
+      submitted() {},
+      setEditor() {},
+    }
+
+    await submitInput(
+      adapter,
+      undefined,
+      "normal",
+      () => [],
+      () => [slashSkill],
+    ).submit(new Event("submit"))
+    const request = await admitted.promise
+    expect(request.text).toBe("/show-me explain @src/cache.ts")
+    expect(request.skills).toEqual([
+      expect.objectContaining({ id: "show-me", mention: { start: 0, end: 8, text: "/show-me" } }),
+    ])
+    expect(request.files).toEqual([
+      { uri: "file:///C:/repo/src/cache.ts", name: "cache.ts", mention: { start: 17, end: 30, text: "@src/cache.ts" } },
+    ])
+  })
+
+  test.each([
+    { text: "/show-me", slash: true, expected: ["show-me"] },
+    { text: "/show-me\nexplain caching", slash: true, expected: ["show-me"] },
+    { text: "/show-me\texplain caching", slash: true, expected: ["show-me"] },
+    { text: "/show-me", slash: false, expected: [] },
+    { text: "/show-me", slash: undefined, expected: [] },
+    { text: "/show-me-extra", slash: true, expected: [] },
+    { text: "Explain /show-me", slash: true, expected: [] },
+  ])("resolves raw slash skill input $text with slash=$slash", async ({ text, slash, expected }) => {
+    const state = createMemoryComposerState({ prompt: text }).capture()
+    const admitted = Promise.withResolvers<Parameters<ComposerSession["data"]["session"]["prompt"]>[0]>()
+    const target = session({ calls: [], prompt: async (value) => admitted.resolve(value) })
+    const adapter: ActiveComposerAdapter = {
+      kind: "active-session",
+      state,
+      ready: () => true,
+      controls,
+      working: () => false,
+      session: () => target,
+      interrupt: async () => undefined,
+      submitted() {},
+      setEditor() {},
+    }
+    await submitInput(
+      adapter,
+      undefined,
+      "normal",
+      () => [],
+      () => [{ ...slashSkill, slash }],
+    ).submit(new Event("submit"))
+    const request = await admitted.promise
+    expect(request.text).toBe(text)
+    expect(request.skills?.map((skill) => skill.id)).toEqual([...expected])
+  })
+
+  test("captures slash skills before creating a session in a new worktree", async () => {
+    const state = createMemoryComposerState({ prompt: "/show-me" }).capture()
+    let skills: readonly Skill.Info[] | undefined = [slashSkill]
+    const admitted = Promise.withResolvers<Parameters<ComposerSession["data"]["session"]["prompt"]>[0]>()
+    const target = session({ calls: [], prompt: async (value) => admitted.resolve(value) })
+    const adapter: NewSessionComposerAdapter = {
+      kind: "new-session",
+      state,
+      ready: () => true,
+      controls,
+      working: () => false,
+      submitted() {},
+      async start() {
+        skills = undefined
+        return { session: target, cleanupReady: Promise.resolve() }
+      },
+    }
+    await submitInput(
+      adapter,
+      undefined,
+      "normal",
+      () => [],
+      () => skills,
+    ).submit(new Event("submit"))
+    expect((await admitted.promise).skills).toEqual([
+      expect.objectContaining({ id: "show-me", mention: { start: 0, end: 8, text: "/show-me" } }),
+    ])
+  })
+
   test("sends one captured value with explicit delivery after selection switches", async () => {
     const state = createMemoryComposerState({ prompt: "ship it" }).capture()
     const calls: string[] = []
@@ -357,8 +471,8 @@ describe("Composer submission", () => {
     expect(promoted.mode.current()).toBe("shell")
   })
 
-  test("reuses the message ID when an unacknowledged admission is retried", async () => {
-    const state = createMemoryComposerState({ prompt: "retry me" }).capture()
+  test.each(["retry me", "/show-me retry me"])("restores and retries an unacknowledged admission: %s", async (text) => {
+    const state = createMemoryComposerState({ prompt: text }).capture()
     const attempts: string[] = []
     const statuses: ("idle" | "running")[] = []
     const first = Promise.withResolvers<void>()
@@ -368,6 +482,7 @@ describe("Composer submission", () => {
       statuses,
       prompt: async (value) => {
         attempts.push(value.id ?? "")
+        expect(value.skills?.map((skill) => skill.id)).toEqual(text.startsWith("/") ? ["show-me"] : [])
         throw new Error("network unavailable")
       },
     })
@@ -386,7 +501,13 @@ describe("Composer submission", () => {
       missingSelection() {},
       failed: () => (attempts.length === 2 ? first.resolve() : second.resolve()),
     }
-    const submission = submitInput(adapter, notify)
+    const submission = submitInput(
+      adapter,
+      notify,
+      "normal",
+      () => [],
+      () => [slashSkill],
+    )
 
     await submission.submit(new Event("submit"))
     await first.promise
@@ -396,7 +517,7 @@ describe("Composer submission", () => {
     expect(attempts).toHaveLength(4)
     expect(new Set(attempts).size).toBe(1)
     expect(statuses).toEqual(["running", "idle", "running", "idle"])
-    expect(state.current()).toMatchObject([{ type: "text", content: "retry me" }])
+    expect(state.current()).toMatchObject([{ type: "text", content: text }])
   })
 
   test("forwards structured mentions to custom commands", async () => {
@@ -472,7 +593,13 @@ describe("Composer submission", () => {
       },
     }
 
-    await submitInput(adapter, undefined, "normal", () => catalog).submit(new Event("submit"))
+    await submitInput(
+      adapter,
+      undefined,
+      "normal",
+      () => catalog,
+      () => [{ ...slashSkill, id: Skill.ID.make("review") }],
+    ).submit(new Event("submit"))
 
     expect(await sent.promise).toBe("command")
     expect(requests).toEqual([

packages/app/src/composer/submit.ts

@@ -1,5 +1,6 @@
 import { SessionMessage } from "@opencode-ai/schema/session-message"
-import type { SessionMessageUser } from "@opencode-ai/client/promise"
+import type { SessionMessageUser, SkillInfo } from "@opencode-ai/client/promise"
+import { Skill } from "@opencode-ai/schema/skill"
 import { Event } from "@opencode-ai/schema/event"
 import type { Accessor } from "solid-js"
 import type { PromptHistoryComment } from "./history/entry"
@@ -28,6 +29,7 @@ type ComposerSubmitInput = {
   adapter: ComposerAdapter
   mode: Accessor<"normal" | "shell">
   commands: Accessor<readonly { name: string }[] | undefined>
+  skills: Accessor<readonly Pick<SkillInfo, "id" | "name" | "slash">[] | undefined>
   editor: () => HTMLDivElement | undefined
   queueScroll: () => void
   addToHistory: (prompt: Prompt, mode: "normal" | "shell") => void
@@ -68,6 +70,7 @@ export function createComposerSubmit(input: ComposerSubmitInput) {
     const comments = input.comments.capture()
     // Capture command intent before starting a session in a worktree whose catalog has not loaded.
     const command = value.mode === "normal" ? findCommand(input.commands(), value.text) : undefined
+    if (value.mode === "normal" && !command) value.prompt = withSlashSkill(value.prompt, input.skills())
 
     try {
       const started =
@@ -287,6 +290,27 @@ function findCommand(commands: ReturnType<ComposerSubmitInput["commands"]>, text
   return { command, arguments: arguments_.join(" ") }
 }
 
+export function withSlashSkill(prompt: Prompt, skills: ReturnType<ComposerSubmitInput["skills"]>): Prompt {
+  const first = prompt[0]
+  if (first?.type !== "text") return prompt
+  const name = /^\/(\S+)(?:\s|$)/.exec(first.content)?.[1]
+  const skill = skills?.find((item) => item.slash === true && item.id === name)
+  if (!skill || prompt.some((part) => part.type === "skill" && part.id === skill.id)) return prompt
+  const content = `/${skill.id}`
+  return [
+    {
+      type: "skill",
+      id: Skill.ID.make(skill.id),
+      name: Skill.Name.make(skill.name),
+      content,
+      start: 0,
+      end: content.length,
+    },
+    { ...first, content: first.content.slice(content.length), start: content.length },
+    ...prompt.slice(1),
+  ]
+}
+
 async function sendCommand(
   session: ComposerSession,
   value: ComposerSubmission,

packages/app/src/composer/suggestions/machine.ts

@@ -35,7 +35,7 @@ export type ComposerInteractionEvent =
 export type ComposerInteractionCommand =
   | { type: "draft.setText"; value: string }
   | { type: "draft.addText"; value: string }
-  | { type: "mention.add"; item: ComposerSuggestion }
+  | { type: "mention.add"; item: ComposerSuggestion; range?: { start: number; end: number } }
   | { type: "popover.filter"; popover: "command" | "context"; query: string }
   | { type: "suggestion.select"; id: string }
   | { type: "focus.editor" }
@@ -178,7 +178,13 @@ function suggestionSelected(
           : replaceTrigger(current, "/", `${item.label} `),
     })
   } else {
-    commands.push({ type: "mention.add", item })
+    commands.push({
+      type: "mention.add",
+      item,
+      ...(item.kind === "skill" && item.label.startsWith("/")
+        ? { range: { start: 0, end: state.popover.type === "command-menu" ? 0 : current.length } }
+        : {}),
+    })
   }
   commands.push({ type: "focus.editor" })
   return changed({ ...state, popover: { type: "closed" }, focus: "editor" }, commands)

packages/app/src/index.css

@@ -319,6 +319,69 @@
     }
   }
 
+  @keyframes session-dropzone-enter {
+    from {
+      opacity: 0;
+    }
+  }
+
+  @keyframes session-dropzone-content-enter {
+    from {
+      opacity: 0;
+      transform: translateY(4px) scale(0.96);
+    }
+  }
+
+  @keyframes session-dropzone-upload-enter {
+    from {
+      opacity: 0;
+      transform: translateY(4px) scale(0.92);
+    }
+  }
+
+  @keyframes session-dropzone-stripes-drift {
+    to {
+      background-position: 33.941px 0;
+    }
+  }
+
+  [data-component="session-dropzone"][data-visible="true"] {
+    animation: session-dropzone-enter 200ms cubic-bezier(0.215, 0.61, 0.355, 1);
+  }
+
+  [data-component="session-dropzone"][data-visible="true"] [data-slot="session-dropzone-content"] {
+    animation: session-dropzone-content-enter 200ms cubic-bezier(0.215, 0.61, 0.355, 1);
+  }
+
+  [data-component="session-dropzone"][data-visible="true"] [data-slot="session-dropzone-upload"] {
+    animation: session-dropzone-upload-enter 240ms cubic-bezier(0.215, 0.61, 0.355, 1);
+  }
+
+  [data-component="session-dropzone"][data-visible="true"] [data-slot="session-dropzone-stripes"] {
+    animation: session-dropzone-stripes-drift 3s linear infinite;
+  }
+
+  [data-component="session-dropzone"] {
+    --session-dropzone-wash: 4%;
+    --session-dropzone-stripe: 7%;
+    --session-dropzone-card: var(--v2-background-bg-base);
+  }
+
+  [data-color-scheme="dark"] [data-component="session-dropzone"] {
+    --session-dropzone-wash: 6%;
+    --session-dropzone-stripe: 14%;
+    --session-dropzone-card: var(--v2-background-bg-layer-01);
+  }
+
+  @media (prefers-reduced-motion: reduce) {
+    [data-component="session-dropzone"][data-visible="true"],
+    [data-component="session-dropzone"][data-visible="true"] [data-slot="session-dropzone-content"],
+    [data-component="session-dropzone"][data-visible="true"] [data-slot="session-dropzone-upload"],
+    [data-component="session-dropzone"][data-visible="true"] [data-slot="session-dropzone-stripes"] {
+      animation: none;
+    }
+  }
+
   [data-slot="home-projects-scroll"] {
     timeline-scope: --home-projects-scroll;
   }

packages/app/src/new-session/view.tsx

@@ -6,6 +6,7 @@ import { Show, createMemo, createSignal } from "solid-js"
 import { Schema } from "effect"
 import createPresence from "solid-presence"
 import { Composer } from "@/composer/composer"
+import { ComposerDropzone } from "@/composer/dropzone"
 import type { ComposerModel } from "@/composer/model"
 import { PromptGitStatus, PromptWorkspaceSelector } from "@/new-session/workspace/selector"
 import {
@@ -54,6 +55,10 @@ export function NewSessionView(props: {
         data-component="new-session"
         class="relative flex-1 min-h-0 overflow-hidden rounded-[10px] bg-v2-background-bg-base shadow-[var(--v2-elevation-raised)]"
       >
+        <ComposerDropzone
+          active={props.composer.state.drag === "active"}
+          input={props.composer.model.selection.current()?.capabilities.input}
+        />
         <div class="absolute inset-x-0 top-[25.375%] flex justify-center px-6">
           <div class={NEW_SESSION_CONTENT_WIDTH}>
             <Wordmark class="h-auto w-full text-v2-background-bg-inverse" />

packages/app/src/runtime/i18n/en.ts

@@ -676,7 +676,7 @@ export const dict = {
   "session.error.incompatible.description":
     "{{server}} is running OpenCode {{version}}, which isn't compatible with this app. Upgrade the server to OpenCode V2 to continue.",
   "session.background.moveTasks": "Move {{tasks}} to background",
-  "session.background.moveRunning": "Move running work to background",
+  "session.background.moveRunning": "Move to background",
   "session.background.inBackground": "Running {{tasks}} in background",
   "session.background.moveInline": "Press {{keybind}} to move running work to the background",
   "session.background.running": "Running work in background",

packages/app/src/runtime/platform/platform.tsx

@@ -59,6 +59,9 @@ type PlatformBase = {
   /** Resolve the native source path for a desktop File. */
   getPathForFile?(file: File): string
 
+  /** Observe native drag cancellation that does not reach the renderer event loop. */
+  onDragCancel?(callback: () => void): () => void
+
   /** Open a native save file dialog and write content to the selected path (desktop only) */
   saveFile?(opts: SaveFilePickerOptions, content: string): Promise<boolean>
 

packages/app/src/session/composer/adapter.ts

@@ -4,16 +4,14 @@ import { useComposerState } from "@/composer/persistence"
 import { useData } from "@/runtime/server/current"
 import { useServerSDK } from "@/runtime/server/client"
 import { useWorkspaceLocation } from "@/workspaces/location"
-import type { SessionModel } from "../model"
 
 export function createActiveComposerAdapter(input: {
-  session: SessionModel
+  sessionID: string
   controls: Accessor<ComposerControls>
   submitted: () => void
   setEditor: (element: HTMLDivElement) => void
 }) {
-  const id = input.session.identity.params.id
-  if (!id) throw new Error("Active Composer requires a Session ID")
+  const id = input.sessionID
 
   const prompt = useComposerState()
   prompt.current()

packages/app/src/session/composer/controller.ts

@@ -0,0 +1,57 @@
+import { createEffect, createMemo, on, type Accessor } from "solid-js"
+import type { ComposerControls } from "@/composer/adapter"
+import { setCursorPosition } from "@/composer/editor/dom"
+import { createComposerModel } from "@/composer/model"
+import { useSettings } from "@/settings/model"
+import { createActiveComposerAdapter } from "./adapter"
+import { createSessionQueue } from "./queue"
+import { createSessionComposerRegionController } from "./session-composer-region-controller"
+
+export function createSessionComposerController(input: {
+  sessionID: string
+  controls: Accessor<ComposerControls>
+  dock: Parameters<typeof createSessionComposerRegionController>[0]
+}) {
+  const settings = useSettings()
+  const region = createSessionComposerRegionController(input.dock)
+  let editor: HTMLDivElement | undefined
+  const adapter = createActiveComposerAdapter({
+    sessionID: input.sessionID,
+    controls: input.controls,
+    submitted: region.onResponseSubmit,
+    setEditor: (element) => {
+      editor = element
+      region.setPromptRef(element)
+    },
+  })
+  const queue = createSessionQueue({
+    sessionID: input.sessionID,
+    draft: adapter.state,
+    working: adapter.working,
+    behavior: settings.general.followUpBehavior,
+    restoreFocus: (cursor) => {
+      const target = editor
+      if (!target) return
+      requestAnimationFrame(() => {
+        target.focus()
+        setCursorPosition(target, cursor)
+      })
+    },
+  })
+  const composer = createComposerModel(adapter, { queue })
+  const editable = createMemo(() => region.showComposer() && !region.child())
+  // Requests hide the view without disposing its draft or queue edit.
+  createEffect(on(editable, () => composer.onDragLeave()))
+
+  return {
+    region,
+    queue,
+    composer,
+    drop: {
+      active: () => editable() && composer.state.drag === "active",
+      input: () => composer.model.selection.current()?.capabilities.input,
+    },
+  }
+}
+
+export type SessionComposerController = ReturnType<typeof createSessionComposerController>

packages/app/src/session/composer/queue.ts

@@ -4,7 +4,6 @@ import { useMutation } from "@tanstack/solid-query"
 import type { SessionInboxInfo } from "@opencode-ai/client/promise"
 import { SessionMessage } from "@opencode-ai/schema/session-message"
 import type { ComposerDelivery } from "@/composer/adapter"
-import type { ComposerModel } from "@/composer/model"
 import type { ComposerStateTarget } from "@/composer/submission-state"
 import type { ImageAttachmentPart, Prompt } from "@/composer/state"
 import { clonePrompt, promptLength } from "@/composer/prompt-parts"
@@ -30,7 +29,7 @@ export function createSessionQueue(input: {
   draft: ComposerStateTarget
   working: Accessor<boolean>
   behavior: Accessor<ComposerDelivery>
-  composer: Accessor<ComposerModel | undefined>
+  restoreFocus: (cursor: number) => void
 }) {
   const data = useData()
   const server = useServerSDK()
@@ -159,9 +158,9 @@ export function createSessionQueue(input: {
       },
     })
     const text = queuedPromptText(item)
-    input.composer()?.dispatch({ type: "mode.normal" })
+    input.draft.mode.set("normal")
     input.draft.set([{ type: "text", content: text, start: 0, end: text.length }], text.length)
-    input.composer()?.restoreFocus(text.length)
+    input.restoreFocus(text.length)
     return true
   }
   const cancelEdit = () => {
@@ -170,10 +169,10 @@ export function createSessionQueue(input: {
     setState("editing", undefined)
     // Mode first, then prompt, then retry: mode and prompt writes both clear
     // the retry marker.
-    input.composer()?.dispatch({ type: editing.stash.mode === "shell" ? "mode.shell" : "mode.normal" })
+    input.draft.mode.set(editing.stash.mode)
     input.draft.set(editing.stash.prompt, editing.stash.cursor)
     if (editing.stash.retry) input.draft.retry.set(editing.stash.retry)
-    input.composer()?.restoreFocus(editing.stash.cursor)
+    input.restoreFocus(editing.stash.cursor)
   }
   const confirmEdit = (delivery: ComposerDelivery) => {
     const editing = state.editing

packages/app/src/session/composer/region.tsx

@@ -4,9 +4,8 @@ import { useDialog } from "@opencode-ai/ui/context/dialog"
 import { isScrollKeyTarget, scrollKey, scrollKeyOwner } from "@opencode-ai/ui/scroll-view"
 import { makeEventListener } from "@solid-primitives/event-listener"
 import { useNavigate } from "@solidjs/router"
-import { createEffect, on, onMount } from "solid-js"
+import { createEffect, createMemo, on, onMount, type Accessor } from "solid-js"
 import { Composer } from "@/composer/composer"
-import { createComposerModel, type ComposerModel } from "@/composer/model"
 import { useComposerState } from "@/composer/persistence"
 import { createComposerControls } from "@/composer/selection"
 import { setCursorPosition } from "@/composer/editor/dom"
@@ -25,18 +24,16 @@ import { restorePromptModel, syncPromptModel, syncSessionModel } from "../sessio
 import type { SessionTimelineInteraction } from "../timeline/interaction"
 import { createSessionRevert } from "../revert"
 import { SessionComposerRegion } from "./session-composer-region"
-import { createSessionComposerRegionController } from "./session-composer-region-controller"
-import { createActiveComposerAdapter } from "./adapter"
-import { createSessionQueue } from "./queue"
+import { createSessionComposerController, type SessionComposerController } from "./controller"
 import { SessionQueuePanel } from "./queue-panel"
 import { resolveSessionComposerSelection } from "./selection"
 import { createSessionRequestModel } from "../requests/model"
-import { useSettings } from "@/settings/model"
 
 export function createActiveSessionRegion(input: {
   session: SessionModel
   screen: SessionScreenLayout
   timeline: SessionTimelineInteraction
+  visible: Accessor<boolean>
 }) {
   const command = useCommand()
   const dialog = useDialog()
@@ -180,7 +177,30 @@ export function createActiveSessionRegion(input: {
     },
   ])
 
+  const dock = {
+    state,
+    parentID: input.session.data.parentID,
+    centered: input.screen.centered,
+    onResponseSubmit: input.timeline.actions.resume,
+    openParent,
+    setPromptRef: (element: HTMLDivElement) => {
+      promptRef = element
+    },
+    setDockRef: input.timeline.view.setDockRef,
+  }
+  const active = createMemo(
+    on(
+      () => (input.visible() ? input.session.identity.sessionID() : undefined),
+      (sessionID) => (sessionID ? createSessionComposerController({ sessionID, controls, dock }) : undefined),
+    ),
+  )
+
   return {
+    active,
+    drop: {
+      active: () => active()?.drop.active() ?? false,
+      input: () => active()?.drop.input(),
+    },
     actions: {
       timeline: {
         get revert() {
@@ -190,76 +210,25 @@ export function createActiveSessionRegion(input: {
         openAttachment,
       } satisfies SessionUserActions,
     },
-    region: {
-      centered: input.screen.centered,
-      openParent,
-      prompt,
-      setDockRef: input.timeline.view.setDockRef,
-      setPromptRef: (element: HTMLDivElement) => {
-        promptRef = element
-      },
-      state,
-    },
-    input: {
-      controls,
-      setPromptRef: (element: HTMLDivElement) => {
-        promptRef = element
-      },
-    },
-    submitted: () => input.timeline.actions.resume(),
+    requests: state,
     workspaceMoveEligible: () => true,
   }
 }
 
 export type ActiveSessionRegionModel = ReturnType<typeof createActiveSessionRegion>
 
-export function ActiveSessionComposerRegion(props: {
-  model: ActiveSessionRegionModel
-  session: SessionModel
-  onResponseSubmit: () => void
-}) {
-  const settings = useSettings()
-  const region = createSessionComposerRegionController({
-    state: props.model.region.state,
-    parentID: props.session.data.parentID,
-    centered: props.model.region.centered,
-    onResponseSubmit: props.onResponseSubmit,
-    openParent: props.model.region.openParent,
-    setPromptRef: props.model.region.setPromptRef,
-    setDockRef: props.model.region.setDockRef,
-  })
-  const adapter = createActiveComposerAdapter({
-    session: props.session,
-    controls: props.model.input.controls,
-    submitted: props.model.submitted,
-    setEditor: props.model.input.setPromptRef,
-  })
-  let composer: ComposerModel | undefined
-  const queue = createSessionQueue({
-    sessionID: requireSessionID(props.session),
-    draft: adapter.state,
-    working: adapter.working,
-    behavior: settings.general.followUpBehavior,
-    composer: () => composer,
-  })
-  composer = createComposerModel(adapter, { queue })
+export function ActiveSessionComposerRegion(props: { model: SessionComposerController }) {
   return (
     <SessionComposerRegion
-      controller={region}
+      controller={props.model.region}
       composer={
         <div class="relative">
-          <SessionQueuePanel queue={queue} />
+          <SessionQueuePanel queue={props.model.queue} />
           <div class="relative z-10">
-            <Composer model={composer} borderUnderlay />
+            <Composer model={props.model.composer} borderUnderlay />
           </div>
         </div>
       }
     />
   )
 }
-
-function requireSessionID(session: SessionModel) {
-  const id = session.identity.params.id
-  if (!id) throw new Error("Active Composer requires a Session ID")
-  return id
-}

packages/app/src/session/screen.tsx

@@ -15,6 +15,7 @@ import { ResizeHandle } from "@opencode-ai/ui/resize-handle"
 import { MessageTimeline, SessionSummaryPanel } from "@/session/timeline/message-timeline"
 import { useServer } from "@/runtime/server/current"
 import { projectForSession } from "@/shell/layout/helpers"
+import { ComposerDropzone } from "@/composer/dropzone"
 import type { SessionModel } from "@/session/model"
 import { SESSION_PANEL_WIDTH_MIN } from "@/session/session-panel-width"
 import { SessionPanelFrame } from "@/session/session-frame"
@@ -134,8 +135,8 @@ export function SessionScreen(props: { session: SessionModel }) {
     session,
     screen,
     timeline,
+    visible: conversationVisible,
   })
-
   useUsageExceededDialogs()
 
   const sessionErrorFallback = (error: unknown, reset: () => void) => {
@@ -176,7 +177,7 @@ export function SessionScreen(props: { session: SessionModel }) {
                           review.mobile.setTab("changes")
                           session.layout.view().terminal.close()
                         }}
-                        backgroundTasks={composer.region.state.background.tasks()}
+                        backgroundTasks={composer.requests.background.tasks()}
                       />
                     )}
                   </Show>
@@ -198,6 +199,11 @@ export function SessionScreen(props: { session: SessionModel }) {
 
   const sessionPanelContent = () => (
     <>
+      <ComposerDropzone
+        active={composer.drop.active()}
+        input={composer.drop.input()}
+        identity={session.layout.tabKey}
+      />
       <Show when={!isDesktop() && !!session.identity.params.id}>{mobileTabs()}</Show>
       {/* Surface query errors without suspending session metadata while messages load. */}
       <Show when={timeline.resource.error}>
@@ -235,7 +241,7 @@ export function SessionScreen(props: { session: SessionModel }) {
                 <MessageTimeline
                   hideHeader={!isDesktop()}
                   session={session}
-                  background={composer.region.state.background}
+                  background={composer.requests.background}
                   actions={composer.actions.timeline}
                   scroll={timeline.scroll}
                   onResumeScroll={timeline.actions.resume}
@@ -263,10 +269,8 @@ export function SessionScreen(props: { session: SessionModel }) {
         </Switch>
       </div>
 
-      <Show when={conversationVisible() ? session.identity.params.id : undefined} keyed>
-        {(_id) => (
-          <ActiveSessionComposerRegion model={composer} session={session} onResponseSubmit={timeline.actions.resume} />
-        )}
+      <Show when={composer.active()} keyed>
+        {(model) => <ActiveSessionComposerRegion model={model} />}
       </Show>
     </>
   )

packages/app/src/session/session-frame.tsx

@@ -14,7 +14,7 @@ export function SessionRouteFrame(props: ParentProps<{ padded?: boolean }>) {
 export function SessionPanelFrame(props: ParentProps<{ raised?: boolean }>) {
   return (
     <div
-      class="flex min-h-0 flex-1 flex-col overflow-hidden rounded-[10px] bg-v2-background-bg-base"
+      class="relative flex min-h-0 flex-1 flex-col overflow-hidden rounded-[10px] bg-v2-background-bg-base"
       classList={{
         "shadow-[var(--v2-elevation-raised)]": props.raised,
       }}

packages/app/src/session/session-identity-header.tsx

@@ -242,7 +242,7 @@ export function SessionIdentityHeader(props: { sessionID: string; session?: Sess
   )
   const title = createMemo(() =>
     pending()
-      ? language.t("command.session.new")
+      ? language.t("session.tab.session")
       : sessionTitle(props.session?.title ?? (parentID() ? undefined : info()?.title)),
   )
   const project = createMemo(() => {

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

@@ -58,7 +58,6 @@ export function BackgroundMoveHint(props: { keybind?: string[]; onMove?: () => v
       type="button"
       variant="ghost-faint"
       size="small"
-      icon="outline-arrow-to-corner-top-right"
       class="max-w-full"
       aria-label={language.t("session.background.moveInline", { keybind: keybind() })}
       onClick={() => props.onMove?.()}

packages/app/src/settings/settings.css

@@ -647,7 +647,8 @@
 
 .settings-tab-search {
   position: relative;
-  width: 100%;
+  width: calc(100% - 2px);
+  margin-inline: 1px;
 }
 
 .settings-tab-search [data-component="text-input-v2"] {

packages/app/src/settings/workspaces/projects.tsx

@@ -42,7 +42,7 @@ export const SettingsProjects: Component = () => {
     const name = () => displayName(props.project)
     return (
       <div
-        class="group flex items-center justify-between gap-5 px-4 py-2.5 rounded-lg bg-v2-background-bg-base shadow-[var(--v2-elevation-raised)] transition-all hover:bg-v2-background-bg-layer-01"
+        class="group mx-px flex items-center justify-between gap-5 px-4 py-2.5 rounded-lg bg-v2-background-bg-base shadow-[var(--v2-elevation-raised)] transition-all hover:bg-v2-background-bg-layer-01"
         onClick={() => openProjectSettings(props.project, props.server)}
       >
         <div class="flex items-center gap-2.5 min-w-0 flex-1">

packages/app/src/shell/shell.tsx

@@ -64,7 +64,7 @@ export default function Layout(props: ParentProps) {
             <aside
               ref={(element) => setState("tabsMount", element)}
               data-slot="vertical-tabs-sidebar"
-              class="relative flex h-full min-h-0 shrink-0 flex-col bg-v2-background-bg-deep px-2.5 pb-[var(--shell-bottom-inset,8px)] pt-[var(--shell-top-inset,8px)]"
+              class="relative flex h-full min-h-0 shrink-0 flex-col bg-v2-background-bg-deep pe-0.5 ps-2.5 pb-[var(--shell-bottom-inset,8px)] pt-[var(--shell-top-inset,8px)]"
               style={{
                 width: `${state.tabsWidth}px`,
                 "padding-bottom": "max(10px, env(safe-area-inset-bottom, 0px))",

packages/app/test-browser/composer-drag-cancel.test.tsx

@@ -0,0 +1,36 @@
+import { expect, test } from "bun:test"
+import { render } from "solid-js/web"
+import { createComposerAttachments } from "@/composer/attachments/attachments"
+
+test("clears drag state on platform cancellation", async () => {
+  let cancel = () => {}
+  let subscribed = false
+  let dragging: "image" | "@mention" | null = "image"
+  const dispose = render(() => {
+    createComposerAttachments({
+      capture: () => ({ current: () => [], cursor: () => 0, set: () => {} }),
+      editor: () => undefined,
+      focusEditor: () => {},
+      addPart: () => false,
+      setDraggingType: (type) => (dragging = type),
+      directory: () => "",
+      isDialogActive: () => false,
+      warn: () => {},
+      duplicate: () => {},
+      onError: () => {},
+      onDragCancel: (callback) => {
+        cancel = callback
+        subscribed = true
+        return () => (subscribed = false)
+      },
+    })
+    return null
+  }, document.createElement("div"))
+  await Promise.resolve()
+
+  cancel()
+
+  expect(dragging).toBeNull()
+  dispose()
+  expect(subscribed).toBeFalse()
+})

packages/cli/script/build.ts

@@ -128,9 +128,7 @@ export default { path: file, version: ${JSON.stringify(opencodePty.version)}, sh
     external: ["node-gyp"],
     format: "esm",
     minify: true,
-    // Bun 1.4.0 cross-compiled bytecode can crash on Windows (oven-sh/bun#40270).
-    // Re-enable after both the builder and embedded runtime move to Bun 1.4.1.
-    bytecode: false,
+    bytecode: true,
     sourcemap: Script.channel === "dev" || Script.channel === "local" ? "inline" : "none",
     splitting: true,
     compile: {

packages/client/src/solid/data.ts

@@ -6,6 +6,7 @@
 import type {
   AgentInfo,
   CommandInfo,
+  ConfigEntry,
   FormCancelInput,
   FormInfo,
   FormReplyInput,
@@ -84,6 +85,7 @@ type LocationData = {
   vcs?: VcsInfo
   agent?: AgentInfo[]
   command?: CommandInfo[]
+  config?: ConfigEntry[]
   integration?: IntegrationInfo[]
   mcpServer?: McpServer[]
   mcpResource?: McpResource[]
@@ -1215,6 +1217,11 @@ export function createData(config: CreateDataInput) {
         )
         break
       case "config.updated":
+        result.location.config.invalidate(location)
+        if (result.location.config.list(location) !== undefined || sync.has(`location.config:${locationKey(location)}`))
+          refresh(() => result.location.config.sync(location))
+        refresh(() => result.location.websearch.refresh(location))
+        break
       case "websearch.updated":
         refresh(() => result.location.websearch.refresh(location))
         break
@@ -1790,6 +1797,7 @@ export function createData(config: CreateDataInput) {
         result.location.vcs.invalidate(location)
         result.location.agent.invalidate(location)
         result.location.command.invalidate(location)
+        result.location.config.invalidate(location)
         result.location.integration.invalidate(location)
         result.location.mcp.server.invalidate(location)
         result.location.mcp.resource.invalidate(location)
@@ -1803,6 +1811,10 @@ export function createData(config: CreateDataInput) {
       vcs: { info: vcs.list, sync: vcs.sync, invalidate: vcs.invalidate },
       agent: locationResource("agent", (location) => api().agent.list({ location })),
       command: locationResource("command", (location) => api().command.list({ location })),
+      config: locationResource("config", async (location) => ({
+        location: { directory: location.directory, workspaceID: location.workspace },
+        data: await api().config.get({ location }),
+      })),
       integration: locationResource("integration", (location) => api().integration.list({ location })),
       mcp: {
         server: locationResource("mcpServer", (location) => api().mcp.list({ location })),

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

@@ -3,6 +3,56 @@ import { createRoot } from "solid-js"
 import { createData, type CreateDataInput } from "../src/solid"
 import { OpenCode, type OpenCodeEvent, type SessionInfo } from "../src/promise"
 
+test("config reads and update refreshes are opt-in", async () => {
+  const listeners = new Set<Parameters<CreateDataInput["event"]["listen"]>[0]>()
+  const requests: string[] = []
+  const location = { directory: "/project" }
+  let model = "provider/first"
+  const api = OpenCode.make({
+    baseUrl: "http://opencode.local",
+    fetch: async (input, init) => {
+      const request = input instanceof Request ? input : new Request(input, init)
+      const url = new URL(request.url)
+      requests.push(url.pathname)
+      if (url.pathname === "/api/location") return Response.json(location)
+      if (url.pathname === "/api/config") return Response.json([{ type: "document", info: { model } }])
+      if (url.pathname === "/api/mcp/resource")
+        return Response.json({ location, data: { resources: [], templates: [] } })
+      return Response.json({ location, data: [] })
+    },
+  })
+  const setup = createRoot((dispose) => ({
+    data: createData({
+      api: () => api,
+      directory: location.directory,
+      event: {
+        on: () => () => {},
+        listen(handler) {
+          listeners.add(handler)
+          return () => listeners.delete(handler)
+        },
+      },
+    }),
+    dispose,
+  }))
+  const event: OpenCodeEvent = { id: "evt_config", created: 1, type: "config.updated", location, data: {} }
+  try {
+    await setup.data.location.sync()
+    listeners.forEach((listener) => listener({ name: event.type, details: event }))
+    expect(requests).not.toContain("/api/config")
+
+    await setup.data.location.config.sync()
+    expect(requests.filter((path) => path === "/api/config")).toHaveLength(1)
+    model = "provider/second"
+    listeners.forEach((listener) => listener({ name: event.type, details: event }))
+    await setup.data.location.config.sync()
+    expect(requests.filter((path) => path === "/api/config")).toHaveLength(2)
+    expect(setup.data.location.config.list()).toEqual([{ type: "document", info: { model } }])
+  } finally {
+    setup.dispose()
+  }
+})
+
 test("event refreshes report failures, remain retryable, and preserve explicit read errors", async () => {
   const listeners = new Set<Parameters<CreateDataInput["event"]["listen"]>[0]>()
   const reported = Promise.withResolvers<unknown>()

packages/console/app/src/routes/zen/util/handler.ts

@@ -1109,6 +1109,8 @@ export async function handler(
     authInfo = authInfo!
 
     const cost = centsToMicroCents(totalCostInCent)
+    // Keep period bounds and persisted timestamps on one snapshot when a queued write crosses a reset boundary.
+    const trackedAt = new Date()
 
     // For hot workspaces, batch balance/usage updates through Redis to avoid
     // row-level lock contention on BillingTable/UserTable. Returns the amount
@@ -1149,7 +1151,7 @@ export async function handler(
           if (billingSource === "subscription") {
             const plan = authInfo.billing.subscription!.plan
             const black = BlackData.getLimits({ plan })
-            const week = getWeekBounds(new Date())
+            const week = getWeekBounds(trackedAt)
             const rollingWindowSeconds = black.rollingWindow * 3600
             return [
               db
@@ -1157,11 +1159,17 @@ export async function handler(
                 .set({
                   fixedUsage: sql`
               CASE
+                WHEN ${SubscriptionTable.timeFixedUpdated} >= ${week.end} THEN ${SubscriptionTable.fixedUsage}
                 WHEN ${SubscriptionTable.timeFixedUpdated} >= ${week.start} THEN ${SubscriptionTable.fixedUsage} + ${cost}
                 ELSE ${cost}
               END
             `,
-                  timeFixedUpdated: sql`now()`,
+                  timeFixedUpdated: sql`
+              CASE
+                WHEN ${SubscriptionTable.timeFixedUpdated} > ${trackedAt} THEN ${SubscriptionTable.timeFixedUpdated}
+                ELSE ${trackedAt}
+              END
+            `,
                   rollingUsage: sql`
               CASE
                 WHEN UNIX_TIMESTAMP(${SubscriptionTable.timeRollingUpdated}) >= UNIX_TIMESTAMP(now()) - ${rollingWindowSeconds} THEN ${SubscriptionTable.rollingUsage} + ${cost}
@@ -1185,8 +1193,8 @@ export async function handler(
           }
           if (billingSource === "lite") {
             const lite = LiteData.getLimits()
-            const week = getWeekBounds(new Date())
-            const month = getMonthlyBounds(new Date(), authInfo.lite!.timeCreated)
+            const week = getWeekBounds(trackedAt)
+            const month = getMonthlyBounds(trackedAt, authInfo.lite!.timeCreated)
             const rollingWindowSeconds = lite.rollingWindow * 3600
             const quotaCost = Math.round(cost * modelInfo.costMultiplier)
             return [
@@ -1195,18 +1203,30 @@ export async function handler(
                 .set({
                   monthlyUsage: sql`
               CASE
+                WHEN ${LiteTable.timeMonthlyUpdated} >= ${month.end} THEN ${LiteTable.monthlyUsage}
                 WHEN ${LiteTable.timeMonthlyUpdated} >= ${month.start} THEN ${LiteTable.monthlyUsage} + ${quotaCost}
                 ELSE ${quotaCost}
               END
             `,
-                  timeMonthlyUpdated: sql`now()`,
+                  timeMonthlyUpdated: sql`
+              CASE
+                WHEN ${LiteTable.timeMonthlyUpdated} > ${trackedAt} THEN ${LiteTable.timeMonthlyUpdated}
+                ELSE ${trackedAt}
+              END
+            `,
                   weeklyUsage: sql`
               CASE
+                WHEN ${LiteTable.timeWeeklyUpdated} >= ${week.end} THEN ${LiteTable.weeklyUsage}
                 WHEN ${LiteTable.timeWeeklyUpdated} >= ${week.start} THEN ${LiteTable.weeklyUsage} + ${quotaCost}
                 ELSE ${quotaCost}
               END
             `,
-                  timeWeeklyUpdated: sql`now()`,
+                  timeWeeklyUpdated: sql`
+              CASE
+                WHEN ${LiteTable.timeWeeklyUpdated} > ${trackedAt} THEN ${LiteTable.timeWeeklyUpdated}
+                ELSE ${trackedAt}
+              END
+            `,
                   rollingUsage: sql`
               CASE
                 WHEN UNIX_TIMESTAMP(${LiteTable.timeRollingUpdated}) >= UNIX_TIMESTAMP(now()) - ${rollingWindowSeconds} THEN ${LiteTable.rollingUsage} + ${quotaCost}

packages/containers/bun-node/Dockerfile

@@ -4,7 +4,7 @@ FROM ${REGISTRY}/build/base:24.04
 SHELL ["/bin/bash", "-lc"]
 
 ARG NODE_VERSION=24.4.0
-ARG BUN_VERSION=1.3.14
+ARG BUN_VERSION=1.4.1
 
 ENV BUN_INSTALL=/opt/bun
 ENV PATH=/opt/bun/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

packages/core/script/build.ts

@@ -41,37 +41,3 @@ const result = await Bun.build({
   },
 })
 if (!result.success) throw new AggregateError(result.logs, "Failed to build Core")
-
-// Bun's Node target eagerly creates its shared require helper, so every split
-// entry evaluates import.meta.url even when it never requires a module. Keep
-// the helper lazy until Bun stops hoisting it into workerd-reachable chunks.
-// https://github.com/oven-sh/bun/issues/12615
-const eagerRequire = "var __require = /* @__PURE__ */ createRequire(import.meta.url);"
-const lazyRequire = `var __require = (specifier) => createRequire(import.meta.url ?? "file:///worker.js")(specifier);
-__require.resolve = (specifier, options) => createRequire(import.meta.url ?? "file:///worker.js").resolve(specifier, options);`
-const rewritten = await Promise.all(
-  result.outputs.map(async (output) => {
-    if (!output.path.endsWith(".js")) return false
-    const source = await output.text()
-
-    const generatedUses = source
-      .replace(/import\s*\{[^}]*\b__require\b[^}]*\}\s*from\s*["'][^"']+["'];/g, "")
-      .replace(/export\s*\{[^}]*\b__require\b[^}]*\};/g, "")
-      .replace(eagerRequire, "")
-    if (/\bnew\s+__require\s*\(/.test(generatedUses))
-      throw new Error(`Unsupported generated require constructor in ${output.path}`)
-    const unsupported = generatedUses.replace(/\b__require\.resolve\s*\(/g, "").replace(/\b__require\s*\(/g, "")
-    if (/\b__require\b/.test(unsupported)) throw new Error(`Unsupported generated require usage in ${output.path}`)
-
-    if (!source.includes(eagerRequire)) return false
-    if (source.indexOf(eagerRequire) !== source.lastIndexOf(eagerRequire))
-      throw new Error(`Multiple eager require helpers in ${output.path}`)
-    const rewrittenSource = source.replace(eagerRequire, lazyRequire)
-    if (rewrittenSource.includes(eagerRequire))
-      throw new Error(`Failed to rewrite eager require helper in ${output.path}`)
-    await Bun.write(output.path, rewrittenSource)
-    return true
-  }),
-)
-if (rewritten.filter(Boolean).length !== 1)
-  throw new Error("Expected exactly one eager require helper; Bun may have fixed #12615 and made this shim removable")

packages/core/src/aisdk.ts

@@ -416,8 +416,9 @@ function callOptions(
   modelID: ID,
   optionKey: string,
 ): LanguageModelV3CallOptions {
+  const flattened = ProviderShared.flattenToolRequest(request)
   return {
-    prompt: prompt(request),
+    prompt: prompt(flattened.request),
     maxOutputTokens: request.generation?.maxTokens,
     temperature: request.generation?.temperature,
     stopSequences: request.generation?.stop === undefined ? undefined : [...request.generation.stop],
@@ -426,7 +427,7 @@ function callOptions(
     presencePenalty: request.generation?.presencePenalty,
     frequencyPenalty: request.generation?.frequencyPenalty,
     seed: request.generation?.seed,
-    tools: request.tools.map(tool),
+    tools: flattened.tools.map(tool),
     toolChoice: toolChoice(request.toolChoice),
     headers: request.http?.headers,
     providerOptions: requestProviderOptions(request.providerOptions, packageName, modelID, optionKey),

packages/core/src/tool/runtime.ts

@@ -18,6 +18,7 @@ const jsonSchemas = Effect.runSync(
 )
 
 export const definition = (tool: Tool.Info<any, any>): ToolDefinition => ({
+  type: "tool",
   name: effectiveName(tool),
   description: tool.description,
   inputSchema: inputJsonSchema(tool.input),

packages/core/src/util/process-lock-ffi.bun.ts

@@ -44,7 +44,7 @@ export function lockLinux(fd: number): LockResult {
   }
 }
 
-function errorCode(pointer: Pointer | null) {
+function errorCode(pointer: Pointer | bigint | null) {
   if (pointer === null) throw new Error("Failed to read process lock error code")
   return read.i32(pointer, 0)
 }

packages/core/test/lib/websocket-server.ts

@@ -19,6 +19,7 @@ export interface WebSocketServerFixture {
 }
 
 export interface WebSocketServerOptions {
+  readonly http?: (request: Request) => Response | Promise<Response>
   readonly upgrade?: (request: Request) => boolean
   readonly open?: (socket: Bun.ServerWebSocket<ConnectionData>) => void
   readonly message?: (socket: Bun.ServerWebSocket<ConnectionData>, message: string | Buffer) => void
@@ -34,6 +35,7 @@ export const makeWebSocketServer = (options: WebSocketServerOptions = {}) =>
         port: 0,
         fetch(request, server) {
           state.headers.push(Object.fromEntries(request.headers.entries()))
+          if (request.headers.get("upgrade") !== "websocket" && options.http) return options.http(request)
           if ((options.upgrade?.(request) ?? true) && server.upgrade(request, { data: { id: connection++ } }))
             return undefined
           return new Response("WebSocket upgrade required", {

packages/core/test/session-checkpoint-transport.test.ts

@@ -0,0 +1,172 @@
+import { expect } from "bun:test"
+import { LLM, LLMRequest, Message } from "@opencode-ai/ai"
+import { LLMClient, RequestExecutor } from "@opencode-ai/ai/route"
+import { configure } from "@opencode-ai/ai/providers/openai"
+import { SessionModelTransport } from "../src/session/model-transport"
+import { WebSocketConstructor } from "../src/effect/websocket-constructor"
+import { Session } from "@opencode-ai/schema/session"
+import { Effect, Layer, Schema } from "effect"
+import { FetchHttpClient } from "effect/unstable/http"
+import { testEffect } from "./lib/effect"
+import { makeWebSocketServer } from "./lib/websocket-server"
+
+const runtime = Layer.mergeAll(
+  LLMClient.layer.pipe(Layer.provide(RequestExecutor.layer), Layer.provide(FetchHttpClient.layer)),
+  SessionModelTransport.layer.pipe(Layer.provide(WebSocketConstructor.layer)),
+)
+const it = testEffect(runtime)
+const sessionID = Session.ID.make("ses_checkpoint_transport")
+const checkpoint = { type: "compaction", encrypted_content: "opaque" }
+const fixture = (mode: "success" | "invalid" | "fallback") =>
+  Effect.gen(function* () {
+    const requests: Array<Record<string, unknown>> = []
+    const http: Array<Record<string, unknown>> = []
+    let disconnect: (() => void) | undefined
+    const server = yield* makeWebSocketServer({
+      upgrade: () => mode !== "fallback" || disconnect === undefined,
+      async http(request) {
+        http.push(Schema.decodeUnknownSync(Schema.Record(Schema.String, Schema.Unknown))(await request.json()))
+        return new Response(
+          `data: ${JSON.stringify({
+            type: "response.completed",
+            response: {
+              id: "resp_http",
+              output: [checkpoint],
+              usage: { input_tokens: 70, output_tokens: 7 },
+            },
+          })}\n\n`,
+          { headers: { "content-type": "text/event-stream", "x-response": "http" } },
+        )
+      },
+      open(socket) {
+        disconnect = () => socket.close()
+      },
+      message(socket, message) {
+        const body = JSON.parse(message.toString())
+        requests.push(body)
+        const id = `resp_${requests.length}`
+        const send = (event: unknown) => socket.send(JSON.stringify(event))
+        if (body.input.at(-1)?.type !== "compaction_trigger") {
+          const item = {
+            type: "message",
+            id: `msg_${requests.length}`,
+            role: "assistant",
+            content: [{ type: "output_text", text: "Hello" }],
+          }
+          send({ type: "response.created", response: { id } })
+          send({ type: "response.output_item.added", output_index: 0, item })
+          send({ type: "response.output_text.delta", item_id: item.id, delta: "Hello" })
+          send({ type: "response.output_item.done", output_index: 0, item })
+          send({ type: "response.completed", response: { id, output: [item] } })
+          return
+        }
+        send({ type: "response.created", response: { id } })
+        send({ type: "response.output_item.done", output_index: 0, item: checkpoint })
+        send({
+          type: "response.completed",
+          response: {
+            id,
+            output: mode === "invalid" ? [checkpoint, { ...checkpoint, encrypted_content: "second" }] : [checkpoint],
+            usage: { input_tokens: 100, output_tokens: 10 },
+          },
+        })
+      },
+    })
+    return {
+      requests,
+      headers: server.state.headers,
+      http,
+      opens: () => server.state.opens,
+      disconnect: () => disconnect?.(),
+      request: LLM.request({
+        model: configure({
+          apiKey: "fixture",
+          baseURL: server.url.replace(/^ws/, "http").replace(/responses$/, ""),
+          headers: { "chatgpt-account-id": "account", "x-codex-beta-features": "remote_compaction_v2" },
+          providerOptions: { parallelToolCalls: true },
+        }).responses("fixture"),
+        prompt: "First",
+        promptCacheKey: "session-key",
+      }),
+    }
+  })
+
+it.live("trigger reuses the append baseline and clears it before the next generation", () =>
+  Effect.gen(function* () {
+    const server = yield* fixture("success")
+    const transport = yield* SessionModelTransport.Service
+    const webSocket = transport.bind(sessionID)
+    const first = yield* LLMClient.generate(server.request, { webSocket })
+    const compacted = yield* LLMClient.compact(
+      LLMRequest.update(server.request, {
+        messages: [...server.request.messages, first.message],
+      }),
+      { mechanism: "trigger", webSocket },
+    )
+    expect(server.requests[1]).toMatchObject({
+      previous_response_id: "resp_1",
+      input: [{ type: "compaction_trigger" }],
+    })
+    expect(compacted.responseID).toBe("resp_2")
+    expect(compacted.usage).toMatchObject({ inputTokens: 100, outputTokens: 10 })
+    expect(compacted.checkpoint.encrypted).toBe("opaque")
+    const messages = [Message.assistant(compacted.checkpoint), Message.user("Continue")]
+    yield* LLMClient.generate(LLMRequest.update(server.request, { messages }), { webSocket })
+    expect(server.requests[2]?.previous_response_id).toBeUndefined()
+    expect(server.requests[2]?.input).toMatchObject([
+      { type: "compaction", encrypted_content: "opaque" },
+      { role: "user", content: [{ type: "input_text", text: "Continue" }] },
+    ])
+    expect(server.requests[1]?.stream).toBeUndefined()
+    expect(server.requests[1]?.store).toBe(false)
+    expect(server.headers[0]).toMatchObject({
+      authorization: "Bearer fixture",
+      "chatgpt-account-id": "account",
+      "x-codex-beta-features": "remote_compaction_v2",
+    })
+    expect(server.opens()).toBe(1)
+    expect(server.http).toHaveLength(0)
+  }),
+)
+
+it.live("invalid trigger output does not retry or commit a continuation checkpoint", () =>
+  Effect.gen(function* () {
+    const server = yield* fixture("invalid")
+    const transport = yield* SessionModelTransport.Service
+    const webSocket = transport.bind(sessionID)
+    const first = yield* LLMClient.generate(server.request, { webSocket })
+    const input = LLMRequest.update(server.request, { messages: [...server.request.messages, first.message] })
+    const error = yield* LLMClient.compact(input, { mechanism: "trigger", webSocket }).pipe(Effect.flip)
+    expect(error.reason._tag).toBe("InvalidProviderOutput")
+    expect(server.requests).toHaveLength(2)
+    expect(server.http).toHaveLength(0)
+    yield* LLMClient.generate(input, { webSocket })
+    expect(server.requests[2]?.previous_response_id).toBeUndefined()
+    expect(server.requests[2]?.input).toHaveLength(2)
+  }),
+)
+
+it.live("trigger recovers over SSE with complete input after the old socket closes and reconnect is rejected", () =>
+  Effect.gen(function* () {
+    const server = yield* fixture("fallback")
+    const transport = yield* SessionModelTransport.Service
+    const webSocket = transport.bind(sessionID)
+    const first = yield* LLMClient.generate(server.request, { webSocket })
+    server.disconnect()
+    // Let the real close event reach the connector before the next send.
+    yield* Effect.sleep("20 millis")
+    const result = yield* LLMClient.compact(
+      LLMRequest.update(server.request, {
+        messages: [...server.request.messages, first.message],
+      }),
+      { mechanism: "trigger", webSocket },
+    )
+    expect(result.responseID).toBe("resp_http")
+    expect(result.usage).toMatchObject({ inputTokens: 70, outputTokens: 7 })
+    expect(server.http).toHaveLength(1)
+    expect(server.http[0]?.previous_response_id).toBeUndefined()
+    expect(server.http[0]?.stream).toBe(true)
+    expect(server.http[0]?.input).toHaveLength(3)
+    expect(server.requests).toHaveLength(1)
+  }),
+)

packages/core/test/session-model-transport-live.test.ts

@@ -74,23 +74,34 @@ describe("SessionModelTransport local WebSocket server", () => {
           const index = requests.length
           const id = `msg_${index}`
           const text = index === 1 ? "Hello" : "Brief"
+          const reasoning = { type: "reasoning", id: `rs_${index}`, summary: [], encrypted_content: "stream-encrypted" }
+          const item = {
+            type: "message",
+            id,
+            status: "completed",
+            role: "assistant",
+            content: [{ type: "output_text", text, annotations: [], logprobs: [] }],
+          }
           socket.send(JSON.stringify({ type: "response.created", response: { id: `resp_${index}` } }))
+          socket.send(JSON.stringify({ type: "response.output_item.done", item: reasoning }))
           socket.send(JSON.stringify({ type: "response.output_item.added", item: { type: "message", id } }))
           socket.send(JSON.stringify({ type: "response.output_text.delta", item_id: id, delta: text }))
           socket.send(JSON.stringify({ type: "response.output_text.done", item_id: id, text }))
           socket.send(
             JSON.stringify({
               type: "response.output_item.done",
-              item: {
-                type: "message",
-                id,
-                status: "completed",
-                role: "assistant",
-                content: [{ type: "output_text", text }],
+              item,
+            }),
+          )
+          socket.send(
+            JSON.stringify({
+              type: "response.completed",
+              response: {
+                id: `resp_${index}`,
+                output: [{ ...reasoning, encrypted_content: "terminal-encrypted" }, item],
               },
             }),
           )
-          socket.send(JSON.stringify({ type: "response.completed", response: { id: `resp_${index}` } }))
         },
       },
       (server) =>
@@ -119,7 +130,7 @@ describe("SessionModelTransport local WebSocket server", () => {
               llm.generate(
                 LLM.request({
                   model,
-                  messages: [Message.user("First"), Message.assistant("Hello"), Message.user("Be brief")],
+                  messages: [Message.user("First"), first.message, Message.user("Be brief")],
                 }),
                 { webSocket: executor },
               ),

packages/core/test/tool-schema.test.ts

@@ -27,6 +27,7 @@ test("tools are structural values", async () => {
   const tool: Info = config
 
   expect(definition(tool)).toEqual({
+    type: "tool",
     name: "foreign",
     description: "Foreign tool",
     inputSchema: {
@@ -142,6 +143,7 @@ test("portable schemas validate and describe typed tools", async () => {
   }
 
   expect(definition(tool)).toEqual({
+    type: "tool",
     name: "portable",
     description: "Portable tool",
     inputSchema: { type: "object", properties: { count: { type: "string" } } },
@@ -161,6 +163,7 @@ test("Zod schemas validate, transform, and describe typed tools", async () => {
   }
 
   expect(definition(tool)).toEqual({
+    type: "tool",
     name: "zod",
     description: "Zod tool",
     inputSchema: {
@@ -317,6 +320,7 @@ test("raw JSON schemas validate and decode tool input", async () => {
   }
 
   expect(definition(tool)).toEqual({
+    type: "tool",
     name: "raw",
     description: "Raw tool",
     inputSchema: input,
@@ -400,6 +404,7 @@ test("missing external input schemas fall back to an empty schema", () => {
   } as unknown as Info
 
   expect(definition(tool)).toEqual({
+    type: "tool",
     name: "external",
     description: "External tool",
     inputSchema: {},

packages/desktop/src/main/ipc.ts

@@ -4,7 +4,7 @@ import { app, BrowserWindow, MessageChannelMain } from "electron"
 import { Effect, Layer } from "effect"
 import { RpcServer } from "effect/unstable/rpc"
 import { DesktopRpcs } from "../shared/ipc-rpc"
-import { IpcTransportPort } from "../shared/ipc-transport"
+import { DragCancelEvent, IpcTransportPort } from "../shared/ipc-transport"
 import { DesktopFiles, openExternalURL } from "./files"
 import { appHandlers } from "./ipc-handlers/app"
 import { eventHandlers } from "./ipc-handlers/events"
@@ -59,6 +59,10 @@ export const registerIpcHandlers = Effect.gen(function* () {
     relaunch: lifecycle.relaunch,
   }
   const wire = (_event: Electron.Event, win: BrowserWindow) => {
+    win.webContents.on("before-input-event", (_event, input) => {
+      if (input.type !== "keyDown" || input.key !== "Escape") return
+      win.webContents.send(DragCancelEvent)
+    })
     win.webContents.on("did-finish-load", () => {
       if (win.isDestroyed() || win.webContents.isDestroyed()) return
       const channel = new MessageChannelMain()

packages/desktop/src/preload/index.ts

@@ -1,5 +1,5 @@
 import { contextBridge, ipcRenderer, webUtils } from "electron"
-import { IpcTransportPort } from "../shared/ipc-transport"
+import { DragCancelEvent, IpcTransportPort } from "../shared/ipc-transport"
 import { windowIDFromArguments } from "../shared/window-bootstrap"
 
 ipcRenderer.on(IpcTransportPort, (event) => {
@@ -7,6 +7,8 @@ ipcRenderer.on(IpcTransportPort, (event) => {
   if (port) window.postMessage(IpcTransportPort, "*", [port])
 })
 
+ipcRenderer.on(DragCancelEvent, () => window.dispatchEvent(new Event(DragCancelEvent)))
+
 contextBridge.exposeInMainWorld("electron", {
   windowID: windowIDFromArguments(process.argv),
   getPathForFile: (file: File) => webUtils.getPathForFile(file),

packages/desktop/src/renderer/platform/index.ts

@@ -7,6 +7,7 @@ import {
 import type { ElectronAPI } from "../api-types"
 import { setPinchZoomEnabled, webviewZoom } from "../window/zoom"
 import { windowFullscreen } from "../window/fullscreen"
+import { DragCancelEvent } from "../../shared/ipc-transport"
 import { createDesktopFiles } from "./files"
 import { createDesktopMenuAction } from "./menu"
 import { createDesktopNotify } from "./notifications"
@@ -53,6 +54,10 @@ export function createDesktopPlatform(
     windowFullscreen,
     getPinchZoomEnabled: () => api.getPinchZoomEnabled(),
     setPinchZoomEnabled,
+    onDragCancel: (callback) => {
+      window.addEventListener(DragCancelEvent, callback)
+      return () => window.removeEventListener(DragCancelEvent, callback)
+    },
     runDesktopMenuAction: createDesktopMenuAction(api),
     checkAppExists: async (appName) => {
       return api.checkAppExists(appName)

packages/desktop/src/shared/ipc-transport.ts

@@ -1 +1,2 @@
 export const IpcTransportPort = "desktop-rpc-port"
+export const DragCancelEvent = "opencode:drag-cancel"

packages/sdk/script/verify-package.ts

@@ -216,9 +216,6 @@ for (const module of modules) {
 
   const transpiler = new Bun.Transpiler({ loader: "js" })
   const bundled = await Bun.file(join(consumer, "dist/worker.js")).text()
-  if (/createRequire\s*\(\s*import\.meta\.url\s*\)/.test(bundled)) {
-    throw new Error("Packed workerd bundle contains Bun's eager Node require initializer")
-  }
   const bunGlobals = Array.from(new Set(bundled.match(/\bBun\.[A-Za-z_$][\w$]*/g) ?? []))
   if (bunGlobals.length > 0) throw new Error(`Packed workerd bundle references Bun globals: ${bunGlobals.join(", ")}`)
   const leaked = [
@@ -230,6 +227,8 @@ for (const module of modules) {
   ].filter((specifier) => specifier === "bun" || specifier.startsWith("bun:"))
   if (leaked.length > 0) throw new Error(`Packed workerd bundle statically imports Bun builtins: ${leaked.join(", ")}`)
 
+  // Boot in workerd to catch eager Node initializers; lazy createRequire calls
+  // in native-only code are valid and must not fail a bundle-wide text check.
   await $`node boot.mjs`.cwd(consumer)
   console.log("packed SDK consumer OK")
 } finally {

packages/session-ui/component-tests/file-tool.spec.ts

@@ -0,0 +1,76 @@
+import { expect, story } from "../../storybook/playwright/story"
+
+for (const theme of ["light", "dark"]) {
+  story(`file tools share Patch's upfront file list in ${theme}`, async ({ mount }, info) => {
+    const root = await mount("current-session-research-agents--agent-research", {
+      args: { scenario: "workflow" },
+      globals: { theme },
+    })
+    const group = root.locator('[data-component="collapsed-tool-group"]').filter({ hasText: "Patch" })
+    const disclosure = group.getByRole("button", { name: /^Used .*Edit.*Write.*Patch$/ })
+    await disclosure.click()
+    for (const name of ["edit", "write", "patch"]) {
+      const tool = group.locator(`[data-timeline-part-id="tool_family_${name}"]`)
+      const file = tool.locator('[data-slot="accordion-trigger"]')
+      await expect(file).toHaveAttribute("aria-expanded", "false")
+      await expect(tool.locator('[data-component="file"]')).toHaveCount(0)
+      await file.click()
+      await expect(file).toHaveAttribute("aria-expanded", "true")
+      await expect(tool.locator('[data-component="file"]')).toBeVisible()
+      await expect(file).toBeFocused()
+      await file.press("Space")
+      await expect(file).toHaveAttribute("aria-expanded", "false")
+      await file.press("Enter")
+      await expect(file).toHaveAttribute("aria-expanded", "true")
+    }
+    await disclosure.click()
+    await disclosure.click()
+    for (const name of ["edit", "write", "patch"]) {
+      const tool = group.locator(`[data-timeline-part-id="tool_family_${name}"]`)
+      await expect(tool.locator('[data-slot="accordion-trigger"]')).toHaveAttribute("aria-expanded", "true")
+      await expect(tool.locator('[data-component="file"]')).toBeVisible()
+    }
+    await root.screenshot({ path: info.outputPath(`file-tools-${theme}.png`) })
+  })
+}
+
+for (const tool of ["edit", "write"]) {
+  for (const controlled of [false, true]) {
+    story(`${tool} supports forceOpen with ${controlled ? "controlled" : "local"} disclosure`, async ({ mount }) => {
+      const root = await mount("current-session-file-changes--file-tool-fallbacks", {
+        args: { tool, controlled, forceOpen: true },
+      })
+      await expect(root.getByRole("button", { name: /example\.ts/ })).toHaveAttribute("aria-expanded", "true")
+      await expect(root.locator('[data-component="file"]')).toBeVisible()
+    })
+  }
+
+  story(`${tool} preserves input fallback and disclosure through completion`, async ({ mount }) => {
+    const root = await mount("current-session-file-changes--file-tool-fallbacks", { args: { tool } })
+    const file = root.getByRole("button", { name: /example\.ts/ })
+    await expect(file).toBeVisible()
+    await expect(file).toHaveAttribute("aria-expanded", "false")
+    await expect(root.getByText("1 file", { exact: true })).toBeVisible()
+    await file.click()
+    await expect(root.locator('[data-component="file"]')).toContainText(tool === "edit" ? "after" : "written")
+    await root.getByRole("button", { name: "Complete file tool" }).click()
+    await expect(root.getByText("Example diagnostic")).toBeVisible()
+    await expect(file).toHaveAttribute("aria-expanded", "true")
+    await file.click()
+    await expect(file).toHaveAttribute("aria-expanded", "false")
+    await expect(root.getByText("Example diagnostic")).toBeVisible()
+  })
+}
+
+story("empty writes still show a file row", async ({ mount }) => {
+  const root = await mount("current-session-file-changes--file-tool-fallbacks", {
+    args: { tool: "write", empty: true },
+  })
+  await root.getByRole("button", { name: "Complete file tool" }).click()
+  const file = root.getByRole("button", { name: /example\.ts/ })
+  await expect(file).toHaveAttribute("aria-expanded", "false")
+  await file.click()
+  await expect(file).toHaveAttribute("aria-expanded", "true")
+  await expect(root.locator('[data-component="file"]')).toBeAttached()
+  await expect(file).toBeVisible()
+})

packages/session-ui/component-tests/session-tool-projection.spec.ts

@@ -25,18 +25,17 @@ story("renders every admitted tool family and hides timeline-only exclusions", a
   ]) {
     await expect(timeline.locator(`[data-timeline-part-id="tool_family_${id}"]`), id).toBeVisible()
   }
-  const patch = timeline.locator('[data-timeline-part-id="tool_family_patch"]')
-  await expect(patch.getByText("1 file", { exact: true })).toBeVisible()
-  await expect(patch.getByRole("button", { name: "Patch 1 file", exact: true })).toHaveCount(0)
-  await expect(patch.getByRole("button")).toHaveCount(1)
-  await expect(patch.locator('[data-scope="apply-patch"] button')).toHaveAttribute("aria-expanded", "false")
-  await expect(patch.locator('[data-slot="message-part-title-filename"]')).toHaveCount(0)
-  await expect(patch.locator('[data-slot="message-part-actions"]')).toHaveCount(0)
-  await expect(patch.locator('[data-slot="basic-tool-tool-title"]')).toHaveCSS("font-size", "13px")
-  const edit = timeline.locator('[data-timeline-part-id="tool_family_edit"]')
-  await expect(edit).toContainText("Edit")
-  await expect(edit.locator('[data-slot="message-part-title"]')).toHaveCSS("font-size", "13px")
-  await expect(edit.locator('[data-slot="message-part-title"]')).toHaveCSS("line-height", "16px")
+  for (const name of ["edit", "write", "patch"]) {
+    const tool = timeline.locator(`[data-timeline-part-id="tool_family_${name}"]`)
+    await expect(tool.getByText("1 file", { exact: true })).toBeVisible()
+    await expect(tool.getByRole("button")).toHaveCount(1)
+    await expect(tool.locator('[data-scope="apply-patch"] button')).toHaveAttribute("aria-expanded", "false")
+    await expect(tool.locator('[data-slot="collapsible-trigger"]')).toHaveAttribute("data-locked", "")
+    await expect(tool.locator('[data-slot="message-part-title-filename"]')).toHaveCount(0)
+    await expect(tool.locator('[data-slot="message-part-actions"]')).toHaveCount(0)
+    await expect(tool.locator('[data-slot="basic-tool-tool-title"]')).toHaveCSS("font-size", "13px")
+    await expect(tool.locator('[data-slot="basic-tool-tool-title"]')).toHaveCSS("line-height", "16px")
+  }
   await expect(timeline.locator('[data-timeline-part-id="tool_family_todo"]')).toHaveCount(0)
 })
 

packages/session-ui/src/components/message-part.css

@@ -466,102 +466,6 @@
   --tool-content-gap: 8px;
 }
 
-[data-component="edit-trigger"],
-[data-component="write-trigger"] {
-  display: flex;
-  align-items: center;
-  justify-content: space-between;
-  gap: 12px;
-  width: 100%;
-
-  [data-slot="message-part-title-area"] {
-    flex-grow: 1;
-    display: flex;
-    align-items: center;
-    gap: 8px;
-    min-width: 0;
-  }
-
-  [data-slot="message-part-title"] {
-    flex: 1 1 auto;
-    display: flex;
-    align-items: center;
-    gap: 8px;
-    min-width: 0;
-    font-family: var(--font-family-sans);
-    font-size: 13px;
-    font-style: normal;
-    font-weight: var(--font-weight-medium);
-    line-height: var(--line-height-compact);
-    letter-spacing: var(--letter-spacing-normal);
-    color: var(--v2-text-text-muted);
-  }
-
-  [data-slot="message-part-title-spinner"] {
-    margin-left: 4px;
-    width: 16px;
-    height: 16px;
-    display: inline-flex;
-    align-items: center;
-    justify-content: center;
-    flex-shrink: 0;
-    color: var(--v2-text-text-muted);
-
-    [data-component="spinner"] {
-      width: 16px;
-      height: 16px;
-    }
-  }
-
-  [data-slot="message-part-title-text"] {
-    flex-shrink: 0;
-    text-transform: capitalize;
-    color: var(--v2-text-text-base);
-  }
-
-  [data-slot="message-part-title-filename"] {
-    /* No text-transform - preserve original filename casing */
-    min-width: 0;
-    overflow: hidden;
-    text-overflow: ellipsis;
-    white-space: nowrap;
-    font-weight: var(--font-weight-regular);
-    direction: ltr;
-    unicode-bidi: isolate;
-  }
-
-  [data-slot="message-part-path"] {
-    display: flex;
-    flex-grow: 1;
-    min-width: 0;
-    font-weight: var(--font-weight-regular);
-    direction: ltr;
-    unicode-bidi: isolate;
-  }
-
-  [data-slot="message-part-directory"] {
-    color: var(--v2-text-text-muted);
-    text-overflow: ellipsis;
-    overflow: hidden;
-    white-space: nowrap;
-    direction: rtl;
-    text-align: left;
-  }
-
-  [data-slot="message-part-filename"] {
-    color: var(--v2-text-text-base);
-    flex-shrink: 0;
-  }
-
-  [data-slot="message-part-actions"] {
-    display: flex;
-    gap: 16px;
-    align-items: center;
-    justify-content: flex-end;
-    flex-shrink: 0;
-  }
-}
-
 [data-component="edit-content"] {
   border-radius: inherit;
   border-top: 0.5px solid var(--v2-border-border-muted);

packages/session-ui/src/timeline/file-changes.stories.tsx

@@ -11,6 +11,7 @@ import {
 } from "../storybook/current-session-fixtures"
 import { storyDocument, storyPatchFile, storyTool } from "../storybook/current-session-scenarios"
 import { SessionTimeline } from "./session-timeline"
+import { ToolDisplay } from "../tools/tool-renderer"
 
 export default {
   title: "OpenCode/Work/File changes",
@@ -261,3 +262,48 @@ export const CreatedANewFile = {
     />
   ),
 }
+
+export const FileToolFallbacks = {
+  args: { tool: "edit", empty: false, forceOpen: false, controlled: true },
+  argTypes: {
+    tool: { control: "select", options: ["edit", "write"] },
+    empty: { control: "boolean" },
+    forceOpen: { control: "boolean" },
+    controlled: { control: "boolean" },
+  },
+  render: (args: { tool: string; empty: boolean; forceOpen: boolean; controlled: boolean }) => {
+    const [state, setState] = createStore({ completed: false, open: false })
+    return (
+      <section class="mx-auto flex w-full max-w-[860px] flex-col gap-4 p-6">
+        <button type="button" onClick={() => setState("completed", true)}>
+          Complete file tool
+        </button>
+        <CurrentSessionProviders document={storyDocument([])}>
+          <ToolDisplay
+            id="tool_file_fallback"
+            tool={args.tool}
+            status={state.completed ? "completed" : "running"}
+            input={{
+              path: "src/example.ts",
+              oldString: "export const before = true\n",
+              newString: "export const after = true\n",
+              content: args.empty ? "" : "export const written = true\n",
+            }}
+            metadata={{
+              diagnostics: state.completed
+                ? {
+                    "src/example.ts": [
+                      { severity: 1, message: "Example diagnostic", range: { start: { line: 0, character: 0 } } },
+                    ],
+                  }
+                : {},
+            }}
+            open={args.controlled ? state.open : undefined}
+            onOpenChange={(open) => setState("open", open)}
+            forceOpen={args.forceOpen}
+          />
+        </CurrentSessionProviders>
+      </section>
+    )
+  },
+}

packages/session-ui/src/tools/tool-renderer.tsx

@@ -528,12 +528,12 @@ export function CurrentContextToolGroup(props: {
       .join(", "),
   )
   const label = createMemo(() => {
-    const notices = props.parts.filter((part) => part.type === "notice").length
-    const title =
-      [names(), notices ? i18n.plural("ui.messagePart.context.notice", notices) : undefined]
-        .filter(Boolean)
-        .join(", ") ||
-      i18n.plural("ui.messagePart.context.thought", props.parts.filter((part) => part.type === "reasoning").length)
+    const thoughts = props.parts.filter((part) => part.type === "reasoning").length
+    if (!names() && !thoughts) {
+      const title = i18n.t("ui.messagePart.context.details")
+      return { text: title, title, before: "", after: "" }
+    }
+    const title = names() || i18n.plural("ui.messagePart.context.thought", thoughts)
     const text = i18n.t("ui.messagePart.tools.used", { tools: title })
     const index = text.indexOf(title)
     return { text, title, before: text.slice(0, index).trim(), after: text.slice(index + title.length).trim() }
@@ -951,20 +951,66 @@ export const ToolRegistry = {
   render: getTool,
 }
 
+function FileTool(props: ToolProps & { title: string; count: number; children: JSX.Element }) {
+  const i18n = useI18n()
+  return (
+    <BasicTool
+      {...props}
+      open
+      onOpenChange={undefined}
+      locked
+      icon="code-lines"
+      defer={false}
+      rail={false}
+      trigger={{
+        title: props.title,
+        subtitle: props.count > 0 ? `${props.count} ${i18n.plural("ui.common.file", props.count)}` : "",
+      }}
+    >
+      {props.children}
+    </BasicTool>
+  )
+}
+
 function ToolFileAccordion(props: {
   path: string
   actions?: JSX.Element
   children: JSX.Element
   defaultOpen?: boolean
+  open?: boolean
+  onOpenChange?: (open: boolean) => void
+  forceOpen?: boolean
+  defer?: boolean
 }) {
   const value = createMemo(() => props.path || "tool-file")
+  const [expanded, setExpanded] = createSignal(props.defaultOpen ?? false)
+  const [visible, setVisible] = createSignal(false)
+  const open = () => props.open ?? expanded()
+  const change = (value: boolean) => {
+    if (props.open === undefined) setExpanded(value)
+    props.onOpenChange?.(value)
+  }
+
+  createEffect(() => {
+    if (props.forceOpen && !open()) change(true)
+  })
+
+  createEffect(() => {
+    if (!open()) {
+      setVisible(false)
+      return
+    }
+    const frame = requestAnimationFrame(() => setVisible(true))
+    onCleanup(() => cancelAnimationFrame(frame))
+  })
 
   return (
     <Accordion
       multiple
       data-scope="apply-patch"
       style={{ "--sticky-accordion-offset": "calc(32px + var(--tool-content-gap))" }}
-      defaultValue={props.defaultOpen === false ? [] : [value()]}
+      value={open() ? [value()] : []}
+      onChange={(next) => change(next.includes(value()))}
     >
       <Accordion.Item value={value()}>
         <StickyAccordionHeader>
@@ -986,7 +1032,9 @@ function ToolFileAccordion(props: {
             </div>
           </Accordion.Trigger>
         </StickyAccordionHeader>
-        <Accordion.Content>{props.children}</Accordion.Content>
+        <Accordion.Content>
+          <Show when={!props.defer || visible()}>{props.children}</Show>
+        </Accordion.Content>
       </Accordion.Item>
     </Accordion>
   )
@@ -1709,7 +1757,6 @@ ToolRegistry.register({
       const value = diff()
       return typeof value?.file === "string" ? value.file : inputPath()
     })
-    const filename = () => getFilename(inputPath())
     const pending = () => props.status === "streaming" || props.status === "running"
     const diffSource = createMemo(
       () => {
@@ -1749,39 +1796,15 @@ ToolRegistry.register({
 
     return (
       <div data-component="edit-tool">
-        <BasicTool
-          {...props}
-          icon="code-lines"
-          rail={false}
-          defer={props.deferContent !== false}
-          trigger={
-            <div data-component="edit-trigger">
-              <div data-slot="message-part-title-area">
-                <div data-slot="message-part-title">
-                  <span data-slot="message-part-title-text">
-                    <TextShimmer text={i18n.t("ui.messagePart.title.edit")} active={pending()} />
-                  </span>
-                  <Show when={!pending()}>
-                    <span data-slot="message-part-title-filename">{filename()}</span>
-                  </Show>
-                </div>
-                <Show when={!pending() && inputPath().includes("/")}>
-                  <div data-slot="message-part-path">
-                    <span data-slot="message-part-directory">{displayDirectory(inputPath())}</span>
-                  </div>
-                </Show>
-              </div>
-              <div data-slot="message-part-actions">
-                <Show when={!pending() ? diff() : undefined}>
-                  {(diff) => <DiffChanges appearance="standard" changes={diff()} />}
-                </Show>
-              </div>
-            </div>
-          }
-        >
+        <FileTool {...props} title={i18n.t("ui.messagePart.title.edit")} count={path() ? 1 : 0}>
           <Show when={path()}>
             <ToolFileAccordion
               path={path()}
+              defaultOpen={props.defaultOpen}
+              open={props.open}
+              onOpenChange={props.onOpenChange}
+              forceOpen={props.forceOpen}
+              defer={props.deferContent !== false}
               actions={
                 <Show when={!pending() ? diff() : undefined}>
                   {(diff) => <DiffChanges appearance="standard" changes={diff()} />}
@@ -1800,7 +1823,7 @@ ToolRegistry.register({
             </ToolFileAccordion>
           </Show>
           <DiagnosticsDisplay diagnostics={diagnostics()} />
-        </BasicTool>
+        </FileTool>
       </div>
     )
   },
@@ -1814,38 +1837,18 @@ ToolRegistry.register({
     const path = createMemo(() => (typeof props.input.path === "string" ? props.input.path : ""))
     const content = createMemo(() => (typeof props.input.content === "string" ? props.input.content : ""))
     const diagnostics = createMemo(() => getDiagnostics(props.metadata.diagnostics, path()))
-    const filename = () => getFilename(path())
-    const pending = () => props.status === "streaming" || props.status === "running"
     return (
       <div data-component="write-tool">
-        <BasicTool
-          {...props}
-          icon="code-lines"
-          rail={false}
-          defer={props.deferContent !== false}
-          trigger={
-            <div data-component="write-trigger">
-              <div data-slot="message-part-title-area">
-                <div data-slot="message-part-title">
-                  <span data-slot="message-part-title-text">
-                    <TextShimmer text={i18n.t("ui.messagePart.title.write")} active={pending()} />
-                  </span>
-                  <Show when={!pending()}>
-                    <span data-slot="message-part-title-filename">{filename()}</span>
-                  </Show>
-                </div>
-                <Show when={!pending() && path().includes("/")}>
-                  <div data-slot="message-part-path">
-                    <span data-slot="message-part-directory">{displayDirectory(path())}</span>
-                  </div>
-                </Show>
-              </div>
-              <div data-slot="message-part-actions">{/* <DiffChanges diff={diff} /> */}</div>
-            </div>
-          }
-        >
-          <Show when={content() && path()}>
-            <ToolFileAccordion path={path()}>
+        <FileTool {...props} title={i18n.t("ui.messagePart.title.write")} count={path() ? 1 : 0}>
+          <Show when={path()}>
+            <ToolFileAccordion
+              path={path()}
+              defaultOpen={props.defaultOpen}
+              open={props.open}
+              onOpenChange={props.onOpenChange}
+              forceOpen={props.forceOpen}
+              defer={props.deferContent !== false}
+            >
               <div data-component="write-content">
                 <Dynamic
                   component={fileComponent}
@@ -1862,7 +1865,7 @@ ToolRegistry.register({
             </ToolFileAccordion>
           </Show>
           <DiagnosticsDisplay diagnostics={diagnostics()} />
-        </BasicTool>
+        </FileTool>
       </div>
     )
   },
@@ -1891,27 +1894,9 @@ ToolRegistry.register({
       files().forEach((file) => props.onFileOpenChange?.(file.path, next.includes(file.path)))
     }
 
-    const subtitle = createMemo(() => {
-      const count = files().length
-      if (count === 0) return ""
-      return `${count} ${i18n.plural("ui.common.file", count)}`
-    })
-
     return (
       <div data-component="apply-patch-tool">
-        <BasicTool
-          {...props}
-          open
-          onOpenChange={undefined}
-          locked
-          icon="code-lines"
-          defer={false}
-          rail={false}
-          trigger={{
-            title: title(),
-            subtitle: subtitle(),
-          }}
-        >
+        <FileTool {...props} title={title()} count={files().length}>
           <Show when={files().length > 0}>
             <Accordion
               multiple
@@ -2000,7 +1985,7 @@ ToolRegistry.register({
               </Index>
             </Accordion>
           </Show>
-        </BasicTool>
+        </FileTool>
       </div>
     )
   },