fix(app): paste plain text into session titles

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

.github/workflows/test.yml

@@ -112,11 +112,12 @@ jobs:
       - name: Run unit tests
         timeout-minutes: 20
         run: |
+          # The runners have four vCPUs, and each Bun test process performs its own concurrent work.
           if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
-            GITHUB_ACTIONS=false bun turbo test
+            GITHUB_ACTIONS=false bun turbo test --concurrency=3
             exit 0
           fi
-          GITHUB_ACTIONS=false bun turbo test --affected
+          GITHUB_ACTIONS=false bun turbo test --affected --concurrency=3
         env:
           OPENCODE_EXPERIMENTAL_DISABLE_FILEWATCHER: ${{ runner.os == 'Windows' && 'true' || 'false' }}
           TURBO_SCM_BASE: ${{ github.event_name == 'pull_request' && format('{0}^1', github.sha) || github.event.before }}

bun.lock

@@ -32,7 +32,7 @@
     },
     "packages/ai": {
       "name": "@opencode/ai",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@aws-sdk/credential-providers": "3.1057.0",
         "@opencode/schema": "workspace:*",
@@ -54,7 +54,7 @@
     },
     "packages/app": {
       "name": "@opencode/app",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@corvu/drawer": "catalog:",
         "@dnd-kit/abstract": "0.5.0",
@@ -111,7 +111,7 @@
     },
     "packages/cli": {
       "name": "@opencode/cli",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "bin": {
         "opencode2": "./bin/opencode2.cjs",
       },
@@ -175,7 +175,7 @@
     },
     "packages/client": {
       "name": "@opencode/client",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@opencode/protocol": "workspace:*",
         "@opencode/schema": "workspace:*",
@@ -201,7 +201,7 @@
     },
     "packages/codemode": {
       "name": "@opencode/codemode",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "acorn": "8.15.0",
         "effect": "catalog:",
@@ -214,7 +214,7 @@
     },
     "packages/console/app": {
       "name": "@opencode/console-app",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@cloudflare/vite-plugin": "1.15.2",
         "@ibm/plex": "6.4.1",
@@ -250,7 +250,7 @@
     },
     "packages/console/core": {
       "name": "@opencode/console-core",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@aws-sdk/client-sts": "3.782.0",
         "@jsx-email/render": "1.1.1",
@@ -277,7 +277,7 @@
     },
     "packages/console/function": {
       "name": "@opencode/console-function",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@openauthjs/openauth": "0.0.0-20250322224806",
         "@opencode/console-core": "workspace:*",
@@ -294,7 +294,7 @@
     },
     "packages/console/mail": {
       "name": "@opencode/console-mail",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@jsx-email/all": "2.2.3",
         "@jsx-email/cli": "1.4.3",
@@ -318,7 +318,7 @@
     },
     "packages/console/support": {
       "name": "@opencode/console-support",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@cloudflare/vite-plugin": "1.15.2",
         "@opencode/console-core": "workspace:*",
@@ -338,7 +338,7 @@
     },
     "packages/core": {
       "name": "@opencode/core",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@ai-sdk/cohere": "3.0.27",
         "@ai-sdk/gateway": "3.0.104",
@@ -406,10 +406,10 @@
     },
     "packages/desktop": {
       "name": "@opencode/desktop",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@zip.js/zip.js": "2.7.62",
-        "electron-context-menu": "4.1.2",
+        "electron-context-menu": "5.0.0",
         "electron-log": "^5",
         "electron-updater": "6.8.9",
         "lighthouse": "13.4.1",
@@ -436,7 +436,7 @@
         "drizzle-kit": "catalog:",
         "drizzle-orm": "catalog:",
         "effect": "catalog:",
-        "electron": "42.10.1",
+        "electron": "44.4.3",
         "electron-builder": "26.15.7",
         "electron-vite": "6.0.0-beta.1",
         "puppeteer-core": "25.9.0",
@@ -455,7 +455,7 @@
     },
     "packages/enterprise": {
       "name": "@opencode/enterprise",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@hono/standard-validator": "catalog:",
         "@opencode-ai/sdk": "1.18.21",
@@ -492,7 +492,7 @@
     },
     "packages/function": {
       "name": "@opencode/function",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@octokit/auth-app": "8.0.1",
         "@octokit/rest": "catalog:",
@@ -508,7 +508,7 @@
     },
     "packages/http-recorder": {
       "name": "@opencode/http-recorder",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@effect/platform-node-shared": "4.0.0-rc.112",
       },
@@ -527,7 +527,7 @@
     },
     "packages/httpapi-codegen": {
       "name": "@opencode/httpapi-codegen",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "effect": "catalog:",
         "prettier": "3.6.2",
@@ -540,7 +540,7 @@
     },
     "packages/latex": {
       "name": "@opencode/latex",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@opencode/plugin": "workspace:*",
         "@opentui/core": "catalog:",
@@ -554,7 +554,7 @@
     },
     "packages/merman": {
       "name": "@opencode/merman",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@opencode/plugin": "workspace:*",
         "@opentui/core": "catalog:",
@@ -569,7 +569,7 @@
     },
     "packages/plugin": {
       "name": "@opencode/plugin",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@ai-sdk/provider": "3.0.8",
         "@opencode/ai": "workspace:*",
@@ -608,7 +608,7 @@
     },
     "packages/plugin-browser": {
       "name": "@opencode/plugin-browser",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@opencode/plugin": "workspace:*",
         "@opencode/schema": "workspace:*",
@@ -638,7 +638,7 @@
     },
     "packages/protocol": {
       "name": "@opencode/protocol",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@opencode/schema": "workspace:*",
         "effect": "catalog:",
@@ -653,7 +653,7 @@
     },
     "packages/schema": {
       "name": "@opencode/schema",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@standard-schema/spec": "catalog:",
         "effect": "catalog:",
@@ -677,7 +677,7 @@
     },
     "packages/sdk": {
       "name": "@opencode/sdk",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@opencode/client": "workspace:*",
         "@opencode/core": "workspace:*",
@@ -698,7 +698,7 @@
     },
     "packages/server": {
       "name": "@opencode/server",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@effect/platform-node": "catalog:",
         "@effect/platform-node-shared": "catalog:",
@@ -720,7 +720,7 @@
     },
     "packages/session-ui": {
       "name": "@opencode/session-ui",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@kobalte/core": "catalog:",
         "@opencode/client": "workspace:*",
@@ -755,7 +755,7 @@
     },
     "packages/simulation": {
       "name": "@opencode/simulation",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@opencode/ai": "workspace:*",
         "@opencode/core": "workspace:*",
@@ -775,7 +775,7 @@
     },
     "packages/stats/app": {
       "name": "@opencode/stats-app",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@ibm/plex": "6.4.1",
         "@kobalte/core": "catalog:",
@@ -809,7 +809,7 @@
     },
     "packages/stats/core": {
       "name": "@opencode/stats-core",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@aws-sdk/client-athena": "3.933.0",
         "@planetscale/database": "1.19.0",
@@ -828,7 +828,7 @@
     },
     "packages/stats/server": {
       "name": "@opencode/stats-server",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@aws-sdk/client-firehose": "3.933.0",
         "@effect/platform-node": "catalog:",
@@ -874,7 +874,7 @@
     },
     "packages/theme": {
       "name": "@opencode/theme",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@opentui/core": "catalog:",
         "effect": "catalog:",
@@ -888,7 +888,7 @@
     },
     "packages/tui": {
       "name": "@opencode/tui",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@opencode/client": "workspace:*",
         "@opencode/core": "workspace:*",
@@ -923,7 +923,7 @@
     },
     "packages/ui": {
       "name": "@opencode/ui",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@kobalte/core": "catalog:",
         "@pierre/diffs": "catalog:",
@@ -958,7 +958,7 @@
     },
     "packages/util": {
       "name": "@opencode/util",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@effect/opentelemetry": "catalog:",
         "@effect/platform-node": "catalog:",
@@ -991,7 +991,7 @@
     },
     "packages/web": {
       "name": "@opencode/web",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "@astrojs/cloudflare": "12.6.3",
         "@astrojs/markdown-remark": "6.3.1",
@@ -1032,7 +1032,7 @@
     },
     "services/update": {
       "name": "@opencode/update",
-      "version": "2.0.10",
+      "version": "2.0.12",
       "dependencies": {
         "jose": "6.0.11",
         "semver": "catalog:",
@@ -3880,13 +3880,13 @@
 
     "ejs": ["ejs@3.1.10", "", { "dependencies": { "jake": "^10.8.5" }, "bin": { "ejs": "bin/cli.js" } }, "sha512-UeJmFfOrAQS8OJWPZ4qtgHyWExa088/MtK5UEyoJGFH67cDEXkZSviOiKRCZ4Xij0zxI3JECgYs3oKx+AizQBA=="],
 
-    "electron": ["electron@42.10.1", "", { "dependencies": { "@electron-internal/extract-zip": "^1.0.1", "@electron/get": "^5.0.0", "@types/node": "^24.9.0" }, "bin": { "electron": "cli.js", "install-electron": "install.js" } }, "sha512-ITc1HPeoDzsxCCaH6MFsN67Nq2nUiJf5N9pBWxzhUpFfKJF0IwiAkKT3emg1lPbvC4OfFE+Cdwe4vhgdOZ1YKg=="],
+    "electron": ["electron@44.4.3", "", { "dependencies": { "@electron-internal/extract-zip": "^1.0.1", "@electron/get": "^5.0.0", "@types/node": "^24.9.0" }, "bin": { "electron": "cli.js", "install-electron": "install.js" } }, "sha512-LTpSFTB40qVCXIX5xMo+cgHI/Jjkbjw7VpB26PccEbroqOn72LBukeaDwPVo1fBYzSzs0c9iPuAucFCO7Tw81Q=="],
 
     "electron-builder": ["electron-builder@26.15.7", "", { "dependencies": { "app-builder-lib": "26.15.7", "builder-util": "26.15.3", "builder-util-runtime": "9.7.0", "chalk": "^4.1.2", "ci-info": "^4.2.0", "dmg-builder": "26.15.7", "fs-extra": "^10.1.0", "lazy-val": "^1.0.5", "simple-update-notifier": "2.0.0", "yargs": "^17.6.2" }, "bin": { "electron-builder": "./cli.js", "install-app-deps": "./install-app-deps.js" } }, "sha512-DBpaNzxsPs1BvEblzFoNriSbzsBqDCy/gseIngeEhYzQG1IxfB7Hvc2tBBVmpWE2BTQGP9J1RrAvDT+Vc/uAxg=="],
 
     "electron-builder-squirrel-windows": ["electron-builder-squirrel-windows@26.15.7", "", { "dependencies": { "app-builder-lib": "26.15.7", "builder-util": "26.15.3", "electron-winstaller": "5.4.0" } }, "sha512-B4uvn2NzFSuf084udWqugludFull6CRJiWe2dLzMnZLl6G5hdAGk0fsBMGlBSpKjvQCJn8IPc+S7OnJ+GXqwLA=="],
 
-    "electron-context-menu": ["electron-context-menu@4.1.2", "", { "dependencies": { "cli-truncate": "^4.0.0", "electron-dl": "^4.0.0", "electron-is-dev": "^3.0.1" } }, "sha512-9xYTUV0oRqKL50N9W71IrXNdVRB0LuBp3R1zkUdUc2wfIa2/QZwYYj5RLuO7Tn7ZSLVIaO3X6u+EIBK+cBvzrQ=="],
+    "electron-context-menu": ["electron-context-menu@5.0.0", "", { "dependencies": { "cli-truncate": "^4.0.0", "electron-dl": "^4.0.0", "electron-is-dev": "^3.0.1" } }, "sha512-rgFpRtwY0/rhsRCoz9rE6VM4WueEsLbIpca7ucOhERVrbGB2dQrxa9xwBNLplU54jRgPuv6nTEbxoplE5bzy2A=="],
 
     "electron-dl": ["electron-dl@4.0.0", "", { "dependencies": { "ext-name": "^5.0.0", "pupa": "^3.1.0", "unused-filename": "^4.0.1" } }, "sha512-USiB9816d2JzKv0LiSbreRfTg5lDk3lWh0vlx/gugCO92ZIJkHVH0UM18EHvKeadErP6Xn4yiTphWzYfbA2Ong=="],
 

nix/hashes.json

@@ -1,8 +1,8 @@
 {
   "nodeModules": {
-    "x86_64-linux": "sha256-8mOzCscBAuogG4tm8CroqjTX5E5yzCvTobbhKvxQP0U=",
-    "aarch64-linux": "sha256-drrRSpzxC8bfaTXBpOyaN0QAyBVV7WJzm0NstJ+8sAE=",
-    "aarch64-darwin": "sha256-YY5A/zxLPONvgnI+DZlzcD2K5Q9PIw4F2YbDxKbT4UU=",
-    "x86_64-darwin": "sha256-/c/Ew4onA+9+l6GRKXz3zWq3QFESM7j5RyGLCWRPQFw="
+    "x86_64-linux": "sha256-8hc0Typ9cA1NDpToM0Pq7q3AutSp+I80Sakthq10F4c=",
+    "aarch64-linux": "sha256-7bzI4zWOdxuoMdMHMuqIAOgnuzWiHmpdCMYCYPbs+3c=",
+    "aarch64-darwin": "sha256-EWDHUSVH2AjsNvoKvzC392H6GjCWVh07cOg2x0mAsng=",
+    "x86_64-darwin": "sha256-7b2BRdRRVG+PMCSd/cm4E+slziwWIKLVttYkotdSrK4="
   }
 }

package.json

@@ -2,7 +2,7 @@
   "$schema": "https://json.schemastore.org/package.json",
   "name": "opencode",
   "description": "AI-powered development tool",
-  "version": "2.0.10",
+  "version": "2.0.12",
   "private": true,
   "type": "module",
   "packageManager": "bun@1.4.2",

packages/ai/README.md

@@ -29,6 +29,47 @@ await Effect.runPromise(program.pipe(Effect.provide(llmLayer)))
 
 Run `LLMClient.stream(request)` instead of `generate` when you want incremental `LLMEvent`s. The event stream is provider-neutral — same shape across OpenAI Chat, OpenAI Responses, Anthropic Messages, Gemini, Bedrock Converse, and any OpenAI-compatible deployment.
 
+## Experimental evaluation
+
+Evaluation models compare shared state with typed choice, score, and boolean questions. The API is
+isolated under an experimental entrypoint and provider namespace while the contract evolves:
+
+```ts
+import { Effect } from "effect"
+import { Evaluation, EvaluationClient } from "@opencode/ai/experimental"
+import { TypeSafeAI } from "@opencode/ai/providers"
+
+const model = TypeSafeAI.configure().experimental.evaluation("jev-latest")
+
+const program = Evaluation.evaluate({
+  model,
+  state: "I was charged twice. Please refund the duplicate payment.",
+  questions: {
+    department: {
+      type: "choice",
+      instructions: "Which team should handle this?",
+      criteria: { billing: "Payments and refunds", technical: "Bugs and outages" },
+    },
+    urgency: {
+      type: "score",
+      instructions: "How urgent is this?",
+      criteria: ["Can wait", "Needs prompt attention", "Blocking revenue"],
+    },
+    refund: { type: "boolean", instructions: "Is the customer asking for a refund?" },
+  },
+})
+
+const response = await Effect.runPromise(program.pipe(Effect.provide(EvaluationClient.fetchLayer)))
+
+console.log(response.answers.department.choice)
+console.log(response.answers.refund.probability)
+```
+
+`TypeSafeAI` reads `TYPESAFE_API_KEY`. `OpenCodeZen` exposes the same selector and reads
+`OPENCODE_API_KEY`. The common API uses `boolean`; System One routes lower it to native `noul`.
+Choice and score confidence plus score legends remain available in provider metadata, and the
+provider's rounded probabilities are returned unchanged.
+
 ## Alibaba Cloud Model Studio
 
 `Alibaba` provides standard Model Studio inference. Configure a region explicitly, then select

packages/ai/package.json

@@ -1,6 +1,6 @@
 {
   "$schema": "https://json.schemastore.org/package.json",
-  "version": "2.0.10",
+  "version": "2.0.12",
   "name": "@opencode/ai",
   "type": "module",
   "license": "MIT",

packages/ai/src/experimental.ts

@@ -0,0 +1,29 @@
+export { EvaluationClient } from "./experimental/evaluation-client.js"
+export {
+  BooleanAnswer,
+  BooleanQuestion,
+  ChoiceAnswer,
+  ChoiceQuestion,
+  Evaluation,
+  EvaluationAnswer,
+  EvaluationInput,
+  EvaluationModel,
+  EvaluationModelSchema,
+  EvaluationQuestion,
+  EvaluationRequest,
+  EvaluationResponse,
+  EvaluationRounding,
+  ScoreAnswer,
+  ScoreQuestion,
+} from "./experimental/evaluation.js"
+export type {
+  AnswerFor,
+  AnswersFor,
+  EvaluationModelOptions,
+  EvaluationOptions,
+  EvaluationQuestions,
+  EvaluationRequestFor,
+  EvaluationRequestInput,
+  EvaluationResponseFor,
+  EvaluationRoute,
+} from "./experimental/evaluation.js"

packages/ai/src/experimental/evaluation-client.ts

@@ -0,0 +1,54 @@
+import { Context, Effect, Layer } from "effect"
+import { RequestExecutor } from "../route/executor.js"
+import { mergeHttpOptions, type AIError } from "../schema/index.js"
+import { sanitizeSurrogates } from "../utils/sanitize.js"
+import {
+  type EvaluationOptions,
+  type EvaluationQuestions,
+  type EvaluationRequestFor,
+  type EvaluationResponseFor,
+} from "./evaluation.js"
+
+export type Execute = RequestExecutor.Interface["execute"]
+
+export interface Interface {
+  readonly evaluate: <Options extends EvaluationOptions, const Questions extends EvaluationQuestions>(
+    request: EvaluationRequestFor<Options, Questions>,
+  ) => Effect.Effect<EvaluationResponseFor<Questions>, AIError>
+}
+
+export class Service extends Context.Service<Service, Interface>()("@opencode/AI/Experimental/EvaluationClient") {}
+
+export const evaluate = <Options extends EvaluationOptions, const Questions extends EvaluationQuestions>(
+  request: EvaluationRequestFor<Options, Questions>,
+): Effect.Effect<EvaluationResponseFor<Questions>, AIError, Service> =>
+  Effect.flatMap(Service, (client) => client.evaluate(request))
+
+export const layer: Layer.Layer<Service, never, RequestExecutor.Service> = Layer.effect(
+  Service,
+  Effect.gen(function* () {
+    const executor = yield* RequestExecutor.Service
+    return Service.of({
+      evaluate: (request) =>
+        request.model.route.evaluate(
+          {
+            ...sanitizeSurrogates({
+              ...request,
+              model: undefined,
+              http: mergeHttpOptions(request.model.http, request.http),
+            }),
+            model: request.model,
+          },
+          executor.execute,
+        ),
+    })
+  }),
+)
+export const fetchLayer = layer.pipe(Layer.provide(RequestExecutor.fetchLayer))
+
+export const EvaluationClient = {
+  Service,
+  layer,
+  fetchLayer,
+  evaluate,
+} as const

packages/ai/src/experimental/evaluation.ts

@@ -0,0 +1,245 @@
+import { Effect, Schema } from "effect"
+import {
+  AIError,
+  HttpOptions,
+  InvalidRequestError,
+  ModelID,
+  ProviderID,
+  ProviderMetadata,
+  Usage,
+} from "../schema/index.js"
+import { EvaluationClient, Service, type Execute } from "./evaluation-client.js"
+
+export const EvaluationInput = Schema.Union([Schema.String, Schema.JsonObject, Schema.Array(Schema.Json)])
+export type EvaluationInput = Schema.Schema.Type<typeof EvaluationInput>
+
+const EvaluationCriterion = Schema.NullOr(EvaluationInput)
+const ChoiceCriteria = Schema.Record(Schema.String, EvaluationCriterion).pipe(
+  Schema.refine((x): x is typeof x => Object.keys(x).length > 0, {
+    message: "Choice criteria must be a nonempty option map",
+  }),
+)
+
+export const ChoiceQuestion = Schema.Struct({
+  type: Schema.Literal("choice"),
+  instructions: EvaluationInput,
+  criteria: ChoiceCriteria,
+})
+export type ChoiceQuestion = Schema.Schema.Type<typeof ChoiceQuestion>
+
+export const ScoreQuestion = Schema.Struct({
+  type: Schema.Literal("score"),
+  instructions: EvaluationInput,
+  criteria: Schema.Array(EvaluationCriterion).check(Schema.isMinLength(2)),
+})
+export type ScoreQuestion = Schema.Schema.Type<typeof ScoreQuestion>
+
+export const BooleanQuestion = Schema.Struct({
+  type: Schema.Literal("boolean"),
+  instructions: EvaluationInput,
+  criteria: Schema.optional(
+    Schema.Struct({
+      true: Schema.optional(EvaluationCriterion),
+      false: Schema.optional(EvaluationCriterion),
+    }),
+  ),
+})
+export type BooleanQuestion = Schema.Schema.Type<typeof BooleanQuestion>
+
+export const EvaluationQuestion = Schema.Union([ChoiceQuestion, ScoreQuestion, BooleanQuestion]).pipe(
+  Schema.toTaggedUnion("type"),
+)
+export type EvaluationQuestion = Schema.Schema.Type<typeof EvaluationQuestion>
+export type EvaluationQuestions = Readonly<Record<string, EvaluationQuestion>>
+const EvaluationQuestions = Schema.Record(Schema.String, EvaluationQuestion).pipe(
+  Schema.refine((x): x is typeof x => Object.keys(x).length > 0, {
+    message: "Evaluation questions must be a nonempty map",
+  }),
+)
+
+const Probability = Schema.Number.check(Schema.isBetween({ minimum: 0, maximum: 1 }))
+
+export const ChoiceAnswer = Schema.Struct({
+  type: Schema.Literal("choice"),
+  choice: Schema.String,
+  probabilities: Schema.optional(Schema.Record(Schema.String, Probability)),
+})
+export type ChoiceAnswer = Schema.Schema.Type<typeof ChoiceAnswer>
+
+export const ScoreAnswer = Schema.Struct({
+  type: Schema.Literal("score"),
+  score: Schema.Number,
+  probabilities: Schema.optional(Schema.Record(Schema.String, Probability)),
+})
+export type ScoreAnswer = Schema.Schema.Type<typeof ScoreAnswer>
+
+export const BooleanAnswer = Schema.Struct({
+  type: Schema.Literal("boolean"),
+  probability: Probability,
+})
+export type BooleanAnswer = Schema.Schema.Type<typeof BooleanAnswer>
+
+export const EvaluationAnswer = Schema.Union([ChoiceAnswer, ScoreAnswer, BooleanAnswer]).pipe(
+  Schema.toTaggedUnion("type"),
+)
+export type EvaluationAnswer = Schema.Schema.Type<typeof EvaluationAnswer>
+
+export type AnswerFor<Question extends EvaluationQuestion> = Question extends {
+  readonly type: "choice"
+  readonly criteria: infer Criteria
+}
+  ? {
+      readonly type: "choice"
+      readonly choice: Extract<keyof Criteria, string>
+      readonly probabilities?: Readonly<Record<Extract<keyof Criteria, string>, number>>
+    }
+  : Question extends { readonly type: "score" }
+    ? ScoreAnswer
+    : BooleanAnswer
+
+export type AnswersFor<Questions extends EvaluationQuestions> = {
+  readonly [ID in keyof Questions]: AnswerFor<Questions[ID]>
+}
+
+export type EvaluationOptions = Record<string, unknown>
+
+export interface EvaluationRoute<Options extends EvaluationOptions = EvaluationOptions> {
+  readonly id: string
+  readonly evaluate: <const Questions extends EvaluationQuestions>(
+    request: EvaluationRequestFor<Options, Questions>,
+    execute: Execute,
+  ) => Effect.Effect<EvaluationResponseFor<Questions>, AIError>
+}
+
+export class EvaluationModel<Options extends EvaluationOptions = EvaluationOptions> {
+  declare protected readonly _Options: (options: Options) => Options
+  readonly id: ModelID
+  readonly provider: ProviderID
+  readonly route: EvaluationRoute<Options>
+  readonly http?: HttpOptions
+
+  constructor(input: EvaluationModel.Input<Options>) {
+    this.id = input.id
+    this.provider = input.provider
+    this.route = input.route
+    this.http = input.http
+  }
+
+  static make<Options extends EvaluationOptions = EvaluationOptions>(input: EvaluationModel.MakeInput<Options>) {
+    return new EvaluationModel<Options>({
+      id: ModelID.make(input.id),
+      provider: ProviderID.make(input.provider),
+      route: input.route,
+      http: input.http,
+    })
+  }
+}
+
+export namespace EvaluationModel {
+  export interface Input<Options extends EvaluationOptions = EvaluationOptions> {
+    readonly id: ModelID
+    readonly provider: ProviderID
+    readonly route: EvaluationRoute<Options>
+    readonly http?: HttpOptions
+  }
+
+  export interface MakeInput<Options extends EvaluationOptions = EvaluationOptions>
+    extends Omit<Input<Options>, "id" | "provider"> {
+    readonly id: string | ModelID
+    readonly provider: string | ProviderID
+  }
+}
+
+export const EvaluationModelSchema = Schema.declare(
+  (value): value is EvaluationModel => value instanceof EvaluationModel,
+  {
+    expected: "Evaluation.Model",
+  },
+)
+
+export class EvaluationRequest extends Schema.Class<EvaluationRequest>("Evaluation.Request")({
+  model: EvaluationModelSchema,
+  state: EvaluationInput,
+  questions: EvaluationQuestions,
+  options: Schema.optional(Schema.Record(Schema.String, Schema.Unknown)),
+  http: Schema.optional(HttpOptions),
+}) {
+  declare protected readonly _EvaluationRequest: void
+}
+
+export type EvaluationModelOptions<Model> = Model extends EvaluationModel<infer Options> ? Options : never
+
+export type EvaluationRequestFor<
+  Options extends EvaluationOptions = EvaluationOptions,
+  Questions extends EvaluationQuestions = EvaluationQuestions,
+> = Omit<EvaluationRequest, "model" | "questions" | "options"> & {
+  readonly model: EvaluationModel<Options>
+  readonly questions: Questions
+  readonly options?: Options
+}
+
+export type EvaluationRequestInput<
+  Model extends object = EvaluationModel,
+  Questions extends EvaluationQuestions = EvaluationQuestions,
+> = Omit<ConstructorParameters<typeof EvaluationRequest>[0], "model" | "questions" | "options" | "http"> & {
+  readonly model: Model
+  readonly questions: Questions
+  readonly options?: NoInfer<EvaluationModelOptions<Model>>
+  readonly http?: HttpOptions.Input
+} & (Model extends EvaluationModel<EvaluationModelOptions<Model>> ? unknown : never)
+
+export class EvaluationRounding extends Schema.Class<EvaluationRounding>("Evaluation.Rounding")({
+  probabilityDecimals: Schema.optional(Schema.Int),
+  scoreDecimals: Schema.optional(Schema.Int),
+}) {}
+
+export class EvaluationResponse extends Schema.Class<EvaluationResponse>("Evaluation.Response")({
+  model: ModelID,
+  answers: Schema.Record(Schema.String, EvaluationAnswer),
+  usage: Schema.optional(Usage),
+  rounding: Schema.optional(EvaluationRounding),
+  providerMetadata: Schema.optional(ProviderMetadata),
+}) {}
+
+export type EvaluationResponseFor<Questions extends EvaluationQuestions> = Omit<EvaluationResponse, "answers"> & {
+  readonly answers: AnswersFor<Questions>
+}
+
+export function request<const Model extends object, const Questions extends EvaluationQuestions>(
+  input: EvaluationRequestInput<Model, Questions>,
+): EvaluationRequestFor<EvaluationModelOptions<Model>, Questions>
+export function request(input: EvaluationRequest): EvaluationRequest
+export function request(input: EvaluationRequest | EvaluationRequestInput) {
+  if (input instanceof EvaluationRequest) return input
+  return new EvaluationRequest({
+    ...input,
+    model: input.model as unknown as EvaluationModel,
+    http: input.http === undefined ? undefined : HttpOptions.make(input.http),
+  })
+}
+
+export function evaluate<const Model extends object, const Questions extends EvaluationQuestions>(
+  input: EvaluationRequestInput<Model, Questions>,
+): Effect.Effect<EvaluationResponseFor<Questions>, AIError, Service>
+export function evaluate(input: EvaluationRequest): Effect.Effect<EvaluationResponse, AIError, Service>
+export function evaluate(input: EvaluationRequest | EvaluationRequestInput) {
+  return Effect.try({
+    try: () => (input instanceof EvaluationRequest ? input : request(input)),
+    catch: (cause) =>
+      new AIError({
+        reason: new InvalidRequestError({
+          message: cause instanceof Error ? cause.message : String(cause),
+          cause,
+        }),
+      }),
+  }).pipe(
+    Effect.flatMap((request) =>
+      EvaluationClient.evaluate(request as EvaluationRequestFor<EvaluationOptions, EvaluationQuestions>),
+    ),
+  )
+}
+
+export const Evaluation = {
+  request,
+  evaluate,
+} as const

packages/ai/src/experimental/system-one.ts

@@ -0,0 +1,222 @@
+import { Effect, Schema } from "effect"
+import { Headers, HttpClientRequest } from "effect/unstable/http"
+import {
+  BooleanAnswer,
+  ChoiceAnswer,
+  ChoiceQuestion,
+  EvaluationInput,
+  EvaluationModel,
+  EvaluationResponse,
+  EvaluationRounding,
+  ScoreAnswer,
+  ScoreQuestion,
+  type EvaluationResponseFor,
+  type EvaluationRoute,
+} from "./evaluation.js"
+import { Auth, type Definition as AuthDefinition } from "../route/auth.js"
+import {
+  AIError,
+  HttpContext,
+  HttpOptions,
+  InvalidProviderOutputError,
+  InvalidRequestError,
+  ModelID,
+  Usage,
+  mergeJsonRecords,
+} from "../schema/index.js"
+
+const Noul = Schema.Struct({
+  type: Schema.Literal("noul"),
+  instructions: EvaluationInput,
+  criteria: Schema.optional(
+    Schema.Struct({
+      true: Schema.optional(Schema.NullOr(EvaluationInput)),
+      false: Schema.optional(Schema.NullOr(EvaluationInput)),
+    }),
+  ),
+})
+const Question = Schema.Union([
+  ChoiceQuestion.pipe(
+    Schema.refine((x): x is typeof x => Object.keys(x.criteria).length <= 255, {
+      message: "System One Choice questions support at most 255 options",
+    }),
+  ),
+  ScoreQuestion.pipe(
+    Schema.refine((x): x is typeof x => x.criteria.length <= 10, {
+      message: "System One Score questions support at most 10 levels",
+    }),
+  ),
+  Noul,
+])
+const Request = Schema.StructWithRest(
+  Schema.Struct({
+    model: Schema.String,
+    state: EvaluationInput,
+    questions: Schema.Record(Schema.String, Question),
+  }),
+  [Schema.Record(Schema.String, Schema.Any)],
+)
+
+const Probability = Schema.Number.check(Schema.isBetween({ minimum: 0, maximum: 1 }))
+const NoulAnswer = Schema.Struct({ type: Schema.Literal("noul"), noul: Probability })
+const Choice = Schema.Struct({
+  type: Schema.Literal("choice"),
+  choice: Schema.String,
+  probabilities: Schema.Record(Schema.String, Probability),
+  confidence: Schema.optional(Probability),
+})
+const Score = Schema.Struct({
+  type: Schema.Literal("score"),
+  score: Schema.Number,
+  probabilities: Schema.Record(Schema.String, Probability),
+  legend: Schema.optional(Schema.Record(Schema.String, Schema.Json)),
+  confidence: Schema.optional(Probability),
+})
+const NativeUsage = Schema.Struct({
+  input_tokens: Schema.optional(Schema.Number),
+  output_tokens: Schema.optional(Schema.Number),
+})
+
+const encode = Schema.encodeUnknownEffect(Schema.fromJsonString(Request))
+const exact = (x: Readonly<Record<string, unknown>>, keys: ReadonlyArray<string>) =>
+  Object.keys(x).length === keys.length && keys.every((key) => Object.hasOwn(x, key))
+
+export interface ModelInput {
+  readonly id: string | ModelID
+  readonly provider: string
+  readonly providerMetadataKey: string
+  readonly auth: AuthDefinition
+  readonly baseURL: string
+  readonly headers?: Record<string, string>
+  readonly http?: HttpOptions
+}
+
+export const model = (cfg: ModelInput) => {
+  const route: EvaluationRoute = {
+    id: "system-one",
+    evaluate: (req, send) =>
+      Effect.gen(function* () {
+        const url = new URL(`${cfg.baseURL.replace(/\/$/, "")}/systemone`)
+        Object.entries(req.http?.query ?? {}).forEach(([key, value]) => url.searchParams.set(key, value))
+        const body = yield* encode({
+          ...mergeJsonRecords(req.options, req.http?.body),
+          model: req.model.id,
+          state: req.state,
+          questions: Object.fromEntries(
+            Object.entries(req.questions).map(([id, x]) => [id, x.type === "boolean" ? { ...x, type: "noul" } : x]),
+          ),
+        }).pipe(
+          Effect.mapError(
+            (cause) => new AIError({ reason: new InvalidRequestError({ message: cause.message, cause }) }),
+          ),
+        )
+        const headers = yield* Auth.toEffect(cfg.auth)({
+          request: req,
+          method: "POST",
+          url: url.toString(),
+          body,
+          headers: Headers.fromInput({ ...cfg.headers, ...req.http?.headers }),
+        })
+        const res = yield* send(
+          HttpClientRequest.post(url).pipe(
+            HttpClientRequest.setHeaders(headers),
+            HttpClientRequest.bodyText(body, "application/json"),
+          ),
+        )
+        const http = new HttpContext({ url: res.request.url, status: res.status, headers: res.headers })
+        const fail = (message: string, cause: unknown, body?: string) =>
+          new AIError({ reason: new InvalidProviderOutputError({ route: route.id, message, body, http, cause }) })
+        const text = yield* res.text.pipe(
+          Effect.mapError((cause) => fail("Failed to read the System One response", cause)),
+        )
+        const entries = Object.entries(req.questions)
+        const output = Schema.Struct({
+          model: Schema.String,
+          answers: Schema.Struct(
+            Object.fromEntries(
+              entries.map(([id, question]) => {
+                if (question.type === "boolean") return [id, NoulAnswer]
+                if (question.type === "choice") {
+                  const keys = Object.keys(question.criteria)
+                  return [
+                    id,
+                    Choice.pipe(
+                      Schema.refine(
+                        (x): x is typeof x =>
+                          Object.hasOwn(question.criteria, x.choice) && exact(x.probabilities, keys),
+                        { message: `Question "${id}" returned an invalid choice answer` },
+                      ),
+                    ),
+                  ]
+                }
+                const keys = question.criteria.map((_, index) => String(index))
+                return [
+                  id,
+                  Score.pipe(
+                    Schema.refine(
+                      (x): x is typeof x =>
+                        x.score >= 0 && x.score <= question.criteria.length - 1 && exact(x.probabilities, keys),
+                      { message: `Question "${id}" returned an invalid score answer` },
+                    ),
+                  ),
+                ]
+              }),
+            ) as Record<string, Schema.Codec<unknown>>,
+          ),
+          usage: Schema.optional(NativeUsage),
+        })
+        const data = yield* Schema.decodeUnknownEffect(Schema.fromJsonString(output))(text).pipe(
+          Effect.mapError((cause) => fail("System One returned an invalid response", cause, text)),
+        )
+
+        const confidence: Record<string, number> = {}
+        const legend: Record<string, Record<string, Schema.Json>> = {}
+        const answers = Object.fromEntries(
+          entries.map(([id, question]) => {
+            const answer = data.answers[id]
+            if (question.type === "boolean")
+              return [
+                id,
+                { type: "boolean", probability: (answer as typeof NoulAnswer.Type).noul } satisfies BooleanAnswer,
+              ]
+            if (question.type === "choice") {
+              const value = answer as typeof Choice.Type
+              if (value.confidence !== undefined) confidence[id] = value.confidence
+              return [
+                id,
+                { type: "choice", choice: value.choice, probabilities: value.probabilities } satisfies ChoiceAnswer,
+              ]
+            }
+            const value = answer as typeof Score.Type
+            if (value.confidence !== undefined) confidence[id] = value.confidence
+            if (value.legend !== undefined) legend[id] = value.legend
+            return [id, { type: "score", score: value.score, probabilities: value.probabilities } satisfies ScoreAnswer]
+          }),
+        )
+        const meta = {
+          ...(Object.keys(confidence).length === 0 ? {} : { confidence }),
+          ...(Object.keys(legend).length === 0 ? {} : { legend }),
+        }
+        return new EvaluationResponse({
+          model: ModelID.make(data.model),
+          answers,
+          usage: data.usage
+            ? new Usage({
+                inputTokens: data.usage.input_tokens,
+                outputTokens: data.usage.output_tokens,
+                totalTokens:
+                  data.usage.input_tokens === undefined && data.usage.output_tokens === undefined
+                    ? undefined
+                    : (data.usage.input_tokens ?? 0) + (data.usage.output_tokens ?? 0),
+                providerMetadata: { [cfg.providerMetadataKey]: data.usage },
+              })
+            : undefined,
+          rounding: new EvaluationRounding({ probabilityDecimals: 2, scoreDecimals: 2 }),
+          providerMetadata: Object.keys(meta).length === 0 ? undefined : { [cfg.providerMetadataKey]: meta },
+        }) as EvaluationResponseFor<typeof req.questions>
+      }),
+  }
+  return EvaluationModel.make({ id: cfg.id, provider: cfg.provider, route, http: cfg.http })
+}
+
+export const SystemOne = { model } as const

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

@@ -73,11 +73,6 @@ const driver = (options: Options, body: string): WebSocketChannelDriver => {
           )
         if (event.type === "error") {
           terminal = true
-          yield* OpenResponses.decodeKnownErrorEvent(event).pipe(
-            Effect.mapError((cause) =>
-              ProviderShared.eventError(options.id, `${options.name} returned a malformed error event`, frame, cause),
-            ),
-          )
           return {
             type: "provider-failure",
             error: OpenResponses.providerFailure(event, `${options.name} stream error`, frame),

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

@@ -108,7 +108,7 @@ const incremental = (
   return input.slice(baseline.length)
 }
 
-const code = (event: OpenResponses.Event) => event.code || event.error?.code || event.response?.error?.code || undefined
+const code = (event: OpenResponses.Event) => OpenResponses.errorDetail(event).code
 
 const rejected = (
   observation: Extract<ChannelObservation, { readonly type: "provider-failure" }>,

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

@@ -1,4 +1,4 @@
-import { Effect, Option, Schema, SchemaGetter } from "effect"
+import { Effect, Option, Schema } from "effect"
 import type { Content } from "@opencode/schema/tool"
 import { HttpTransport } from "../route/transport/index.js"
 import { Protocol } from "../route/protocol.js"
@@ -333,53 +333,13 @@ export const StreamItem = Schema.StructWithRest(
 export type StreamItem = Schema.Schema.Type<typeof StreamItem>
 export type OutputItem = StreamItem & { readonly id: string }
 
-// Responses-compatible providers put streaming error details at the top level or
-// under `error`, and response failures under `response.error`. Accept all three shapes.
+// Responses-compatible providers put error details at the top level, under `error`, or under
+// `response.error`, and gateways reshape them freely: strings, numeric codes, extra fields. Those
+// fields decode as opaque values and `errorDetail` reads them defensively, so an error frame can
+// only fail on invalid JSON and otherwise always classifies with the raw body as the fallback.
 // https://www.openresponses.org/specification
-const OpenResponsesErrorObject = Schema.Struct({
-  type: optionalNull(Schema.String),
-  code: optionalNull(Schema.String),
-  message: optionalNull(Schema.String),
-  param: optionalNull(Schema.String),
-})
-const OpenResponsesErrorPayload = Schema.Union([Schema.String, OpenResponsesErrorObject]).pipe(
-  Schema.decodeTo(OpenResponsesErrorObject, {
-    decode: SchemaGetter.transform((error) => (typeof error === "string" ? { message: error } : error)),
-    encode: SchemaGetter.passthrough(),
-  }),
-)
-type OpenResponsesErrorPayload = Schema.Schema.Type<typeof OpenResponsesErrorPayload>
-
-const WebSocketErrorHeader = Schema.Union([Schema.String, Schema.Number, Schema.Boolean])
-export const WebSocketErrorEvent = Schema.StructWithRest(
-  Schema.Struct({
-    type: Schema.tag("error"),
-    status: Schema.optional(Schema.Number),
-    status_code: Schema.optional(Schema.Number),
-    code: optionalNull(Schema.String),
-    message: Schema.optional(Schema.String),
-    param: optionalNull(Schema.String),
-    error: optionalNull(OpenResponsesErrorPayload),
-    headers: Schema.optional(Schema.Record(Schema.String, WebSocketErrorHeader)),
-  }),
-  [Schema.Record(Schema.String, Schema.Unknown)],
-)
-const decodeWebSocketErrorEvent = Schema.decodeUnknownEffect(WebSocketErrorEvent)
-
-export const decodeKnownErrorEvent = (event: Event) =>
-  decodeWebSocketErrorEvent({
-    ...event,
-    status: typeof event.status === "number" ? event.status : undefined,
-    status_code: typeof event.status_code === "number" ? event.status_code : undefined,
-    headers: ProviderShared.isRecord(event.headers)
-      ? Object.fromEntries(
-          Object.entries(event.headers).filter(
-            (entry): entry is [string, string | number | boolean] =>
-              typeof entry[1] === "string" || typeof entry[1] === "number" || typeof entry[1] === "boolean",
-          ),
-        )
-      : undefined,
-  })
+const asText = (value: unknown) =>
+  typeof value === "string" && value.length > 0 ? value : typeof value === "number" ? String(value) : undefined
 
 export const Event = Schema.StructWithRest(
   Schema.Struct({
@@ -400,31 +360,18 @@ export const Event = Schema.StructWithRest(
           incomplete_details: optionalNull(Schema.Struct({ reason: Schema.optional(Schema.String) })),
           output: Schema.optional(Schema.Array(StreamItem)),
           usage: optionalNull(OpenResponsesUsage),
-          error: optionalNull(OpenResponsesErrorPayload),
+          error: Schema.optional(Schema.Unknown),
         }),
         [Schema.Record(Schema.String, Schema.Unknown)],
       ),
     ),
-    code: optionalNull(Schema.String),
-    message: Schema.optional(Schema.String),
-    param: optionalNull(Schema.String),
-    error: optionalNull(OpenResponsesErrorPayload),
+    code: Schema.optional(Schema.Unknown),
+    message: Schema.optional(Schema.Unknown),
+    error: Schema.optional(Schema.Unknown),
     status: Schema.optional(Schema.Unknown),
     status_code: Schema.optional(Schema.Unknown),
-    headers: Schema.optional(Schema.Unknown),
   }),
   [Schema.Record(Schema.String, Schema.Unknown)],
-).pipe(
-  Schema.decode({
-    decode: SchemaGetter.transform((event) => {
-      if (event.type !== "error" || event.error != null) return event
-      const { code, message, param, ...rest } = event
-      if (code === undefined && message === undefined && param === undefined) return event
-      // Flat errors (for example, Meta's) can also arrive through generic Responses endpoints.
-      return { ...rest, error: { code, message, param } }
-    }),
-    encode: SchemaGetter.passthrough(),
-  }),
 )
 export type Event = Schema.Schema.Type<typeof Event>
 export type NormalizedEvent = Event & { readonly item?: OutputItem | null }
@@ -433,16 +380,15 @@ const decodeEventValue = Schema.decodeUnknownEffect(Event)
 const decodeFrame = Schema.decodeUnknownEffect(ProviderShared.Json)
 
 /**
- * Decodes one WebSocket frame. xAI answers a rejected `response.create` with `{ "error": { "message", "type" } }` and no
- * event type; that envelope reads as an error event so the failure classifies instead of failing decoding.
+ * Decodes one WebSocket frame. Some providers and gateways answer a rejected `response.create` with a bare
+ * `{ "error": ... }` envelope and no event type; that reads as an error event so it classifies instead of
+ * failing decoding.
  */
 export const decodeChannelEvent = (frame: string) =>
   decodeFrame(frame).pipe(
     Effect.flatMap((value) =>
       decodeEventValue(
-        ProviderShared.isRecord(value) &&
-          value.type === undefined &&
-          (typeof value.error === "string" || ProviderShared.isRecord(value.error))
+        ProviderShared.isRecord(value) && value.type === undefined && value.error != null
           ? { ...value, type: "error" }
           : value,
       ),
@@ -1422,22 +1368,21 @@ const onResponseFinish = Effect.fn("OpenResponses.onResponseFinish")(function* (
   return [{ ...current, lifecycle }, events] satisfies StepResult
 })
 
-// Build the prettiest summary available from whatever the provider supplied.
-// When both code and message are present, prefix the code so consumers see
-// the failure mode (e.g. `rate_limit_exceeded: Slow down`) instead of just
-// the bare message — production rate limits and context-length failures used
-// to be indistinguishable from generic stream drops. Returns undefined when
-// the payload carries no usable summary.
-const providerErrorMessage = (event: Event, nested: OpenResponsesErrorPayload | undefined): string | undefined => {
-  const message = event.message || nested?.message || undefined
-  const code = event.code || nested?.code || undefined
-  if (message && code) return `${code}: ${message}`
-  return message || code
+/** Error code and message from wherever the frame put them; top-level fields win over nested ones. */
+export const errorDetail = (event: Event) => {
+  const raw = event.error ?? event.response?.error
+  const nested = typeof raw === "string" ? { message: raw } : ProviderShared.isRecord(raw) ? raw : undefined
+  return {
+    message: asText(event.message) ?? asText(nested?.message),
+    code: asText(event.code) ?? asText(nested?.code),
+  }
 }
 
+// Prefix the code when both are present (`rate_limit_exceeded: Slow down`) so the failure mode is
+// visible; fall back to the raw frame rather than a generic message when neither decodes.
 export const providerFailure = (event: Event, fallback: string, body = ProviderShared.encodeJson(event)) => {
-  const nested = event.error ?? event.response?.error ?? undefined
-  const summary = providerErrorMessage(event, nested)
+  const detail = errorDetail(event)
+  const summary = detail.message && detail.code ? `${detail.code}: ${detail.message}` : (detail.message ?? detail.code)
   const message = summary ?? (body === "{}" ? fallback : body)
   const status =
     typeof event.status === "number"
@@ -1520,18 +1465,7 @@ export const step = (state: ParserState, event: NormalizedEvent) => {
   if (event.type === "response.output_item.done") return onOutputItemDone(state, event.item)
   if (event.type === "response.completed" || event.type === "response.incomplete") return onResponseFinish(state, event)
   if (event.type === "response.failed") return providerFailure(event, `${state.name} response failed`)
-  if (event.type === "error")
-    return decodeKnownErrorEvent(event).pipe(
-      Effect.mapError((cause) =>
-        ProviderShared.eventError(
-          state.id,
-          `${state.name} returned a malformed error event`,
-          ProviderShared.encodeJson(event),
-          cause,
-        ),
-      ),
-      Effect.flatMap(() => providerFailure(event, `${state.name} stream error`)),
-    )
+  if (event.type === "error") return providerFailure(event, `${state.name} stream error`)
   return Effect.succeed<StepResult>([state, NO_EVENTS])
 }
 

packages/ai/src/providers/google-vertex.ts

@@ -38,23 +38,13 @@ export type Settings = ProviderPackage.Settings &
 
 const fromRequest = Effect.fn("GoogleVertex.fromRequest")(function* (request: LLMRequest) {
   const { serviceTier: _, ...body } = yield* Gemini.protocol.body.from(request)
-  // Vertex's native REST schema rejects `id` on FunctionCall/FunctionResponse parts with HTTP 400,
-  // unlike AI Studio, so history minted there cannot be lowered verbatim.
-  const contents = body.contents.map((content) => ({
-    ...content,
-    parts: (content.parts ?? []).map((part) => {
-      if ("functionCall" in part) return { ...part, functionCall: { ...part.functionCall, id: undefined } }
-      if ("functionResponse" in part) return { ...part, functionResponse: { ...part.functionResponse, id: undefined } }
-      return part
-    }),
-  }))
   const value = request.providerOptions?.labels
   const labels = ProviderShared.isRecord(value)
     ? Object.fromEntries(
         Object.entries(value).filter((entry): entry is [string, string] => typeof entry[1] === "string"),
       )
     : undefined
-  return { ...body, contents, labels }
+  return { ...body, labels }
 })
 
 const protocol = {

packages/ai/src/providers/index.ts

@@ -24,8 +24,10 @@ export * as Moonshot from "./moonshot.js"
 export * as OpenAI from "./openai.js"
 export * as OpenAICompatible from "./openai-compatible.js"
 export * as OpenAICompatibleResponses from "./openai-compatible-responses.js"
+export * as OpenCodeZen from "./opencode-zen.js"
 export * as OpenRouter from "./openrouter.js"
 export * as TogetherAI from "./togetherai.js"
+export * as TypeSafeAI from "./typesafe-ai.js"
 export * as XAI from "./xai.js"
 export * as ZAI from "./zai.js"
 export * as ZAICodingPlan from "./zai-coding-plan.js"

packages/ai/src/providers/opencode-zen.ts

@@ -0,0 +1,31 @@
+import { HttpOptions, ProviderID, type ModelID } from "../schema/index.js"
+import { AuthOptions, type ProviderAuthOption } from "../route/auth-options.js"
+import { SystemOne } from "../experimental/system-one.js"
+
+export const id = ProviderID.make("opencode")
+const baseURL = "https://opencode.ai/zen/v1"
+
+export type Options = ProviderAuthOption<"optional"> & {
+  readonly baseURL?: string
+  readonly headers?: Record<string, string>
+  readonly http?: HttpOptions.Input
+}
+
+export const configure = (input: Options = {}) => {
+  const evaluation = (modelID: string | ModelID) =>
+    SystemOne.model({
+      id: modelID,
+      provider: id,
+      providerMetadataKey: "opencode",
+      auth: AuthOptions.bearer(input, "OPENCODE_API_KEY"),
+      baseURL: input.baseURL ?? baseURL,
+      headers: input.headers,
+      http: input.http === undefined ? undefined : HttpOptions.make(input.http),
+    })
+  return { id, experimental: { evaluation }, configure }
+}
+
+export const provider = configure()
+export const experimental = provider.experimental
+
+export * as OpenCodeZen from "./opencode-zen.js"

packages/ai/src/providers/typesafe-ai.ts

@@ -0,0 +1,31 @@
+import { HttpOptions, ProviderID, type ModelID } from "../schema/index.js"
+import { AuthOptions, type ProviderAuthOption } from "../route/auth-options.js"
+import { SystemOne } from "../experimental/system-one.js"
+
+export const id = ProviderID.make("typesafe-ai")
+const baseURL = "https://api.typesafe.ai/v1"
+
+export type Options = ProviderAuthOption<"optional"> & {
+  readonly baseURL?: string
+  readonly headers?: Record<string, string>
+  readonly http?: HttpOptions.Input
+}
+
+export const configure = (input: Options = {}) => {
+  const evaluation = (modelID: string | ModelID) =>
+    SystemOne.model({
+      id: modelID,
+      provider: id,
+      providerMetadataKey: "typesafe",
+      auth: AuthOptions.bearer(input, "TYPESAFE_API_KEY"),
+      baseURL: input.baseURL ?? baseURL,
+      headers: input.headers,
+      http: input.http === undefined ? undefined : HttpOptions.make(input.http),
+    })
+  return { id, experimental: { evaluation }, configure }
+}
+
+export const provider = configure()
+export const experimental = provider.experimental
+
+export * as TypeSafeAI from "./typesafe-ai.js"

packages/ai/src/route/transport/websocket.ts

@@ -215,7 +215,9 @@ export const fromWebSocket = (
 ): Effect.Effect<WebSocketConnection, AIError> =>
   Effect.gen(function* () {
     yield* waitOpen(ws, input)
-    const messages = yield* Queue.bounded<string | Uint8Array, AIError | Cause.Done<void>>(128)
+    // The socket pushes frames synchronously and cannot be paused, so the hand-off to the consumer
+    // fiber must absorb whole read buffers. Bun delivers over a thousand small frames in one tick.
+    const messages = yield* Queue.unbounded<string | Uint8Array, AIError | Cause.Done<void>>()
 
     const oversized = (message: string | Uint8Array) =>
       typeof message === "string" ? new Blob([message]).size > MAX_FRAME_BYTES : message.byteLength > MAX_FRAME_BYTES
@@ -238,19 +240,7 @@ export const fromWebSocket = (
     }
     const offer = (message: string | Uint8Array) => {
       if (rejectOversized(message)) return
-      if (Queue.offerUnsafe(messages, message)) return
-      Queue.failCauseUnsafe(
-        messages,
-        Cause.fail(
-          transportError("WebSocket inbound queue overflow", {
-            body: typeof message === "string" ? message : new TextDecoder().decode(message),
-            url: input.url,
-            operation: "read",
-            code: "queue-overflow",
-            phase: "receive",
-          }),
-        ),
-      )
+      Queue.offerUnsafe(messages, message)
     }
 
     const onMessage = (event: MessageEvent) => {

packages/ai/test/evaluation.test.ts

@@ -0,0 +1,173 @@
+import { describe, expect } from "bun:test"
+import { Effect, Layer } from "effect"
+import { HttpClientRequest } from "effect/unstable/http"
+import { Evaluation, EvaluationClient } from "../src/experimental.js"
+import { OpenCodeZen, TypeSafeAI } from "../src/providers.js"
+import { it } from "./lib/effect.js"
+import { dynamicResponse } from "./lib/http.js"
+
+describe("experimental Evaluation", () => {
+  it.effect("evaluates typed questions through System One", () =>
+    Effect.gen(function* () {
+      const response = yield* Evaluation.evaluate({
+        model: TypeSafeAI.configure({
+          apiKey: "test",
+          baseURL: "https://typesafe.test/v1/",
+          headers: { "x-default": "yes" },
+          http: { body: { deployment: "test" }, query: { api: "v1" } },
+        }).experimental.evaluation("jev-latest"),
+        state: { ticket: "Please refund the duplicate charge." },
+        questions: {
+          department: {
+            type: "choice",
+            instructions: "Which team should handle this?",
+            criteria: { billing: "Payments and refunds", technical: "Bugs and outages" },
+          },
+          urgency: {
+            type: "score",
+            instructions: "How urgent is this?",
+            criteria: ["Can wait", "Needs attention", "Blocking"],
+          },
+          refund: { type: "boolean", instructions: "Is the customer asking for a refund?" },
+        },
+        options: { trace: { enabled: true } },
+        http: { body: { request_metadata: "value" }, headers: { "x-request": "yes" }, query: { trace: "1" } },
+      })
+
+      expect(response.model).toBe("jev-1.13.0")
+      expect(response.answers.department).toEqual({
+        type: "choice",
+        choice: "billing",
+        probabilities: { billing: 0.9, technical: 0.1 },
+      })
+      expect(response.answers.urgency).toEqual({
+        type: "score",
+        score: 1.2,
+        probabilities: { "0": 0, "1": 0.8, "2": 0.2 },
+      })
+      expect(response.answers.refund).toEqual({ type: "boolean", probability: 0.97 })
+      expect(response.usage?.totalTokens).toBe(36)
+      expect(response.providerMetadata).toEqual({
+        typesafe: {
+          confidence: { department: 0.8, urgency: 0.6 },
+          legend: { urgency: { "0": "Can wait", "1": "Needs attention", "2": "Blocking" } },
+        },
+      })
+    }).pipe(
+      Effect.provide(
+        EvaluationClient.layer.pipe(
+          Layer.provide(
+            dynamicResponse((input) =>
+              Effect.gen(function* () {
+                const request = yield* HttpClientRequest.toWeb(input.request).pipe(Effect.orDie)
+                expect(request.url).toBe("https://typesafe.test/v1/systemone?api=v1&trace=1")
+                expect(request.headers.get("authorization")).toBe("Bearer test")
+                expect(request.headers.get("x-default")).toBe("yes")
+                expect(request.headers.get("x-request")).toBe("yes")
+                expect(JSON.parse(input.text)).toEqual({
+                  deployment: "test",
+                  request_metadata: "value",
+                  trace: { enabled: true },
+                  model: "jev-latest",
+                  state: { ticket: "Please refund the duplicate charge." },
+                  questions: {
+                    department: {
+                      type: "choice",
+                      instructions: "Which team should handle this?",
+                      criteria: { billing: "Payments and refunds", technical: "Bugs and outages" },
+                    },
+                    urgency: {
+                      type: "score",
+                      instructions: "How urgent is this?",
+                      criteria: ["Can wait", "Needs attention", "Blocking"],
+                    },
+                    refund: { type: "noul", instructions: "Is the customer asking for a refund?" },
+                  },
+                })
+                return input.respond(
+                  JSON.stringify({
+                    model: "jev-1.13.0",
+                    answers: {
+                      department: {
+                        type: "choice",
+                        choice: "billing",
+                        probabilities: { billing: 0.9, technical: 0.1 },
+                        confidence: 0.8,
+                      },
+                      urgency: {
+                        type: "score",
+                        score: 1.2,
+                        probabilities: { "0": 0, "1": 0.8, "2": 0.2 },
+                        legend: { "0": "Can wait", "1": "Needs attention", "2": "Blocking" },
+                        confidence: 0.6,
+                      },
+                      refund: { type: "noul", noul: 0.97 },
+                    },
+                    usage: { input_tokens: 30, output_tokens: 6 },
+                  }),
+                  { headers: { "content-type": "application/json" } },
+                )
+              }),
+            ),
+          ),
+        ),
+      ),
+    ),
+  )
+
+  it.effect("configures the OpenCode Zen System One endpoint", () =>
+    Evaluation.evaluate({
+      model: OpenCodeZen.configure({ apiKey: "zen-key", baseURL: "https://zen.test/v1" }).experimental.evaluation(
+        "jev-1.13",
+      ),
+      state: "hello",
+      questions: { greeting: { type: "boolean", instructions: "Is this a greeting?" } },
+    }).pipe(
+      Effect.tap((response) =>
+        Effect.sync(() => {
+          expect(response.answers.greeting.probability).toBe(0.99)
+          expect(response.usage?.providerMetadata).toEqual({
+            opencode: { input_tokens: 10, output_tokens: 2 },
+          })
+        }),
+      ),
+      Effect.provide(
+        EvaluationClient.layer.pipe(
+          Layer.provide(
+            dynamicResponse((input) => {
+              expect(input.request.url).toBe("https://zen.test/v1/systemone")
+              expect(input.request.headers.authorization).toBe("Bearer zen-key")
+              return Effect.succeed(
+                input.respond(
+                  JSON.stringify({
+                    model: "jev-1.13.0",
+                    answers: { greeting: { type: "noul", noul: 0.99 } },
+                    usage: { input_tokens: 10, output_tokens: 2 },
+                  }),
+                  { headers: { "content-type": "application/json" } },
+                ),
+              )
+            }),
+          ),
+        ),
+      ),
+    ),
+  )
+
+  it.effect("rejects malformed questions before network I/O", () =>
+    Effect.gen(function* () {
+      const error = yield* Evaluation.evaluate({
+        model: TypeSafeAI.experimental.evaluation("jev-latest"),
+        state: "hello",
+        questions: { score: { type: "score", instructions: "How much?", criteria: ["only"] } },
+      }).pipe(Effect.flip)
+      expect(error.reason._tag).toBe("InvalidRequest")
+    }).pipe(
+      Effect.provide(
+        EvaluationClient.layer.pipe(
+          Layer.provide(dynamicResponse(() => Effect.die("invalid evaluation reached the network"))),
+        ),
+      ),
+    ),
+  )
+})

packages/ai/test/evaluation.types.ts

@@ -0,0 +1,60 @@
+import { Effect } from "effect"
+import { Evaluation, EvaluationClient, EvaluationModel, type EvaluationRoute } from "../src/experimental.js"
+import type { Service } from "../src/experimental/evaluation-client.js"
+import { OpenCodeZen, TypeSafeAI } from "../src/providers.js"
+
+type Requirements<T> = T extends Effect.Effect<infer _A, infer _E, infer R> ? R : never
+type Success<T> = T extends Effect.Effect<infer A, infer _E, infer _R> ? A : never
+type Equal<A, B> = [A, B] extends [B, A] ? true : false
+type Assert<T extends true> = T
+
+const model = TypeSafeAI.configure({ apiKey: "test" }).experimental.evaluation("jev-latest")
+const request = Evaluation.request({
+  model,
+  state: { ticket: "refund" },
+  questions: {
+    topic: {
+      type: "choice",
+      instructions: "Which team?",
+      criteria: { billing: null, support: { includes: ["help"] } },
+    },
+    severity: { type: "score", instructions: "How severe?", criteria: ["Low", "High"] },
+    refund: { type: "boolean", instructions: "Refund?" },
+  },
+})
+
+const result = EvaluationClient.evaluate(request)
+type Result = Success<typeof result>
+type Choice = Assert<Equal<Result["answers"]["topic"]["choice"], "billing" | "support">>
+type ClientRequirements = Assert<Equal<Requirements<typeof result>, Service>>
+void (true satisfies Choice)
+void (true satisfies ClientRequirements)
+
+Effect.gen(function* () {
+  const response = yield* Evaluation.evaluate({
+    model: OpenCodeZen.experimental.evaluation("jev-1.13"),
+    state: ["hello"],
+    questions: { greeting: { type: "boolean", instructions: "Greeting?" } },
+  })
+  response.answers.greeting.probability satisfies number
+  // @ts-expect-error Boolean answers do not contain a selected choice.
+  response.answers.greeting.choice
+  // @ts-expect-error Unknown question IDs are not exposed.
+  response.answers.missing
+})
+
+declare const route: EvaluationRoute<{ readonly temperature?: number }>
+const custom = EvaluationModel.make({ id: "custom", provider: "custom", route })
+Evaluation.evaluate({
+  model: custom,
+  state: "hello",
+  questions: { ok: { type: "boolean", instructions: "OK?" } },
+  options: { temperature: 0.5 },
+})
+// @ts-expect-error Selected evaluation models retain their request option types.
+Evaluation.evaluate({
+  model: custom,
+  state: "hello",
+  questions: { ok: { type: "boolean", instructions: "OK?" } },
+  options: { temperature: "high" },
+})

packages/ai/test/exports.test.ts

@@ -8,9 +8,11 @@ import {
   CloudflareWorkersAI,
   DeepSeek,
   Fireworks,
+  OpenCodeZen,
   OpenAI,
   OpenAICompatible,
   OpenRouter,
+  TypeSafeAI,
   XAI,
 } from "@opencode/ai/providers"
 import {
@@ -23,6 +25,7 @@ import {
 } from "@opencode/ai/protocols"
 import * as AnthropicMessages from "@opencode/ai/protocols/anthropic-messages"
 import { TestLLM } from "@opencode/ai/testing"
+import { Evaluation, EvaluationClient } from "@opencode/ai/experimental"
 
 describe("public exports", () => {
   test("root exposes app-facing runtime APIs", () => {
@@ -37,6 +40,9 @@ describe("public exports", () => {
     expect(TestLLM.layer).toBeFunction()
     expect(TestLLM.testLayer).toBeFunction()
     expect(TestLLM.Test.of).toBeFunction()
+    expect(Evaluation.evaluate).toBeFunction()
+    expect(EvaluationClient.layer).toBeDefined()
+    expect(EvaluationClient.fetchLayer).toBeDefined()
   })
 
   test("route barrel exposes route-authoring APIs", () => {
@@ -66,6 +72,8 @@ describe("public exports", () => {
     expect(CloudflareWorkersAI.configure).toBeFunction()
     expect(CloudflareWorkersAI.configure({ accountId: "fixture", apiKey: "fixture" }).model).toBeFunction()
     expect(OpenRouter.model).toBeFunction()
+    expect(TypeSafeAI.experimental.evaluation).toBeFunction()
+    expect(OpenCodeZen.experimental.evaluation).toBeFunction()
     expect(XAI.model).toBeFunction()
     expect(XAI.provider.responses).toBe(XAI.responses)
     expect(XAI.provider.chat).toBe(XAI.chat)

packages/ai/test/fixtures/recordings/google-vertex/calls-a-tool.json

@@ -1,9 +1,13 @@
 {
   "version": 1,
   "metadata": {
-    "tags": ["prefix:google-vertex", "provider:google-vertex", "protocol:gemini"],
+    "tags": [
+      "prefix:google-vertex",
+      "provider:google-vertex",
+      "protocol:gemini"
+    ],
     "name": "google-vertex/calls-a-tool",
-    "recordedAt": "2026-08-23T17:21:51.036Z"
+    "recordedAt": "2026-09-22T03:46:29.725Z"
   },
   "interactions": [
     {
@@ -21,7 +25,7 @@
         "headers": {
           "content-type": "text/event-stream"
         },
-        "body": "data: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"functionCall\": {\"name\": \"lookup_weather\",\"args\": {\"city\": \"Paris\"},\"id\": \"call_425130\"},\"thoughtSignature\": \"AY89a1+1fXnLgYhHMuN3Ak6LBhT6PcrYOW7iPav4LfsacvG/Z6l1yJ+AsU7vWhFj/JyPIbsJJQ+GjohM9sCIZ6nqUOIg3reo/7osmrCvFrVHedTHQcwiPzoz2Kp3gb+uWjFAXxk1EX4IRAKcu0ox1W/Z9PpuZvHkTerGO2a82e02N6MAF1YhhtbXFvSdqLRih2Os68rdOk5/Bcld7ol8qUgeyIZ3CtI3OJ5jwRcD8LjvK33A7ZFzH5Bxp/peUmXvqnu5iNhnGBxZaJy/vupCtxRZxjaS+ojG0/UhyrnRiKIpbzQ0FBkxePPn8GCX/LOe2y3GUc98co8lN8OOuCd9ZmEdx5AjHmQkPO9fAV9SxG6Bda6SDWVL8o/Uz3WSQYoUEfAdoajEWIBvcisoeCJjb7zgmRRZ9VQSPl3RXj5LFRvX8jn0YKV1CahYbc24jA==\"}]}}],\"usageMetadata\": {\"trafficType\": \"ON_DEMAND\"},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-08-23T17:21:50.308576Z\",\"responseId\": \"LiyLauDqErCErb8Pj8aWkAs\"}\r\n\r\ndata: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"text\": \"\"}]},\"finishReason\": \"STOP\"}],\"usageMetadata\": {\"promptTokenCount\": 39,\"candidatesTokenCount\": 16,\"totalTokenCount\": 102,\"trafficType\": \"ON_DEMAND\",\"promptTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 39}],\"candidatesTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 16}],\"thoughtsTokenCount\": 47},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-08-23T17:21:50.308576Z\",\"responseId\": \"LiyLauDqErCErb8Pj8aWkAs\"}\r\n\r\n"
+        "body": "data: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"functionCall\": {\"name\": \"lookup_weather\",\"args\": {\"city\": \"Paris\"},\"id\": \"call_28936\"},\"thoughtSignature\": \"AY89a1/MVeBxtwu9l/96clFobOrrd7Q5MTf5o8/A22fc++1EsFYVeCFx9WCGmJ+D3yW3FWlRXKtJECYfprSoxixCSOYBNiV9g8/IkejbAxF26k1vxTsHkoqts0O2s8GqqBSRAavJfKQ/taTRbPuIq+b+RKZ8SDJFoWDnFjXpdS5S164uJTjmgs4ALd8oB1oQRycMsTbAY51TmkcNUnhARpjKQfqiizz4KfSRFjx7xDnza0v4jj73m2GV86eLDhVT7trIT+Dl5DsJt6RBLOE2Amse54mcpIbsYaANlY1YDU6FKuUBqnuwpl0OfhMXwWuYMogv1tH/0rTXsqNwmHyt/b9ZZXqYCdFXpMGt8udmoZ0d\"}]}}],\"usageMetadata\": {\"trafficType\": \"ON_DEMAND\"},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-09-22T03:46:28.953809Z\",\"responseId\": \"FPqxatGbOsSorb8PtY2z8Q4\"}\r\n\r\ndata: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"text\": \"\"}]},\"finishReason\": \"STOP\"}],\"usageMetadata\": {\"promptTokenCount\": 39,\"candidatesTokenCount\": 16,\"totalTokenCount\": 93,\"trafficType\": \"ON_DEMAND\",\"promptTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 39}],\"candidatesTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 16}],\"thoughtsTokenCount\": 38},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-09-22T03:46:28.953809Z\",\"responseId\": \"FPqxatGbOsSorb8PtY2z8Q4\"}\r\n\r\n"
       }
     }
   ]

packages/ai/test/fixtures/recordings/google-vertex/continues-after-a-tool-result.json

@@ -1,9 +1,13 @@
 {
   "version": 1,
   "metadata": {
-    "tags": ["prefix:google-vertex", "provider:google-vertex", "protocol:gemini"],
+    "tags": [
+      "prefix:google-vertex",
+      "provider:google-vertex",
+      "protocol:gemini"
+    ],
     "name": "google-vertex/continues-after-a-tool-result",
-    "recordedAt": "2026-08-23T17:21:51.853Z"
+    "recordedAt": "2026-09-22T03:46:30.691Z"
   },
   "interactions": [
     {
@@ -14,14 +18,14 @@
         "headers": {
           "content-type": "application/json"
         },
-        "body": "{\"contents\":[{\"role\":\"user\",\"parts\":[{\"text\":\"What is the weather in Paris?\"}]},{\"role\":\"model\",\"parts\":[{\"functionCall\":{\"name\":\"lookup_weather\",\"args\":{\"city\":\"Paris\"}},\"thoughtSignature\":\"skip_thought_signature_validator\"}]},{\"role\":\"user\",\"parts\":[{\"functionResponse\":{\"name\":\"lookup_weather\",\"response\":{\"name\":\"lookup_weather\",\"content\":\"18C, light rain\"}}}]}],\"tools\":[{\"functionDeclarations\":[{\"name\":\"lookup_weather\",\"description\":\"Look up the current weather for a city\",\"parameters\":{\"required\":[\"city\"],\"type\":\"object\",\"properties\":{\"city\":{\"type\":\"string\"}}}}]}]}"
+        "body": "{\"contents\":[{\"role\":\"user\",\"parts\":[{\"text\":\"What is the weather in Paris?\"}]},{\"role\":\"model\",\"parts\":[{\"functionCall\":{\"id\":\"call_paris_1\",\"name\":\"lookup_weather\",\"args\":{\"city\":\"Paris\"}},\"thoughtSignature\":\"skip_thought_signature_validator\"}]},{\"role\":\"user\",\"parts\":[{\"functionResponse\":{\"id\":\"call_paris_1\",\"name\":\"lookup_weather\",\"response\":{\"name\":\"lookup_weather\",\"content\":\"18C, light rain\"}}}]}],\"tools\":[{\"functionDeclarations\":[{\"name\":\"lookup_weather\",\"description\":\"Look up the current weather for a city\",\"parameters\":{\"required\":[\"city\"],\"type\":\"object\",\"properties\":{\"city\":{\"type\":\"string\"}}}}]}]}"
       },
       "response": {
         "status": 200,
         "headers": {
           "content-type": "text/event-stream"
         },
-        "body": "data: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"text\": \"The weather in Paris is currently 18°C with light rain.\"}]}}],\"usageMetadata\": {\"trafficType\": \"ON_DEMAND\"},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-08-23T17:21:51.220919Z\",\"responseId\": \"LyyLave9DbWnrb8P1IjLmQQ\"}\r\n\r\ndata: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"text\": \"\",\"thoughtSignature\": \"AY89a197c+fpHJftPtcufnqMAyoRQKVEQK+KeG+RVHVx2wKil3L4jP4YWvfVbcuOFr2jio4Kre/hCrDANAoMFSvaZrdaPeo1b5bXQSmJKMH03yM5M6q6ME6JiBvXym143U4exIde4UbOh2tMeyXMvB3aWxcavIHd78g5G5QPLreo6A3LO5871cYYVeRwteY+/zbEdqfaAq1hlk6WYpWkNljYpjMyKwr15YC8rFLh3HYayS9tTN++GGrk/reZn6C3OEPlzPou/pXRATzcEAGVl/TW\"}]},\"finishReason\": \"STOP\"}],\"usageMetadata\": {\"promptTokenCount\": 59,\"candidatesTokenCount\": 15,\"totalTokenCount\": 98,\"trafficType\": \"ON_DEMAND\",\"promptTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 59}],\"candidatesTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 15}],\"thoughtsTokenCount\": 24},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-08-23T17:21:51.220919Z\",\"responseId\": \"LyyLave9DbWnrb8P1IjLmQQ\"}\r\n\r\n"
+        "body": "data: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"text\": \"The weather\"}]}}],\"usageMetadata\": {\"trafficType\": \"ON_DEMAND\"},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-09-22T03:46:29.830958Z\",\"responseId\": \"Ffqxau7bMoCOrb8P_Iu5sA0\"}\r\n\r\ndata: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"text\": \" in Paris is currently 18°C with light rain.\"}]}}],\"usageMetadata\": {\"trafficType\": \"ON_DEMAND\"},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-09-22T03:46:29.830958Z\",\"responseId\": \"Ffqxau7bMoCOrb8P_Iu5sA0\"}\r\n\r\ndata: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"text\": \"\",\"thoughtSignature\": \"AY89a18aVI8Uxr2VaOI822u0DyuQdy4B00uhLnjqYb5Qb6Mkscccm018knLtYThB5UX8dRv1VFsORSQ0Qo6Gx9RCng2AK9EPce7p\"}]},\"finishReason\": \"STOP\"}],\"usageMetadata\": {\"promptTokenCount\": 59,\"candidatesTokenCount\": 15,\"totalTokenCount\": 74,\"trafficType\": \"ON_DEMAND\",\"promptTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 59}],\"candidatesTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 15}]},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-09-22T03:46:29.830958Z\",\"responseId\": \"Ffqxau7bMoCOrb8P_Iu5sA0\"}\r\n\r\n"
       }
     }
   ]

packages/ai/test/fixtures/recordings/google-vertex/streams-text.json

@@ -1,9 +1,13 @@
 {
   "version": 1,
   "metadata": {
-    "tags": ["prefix:google-vertex", "provider:google-vertex", "protocol:gemini"],
+    "tags": [
+      "prefix:google-vertex",
+      "provider:google-vertex",
+      "protocol:gemini"
+    ],
     "name": "google-vertex/streams-text",
-    "recordedAt": "2026-08-23T17:21:50.112Z"
+    "recordedAt": "2026-09-22T03:46:28.840Z"
   },
   "interactions": [
     {
@@ -21,7 +25,7 @@
         "headers": {
           "content-type": "text/event-stream"
         },
-        "body": "data: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"text\": \"Hello\"}]}}],\"usageMetadata\": {\"trafficType\": \"ON_DEMAND\"},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-08-23T17:21:48.528714Z\",\"responseId\": \"LCyLasqiIO6crb8P1sDboQc\"}\r\n\r\ndata: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"text\": \"\",\"thoughtSignature\": \"AY89a1+BGsRqlGpfT0psLB4jeTkT5rDV2HFOlrRuF7aVxDOjqNVUku6t4azeSnxpd+msHWuwXj4RS+7gmVlzVs+JNi8uj+iZWTBCi71vSh9kdK9ed/sHv9J7uL9ZWSOcgbhX/hxdXaUp5yVbQzHFXPjR9A/IkEkHV8VKarDZVFE1T1uASia74lkmyBeZZz+DQmRsLwbUHzFUKlF3qnk/SliLo21ZgASd7itlALQ0PBLJZwgeI3g7tDscDSE18hnB11Fky8q7MLd3HY16zbDvHBEMb18pmmPelPI01KdrCIwMSou/01/u5jiSUCc3pFksZawUj3tAHocHSC3ZKAQQQuUXGe5tm61C2E40/NANBeePc1S4HYE6Yo/vtX6tE02LDky5IQWX09H6+DZ7fpopP5nCUfcKPHa3hVjYquWYYMtZgXO4ZpxfVd3lt1VUDuJNN3BMMCZapjBoJZFPXPJ5t/yg9Rnd791+msGH77b4wztz1vtsPrT9oV9g6SDo9ZUH6BaOcbK7fw8FaXcGw+55malEwQy6zpRLGecooBu70p6RwhaAUyKIMX49y+F2hkNxQxDeBUNckJnu6n4w+KLyjP+bR0gqPJbGjVfteHm+QujqjJdBBT/m1u9kPo1nIbzdEs/PIADBdbuV7TkD/HoRFKpLnNmM2no8ioTtFEjKBDz4ippGi15r8pGgA6wIb/1HAvOGh+PVERdGcbelVTgfONwBqjQ7B1wmEizCfyYuMIskfwjxDGayfKlpDxrnNeogtEct9u5/DjEKlURlg9MtmW1B9P8BXYJ+7SCiRJWwW6bzB+5C+MLCnETl/mljDizoJMHK8DKIhI4oxBsrWXEuoHFwEwGIeOZq0BofH2Jz/l6+KIboV/zd581Kk0zPg/rlI6acfjUEtXtbF+t0+jzoJN7006x4i2tqXeJZ+4e5yisSArEsfJ0YzNWoJtBHG9V9/euDcEP3+jsr98efaQaQbLMPvT/Hb7CYQ7ChhGfcGxQ=\"}]},\"finishReason\": \"STOP\"}],\"usageMetadata\": {\"promptTokenCount\": 7,\"candidatesTokenCount\": 1,\"totalTokenCount\": 150,\"trafficType\": \"ON_DEMAND\",\"promptTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 7}],\"candidatesTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 1}],\"thoughtsTokenCount\": 142},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-08-23T17:21:48.528714Z\",\"responseId\": \"LCyLasqiIO6crb8P1sDboQc\"}\r\n\r\n"
+        "body": "data: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"text\": \"Hello\"}]}}],\"usageMetadata\": {\"trafficType\": \"ON_DEMAND\"},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-09-22T03:46:26.748531Z\",\"responseId\": \"EvqxavPXLbqerb8P1eSViQs\"}\r\n\r\ndata: {\"candidates\": [{\"content\": {\"role\": \"model\",\"parts\": [{\"text\": \"\",\"thoughtSignature\": \"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\"}]},\"finishReason\": \"STOP\"}],\"usageMetadata\": {\"promptTokenCount\": 7,\"candidatesTokenCount\": 1,\"totalTokenCount\": 285,\"trafficType\": \"ON_DEMAND\",\"promptTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 7}],\"candidatesTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 1}],\"thoughtsTokenCount\": 277},\"modelVersion\": \"gemini-3.5-flash\",\"createTime\": \"2026-09-22T03:46:26.748531Z\",\"responseId\": \"EvqxavPXLbqerb8P1eSViQs\"}\r\n\r\n"
       }
     }
   ]

packages/ai/test/fixtures/recordings/opencode-zen-evaluation/evaluates-choice-score-and-boolean-questions.json

@@ -0,0 +1,33 @@
+{
+  "version": 1,
+  "metadata": {
+    "model": "jev-1.13-free",
+    "tags": [
+      "prefix:opencode-zen-evaluation",
+      "provider:opencode",
+      "protocol:system-one"
+    ],
+    "name": "opencode-zen-evaluation/evaluates-choice-score-and-boolean-questions",
+    "recordedAt": "2026-09-22T03:44:57.511Z"
+  },
+  "interactions": [
+    {
+      "transport": "http",
+      "request": {
+        "method": "POST",
+        "url": "https://opencode.ai/zen/v1/systemone",
+        "headers": {
+          "content-type": "application/json"
+        },
+        "body": "{\"model\":\"jev-1.13-free\",\"state\":\"I was charged twice for the same invoice. Please refund the duplicate payment today.\",\"questions\":{\"department\":{\"type\":\"choice\",\"instructions\":\"Which team should handle this support request?\",\"criteria\":{\"billing\":\"Payments, invoices, refunds, or failed charges\",\"technical\":\"Bugs, outages, or integrations\",\"sales\":\"Pricing, upgrades, or new accounts\"}},\"urgency\":{\"type\":\"score\",\"instructions\":\"How urgent is this support request?\",\"criteria\":[\"Can wait for normal support\",\"Needs prompt attention\",\"Actively blocking revenue\"]},\"refund\":{\"type\":\"noul\",\"instructions\":\"Is the customer asking for a refund?\"}}}"
+      },
+      "response": {
+        "status": 200,
+        "headers": {
+          "content-type": "application/json"
+        },
+        "body": "{\"model\":\"jev-1.13-free\",\"answers\":{\"department\":{\"type\":\"choice\",\"choice\":\"billing\",\"confidence\":1,\"probabilities\":{\"technical\":0,\"sales\":0,\"billing\":1}},\"urgency\":{\"type\":\"score\",\"score\":1.02,\"confidence\":0.95,\"legend\":{\"0\":\"Can wait for normal support\",\"1\":\"Needs prompt attention\",\"2\":\"Actively blocking revenue\"},\"probabilities\":{\"0\":0,\"1\":0.97,\"2\":0.03}},\"refund\":{\"type\":\"noul\",\"noul\":0.99}},\"usage\":{\"input_tokens\":422,\"output_tokens\":69}}"
+      }
+    }
+  ]
+}

packages/ai/test/fixtures/recordings/typesafe-evaluation/evaluates-choice-score-and-boolean-questions.json

@@ -0,0 +1,33 @@
+{
+  "version": 1,
+  "metadata": {
+    "model": "jev-latest",
+    "tags": [
+      "prefix:typesafe-evaluation",
+      "provider:typesafe-ai",
+      "protocol:system-one"
+    ],
+    "name": "typesafe-evaluation/evaluates-choice-score-and-boolean-questions",
+    "recordedAt": "2026-09-22T03:44:28.626Z"
+  },
+  "interactions": [
+    {
+      "transport": "http",
+      "request": {
+        "method": "POST",
+        "url": "https://api.typesafe.ai/v1/systemone",
+        "headers": {
+          "content-type": "application/json"
+        },
+        "body": "{\"model\":\"jev-latest\",\"state\":\"I was charged twice for the same invoice. Please refund the duplicate payment today.\",\"questions\":{\"department\":{\"type\":\"choice\",\"instructions\":\"Which team should handle this support request?\",\"criteria\":{\"billing\":\"Payments, invoices, refunds, or failed charges\",\"technical\":\"Bugs, outages, or integrations\",\"sales\":\"Pricing, upgrades, or new accounts\"}},\"urgency\":{\"type\":\"score\",\"instructions\":\"How urgent is this support request?\",\"criteria\":[\"Can wait for normal support\",\"Needs prompt attention\",\"Actively blocking revenue\"]},\"refund\":{\"type\":\"noul\",\"instructions\":\"Is the customer asking for a refund?\"}}}"
+      },
+      "response": {
+        "status": 200,
+        "headers": {
+          "content-type": "application/json"
+        },
+        "body": "{\"model\":\"jev-1.13.0\",\"answers\":{\"department\":{\"type\":\"choice\",\"choice\":\"billing\",\"confidence\":1.0,\"probabilities\":{\"billing\":1.0,\"sales\":0.0,\"technical\":0.0}},\"urgency\":{\"type\":\"score\",\"score\":1.01,\"confidence\":0.97,\"legend\":{\"0\":\"Can wait for normal support\",\"1\":\"Needs prompt attention\",\"2\":\"Actively blocking revenue\"},\"probabilities\":{\"0\":0.0,\"1\":0.98,\"2\":0.02}},\"refund\":{\"type\":\"noul\",\"noul\":0.99}},\"usage\":{\"input_tokens\":422,\"output_tokens\":69}}"
+      }
+    }
+  ]
+}

packages/ai/test/provider/evaluation.recorded.test.ts

@@ -0,0 +1,79 @@
+import { describe, expect } from "bun:test"
+import { Effect } from "effect"
+import { Evaluation } from "../../src/experimental.js"
+import { OpenCodeZen, TypeSafeAI } from "../../src/providers.js"
+import { recordedTests } from "../recorded-test.js"
+
+const questions = {
+  department: {
+    type: "choice",
+    instructions: "Which team should handle this support request?",
+    criteria: {
+      billing: "Payments, invoices, refunds, or failed charges",
+      technical: "Bugs, outages, or integrations",
+      sales: "Pricing, upgrades, or new accounts",
+    },
+  },
+  urgency: {
+    type: "score",
+    instructions: "How urgent is this support request?",
+    criteria: ["Can wait for normal support", "Needs prompt attention", "Actively blocking revenue"],
+  },
+  refund: { type: "boolean", instructions: "Is the customer asking for a refund?" },
+} as const
+
+const state = "I was charged twice for the same invoice. Please refund the duplicate payment today."
+
+const typesafe = recordedTests({
+  prefix: "typesafe-evaluation",
+  provider: "typesafe-ai",
+  protocol: "system-one",
+  requires: ["TYPESAFE_API_KEY"],
+  metadata: { model: "jev-latest" },
+})
+
+const zen = recordedTests({
+  prefix: "opencode-zen-evaluation",
+  provider: "opencode",
+  protocol: "system-one",
+  requires: ["OPENCODE_API_KEY"],
+  metadata: { model: "jev-1.13-free" },
+})
+
+describe("experimental Evaluation recorded", () => {
+  typesafe.effect("evaluates choice score and boolean questions", () =>
+    assertEvaluation(
+      TypeSafeAI.configure({ apiKey: process.env.TYPESAFE_API_KEY ?? "fixture" }).experimental.evaluation("jev-latest"),
+      "typesafe",
+    ),
+  )
+
+  zen.effect("evaluates choice score and boolean questions", () =>
+    assertEvaluation(
+      OpenCodeZen.configure({ apiKey: process.env.OPENCODE_API_KEY ?? "fixture" }).experimental.evaluation(
+        "jev-1.13-free",
+      ),
+      "opencode",
+    ),
+  )
+})
+
+const assertEvaluation = (
+  model: ReturnType<typeof TypeSafeAI.experimental.evaluation>,
+  metadataKey: "typesafe" | "opencode",
+) =>
+  Effect.gen(function* () {
+    const response = yield* Evaluation.evaluate({ model, state, questions })
+    expect(response.model).toStartWith("jev-")
+    expect(response.answers.department.type).toBe("choice")
+    expect(response.answers.department.choice).toBe("billing")
+    expect(response.answers.department.probabilities?.billing).toBeGreaterThan(0.5)
+    expect(response.answers.urgency.type).toBe("score")
+    expect(response.answers.urgency.score).toBeGreaterThanOrEqual(0)
+    expect(response.answers.urgency.score).toBeLessThanOrEqual(2)
+    expect(response.answers.refund.type).toBe("boolean")
+    expect(response.answers.refund.probability).toBeGreaterThan(0.5)
+    expect(response.usage?.inputTokens).toBeGreaterThan(0)
+    expect(response.usage?.outputTokens).toBeGreaterThan(0)
+    expect(response.providerMetadata?.[metadataKey]?.confidence).toBeDefined()
+  })

packages/ai/test/provider/google-vertex.test.ts

@@ -114,7 +114,7 @@ describe("Google Vertex providers", () => {
     }),
   )
 
-  it.effect("strips function call ids Vertex does not accept from lowered bodies", () =>
+  it.effect("preserves function call ids in lowered Vertex bodies", () =>
     Effect.gen(function* () {
       const prepared = yield* compileRequest(
         LLM.request({
@@ -142,15 +142,14 @@ describe("Google Vertex providers", () => {
         }),
       )
 
-      expect(JSON.stringify(prepared.body.contents)).not.toContain('"id"')
       expect(prepared.body.contents).toMatchObject([
-        { role: "model", parts: [{ functionCall: { id: undefined, name: "lookup", args: { query: "weather" } } }] },
+        { role: "model", parts: [{ functionCall: { id: "call_1", name: "lookup", args: { query: "weather" } } }] },
         {
           role: "user",
           parts: [
             {
               functionResponse: {
-                id: undefined,
+                id: "call_1",
                 name: "lookup",
                 response: { name: "lookup", content: "sunny" },
               },
@@ -235,12 +234,23 @@ describe("Google Vertex providers", () => {
           parts: [
             { text: "Thinking.", thought: true, thoughtSignature: "reasoning_sig" },
             { text: "Checking.", thoughtSignature: "text_sig" },
-            { functionCall: { name: "lookup", args: { query: "weather" } }, thoughtSignature: "tool_sig" },
+            {
+              functionCall: { id: "provider_call_1", name: "lookup", args: { query: "weather" } },
+              thoughtSignature: "tool_sig",
+            },
           ],
         },
         {
           role: "user",
-          parts: [{ functionResponse: { name: "lookup", response: { name: "lookup", content: "sunny" } } }],
+          parts: [
+            {
+              functionResponse: {
+                id: "provider_call_1",
+                name: "lookup",
+                response: { name: "lookup", content: "sunny" },
+              },
+            },
+          ],
         },
       ])
     }),

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

@@ -11,66 +11,78 @@ import { sseEvents } from "../lib/sse.js"
 
 const decodeEvent = Schema.decodeUnknownEffect(OpenResponses.protocol.stream.event)
 
-it.effect("normalizes flat errors in shared SSE and WebSocket decoding", () =>
+it.effect("decodes error frames verbatim in shared SSE and WebSocket decoding", () =>
   Effect.gen(function* () {
-    const frame = {
-      type: "error",
-      sequence_number: 4,
-      code: "server_shutting_down",
-      message: "Server is shutting down. Please retry your request.",
-      param: null,
-    }
     for (const decode of [decodeEvent, OpenResponses.decodeChannelEvent]) {
-      const event = yield* decode(JSON.stringify(frame))
-      expect(event).toEqual({
-        type: "error",
-        sequence_number: 4,
-        error: { code: frame.code, message: frame.message, param: null },
-      })
-
-      for (const unchanged of [
-        event,
+      for (const frame of [
+        { type: "error", sequence_number: 4, code: "server_shutting_down", message: "Shutting down", param: null },
         { type: "error" },
+        { type: "error", error: "Gateway failed" },
+        { type: "error", error: { code: 429, message: "slow down" } },
+        { type: "error", error: 42 },
+        { type: "error", code: 500, message: ["not", "a", "string"] },
+        { type: "response.failed", response: { id: "resp_failed", error: "Gateway failed" } },
+        { type: "response.failed", response: { id: "resp_failed", error: ["weird"] } },
         {
           type: "response.failed",
           response: { id: "resp_failed", error: { code: "server_error", message: "Internal server error" } },
         },
         { type: "response.output_text.delta", item_id: "msg_text", delta: "Hello" },
       ]) {
-        expect(yield* decode(JSON.stringify(unchanged))).toEqual(unchanged)
+        expect(yield* decode(JSON.stringify(frame))).toEqual(frame)
       }
     }
   }),
 )
 
-it.effect("continues to normalize untyped xAI WebSocket errors", () =>
+it.effect("reads bare WebSocket error envelopes as error events", () =>
   Effect.gen(function* () {
     const message = "gRPC error: Response with id=resp_missing not found"
-    for (const error of [{ type: "api_error", message }, message]) {
-      expect(yield* OpenResponses.decodeChannelEvent(JSON.stringify({ error }))).toEqual({
-        type: "error",
-        error: typeof error === "string" ? { message } : error,
-      })
+    for (const error of [{ type: "api_error", message }, message, 42]) {
+      expect(yield* OpenResponses.decodeChannelEvent(JSON.stringify({ error }))).toEqual({ type: "error", error })
+    }
+    for (const frame of [{ error: null }, { message }]) {
+      expect(yield* OpenResponses.decodeChannelEvent(JSON.stringify(frame)).pipe(Effect.flip)).toBeDefined()
     }
   }),
 )
 
-it.effect("normalizes string errors in shared SSE and WebSocket decoding", () =>
+it.effect("extracts error details from every shape and falls back to the raw frame", () =>
   Effect.gen(function* () {
-    for (const decode of [decodeEvent, OpenResponses.decodeChannelEvent]) {
-      expect(yield* decode(JSON.stringify({ type: "error", error: "Gateway failed" }))).toEqual({
-        type: "error",
-        error: { message: "Gateway failed" },
-      })
-      expect(
-        yield* decode(
-          JSON.stringify({ type: "response.failed", response: { id: "resp_failed", error: "Gateway failed" } }),
-        ),
-      ).toEqual({
-        type: "response.failed",
-        response: { id: "resp_failed", error: { message: "Gateway failed" } },
-      })
+    const cases: Array<[frame: Record<string, unknown>, message: string, tag: string]> = [
+      [
+        { type: "error", code: "server_shutting_down", message: "Shutting down" },
+        "server_shutting_down: Shutting down",
+        "UnknownProvider",
+      ],
+      [{ type: "error", error: "Gateway failed" }, "Gateway failed", "UnknownProvider"],
+      [{ type: "error", error: { code: 429, message: "slow down" } }, "429: slow down", "UnknownProvider"],
+      [{ type: "error", error: { message: "slow down" }, status: 429 }, "slow down", "RateLimit"],
+      [{ type: "error", code: 500, message: ["not", "a", "string"] }, "500", "UnknownProvider"],
+      [
+        { type: "response.failed", response: { id: "resp_failed", error: "Gateway failed" } },
+        "Gateway failed",
+        "UnknownProvider",
+      ],
+    ]
+    for (const [frame, message, tag] of cases) {
+      const event = yield* OpenResponses.decodeChannelEvent(JSON.stringify(frame))
+      const error = OpenResponses.providerFailure(event, "fallback", JSON.stringify(frame))
+      expect(error.message).toBe(message)
+      expect(error.reason._tag).toBe(tag)
+      expect(error.reason.body).toBe(JSON.stringify(frame))
     }
+    for (const frame of [
+      { type: "error", error: 42 },
+      { type: "response.failed", response: { id: "resp_failed", error: ["weird"] } },
+    ]) {
+      const event = yield* OpenResponses.decodeChannelEvent(JSON.stringify(frame))
+      const error = OpenResponses.providerFailure(event, "fallback", JSON.stringify(frame))
+      expect(error.message).toBe(JSON.stringify(frame))
+      expect(error.reason._tag).toBe("UnknownProvider")
+    }
+    expect(OpenResponses.providerFailure({ type: "error" }, "fallback", "{}").message).toBe("fallback")
+    expect(OpenResponses.providerFailure({ type: "error" }, "fallback", "{}").reason._tag).toBe("ProviderInternal")
   }),
 )
 

packages/ai/test/recorded-test.ts

@@ -6,6 +6,8 @@ import * as path from "node:path"
 import { fileURLToPath } from "node:url"
 import { LLMClient, RequestExecutor } from "../src/route.js"
 import { ImageClient } from "../src/image-client.js"
+import { EvaluationClient } from "../src/experimental/evaluation-client.js"
+import type { Service as EvaluationClientService } from "../src/experimental/evaluation-client.js"
 import type { Service as ImageClientService } from "../src/image-client.js"
 import type { Service as LLMClientService } from "../src/route/client.js"
 import type { Service as RequestExecutorService } from "../src/route/executor.js"
@@ -18,7 +20,12 @@ import {
 const __dirname = path.dirname(fileURLToPath(import.meta.url))
 const FIXTURES_DIR = path.resolve(__dirname, "fixtures", "recordings")
 
-type RecordedEnv = RequestExecutorService | LLMClientService | ImageClientService | Socket.WebSocketConstructor
+type RecordedEnv =
+  | RequestExecutorService
+  | LLMClientService
+  | ImageClientService
+  | EvaluationClientService
+  | Socket.WebSocketConstructor
 
 type RecordedTestsOptions = RecordedGroupOptions & {
   readonly options?: HttpRecorder.RecorderOptions
@@ -92,6 +99,7 @@ export const recordedTests = (options: RecordedTestsOptions) =>
         requestExecutor,
         LLMClient.layer.pipe(Layer.provide(requestExecutor)),
         ImageClient.layer.pipe(Layer.provide(requestExecutor)),
+        EvaluationClient.layer.pipe(Layer.provide(requestExecutor)),
         webSocket,
       )
     },

packages/app/component-tests/browser-pane.fixture.tsx

@@ -19,6 +19,13 @@ export function mountBrowserPane() {
       session: "Alpha",
       mounted: true,
       visible: true,
+      url: undefined as string | undefined,
+      loading: false,
+      generation: 0,
+      delayNavigation: false,
+      pendingURL: undefined as string | undefined,
+      loadErrors: {} as Record<string, string | undefined>,
+      error: undefined as string | undefined,
       layouts: {} as Record<string, BrowserPaneLayout | undefined>,
     })
     const tabs = ["Alpha", "Beta"].map((name) => ({
@@ -47,13 +54,33 @@ export function mountBrowserPane() {
       opened: () => !!registrations.get(store.session),
       state: () => ({ tabs: tabs.filter((tab) => tab.title === store.session), focusedTabID: null }),
       tabs: () => tabs.filter((tab) => tab.title === store.session),
-      active: () => tabs.find((tab) => tab.title === store.session) ?? tabs[0],
+      active: () => {
+        const tab = tabs.find((tab) => tab.title === store.session) ?? tabs[0]
+        return {
+          ...tab,
+          url: store.url ?? tab.url,
+          loading: store.loading,
+          generation: store.generation,
+          loadError: store.loadErrors[store.session],
+        }
+      },
       registration: () => registrations.get(store.session),
-      error: () => undefined,
+      error: () => store.error ?? (store.loadErrors[store.session] ? "Request failed" : undefined),
       suspended: () => false,
       close: () => undefined,
       open: () => undefined,
-      command: () => undefined,
+      command: (command) => {
+        setStore("error", undefined)
+        if (command.type === "navigate" || command.type === "reload") setStore("loadErrors", store.session, undefined)
+        if (command.type === "navigate") {
+          if (store.delayNavigation) {
+            setStore("pendingURL", command.url)
+            return
+          }
+          setStore({ url: command.url, loading: false, generation: store.generation + 1 })
+        }
+        if (command.type === "stop") setStore("loading", false)
+      },
     }
     return (
       <>
@@ -64,6 +91,32 @@ export function mountBrowserPane() {
             {(name) => <button onClick={() => setStore({ session: name, mounted: name !== "Empty" })}>{name}</button>}
           </For>
           <button onClick={() => setStore("mounted", false)}>Unmount pane</button>
+          <button onClick={() => setStore({ url: "about:blank", loading: false })}>Blank page</button>
+          <button onClick={() => setStore({ url: "about:blank", loading: true })}>Loading page</button>
+          <button
+            onClick={() =>
+              setStore({ loading: true, generation: store.generation + 1, loadErrors: { [store.session]: undefined } })
+            }
+          >
+            Load current page
+          </button>
+          <button onClick={() => setStore("loadErrors", store.session, "ERR_CONNECTION_REFUSED")}>Failed page</button>
+          <button onClick={() => setStore("delayNavigation", true)}>Delay navigation</button>
+          <button onClick={() => setStore({ error: "ERR_BLOCKED_BY_CLIENT", pendingURL: undefined })}>
+            Block navigation
+          </button>
+          <button
+            onClick={() =>
+              setStore({
+                url: store.pendingURL,
+                pendingURL: undefined,
+                loading: false,
+                generation: store.generation + 1,
+              })
+            }
+          >
+            Complete navigation
+          </button>
           <button onClick={() => setStore("visible", (visible) => !visible)}>Toggle Review tab</button>
         </nav>
         <div style={{ width: "640px", height: "360px", border: "1px solid #555" }}>

packages/app/component-tests/browser-pane.spec.ts

@@ -57,3 +57,153 @@ story("hides the native view immediately while the pane stays mounted", async ({
   await toggle.click()
   await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "true")
 })
+
+story("shows the empty state over a blank native page and restores navigation", async ({ page }) => {
+  const root = page.getByTestId("browser-pane-fixture")
+  await root.getByRole("button", { name: "Blank page", exact: true }).click()
+  await expect(root.getByText("Enter URL", { exact: true })).toBeVisible()
+  await expect(root.getByText('Or prompt "Open in the app browser"', { exact: true })).toBeVisible()
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "false")
+  await expect(root.getByRole("button", { name: "Reload", exact: true })).toBeDisabled()
+
+  const address = root.getByRole("textbox", { name: "Browser address", exact: true })
+  await address.fill("https://example.com/")
+  await expect(root.getByText("Enter URL", { exact: true })).toBeVisible()
+  await address.press("Enter")
+  await expect(address).not.toBeFocused()
+  await expect(root.getByText("Enter URL", { exact: true })).toBeHidden()
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "true")
+  await expect(root.getByRole("button", { name: "Reload", exact: true })).toBeEnabled()
+})
+
+story("keeps Stop available and hides the empty state while a blank page loads", async ({ page }) => {
+  const root = page.getByTestId("browser-pane-fixture")
+  await root.getByRole("button", { name: "Loading page", exact: true }).click()
+  await expect(root.getByText("Enter URL", { exact: true })).toBeHidden()
+  await root.getByRole("button", { name: "Stop", exact: true }).click()
+  await expect(root.getByText("Enter URL", { exact: true })).toBeVisible()
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "false")
+})
+
+story("keeps the submitted URL visible until the browser reports navigation", async ({ page }) => {
+  const root = page.getByTestId("browser-pane-fixture")
+  await root.getByRole("button", { name: "Blank page", exact: true }).click()
+  await root.getByRole("button", { name: "Delay navigation", exact: true }).click()
+  const address = root.getByRole("textbox", { name: "Browser address", exact: true })
+  await address.fill("https://example.com/")
+  await address.press("Enter")
+  await expect(address).not.toBeFocused()
+  await expect(address).toHaveValue("https://example.com/")
+  await expect(root.getByText("Enter URL", { exact: true })).toBeHidden()
+
+  await root.getByRole("button", { name: "Complete navigation", exact: true }).click()
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "true")
+  await expect(address).toHaveValue("https://example.com/")
+
+  await address.fill("https://unsubmitted.example/")
+  await root.getByRole("button", { name: "Delay navigation", exact: true }).click()
+  await expect(address).toHaveValue("https://example.com/")
+})
+
+story("restores the current URL when a submitted navigation is blocked", async ({ page }) => {
+  const root = page.getByTestId("browser-pane-fixture")
+  await root.getByRole("button", { name: "Delay navigation", exact: true }).click()
+  const address = root.getByRole("textbox", { name: "Browser address", exact: true })
+  await address.fill("https://blocked.example/")
+  await address.press("Enter")
+  await expect(address).toHaveValue("https://blocked.example/")
+  await root.getByRole("button", { name: "Block navigation", exact: true }).click()
+  await expect(root.getByText("ERR_BLOCKED_BY_CLIENT", { exact: true })).toBeVisible()
+  await expect(address).toHaveValue("https://alpha.example/")
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "true")
+})
+
+story("shows a themed failure state for only the failed tab and allows retry", async ({ page }) => {
+  const root = page.getByTestId("browser-pane-fixture")
+  await root.getByRole("button", { name: "Failed page", exact: true }).click()
+  await expect(root.getByText("URL can't be reached", { exact: true })).toBeVisible()
+  await expect(root.getByText("Check the URL and your connection, then try again.", { exact: true })).toBeVisible()
+  await expect(root.getByText("Request failed", { exact: true })).toBeHidden()
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "false")
+  await expect(root.getByRole("textbox", { name: "Browser address", exact: true })).toHaveValue(
+    "https://alpha.example/",
+  )
+
+  await root.getByRole("button", { name: "Beta", exact: true }).click()
+  await expect(root.getByText("URL can't be reached", { exact: true })).toBeHidden()
+  await expect(root.getByTestId("native-Beta")).toHaveAttribute("data-visible", "true")
+  await root.getByRole("button", { name: "Alpha", exact: true }).click()
+  await expect(root.getByText("URL can't be reached", { exact: true })).toBeVisible()
+
+  await root.getByRole("button", { name: "Reload", exact: true }).click()
+  await expect(root.getByText("URL can't be reached", { exact: true })).toBeHidden()
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "true")
+})
+
+story("returns a failed tab to the empty state when an empty URL is submitted", async ({ page }) => {
+  const root = page.getByTestId("browser-pane-fixture")
+  await root.getByRole("button", { name: "Failed page", exact: true }).click()
+  await expect(root.getByText("URL can't be reached", { exact: true })).toBeVisible()
+  await root.getByRole("button", { name: "Delay navigation", exact: true }).click()
+
+  const address = root.getByRole("textbox", { name: "Browser address", exact: true })
+  await address.fill("")
+  await address.press("Enter")
+  await expect(address).not.toBeFocused()
+  await expect(address).toHaveValue("")
+  await root.getByRole("button", { name: "Load current page", exact: true }).click()
+  await expect(root.getByRole("button", { name: "Stop", exact: true })).toBeEnabled()
+  await root.getByRole("button", { name: "Complete navigation", exact: true }).click()
+  await expect(root.getByText("URL can't be reached", { exact: true })).toBeHidden()
+  await expect(root.getByText("Enter URL", { exact: true })).toBeVisible()
+  await expect(root.getByRole("button", { name: "Reload", exact: true })).toBeDisabled()
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "false")
+})
+
+story("selects the full URL when the address field gains focus", async ({ page }) => {
+  const root = page.getByTestId("browser-pane-fixture")
+  const address = root.getByRole("textbox", { name: "Browser address", exact: true })
+  await address.click()
+  await expect(address).toHaveJSProperty("selectionStart", 0)
+  await expect(address).toHaveJSProperty("selectionEnd", "https://alpha.example/".length)
+  await address.pressSequentially("https://example.com/")
+  await expect(address).toHaveValue("https://example.com/")
+  await address.press("Enter")
+  await expect(address).not.toBeFocused()
+  await address.focus()
+  await expect(address).toHaveJSProperty("selectionStart", 0)
+  await expect(address).toHaveJSProperty("selectionEnd", "https://example.com/".length)
+  await address.press("ArrowRight")
+  await address.click()
+  await expect(address).toHaveJSProperty("selectionStart", 0)
+  await expect(address).toHaveJSProperty("selectionEnd", "https://example.com/".length)
+})
+
+story("keeps the current page visible while a submitted URL loads", async ({ page }) => {
+  const root = page.getByTestId("browser-pane-fixture")
+  await root.getByRole("button", { name: "Delay navigation", exact: true }).click()
+  const address = root.getByRole("textbox", { name: "Browser address", exact: true })
+  await address.fill("https://example.com/")
+  await address.press("Enter")
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "true")
+  await expect(address).toHaveValue("https://example.com/")
+
+  await root.getByRole("button", { name: "Load current page", exact: true }).click()
+  await expect(root.getByRole("button", { name: "Stop", exact: true })).toBeEnabled()
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "true")
+  await root.getByRole("button", { name: "Complete navigation", exact: true }).click()
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "true")
+  await expect(address).toHaveValue("https://example.com/")
+})
+
+story("keeps the current page and restores its URL when an empty address is submitted", async ({ page }) => {
+  const root = page.getByTestId("browser-pane-fixture")
+  const address = root.getByRole("textbox", { name: "Browser address", exact: true })
+  await address.fill("")
+  await address.press("Enter")
+  await expect(address).not.toBeFocused()
+  await expect(address).toHaveValue("https://alpha.example/")
+  await expect(root.getByTestId("native-Alpha")).toHaveAttribute("data-visible", "true")
+  await expect(root.getByText("Enter URL", { exact: true })).toBeHidden()
+  await expect(root.getByRole("button", { name: "Reload", exact: true })).toBeEnabled()
+})

packages/app/e2e/performance/devex/desktop-startup.ts

@@ -17,14 +17,12 @@ const milestones = [
   "electronSpawnStarted",
   "debugEndpointReady",
   "electronStarted",
+  "layersReady",
+  "windowVisible",
   "serviceEnsureStarted",
   "serviceSpawnRequested",
   "serviceReady",
-  "backgroundLoadingReady",
   "rendererViteConnected",
-  "rendererInitializationStarted",
-  "rendererInitializationReady",
-  "windowVisible",
   "homeReady",
 ] as const
 const phases = [
@@ -128,14 +126,12 @@ const milestonePatterns: ReadonlyArray<{ name: Milestone; text: string }> = [
   { name: "electronSpawnStarted", text: "starting electron app..." },
   { name: "debugEndpointReady", text: "DevTools listening on ws://" },
   { name: "electronStarted", text: "app starting" },
+  { name: "layersReady", text: "layers ready" },
+  { name: "windowVisible", text: "main window visible" },
   { name: "serviceEnsureStarted", text: "starting v2 background service" },
   { name: "serviceSpawnRequested", text: "v2 CLI background service starting" },
   { name: "serviceReady", text: "v2 CLI background service ready" },
-  { name: "backgroundLoadingReady", text: "loading task finished" },
   { name: "rendererViteConnected", text: "[vite] connected." },
-  { name: "rendererInitializationStarted", text: "awaiting server ready" },
-  { name: "rendererInitializationReady", text: "server ready" },
-  { name: "windowVisible", text: "main window visible" },
 ]
 
 async function createColdProfile() {
@@ -404,14 +400,12 @@ function requireMilestones(observed: Partial<Record<Milestone, number>>) {
     electronSpawnStarted: get("electronSpawnStarted"),
     debugEndpointReady: get("debugEndpointReady"),
     electronStarted: get("electronStarted"),
+    layersReady: get("layersReady"),
+    windowVisible: get("windowVisible"),
     serviceEnsureStarted: get("serviceEnsureStarted"),
     serviceSpawnRequested: get("serviceSpawnRequested"),
     serviceReady: get("serviceReady"),
-    backgroundLoadingReady: get("backgroundLoadingReady"),
     rendererViteConnected: get("rendererViteConnected"),
-    rendererInitializationStarted: get("rendererInitializationStarted"),
-    rendererInitializationReady: get("rendererInitializationReady"),
-    windowVisible: get("windowVisible"),
     homeReady: get("homeReady"),
   }
 }

packages/app/e2e/performance/unit/desktop-startup.test.ts

@@ -20,14 +20,12 @@ describe("desktop startup benchmark", () => {
       ["electronSpawnStarted", "starting electron app..."],
       ["debugEndpointReady", "DevTools listening on ws://"],
       ["electronStarted", "app starting"],
+      ["layersReady", "layers ready"],
+      ["windowVisible", "main window visible"],
       ["serviceEnsureStarted", "starting v2 background service"],
       ["serviceSpawnRequested", "v2 CLI background service starting"],
       ["serviceReady", "v2 CLI background service ready"],
-      ["backgroundLoadingReady", "loading task finished"],
       ["rendererViteConnected", "[vite] connected."],
-      ["rendererInitializationStarted", "awaiting server ready"],
-      ["rendererInitializationReady", "server ready"],
-      ["windowVisible", "main window visible"],
     ] as const
     cases.forEach(([milestone, line]) => {
       expect(milestoneForLine(`\u001b[32m${line}\u001b[39m`)).toBe(milestone)
@@ -58,14 +56,12 @@ function sample(run: number, commandToHomeReadyMs: number): DesktopStartupSample
     electronSpawnStarted: 7,
     debugEndpointReady: 8,
     electronStarted: 9,
-    serviceEnsureStarted: 10,
-    serviceSpawnRequested: 11,
-    serviceReady: 12,
-    backgroundLoadingReady: 13,
-    rendererViteConnected: 14,
-    rendererInitializationStarted: 15,
-    rendererInitializationReady: 16,
-    windowVisible: 17,
+    layersReady: 10,
+    windowVisible: 11,
+    serviceEnsureStarted: 12,
+    serviceSpawnRequested: 13,
+    serviceReady: 14,
+    rendererViteConnected: 15,
     homeReady: commandToHomeReadyMs,
   }
   return {
@@ -80,8 +76,8 @@ function sample(run: number, commandToHomeReadyMs: number): DesktopStartupSample
       electronStartup: 2,
       serviceSpawnWait: 1,
       serviceProcessStartup: 1,
-      rendererStartup: commandToHomeReadyMs - 14,
-      visibleWindowToHome: commandToHomeReadyMs - 17,
+      rendererStartup: commandToHomeReadyMs - 15,
+      visibleWindowToHome: commandToHomeReadyMs - 11,
     },
     service: { version: "2.0.0-local-test", url: "http://127.0.0.1:3000", pid: run },
   }

packages/app/e2e/regression/btw-sidebar.spec.ts

@@ -0,0 +1,145 @@
+import { base64Encode } from "@opencode/util/encode"
+import { expect, test } from "@playwright/test"
+import { mockOpenCodeServer } from "../utils/mock-server"
+import { expectSessionTitle } from "../utils/waits"
+
+const directory = "C:/OpenCode/BtwSidebar"
+const projectID = "proj_btw_sidebar"
+const sessionID = "ses_btw_sidebar"
+const otherSessionID = "ses_btw_sidebar_other"
+const title = "Side question session"
+const otherTitle = "Other side question session"
+const server = `http://${process.env.PLAYWRIGHT_SERVER_HOST ?? "127.0.0.1"}:${process.env.PLAYWRIGHT_SERVER_PORT ?? "4096"}`
+const sessionHref = (id: string) => `/server/${base64Encode(server)}/session/${id}`
+
+test.use({ viewport: { width: 1440, height: 900 } })
+
+test("answers /btw in the side panel without admitting a prompt", async ({ page }) => {
+  const generations: { sessionID: string; prompt: string }[] = []
+  const prompts: unknown[] = []
+  const generated = Promise.withResolvers<void>()
+  await mockOpenCodeServer(page, {
+    directory,
+    project: {
+      id: projectID,
+      worktree: directory,
+      vcs: "git",
+      name: "btw-sidebar",
+      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,
+        slug: sessionID,
+        projectID,
+        directory,
+        title,
+        version: "dev",
+        time: { created: 1700000000000, updated: 1700000000000 },
+      },
+      {
+        id: otherSessionID,
+        slug: otherSessionID,
+        projectID,
+        directory,
+        title: otherTitle,
+        version: "dev",
+        time: { created: 1700000001000, updated: 1700000001000 },
+      },
+    ],
+    pageMessages: () => ({ items: [] }),
+    vcsDiff: [],
+    onPrompt: (input) => prompts.push(input),
+    generate: async (input) => {
+      generations.push(input)
+      if (input.sessionID === otherSessionID) return { text: "This answer belongs to the **other session**." }
+      await generated.promise
+      return {
+        text: "The retry loop uses **exponential backoff** and stops after three attempts.\n\n```ts\nconst delay = 2 ** attempt\n```",
+      }
+    },
+  })
+  await page.addInitScript(
+    ({ directory, server, sessionID, otherSessionID }) => {
+      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: "session", server, sessionId: sessionID },
+          { type: "session", server, sessionId: otherSessionID },
+        ]),
+      )
+    },
+    { directory, server, sessionID, otherSessionID },
+  )
+
+  await page.goto(sessionHref(sessionID))
+  await expectSessionTitle(page, title)
+  const editor = page.locator('[data-component="composer-editor"]')
+  await expect(editor).toBeEditable()
+
+  await editor.fill("/btw")
+  const suggestion = page.locator('[data-suggestion-id="session.btw"]')
+  await expect(suggestion).toBeVisible()
+  await suggestion.click()
+  await expect(editor).toHaveText("/btw ")
+  await editor.press("Enter")
+
+  const panel = page.locator('[data-slot="session-btw-panel"]')
+  await expect(panel).toBeHidden()
+  await expect(page.getByText("Add a question after /btw", { exact: true })).toBeVisible()
+  expect(generations).toEqual([])
+  expect(prompts).toEqual([])
+
+  await editor.fill("/btw how does the retry loop work?")
+  await editor.press("Enter")
+
+  const tab = page.getByRole("tab", { name: "/btw" })
+  await expect(panel).toBeVisible()
+  await expect(panel.getByRole("textbox")).toHaveCount(0)
+  await expect(panel.getByRole("status")).toContainText("Working")
+  await expect(tab).toHaveAttribute("data-selected", "")
+  generated.resolve()
+  await expect(panel.getByText("how does the retry loop work?", { exact: true })).toBeVisible()
+  await expect(panel.getByText("exponential backoff", { exact: false })).toBeVisible()
+  await expect(panel.getByText("const delay = 2 ** attempt", { exact: true })).toBeVisible()
+  expect(generations).toHaveLength(1)
+  expect(generations[0]?.sessionID).toBe(sessionID)
+  expect(generations[0]?.prompt).toContain("how does the retry loop work?")
+  expect(prompts).toEqual([])
+  await expect(editor).toHaveText("")
+
+  await page.locator(`[data-titlebar-tab-link][href="${sessionHref(otherSessionID)}"]`).click()
+  await expectSessionTitle(page, otherTitle)
+  await editor.fill("/btw what belongs here?")
+  await editor.press("Enter")
+  await expect(panel.getByText("other session", { exact: false })).toBeVisible()
+
+  await page.locator(`[data-titlebar-tab-link][href="${sessionHref(sessionID)}"]`).click()
+  await expectSessionTitle(page, title)
+  await expect(panel.getByText("exponential backoff", { exact: false })).toBeVisible()
+  await expect(panel.getByText("other session", { exact: false })).toHaveCount(0)
+
+  await page.reload()
+  await expectSessionTitle(page, title)
+  await expect(page.getByRole("tab", { name: "/btw" })).toHaveCount(0)
+  await expect(page.locator('[data-slot="session-btw-panel"]')).toHaveCount(0)
+})

packages/app/e2e/regression/session-rename.spec.ts

@@ -2,6 +2,8 @@ import { expect, test } from "@playwright/test"
 import { fixture, pageMessages } from "../smoke/session-timeline.fixture"
 import { mockOpenCodeServer } from "../utils/mock-server"
 
+test.use({ permissions: ["clipboard-read", "clipboard-write"] })
+
 test.beforeEach(async ({ page }) => {
   const sessions = fixture.sessions.map((session) => ({ ...session }))
   await mockOpenCodeServer(page, {
@@ -95,7 +97,7 @@ test("renames and closes the session tab from its context menu", async ({ page }
   await expect(tab).toBeFocused()
   await tab.press("Shift+F10")
   await page.getByRole("menuitem", { name: "Rename", exact: true }).click()
-  const input = page.locator('[data-slot="tab-title"][contenteditable="true"]')
+  const input = page.locator('[data-slot="tab-title"][contenteditable="plaintext-only"]')
   await expect(input).toBeFocused()
   await input.fill("Renamed from tab")
   await input.press("Enter")
@@ -112,6 +114,28 @@ test("renames and closes the session tab from its context menu", async ({ page }
   ).toBeVisible()
 })
 
+test("pastes rich text into the session tab title as plain text", async ({ page }) => {
+  const tab = page.locator('[data-slot="titlebar-tabs"] a').filter({ hasText: fixture.expected.targetTitle })
+  await tab.click({ button: "right" })
+  await page.getByRole("menuitem", { name: "Rename", exact: true }).click()
+  const input = page.locator('[data-slot="tab-title"][contenteditable="plaintext-only"]')
+  await expect(input).toBeFocused()
+  await page.evaluate(async () => {
+    await navigator.clipboard.write([
+      new ClipboardItem({
+        "text/html": new Blob(['<span style="font-size: 48px">Rich title</span>'], { type: "text/html" }),
+        "text/plain": new Blob(["Rich title"], { type: "text/plain" }),
+      }),
+    ])
+  })
+  await input.press("ControlOrMeta+A")
+  await input.press("ControlOrMeta+V")
+  await expect(input).toHaveText("Rich title")
+  await expect(input.locator("*")).toHaveCount(0)
+  await input.press("Enter")
+  await expect(page.getByRole("heading", { name: "Rich title", exact: true })).toBeVisible()
+})
+
 test("renames an inactive tab without switching sessions", async ({ page }) => {
   await page.getByRole("button", { name: "Home", exact: true }).click()
   await page.locator('[data-component="home-session-row"]').filter({ hasText: fixture.expected.sourceTitle }).click()
@@ -119,7 +143,7 @@ test("renames an inactive tab without switching sessions", async ({ page }) => {
   const tab = page.locator('[data-slot="titlebar-tabs"] a').filter({ hasText: fixture.expected.targetTitle })
   await tab.click({ button: "right" })
   await page.getByRole("menuitem", { name: "Rename", exact: true }).click()
-  const input = page.locator('[data-slot="tab-title"][contenteditable="true"]')
+  const input = page.locator('[data-slot="tab-title"][contenteditable="plaintext-only"]')
   await expect(input).toBeFocused()
   await input.fill("Inactive tab renamed")
   await input.press("Tab")

packages/app/e2e/regression/session-summary-layout.spec.ts

@@ -71,7 +71,7 @@ for (const direction of ["ltr", "rtl"] as const) {
     const shifted = await content.evaluate((element) => getComputedStyle(element).translate)
     await content.evaluate((element) => element.setAttribute("data-summary-motion", ""))
     // Keep issuing resize events before the idle timer expires, including crossing the width cutoff.
-    for (const width of [1520, 1280, 1600]) {
+    for (const width of [1520, 1280, 1800]) {
       await page.setViewportSize({ width, height: 900 })
       await expect(panel).toHaveAttribute("data-summary-resizing", "true")
       await page.clock.runFor(100)
@@ -84,6 +84,7 @@ for (const direction of ["ltr", "rtl"] as const) {
     await expect(content).toHaveAttribute("data-summary-motion", "transitionrun,transitionend,")
     await expect(content).not.toHaveCSS("translate", shifted)
     await page.setViewportSize({ width: 1440, height: 900 })
+    await expect(panel).toHaveAttribute("data-summary-resizing", "false")
     await expect(content).toHaveCSS("translate", shifted)
 
     await content.evaluate((element) => element.setAttribute("data-summary-motion", ""))
@@ -112,7 +113,8 @@ for (const direction of ["ltr", "rtl"] as const) {
     await expect(summary).toBeVisible()
 
     await page.setViewportSize({ width: 1800, height: 900 })
-    await expect(content).toHaveCSS("translate", "0px")
+    await expect(panel).toHaveAttribute("data-summary-resizing", "false")
+    await expect(content).toHaveCSS("translate", "none")
     await expect(summary).toBeVisible()
 
     await page.emulateMedia({ reducedMotion: "reduce" })

packages/app/e2e/regression/settings-loading.spec.ts

@@ -116,7 +116,7 @@ test("single-server settings expose scoped pages without a server picker", async
   await expect(connection.getByRole("heading", { name: "Connection", exact: true })).toBeVisible()
   await expect(connection.locator('[data-component="settings-list"]')).toHaveCSS("padding-left", "16px")
   await expect(connection.locator(".settings-servers-row")).toHaveCSS("padding-top", "20px")
-  await expect(connection.locator(".settings-servers-lead")).toHaveCSS("column-gap", "4px")
+  await expect(connection.locator(".settings-servers-lead")).toHaveCSS("column-gap", "10px")
   await expect(connection.locator(".settings-servers-copy")).toHaveCSS("row-gap", "6px")
   await expect(settings.getByRole("heading", { name: "Preferences", exact: true })).toBeVisible()
   await expect(settings.getByText("Terminal shell", { exact: true })).toBeVisible()

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

@@ -197,6 +197,13 @@ const Group = HttpApiGroup.make("mock")
       success: Json,
     }),
   )
+  .add(
+    HttpApiEndpoint.post("sessionGenerate", "/api/session/:sessionID/generate", {
+      params: SessionParams,
+      payload: Schema.Struct({ prompt: Schema.String }),
+      success: Json,
+    }),
+  )
   .add(
     HttpApiEndpoint.post("sessionSwitchAgent", "/api/session/:sessionID/agent", {
       params: SessionParams,

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

@@ -42,6 +42,7 @@ export interface MockServerConfig {
   sessionStatus?: Record<string, unknown> | (() => Record<string, unknown>)
   inbox?: unknown[] | (() => unknown[])
   onPrompt?: (input: { sessionID: string; body: Record<string, unknown> }) => void
+  generate?: (input: { sessionID: string; prompt: string }) => { text: string } | Promise<{ text: string }>
   onInboxChange?: (input: { sessionID: string; inboxID: string; action: "cancel" | "steer" | "queue" }) => void
 }
 
@@ -456,6 +457,12 @@ function mockHandlers(config: MockServerConfig, state: { cursors: Map<string, st
               },
             }
           }),
+        sessionGenerate: (ctx) =>
+          Effect.promise(async () => ({
+            data: (await config.generate?.({ sessionID: ctx.params.sessionID, prompt: ctx.payload.prompt })) ?? {
+              text: "Side-question answer",
+            },
+          })),
         sessionInboxCancel: (ctx) =>
           Effect.sync(() =>
             config.onInboxChange?.({ sessionID: ctx.params.sessionID, inboxID: ctx.params.inboxID, action: "cancel" }),

packages/app/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@opencode/app",
-  "version": "2.0.10",
+  "version": "2.0.12",
   "description": "",
   "type": "module",
   "exports": {

packages/app/src/composer/client-slash-command.test.ts

@@ -0,0 +1,32 @@
+import { describe, expect, test } from "bun:test"
+import { parseClientSlashCommand } from "./client-slash-command"
+
+const options = [
+  { id: "session.btw", trigger: "btw", arguments: true, type: "builtin" as const },
+  { id: "custom.btw", trigger: "custom", type: "custom" as const },
+  { id: "model.choose", trigger: "model", type: "builtin" as const },
+]
+
+describe("parseClientSlashCommand", () => {
+  test("parses inline and multiline arguments", () => {
+    expect(parseClientSlashCommand(options, "/btw why this approach?")).toEqual({
+      id: "session.btw",
+      input: "why this approach?",
+    })
+    expect(parseClientSlashCommand(options, "/btw\nwhy this approach?")).toEqual({
+      id: "session.btw",
+      input: "why this approach?",
+    })
+  })
+
+  test("accepts a bare argument command", () => {
+    expect(parseClientSlashCommand(options, "/btw")).toEqual({ id: "session.btw", input: "" })
+  })
+
+  test("rejects prefixes, custom commands, and ordinary slash commands", () => {
+    expect(parseClientSlashCommand(options, "/btwx nope")).toBeUndefined()
+    expect(parseClientSlashCommand(options, "/custom nope")).toBeUndefined()
+    expect(parseClientSlashCommand(options, "/model opus")).toBeUndefined()
+    expect(parseClientSlashCommand(options, "ask /btw later")).toBeUndefined()
+  })
+})

packages/app/src/composer/client-slash-command.ts

@@ -0,0 +1,24 @@
+type ClientSlashCommand = {
+  id: string
+  trigger: string
+  arguments?: boolean
+  type: "builtin" | "custom"
+}
+
+export function parseSlashCommand(text: string) {
+  if (!text.startsWith("/")) return
+  const separator = text.search(/\s/)
+  const name = text.slice(1, separator === -1 ? undefined : separator)
+  return { name, input: separator === -1 ? "" : text.slice(separator).trim() }
+}
+
+export function parseClientSlashCommand(options: readonly ClientSlashCommand[], text: string) {
+  const command = parseSlashCommand(text)
+  if (!command) return
+  const option = options.find((item) => item.type === "builtin" && item.arguments && item.trigger === command.name)
+  if (!option) return
+  return {
+    id: option.id,
+    input: command.input,
+  }
+}

packages/app/src/composer/model.ts

@@ -24,6 +24,7 @@ import { createComposerHistory } from "./history/store"
 import { composerPlaceholder } from "./placeholder"
 import { createComposerSubmit } from "./submit"
 import { useAttachmentDestination } from "./attachments/destination"
+import { parseClientSlashCommand } from "./client-slash-command"
 
 export type ComposerModel = ComposerEditorModel & {
   readonly model: ComposerControls["model"]
@@ -73,9 +74,7 @@ export function createComposerModel(adapter: ComposerAdapter, options?: { queue?
       return [...result, path]
     }, [])
   })
-  const attachments = createMemo(() =>
-    prompt.current().filter(isAttachment),
-  )
+  const attachments = createMemo(() => prompt.current().filter(isAttachment))
   const commentCount = createMemo(() => {
     if (mode() === "shell") return 0
     return prompt.context.items().filter((item) => !!item.comment?.trim()).length
@@ -242,6 +241,7 @@ export function createComposerModel(adapter: ComposerAdapter, options?: { queue?
         trigger: item.slash!,
         title: item.title,
         description: item.description,
+        arguments: item.slashArguments,
         type: "builtin" as const,
       })),
   ])
@@ -299,6 +299,11 @@ export function createComposerModel(adapter: ComposerAdapter, options?: { queue?
       clear: comments.clear,
       restore: restoreHistoryComments,
     },
+    clientCommand: (text) => {
+      const selected = parseClientSlashCommand(slashCommands(), text)
+      if (!selected) return
+      return () => command.trigger(selected.id, "slash", selected.input)
+    },
   })
   const controller = createComposerEditor({
     store: prompt.store,
@@ -340,6 +345,7 @@ export function createComposerModel(adapter: ComposerAdapter, options?: { queue?
       if (item.kind !== "command") return
       const selected = slashCommands().find((entry) => entry.id === item.id)
       if (!selected || selected.type === "custom") return
+      if (selected.arguments) return
       return () => command.trigger(selected.id, "slash")
     },
     attachments: {

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

@@ -54,14 +54,17 @@ function submitInput(
   mode: "normal" | "shell" = "normal",
   commands: () => readonly { name: string }[] | undefined = () => [],
   history: string[] = [],
+  clientCommand?: (text: string) => (() => void | Promise<void>) | undefined,
 ) {
   return createComposerSubmit({
     adapter,
     mode: () => mode,
     commands,
+    clientCommand,
     editor: () => undefined,
     queueScroll() {},
-    addToHistory: (prompt) => history.push(`add:${prompt.map((part) => ("content" in part ? part.content : part.type)).join("")}`),
+    addToHistory: (prompt) =>
+      history.push(`add:${prompt.map((part) => ("content" in part ? part.content : part.type)).join("")}`),
     removeFromHistory: (prompt) =>
       history.push(`remove:${prompt.map((part) => ("content" in part ? part.content : part.type)).join("")}`),
     resetHistory() {},
@@ -118,6 +121,61 @@ function session(input: {
 }
 
 describe("Composer submission", () => {
+  test("runs a client argument command without admitting it to the session", async () => {
+    const state = createMemoryComposerState().capture()
+    state.set([
+      { type: "text", content: "/btw why this approach?", start: 0, end: 23 },
+      {
+        type: "image",
+        id: "attachment",
+        filename: "diagram.png",
+        mime: "image/png",
+        blob: { id: "attachment", url: "data:image/png;base64,YQ==" },
+      },
+    ])
+    state.context.add({ type: "file", path: "src/retry.ts" })
+    const calls: string[] = []
+    const target = session({
+      calls,
+      prompt: async () => {
+        throw new Error("client command must not call prompt")
+      },
+    })
+    const adapter: ActiveComposerAdapter = {
+      kind: "active-session",
+      state,
+      ready: () => true,
+      controls,
+      working: () => false,
+      session: () => target,
+      interrupt: async () => undefined,
+      submitted() {},
+      setEditor() {},
+    }
+
+    const history: string[] = []
+    await submitInput(adapter, undefined, "normal", undefined, history, (text) => {
+      expect(text).toBe("/btw why this approach?")
+      return () => {
+        calls.push("btw")
+      }
+    }).submit(new Event("submit"))
+
+    expect(calls).toEqual(["btw"])
+    expect(history).toEqual([])
+    expect(state.current()).toEqual([
+      { type: "text", content: "", start: 0, end: 0 },
+      {
+        type: "image",
+        id: "attachment",
+        filename: "diagram.png",
+        mime: "image/png",
+        blob: { id: "attachment", url: "data:image/png;base64,YQ==" },
+      },
+    ])
+    expect(state.context.items()).toHaveLength(1)
+  })
+
   test("applies the captured agent and model before a custom command without passing over its overrides", async () => {
     const state = createMemoryComposerState({ prompt: "/review changes" }).capture()
     const calls: string[] = []
@@ -625,12 +683,7 @@ describe("Composer submission", () => {
       },
     }
 
-    await submitInput(
-      adapter,
-      undefined,
-      "normal",
-      () => catalog,
-    ).submit(new Event("submit"))
+    await submitInput(adapter, undefined, "normal", () => catalog).submit(new Event("submit"))
 
     expect(await sent.promise).toBe("command")
     expect(requests).toEqual([

packages/app/src/composer/submit.ts

@@ -11,6 +11,7 @@ import { setCursorPosition } from "./editor/dom"
 import { blobDataUrl, resolveBlobUrl } from "@/runtime/persistence/drafts"
 import { isAttachment } from "./prompt-parts"
 import type { ModelSelection } from "@/providers/models/selection"
+import { parseSlashCommand } from "./client-slash-command"
 
 const submitting = new WeakSet<object>()
 
@@ -37,6 +38,7 @@ type ComposerSubmitInput = {
   setMode: (mode: "normal" | "shell") => void
   closePopover: () => void
   delivery?: (alternate: boolean) => ComposerDelivery
+  clientCommand?: (text: string) => (() => void | Promise<void>) | undefined
   notify: {
     missingSelection: () => void
     failed: (kind: "shell" | "command" | "prompt", error: unknown) => void
@@ -52,15 +54,31 @@ export function createComposerSubmit(input: ComposerSubmitInput) {
   const submit = async (event: globalThis.Event, options?: { alternate?: boolean }) => {
     event.preventDefault()
 
+    const prompt = clonePrompt(input.adapter.state.current())
+    const text = submissionText(prompt)
+    const clientCommand = input.mode() === "normal" ? input.clientCommand?.(text) : undefined
+    if (clientCommand) {
+      if (submitting.has(input.adapter.state)) return
+      submitting.add(input.adapter.state)
+      try {
+        clearClientCommand(input, prompt)
+        await clientCommand()
+      } catch (error) {
+        input.notify.failed("command", error)
+      } finally {
+        submitting.delete(input.adapter.state)
+      }
+      return
+    }
     const submission = createComposerSubmission({
       target: input.adapter.state,
-      prompt: clonePrompt(input.adapter.state.current()),
+      prompt,
       context: input.adapter.state.context.items().map((item) => ({
         ...item,
         selection: item.selection ? { ...item.selection } : undefined,
       })),
     })
-    const read = readSubmission(input, submission.prompt, submission.context, options?.alternate ?? false)
+    const read = readSubmission(input, submission.prompt, submission.context, text, options?.alternate ?? false)
     if (!read) {
       if (input.adapter.working() && input.adapter.kind === "active-session") void input.adapter.interrupt()
       return
@@ -150,6 +168,17 @@ export function createComposerSubmit(input: ComposerSubmitInput) {
   }
 }
 
+function clearClientCommand(input: ComposerSubmitInput, prompt: Prompt) {
+  input.adapter.state.set([{ type: "text", content: "", start: 0, end: 0 }, ...prompt.filter(isAttachment)], 0)
+  input.adapter.state.mode.set("normal")
+  input.setMode("normal")
+  input.closePopover()
+}
+
+function submissionText(prompt: Prompt) {
+  return prompt.map((part) => ("content" in part ? part.content : "")).join("")
+}
+
 function handoffMessage(value: ComposerSubmission): SessionMessageUser {
   return {
     id: value.id,
@@ -193,9 +222,9 @@ function readSubmission(
   input: ComposerSubmitInput,
   prompt: Prompt,
   context: ComposerSubmission["context"],
+  text: string,
   alternate: boolean,
 ): ComposerSubmission | undefined {
-  const text = prompt.map((part) => ("content" in part ? part.content : "")).join("")
   const mode = input.mode()
   if (mode === "shell" && !text.trim()) return
   const images = prompt.filter((part): part is ImageAttachmentPart => part.type === "image")
@@ -298,14 +327,11 @@ async function sendShell(session: ComposerSession, value: ComposerSubmission) {
 }
 
 function findCommand(commands: ReturnType<ComposerSubmitInput["commands"]>, text: string) {
-  if (!text.startsWith("/")) return
-  const [name, ...arguments_] = text.split(" ")
-  const command = name.slice(1)
-  if (!commands?.some((item) => item.name === command)) return
-  return { command, arguments: arguments_.join(" ") }
+  const parsed = parseSlashCommand(text)
+  if (!parsed || !commands?.some((item) => item.name === parsed.name)) return
+  return { command: parsed.name, arguments: parsed.input }
 }
 
-
 async function sendCommand(
   session: ComposerSession,
   value: ComposerSubmission,
@@ -390,7 +416,10 @@ async function sendPrompt(
 
 async function buildSubmissionRequest(session: ComposerSession, value: ComposerSubmission) {
   const images = await Promise.all(
-    value.images.map(async (attachment) => ({ ...attachment, dataUrl: await blobDataUrl(attachment.blob, attachment.mime) })),
+    value.images.map(async (attachment) => ({
+      ...attachment,
+      dataUrl: await blobDataUrl(attachment.blob, attachment.mime),
+    })),
   )
   return buildPromptRequest({
     prompt: value.prompt,

packages/app/src/home/sessions/command-palette.tsx

@@ -47,7 +47,7 @@ export function HomeCommandPalette(props: {
     state.cleanup = undefined
     dialog.close()
     if (item.type === "command") {
-      item.option?.onSelect?.("palette")
+      void item.option?.onSelect?.("palette")
       return
     }
     if (item.type === "session") props.onSelectSession(item)

packages/app/src/index.css

@@ -65,14 +65,14 @@
   }
 
   /* Keep the 1000px conversation intact, with 320px for the summary and its gutters.
-     Move only as far as needed; wider panels already have enough space in the margin. */
-  @container session-chat (min-width: 1320px) {
+     When they overlap, center the conversation in the space that remains beside the summary. */
+  @container session-chat (min-width: 1320px) and (width < 1640px) {
     [data-slot="session-chat-panel"][data-summary-open="true"]
       :is([data-timeline-virtual-content], [data-component="session-composer-dock"] > div) {
-      --session-summary-translate: min(0px, calc(50cqi - 820px));
+      --session-summary-translate: -160px;
 
       &:dir(rtl) {
-        --session-summary-translate: max(0px, calc(820px - 50cqi));
+        --session-summary-translate: 160px;
       }
     }
   }

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

@@ -151,6 +151,8 @@ export const dict = {
   "command.session.compact.description": "Summarize the session to reduce context size",
   "command.session.fork": "Fork from message",
   "command.session.fork.description": "Create a new session from a previous message",
+  "command.session.btw": "Ask a side question",
+  "command.session.btw.description": "Get a one-shot answer without adding to the conversation",
   "command.session.export": "Export session",
   "command.session.export.description": "Export the full session transcript as JSON",
   "command.session.import": "Import session",
@@ -625,6 +627,16 @@ export const dict = {
   "toast.file.loadFailed.title": "Failed to load file",
   "file.error.notFound": "File not found: {{name}}",
   "toast.file.listFailed.title": "Failed to list files",
+  "file.view.preview": "Preview",
+  "file.view.source": "Source",
+  "file.view.openInBrowser": "Open in browser",
+  "file.view.binary": "Binary file · {{size}}",
+  "file.view.table.rows.one": "{{count}} row",
+  "file.view.table.rows.other": "{{count}} rows",
+  "file.view.table.columns.one": "{{count}} column",
+  "file.view.table.columns.other": "{{count}} columns",
+  "file.view.table.truncated": "Showing the first {{shown}} of {{total}} rows.",
+  "file.view.fontSample": "Sphinx of black quartz, judge my vow.",
 
   "toast.context.noLineSelection.title": "No line selection",
   "toast.context.noLineSelection.description": "Select a line range in a file tab first.",
@@ -746,6 +758,7 @@ export const dict = {
   "session.tab.browser": "Browser",
   "session.tab.add": "Add tab",
   "session.tab.context": "Context",
+  "session.tab.btw": "/btw",
   "session.tab.unknown": "Unknown Session",
   "session.panel.reviewAndFiles": "Review and files",
   "session.error.notFound": "This session cannot be found",
@@ -906,6 +919,10 @@ export const dict = {
   "session.browser.replaced": "Browser control moved to another desktop window.",
   "session.browser.suspended": "Browser suspended. Interact with this session to reconnect.",
   "session.browser.address.placeholder": "Enter URL",
+  "session.browser.empty.title": "Enter URL",
+  "session.browser.empty.description": 'Or prompt "Open in the app browser"',
+  "session.browser.failed.title": "URL can't be reached",
+  "session.browser.failed.description": "Check the URL and your connection, then try again.",
 
   "titlebar.update": "Update",
   "titlebar.tabs": "Tabs",
@@ -919,6 +936,10 @@ export const dict = {
   "common.dismiss": "Dismiss",
   "common.moreCountSuffix": " (+{{count}} more)",
   "common.requestFailed": "Request failed",
+  "session.btw.questionRequired": "Add a question after /btw",
+  "session.btw.error": "Couldn’t answer that question",
+  "session.btw.retry": "Retry",
+  "session.btw.copy": "Copy answer",
   "common.moreOptions": "More options",
   "common.learnMore": "Learn more",
   "common.rename": "Rename",

packages/app/src/runtime/platform/browser-pane.ts

@@ -19,6 +19,7 @@ export type BrowserPaneCommand = Browser.Action
 export type BrowserPaneState = Browser.State | null
 export type BrowserPaneEvent =
   | { type: "focus"; tabID: Browser.TabID }
+  | { type: "preview"; path: string }
   | { type: "state"; state: BrowserPaneState; error?: string }
 
 export type BrowserPaneRegistration = {

packages/app/src/runtime/server/types.ts

@@ -33,6 +33,8 @@ export type FileContent = {
   }
   encoding?: "base64"
   mimeType?: string
+  /** On-disk size when the bytes themselves are not retained. */
+  size?: number
 }
 
 export type Path = {

packages/app/src/session/browser/attachments.ts

@@ -1,14 +1,15 @@
-import { createEffect, createMemo, getOwner, on, onCleanup, runWithOwner } from "solid-js"
+import { batch, createEffect, createMemo, createRoot, getOwner, on, onCleanup, runWithOwner } from "solid-js"
 import { createStore, reconcile } from "solid-js/store"
 import { createSimpleContext } from "@opencode/ui/context"
-import type { Browser } from "@opencode/plugin-browser/rpc"
 import { useLanguage } from "@/runtime/i18n/language"
 import type { BrowserPaneCommand } from "@/runtime/platform/browser-pane"
 import { usePlatform } from "@/runtime/platform/platform"
 import type { useServer } from "@/runtime/server/current"
+import type { SessionStateKey } from "@/runtime/server/scope"
 import { useSettings } from "@/settings/model"
 import { findSessionTab, tabKey, useTabs } from "@/shell/tabs/tabs"
-import { useCurrentRoute } from "@/shell/state/layout"
+import { useCurrentRoute, useLayout } from "@/shell/state/layout"
+import { sessionBrowserTab } from "@/shell/state/session-tabs"
 import { createEventListener } from "@solid-primitives/event-listener"
 import { createBrowserConnection, type BrowserConnectionState } from "./connection"
 
@@ -35,13 +36,14 @@ export const { use: useBrowserAttachments, provider: BrowserAttachmentsProvider
     const settings = useSettings()
     const language = useLanguage()
     const shellTabs = useTabs()
+    const layout = useLayout()
     const route = useCurrentRoute()
     const owner = getOwner()
     const [store, setStore] = createStore<Record<string, BrowserAttachment | undefined>>({})
     // Servers whose plugin lacks the browser RPC; sessions on them stop retrying.
     const [unsupported, setUnsupported] = createStore<Record<string, true | undefined>>({})
     const live = new Map<string, Live>()
-    const focus = new Map<string, Set<(tabID: Browser.TabID) => void>>()
+    const preview = new Map<string, Set<(path: string) => void>>()
     const key = (server: Server, sessionID: string) => `${server.key}\n${sessionID}`
     const enabled = createMemo(
       () => !!platform.browserPane && settings.ready() && settings.general.experimentalBrowser(),
@@ -87,11 +89,14 @@ export const { use: useBrowserAttachments, provider: BrowserAttachmentsProvider
       enabled,
       supported: (server: Server) => !unsupported[server.key],
       state: (server: Server, sessionID: string) => store[key(server, sessionID)],
-      attach(server: Server, sessionID: string) {
+      attach(server: Server, sessionID: string, sessionKey: SessionStateKey) {
         const id = key(server, sessionID)
         if (live.has(id)) return
         const pane = platform.browserPane
         if (!pane || !enabled() || unsupported[server.key] || server.health?.incompatible) return
+        // Focus requests write to the owning session's layout even while another shell tab is routed,
+        // so the Review pane and browser tab are already selected when the user returns to it.
+        const tabs = createRoot((dispose) => ({ dispose, layout: layout.tabs(sessionKey) }), owner)
         const connection = createBrowserConnection({
           pane,
           // Resolve the current port at every wake, including after sidecar replacement.
@@ -100,7 +105,15 @@ export const { use: useBrowserAttachments, provider: BrowserAttachmentsProvider
             sessionID,
             endpoint: { ...server.conn.http, url: server.ctx.sdk.url },
           }),
-          focus: (tabID) => focus.get(id)?.forEach((listener) => listener(tabID)),
+          focus: (tabID) => {
+            const tab = sessionBrowserTab(tabID)
+            batch(() => {
+              shellTabs.setPane(findSessionTab(shellTabs.store, server.key, sessionID), "review", true)
+              if (!tabs.layout.all().includes(tab)) tabs.layout.setAll([...tabs.layout.all(), tab])
+              tabs.layout.setActive(tab)
+            })
+          },
+          preview: (path) => preview.get(id)?.forEach((listener) => listener(path)),
           change: (state) => {
             if (state.error === "browser.pane.unsupported") {
               setUnsupported(server.key, true)
@@ -138,17 +151,18 @@ export const { use: useBrowserAttachments, provider: BrowserAttachmentsProvider
         entry.dispose = () => {
           unsubscribe?.forEach((dispose) => dispose())
           connection.dispose()
+          tabs.dispose()
         }
       },
-      /** Desktop focus requests for a mounted session route; nothing is replayed to routes mounted later. */
-      onFocus(server: Server, sessionID: string, listener: (tabID: Browser.TabID) => void) {
+      /** Agent requests to show a file in this session's Review pane. */
+      onPreview(server: Server, sessionID: string, listener: (path: string) => void) {
         const id = key(server, sessionID)
-        const listeners = focus.get(id) ?? new Set()
+        const listeners = preview.get(id) ?? new Set()
         listeners.add(listener)
-        focus.set(id, listeners)
+        preview.set(id, listeners)
         return () => {
           listeners.delete(listener)
-          if (!listeners.size) focus.delete(id)
+          if (!listeners.size) preview.delete(id)
         }
       },
       command(server: Server, sessionID: string, command: BrowserPaneCommand) {

packages/app/src/session/browser/connection.test.ts

@@ -28,10 +28,12 @@ function fixture() {
     commands: Browser.Action[]
   }[] = []
   const endpoint = { url: "http://localhost:4096" }
+  const previews: string[] = []
   const connection = createBrowserConnection({
     target: () => ({ serverKey: "browser-test", sessionID: "ses_browser", endpoint: { ...endpoint } }),
     change: (state) => states.push(state),
     focus: () => {},
+    preview: (path) => previews.push(path),
     pane: {
       register(target, emit) {
         const call = { target, emit, closed: false, commands: [] as Browser.Action[] }
@@ -50,9 +52,21 @@ function fixture() {
   })
   connection.wake()
   calls[0].emit({ type: "state", state: browser })
-  return { connection, calls, states, endpoint }
+  return { connection, calls, states, endpoint, previews }
 }
 
+test("preview requests reach the session without touching connection state", () => {
+  const app = fixture()
+  try {
+    const before = app.states.length
+    app.calls[0].emit({ type: "preview", path: "docs/report.pdf" })
+    expect(app.previews).toEqual(["docs/report.pdf"])
+    expect(app.states).toHaveLength(before)
+  } finally {
+    app.connection.dispose()
+  }
+})
+
 test("suspension retains tabs and reconnects once on demand using the current endpoint", async () => {
   const app = fixture()
   try {

packages/app/src/session/browser/connection.ts

@@ -19,6 +19,7 @@ export function createBrowserConnection(input: {
   target: () => BrowserPaneTarget
   change: (state: BrowserConnectionState) => void
   focus: (tabID: Browser.TabID) => void
+  preview: (path: string) => void
 }) {
   const state: BrowserConnectionState = { browser: null, suspended: false }
   let disposed = false
@@ -33,6 +34,7 @@ export function createBrowserConnection(input: {
       (event) => {
         if (disposed || state.registration !== registration) return
         if (event.type === "focus") return input.focus(event.tabID)
+        if (event.type === "preview") return input.preview(event.path)
         if (event.error === "browser.pane.unsupported" || event.error === "browser.pane.replaced") {
           blocked = true
           registration.close()

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

@@ -1,4 +1,4 @@
-import { batch, createEffect, createMemo, on, onCleanup } from "solid-js"
+import { batch, createEffect, createMemo, on } from "solid-js"
 import type { Browser } from "@opencode/plugin-browser/rpc"
 import { createStore } from "solid-js/store"
 import { useLanguage } from "@/runtime/i18n/language"
@@ -33,13 +33,6 @@ export function createSessionBrowser(session: SessionModel) {
       attachment()?.browser?.tabs.filter((tab) => session.layout.tabs().all().includes(sessionBrowserTab(tab.id))) ??
       [],
   )
-  const focus = (tabID: Browser.TabID) => {
-    session.layout.view().reviewPanel.open()
-    const tabs = session.layout.tabs()
-    const key = sessionBrowserTab(tabID)
-    if (!tabs.all().includes(key)) tabs.setAll([...tabs.all(), key])
-    tabs.setActive(key)
-  }
   const command = (command: BrowserPaneCommand) => {
     const sessionID = session.identity.sessionID()
     if (!sessionID) return
@@ -66,8 +59,7 @@ export function createSessionBrowser(session: SessionModel) {
   createEffect(() => {
     const sessionID = session.identity.sessionID()
     if (!sessionID) return
-    if (attachments.enabled()) attachments.attach(server, sessionID)
-    onCleanup(attachments.onFocus(server, sessionID, focus))
+    if (attachments.enabled()) attachments.attach(server, sessionID, session.layout.sessionKey())
   })
   createEffect(
     on(

packages/app/src/session/browser/pane.tsx

@@ -20,13 +20,18 @@ export function SessionBrowserPane(props: { browser: ReturnType<typeof createSes
   const command = useCommand()
   const state = props.browser.active
   const address = () => (state()?.url === "about:blank" ? "" : (state()?.url ?? ""))
+  const failed = () => !!state()?.loadError
   const registration = props.browser.registration
   const button = { variant: "ghost", size: "large" } as const
   const [store, setStore] = createStore({
     address: "",
     editing: false,
+    submitted: false,
+    // A submitted navigation the browser has not reported yet; keeps the empty state hidden meanwhile.
+    navigating: false,
     visible: typeof document === "undefined" || document.visibilityState === "visible",
   })
+  const empty = () => !address() && !state()?.loading && !store.navigating
   let surface: HTMLDivElement | undefined
   let addressDisplay: HTMLDivElement | undefined
   let frame: number | undefined
@@ -43,7 +48,7 @@ export function SessionBrowserPane(props: { browser: ReturnType<typeof createSes
       title: language.t("command.browser.reload"),
       category: language.t("command.category.view"),
       keybind: "f5",
-      disabled: !props.visible || !state(),
+      disabled: !props.visible || !address(),
       onSelect: () => {
         const tab = state()
         if (tab) props.browser.command({ type: "reload", tabID: tab.id })
@@ -71,7 +76,9 @@ export function SessionBrowserPane(props: { browser: ReturnType<typeof createSes
     const top = Math.round(rect.top * zoom)
     const right = Math.round(rect.right * zoom)
     const bottom = Math.round(rect.bottom * zoom)
-    const visible = props.visible && store.visible && !dialog.active && !covered(rect)
+    // The desktop page hides blank and loading documents itself; only hide here
+    // while the pane shows its own empty or failed state over the surface.
+    const visible = props.visible && store.visible && !empty() && !failed() && !dialog.active && !covered(rect)
     // The cutout exposes the app backdrop outside the rounded Review card,
     // not the browser surface inside it.
     const color = getComputedStyle(
@@ -107,7 +114,25 @@ export function SessionBrowserPane(props: { browser: ReturnType<typeof createSes
     if (frame === undefined) frame = requestAnimationFrame(tick)
   }
 
-  createEffect(() => !store.editing && setStore("address", address()))
+  createEffect(on([() => state()?.id, address], () => !store.editing && setStore("address", address())))
+  // Any reported movement, including a rejected or blocked request, ends the submitted navigation.
+  createEffect(
+    on(
+      [() => state()?.id, () => state()?.generation, () => state()?.loading, () => props.browser.error()],
+      () => setStore("navigating", false),
+      { defer: true },
+    ),
+  )
+  // A blocked or rejected submission leaves the page where it was; show that page's URL again.
+  createEffect(
+    on(
+      () => props.browser.error(),
+      (error) => {
+        if (error && !store.editing) setStore("address", address())
+      },
+      { defer: true },
+    ),
+  )
   createEffect(
     on(registration, (current) => {
       // Session routes can change before this pane unmounts. Hide the registration
@@ -123,6 +148,8 @@ export function SessionBrowserPane(props: { browser: ReturnType<typeof createSes
         () => store.visible,
         () => props.visible,
         () => state()?.id,
+        empty,
+        failed,
         registration,
       ],
       () => {
@@ -157,7 +184,7 @@ export function SessionBrowserPane(props: { browser: ReturnType<typeof createSes
 
   return (
     <aside id="browser-panel" class="relative size-full min-w-0 overflow-hidden bg-v2-background-bg-base flex flex-col">
-      <div class="h-10 shrink-0 flex items-center gap-1 px-2 border-b border-v2-border-border-muted">
+      <div class="h-10 shrink-0 flex items-center gap-1 px-3 border-b border-v2-border-border-muted">
         <For each={["back", "forward"] as const}>
           {(direction) => (
             <Tooltip placement="top" value={language.t(direction === "back" ? "common.goBack" : "common.goForward")}>
@@ -193,7 +220,7 @@ export function SessionBrowserPane(props: { browser: ReturnType<typeof createSes
         >
           <IconButton
             {...button}
-            disabled={!state()}
+            disabled={!state()?.loading && !address()}
             aria-label={language.t(state()?.loading ? "prompt.action.stop" : "error.page.action.reload")}
             onClick={() => {
               const tab = state()
@@ -212,8 +239,13 @@ export function SessionBrowserPane(props: { browser: ReturnType<typeof createSes
           onSubmit={(event) => {
             event.preventDefault()
             const tab = state()
-            if (tab && store.address.trim())
-              props.browser.command({ type: "navigate", tabID: tab.id, url: store.address })
+            const url = store.address.trim()
+            if (!tab) return
+            if (url || failed()) {
+              setStore({ submitted: true, address: url, navigating: true })
+              props.browser.command({ type: "navigate", tabID: tab.id, url: url || "about:blank" })
+            }
+            event.currentTarget.querySelector("input")?.blur()
           }}
         >
           <input
@@ -224,8 +256,14 @@ export function SessionBrowserPane(props: { browser: ReturnType<typeof createSes
             disabled={!state()}
             placeholder={language.t("session.browser.address.placeholder")}
             aria-label={language.t("session.browser.address")}
-            onFocus={() => setStore("editing", true)}
-            onBlur={() => setStore({ editing: false, address: address() })}
+            onFocus={(event) => {
+              setStore("editing", true)
+              event.currentTarget.select()
+            }}
+            onClick={(event) => event.currentTarget.select()}
+            onBlur={() =>
+              setStore({ editing: false, address: store.submitted ? store.address : address(), submitted: false })
+            }
             onInput={(event) => setStore("address", event.currentTarget.value)}
             onScroll={(event) => {
               if (addressDisplay) addressDisplay.scrollLeft = event.currentTarget.scrollLeft
@@ -243,12 +281,27 @@ export function SessionBrowserPane(props: { browser: ReturnType<typeof createSes
           </div>
         </form>
       </div>
-      <Show when={props.browser.error()}>
+      <Show when={props.browser.error() && !failed()}>
         <div class="shrink-0 px-3 py-1.5 text-12-regular text-text-danger-base border-b border-v2-border-border-muted">
           {props.browser.error()}
         </div>
       </Show>
       <div ref={surface} class="min-h-0 flex-1 bg-v2-background-bg-base flex items-center justify-center">
+        <Show when={(empty() || failed()) && !props.browser.suspended()}>
+          {/* Add the 40px toolbar to the file empty state's 160px bottom padding to align their centers. */}
+          <div
+            dir="auto"
+            class="flex size-full flex-col items-center justify-center gap-2 p-6 pb-[200px] text-center text-text-weak"
+          >
+            <Icon name="globe" size="large" class="mb-2 shrink-0" />
+            <div class="text-[13px] font-medium leading-[var(--line-height-compact)] text-text-strong">
+              {language.t(failed() ? "session.browser.failed.title" : "session.browser.empty.title")}
+            </div>
+            <div class="text-13-regular leading-[var(--line-height-base)]">
+              {language.t(failed() ? "session.browser.failed.description" : "session.browser.empty.description")}
+            </div>
+          </div>
+        </Show>
         <Show when={props.browser.suspended()}>
           <p class="px-6 text-center text-13-regular text-v2-text-text-subtle" role="status">
             {language.t("session.browser.suspended")}

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

@@ -0,0 +1,114 @@
+import { createEffect, onCleanup } from "solid-js"
+import { createStore } from "solid-js/store"
+import { useLanguage } from "@/runtime/i18n/language"
+import { useServerSDK } from "@/runtime/server/client"
+import { useCommand } from "@/shell/commands/command"
+import { showToast } from "@/shell/notifications/toast"
+import { SESSION_BTW_TAB } from "@/session/helpers"
+import type { SessionModel } from "../model"
+
+const instructions = [
+  "The user is asking a quick side question about the conversation so far.",
+  "Answer directly and concisely in markdown from what you already know.",
+  "Do not call any tools and do not take any actions.",
+].join(" ")
+
+const empty = {
+  question: "",
+  answer: "",
+  error: false,
+  pending: false,
+}
+
+export function createSessionBtw(session: SessionModel) {
+  const command = useCommand()
+  const language = useLanguage()
+  const server = useServerSDK()
+  const [states, setStates] = createStore<Record<string, typeof empty>>({})
+  const requests = new Map<string, number>()
+  const controllers = new Map<string, AbortController>()
+  const state = () => states[session.identity.sessionKey()] ?? empty
+
+  createEffect(() => {
+    const key = session.identity.sessionKey()
+    onCleanup(() => {
+      const controller = controllers.get(key)
+      if (!controller) return
+      controller.abort()
+      controllers.delete(key)
+      if (states[key]?.pending) setStates(key, { pending: false, error: true })
+    })
+  })
+
+  const open = () => {
+    session.layout.view().reviewPanel.open()
+    const tabs = session.layout.tabs()
+    if (tabs.active() !== SESSION_BTW_TAB) tabs.open(SESSION_BTW_TAB)
+  }
+  const ask = (value?: string) => {
+    const question = value?.trim()
+    if (!question) {
+      showToast({ title: language.t("session.btw.questionRequired") })
+      return
+    }
+    open()
+    const sessionID = session.identity.sessionID()
+    if (!sessionID) return
+
+    const key = session.identity.sessionKey()
+    const request = (requests.get(key) ?? 0) + 1
+    requests.set(key, request)
+    controllers.get(key)?.abort()
+    const controller = new AbortController()
+    controllers.set(key, controller)
+    const owner = session.ownership.capture()
+    setStates(key, { question, answer: "", error: false, pending: true })
+    return server.api.session
+      .generate(
+        {
+          sessionID,
+          prompt: [instructions, question].join("\n\n"),
+        },
+        { signal: controller.signal },
+      )
+      .then((result) => {
+        owner.run(() => {
+          if (requests.get(key) !== request) return
+          setStates(key, { answer: result.text.trim(), pending: false })
+        })
+      })
+      .catch(() => {
+        owner.run(() => {
+          if (controller.signal.aborted || requests.get(key) !== request) return
+          setStates(key, { error: true, pending: false })
+        })
+      })
+      .finally(() => {
+        if (controllers.get(key) === controller) controllers.delete(key)
+      })
+  }
+
+  command.register("session.btw", () => [
+    {
+      id: "session.btw",
+      title: language.t("command.session.btw"),
+      description: language.t("command.session.btw.description"),
+      category: language.t("command.category.session"),
+      slash: "btw",
+      slashArguments: true,
+      hidden: true,
+      disabled: !session.isDesktop(),
+      onSelect: (_source, input) => ask(input),
+    },
+  ])
+
+  return {
+    answer: () => state().answer,
+    error: () => state().error,
+    pending: () => state().pending,
+    question: () => state().question,
+    retry: () => ask(state().question),
+  }
+}
+
+export type SessionBtwModel = ReturnType<typeof createSessionBtw>

packages/app/src/session/btw/panel.tsx

@@ -0,0 +1,80 @@
+import { createEffect, createSignal, Match, Show, Switch } from "solid-js"
+import { Button } from "@opencode/ui/button"
+import { Icon } from "@opencode/ui/icon"
+import { IconButton } from "@opencode/ui/icon-button"
+import { ScrollView } from "@opencode/ui/scroll-view"
+import { TextShimmer } from "@opencode/ui/text-shimmer"
+import { Tooltip } from "@opencode/ui/tooltip"
+import { Markdown } from "@opencode/session-ui/markdown"
+import { useLanguage } from "@/runtime/i18n/language"
+import { usePlatform } from "@/runtime/platform/platform"
+import { showToast } from "@/shell/notifications/toast"
+import type { SessionBtwModel } from "./model"
+
+export function SessionBtwPanel(props: { btw: SessionBtwModel }) {
+  const language = useLanguage()
+  const platform = usePlatform()
+  const [copied, setCopied] = createSignal(false)
+
+  createEffect(() => {
+    props.btw.answer()
+    setCopied(false)
+  })
+
+  const copy = () => {
+    const answer = props.btw.answer()
+    if (!answer) return
+    void (platform.writeClipboardText?.(answer) ?? navigator.clipboard.writeText(answer)).then(
+      () => setCopied(true),
+      () => showToast({ title: language.t("common.requestFailed") }),
+    )
+  }
+
+  return (
+    <div class="flex h-full min-h-0 flex-col bg-v2-background-bg-base" data-slot="session-btw-panel">
+      <div class="flex shrink-0 items-start justify-between gap-3 border-b border-v2-border-border-base px-5 py-4">
+        <div class="min-w-0 text-13-regular text-text-weak">{props.btw.question()}</div>
+        <Show when={props.btw.answer()}>
+          <Tooltip value={copied() ? language.t("common.copied") : language.t("session.btw.copy")}>
+            <IconButton
+              size="small"
+              variant="ghost-muted"
+              icon={<Icon name={copied() ? "check" : "outline-copy"} />}
+              aria-label={copied() ? language.t("common.copied") : language.t("session.btw.copy")}
+              onClick={copy}
+            />
+          </Tooltip>
+        </Show>
+      </div>
+
+      <div class="relative min-h-0 flex-1">
+        <Switch>
+          <Match when={props.btw.pending()}>
+            <div
+              data-component="session-working"
+              role="status"
+              class="flex h-9 items-center px-5 pt-3 text-[13px] font-[530] leading-text-compact"
+            >
+              <TextShimmer text={language.t("session.timeline.working")} active />
+            </div>
+          </Match>
+          <Match when={props.btw.error()}>
+            <div class="flex h-full flex-col items-center justify-center gap-3 px-8 pb-24 text-center">
+              <div class="text-13-regular text-text-weak">{language.t("session.btw.error")}</div>
+              <Button size="small" variant="outline" onClick={props.btw.retry}>
+                {language.t("session.btw.retry")}
+              </Button>
+            </div>
+          </Match>
+          <Match when={props.btw.answer()}>
+            <ScrollView class="absolute inset-0">
+              <div class="px-5 py-4 pb-8">
+                <Markdown text={props.btw.answer()} class="text-14-regular" />
+              </div>
+            </ScrollView>
+          </Match>
+        </Switch>
+      </div>
+    </div>
+  )
+}

packages/app/src/session/files/artifact-view.css

@@ -0,0 +1,94 @@
+/* The control defaults to a fixed 232px with equal segments; here it hugs its two labels. */
+[data-slot="artifact-toolbar"] [data-slot="segmented-control-v2"] {
+  width: auto;
+}
+
+[data-slot="artifact-toolbar"] [data-slot="segmented-control-v2-item"] {
+  flex: 0 0 auto;
+  padding: 0 14px;
+}
+
+/* Shrink-wrapped segments round the label box down a fraction; the ellipsis overflow then clips glyph edges. */
+[data-slot="artifact-toolbar"] [data-slot="segmented-control-v2-item-label"] {
+  overflow: visible;
+  max-width: none;
+}
+
+[data-slot="artifact-stage"] {
+  --artifact-check: color-mix(in oklch, var(--v2-text-text-base) 5%, transparent);
+  background-color: var(--v2-background-bg-deep);
+}
+
+[data-slot="artifact-stage"][data-checker] {
+  background-image:
+    linear-gradient(45deg, var(--artifact-check) 25%, transparent 25%),
+    linear-gradient(-45deg, var(--artifact-check) 25%, transparent 25%),
+    linear-gradient(45deg, transparent 75%, var(--artifact-check) 75%),
+    linear-gradient(-45deg, transparent 75%, var(--artifact-check) 75%);
+  background-size: 16px 16px;
+  background-position:
+    0 0,
+    0 8px,
+    8px -8px,
+    -8px 0;
+}
+
+[data-slot="artifact-media"] {
+  display: block;
+  border-radius: 4px;
+  box-shadow:
+    0 0 0 0.5px var(--v2-border-border-base),
+    0 12px 32px -12px color-mix(in oklch, var(--v2-text-text-base) 25%, transparent);
+}
+
+[data-slot="artifact-stage"][data-zoom="fit"] [data-slot="artifact-media"] {
+  max-width: 100%;
+  max-height: 100%;
+  object-fit: contain;
+}
+
+[data-slot="artifact-stage"][data-zoom="fit"][data-overflow] [data-slot="artifact-media"] {
+  cursor: zoom-in;
+}
+
+[data-slot="artifact-stage"][data-zoom="actual"] [data-slot="artifact-media"] {
+  cursor: zoom-out;
+}
+
+[data-slot="artifact-table"] {
+  border-collapse: separate;
+  border-spacing: 0;
+  font-variant-numeric: tabular-nums;
+}
+
+[data-slot="artifact-table"] th,
+[data-slot="artifact-table"] td {
+  padding: 5px 12px;
+  border-bottom: 1px solid var(--v2-border-border-muted);
+  border-inline-end: 1px solid var(--v2-border-border-muted);
+  white-space: pre;
+  max-width: 40ch;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  text-align: start;
+  line-height: var(--line-height-compact);
+}
+
+[data-slot="artifact-table"] th {
+  position: sticky;
+  top: 0;
+  z-index: 1;
+  background: var(--v2-background-bg-layer-01);
+  font-weight: var(--font-weight-medium);
+  color: var(--v2-text-text-muted);
+}
+
+[data-slot="artifact-table"] tbody tr:hover td {
+  background: color-mix(in oklch, var(--v2-text-text-base) 3%, transparent);
+}
+
+[data-slot="artifact-table"] td[data-index] {
+  color: var(--v2-text-text-faint);
+  text-align: end;
+  user-select: none;
+}

packages/app/src/session/files/artifact-view.tsx

@@ -0,0 +1,454 @@
+import { createEffect, createMemo, For, Match, on, onCleanup, Show, Switch, type JSX } from "solid-js"
+import { createStore } from "solid-js/store"
+import { createResizeObserver } from "@solid-primitives/resize-observer"
+import { Button } from "@opencode/ui/button"
+import { FileIcon } from "@opencode/ui/file-icon"
+import { SegmentedControl, SegmentedControlItem } from "@opencode/ui/segmented-control"
+import { ScrollView } from "@opencode/ui/scroll-view"
+import { Markdown } from "@opencode/session-ui/markdown"
+import { MarkdownProvider, useMarkdown } from "@opencode/session-ui/context/markdown"
+import { getDirectory, getFilename } from "@opencode/util/path"
+import type { FileContent } from "@/runtime/server/types"
+import { useLanguage } from "@/runtime/i18n/language"
+import {
+  artifactKind,
+  blobUrlFromContent,
+  contentBytes,
+  parseDelimited,
+  resolveArtifactPath,
+  type ArtifactKind,
+} from "@/workspaces/files/artifact"
+import { useArtifactOpener } from "@/session/files/open-artifact"
+import "./artifact-view.css"
+
+type ArtifactMode = "preview" | "source"
+
+/** Facts a viewer learns from the decoded media, shown in the toolbar. */
+type ArtifactInfo = { width?: number; height?: number; duration?: number; rows?: number; columns?: number }
+
+type MediaProps = {
+  path: string
+  content: FileContent
+  onInfo: (info: ArtifactInfo) => void
+  /** The browser could not decode the bytes; the host falls back to the binary placeholder. */
+  onError: () => void
+}
+
+/** Kinds that render a preview from their text and can toggle back to highlighted source. */
+const previewableKinds = new Set<ArtifactKind>(["svg", "html", "markdown", "mermaid", "table"])
+
+/**
+ * Renders a loaded non-text file: media, documents, and data get a dedicated viewer with a toolbar;
+ * previewable text kinds can switch to `source`, which the host supplies (its code view).
+ */
+export function ArtifactView(props: { path: string; content: FileContent; cacheKey?: string; source: JSX.Element }) {
+  const language = useLanguage()
+  const [state, setState] = createStore({
+    mode: "preview" as ArtifactMode,
+    info: {} as ArtifactInfo,
+    // Media the browser could not decode falls back to the binary placeholder.
+    undecodable: false,
+  })
+  createEffect(
+    on(
+      () => props.content,
+      () => setState({ mode: "preview", info: {}, undecodable: false }),
+      { defer: true },
+    ),
+  )
+
+  const kind = createMemo<ArtifactKind | "binary">(() => {
+    if (props.content.type === "binary" && !props.content.mimeType) return "binary"
+    if (state.undecodable) return "binary"
+    return artifactKind(props.path)
+  })
+  const previewable = createMemo(() => {
+    const value = kind()
+    return value !== "binary" && previewableKinds.has(value)
+  })
+  const meta = createMemo(() => {
+    const info = state.info
+    return [
+      info.width && info.height ? `${info.width} × ${info.height}` : undefined,
+      info.duration ? formatDuration(info.duration) : undefined,
+      info.rows !== undefined ? language.plural("file.view.table.rows", Math.max(0, info.rows - 1)) : undefined,
+      info.columns !== undefined ? language.plural("file.view.table.columns", info.columns) : undefined,
+      formatBytes(language.intl(), contentBytes(props.content)),
+    ].filter((item): item is string => !!item)
+  })
+
+  const media = { onInfo: (info: ArtifactInfo) => setState("info", info), onError: () => setState("undecodable", true) }
+  const rendered = () => (
+    <ScrollView class="min-h-0 flex-1">
+      <Show
+        when={kind() === "markdown"}
+        fallback={<ArtifactMermaid text={props.content.content} cacheKey={props.cacheKey} />}
+      >
+        <ArtifactMarkdown path={props.path} text={props.content.content} cacheKey={props.cacheKey} />
+      </Show>
+    </ScrollView>
+  )
+
+  return (
+    <>
+      <ArtifactToolbar
+        mode={state.mode}
+        onModeChange={previewable() ? (mode) => setState("mode", mode) : undefined}
+        meta={meta()}
+        actions={
+          <Show when={kind() === "html"}>
+            <OpenInBrowserButton path={props.path} />
+          </Show>
+        }
+      />
+      <Show when={!previewable() || state.mode === "preview"} fallback={props.source}>
+        <Switch>
+          <Match when={kind() === "image" || kind() === "svg"}>
+            <ArtifactImage path={props.path} content={props.content} {...media} />
+          </Match>
+          <Match when={kind() === "video"}>
+            <ArtifactVideo path={props.path} content={props.content} {...media} />
+          </Match>
+          <Match when={kind() === "audio"}>
+            <ArtifactAudio path={props.path} content={props.content} {...media} />
+          </Match>
+          <Match when={kind() === "pdf" || kind() === "html"}>
+            <ArtifactFrame path={props.path} content={props.content} kind={kind() === "pdf" ? "pdf" : "html"} />
+          </Match>
+          <Match when={kind() === "font"}>
+            <ArtifactFont path={props.path} content={props.content} />
+          </Match>
+          <Match when={kind() === "table"}>
+            <ArtifactTable path={props.path} text={props.content.content} onInfo={media.onInfo} />
+          </Match>
+          <Match when={kind() === "markdown" || kind() === "mermaid"}>{rendered()}</Match>
+          <Match when={kind() === "binary"}>
+            <ArtifactBinary path={props.path} size={formatBytes(language.intl(), contentBytes(props.content))} />
+          </Match>
+        </Switch>
+      </Show>
+    </>
+  )
+}
+
+function formatBytes(locale: string, bytes: number) {
+  const units = ["byte", "kilobyte", "megabyte", "gigabyte"] as const
+  const index = Math.min(units.length - 1, bytes > 0 ? Math.floor(Math.log10(bytes) / 3) : 0)
+  const value = bytes / 1000 ** index
+  return new Intl.NumberFormat(locale, {
+    style: "unit",
+    unit: units[index],
+    // "short" bytes render as the singular "byte"; the long form pluralizes correctly.
+    unitDisplay: index === 0 ? "long" : "short",
+    maximumFractionDigits: value >= 100 || index === 0 ? 0 : 1,
+  }).format(value)
+}
+
+function formatDuration(seconds: number) {
+  const total = Math.round(seconds)
+  const minutes = Math.floor(total / 60)
+  return `${minutes}:${String(total % 60).padStart(2, "0")}`
+}
+
+function ArtifactToolbar(props: {
+  mode?: ArtifactMode
+  onModeChange?: (mode: ArtifactMode) => void
+  meta: string[]
+  actions?: JSX.Element
+}) {
+  const language = useLanguage()
+  return (
+    <div data-slot="artifact-toolbar" class="flex h-10 shrink-0 items-center gap-3 px-4">
+      <Show when={props.onModeChange}>
+        <SegmentedControl
+          value={props.mode ?? "preview"}
+          onChange={(value) => {
+            if (value === "preview" || value === "source") props.onModeChange?.(value)
+          }}
+        >
+          <SegmentedControlItem value="preview">{language.t("file.view.preview")}</SegmentedControlItem>
+          <SegmentedControlItem value="source">{language.t("file.view.source")}</SegmentedControlItem>
+        </SegmentedControl>
+      </Show>
+      <div class="ms-auto flex min-w-0 items-center gap-3">
+        <div class="flex min-w-0 items-center gap-2 text-12-regular text-text-weak">
+          <For each={props.meta}>
+            {(item, index) => (
+              <>
+                <Show when={index() > 0}>
+                  <span aria-hidden class="text-text-faint">
+                    ·
+                  </span>
+                </Show>
+                <span class="truncate tabular-nums">{item}</span>
+              </>
+            )}
+          </For>
+        </div>
+        {props.actions}
+      </div>
+    </div>
+  )
+}
+
+function OpenInBrowserButton(props: { path: string }) {
+  const language = useLanguage()
+  const artifacts = useArtifactOpener()
+  return (
+    <Show when={artifacts.canOpenInBrowser(props.path)}>
+      <Button size="small" variant="ghost" icon="globe" onClick={() => artifacts.openInBrowser(props.path)}>
+        {language.t("file.view.openInBrowser")}
+      </Button>
+    </Show>
+  )
+}
+
+function createBlobUrl(content: () => FileContent) {
+  return createMemo(() => {
+    const value = blobUrlFromContent(content())
+    onCleanup(() => URL.revokeObjectURL(value))
+    return value
+  })
+}
+
+/** Images and SVG previews: fit the pane, click to inspect at 1:1 when the image is larger. */
+function ArtifactImage(props: MediaProps) {
+  const url = createBlobUrl(() => props.content)
+  const [state, setState] = createStore({ zoom: "fit" as "fit" | "actual", overflow: false, width: 0, height: 0 })
+  let stage: HTMLDivElement | undefined
+  const measure = () => {
+    if (!stage) return
+    setState("overflow", state.width > stage.clientWidth - 48 || state.height > stage.clientHeight - 48)
+  }
+  createResizeObserver(
+    () => stage,
+    () => measure(),
+  )
+  createEffect(() => {
+    url()
+    setState({ zoom: "fit", overflow: false })
+  })
+  return (
+    <div
+      ref={stage}
+      data-slot="artifact-stage"
+      data-checker
+      data-zoom={state.zoom}
+      data-overflow={state.overflow || undefined}
+      class="relative min-h-0 flex-1 overflow-auto"
+    >
+      <div
+        classList={{
+          "absolute inset-0 flex items-center justify-center p-6": state.zoom === "fit",
+          "flex min-h-full min-w-full w-max items-center justify-center p-6": state.zoom === "actual",
+        }}
+      >
+        <img
+          data-slot="artifact-media"
+          src={url()}
+          alt={getFilename(props.path)}
+          draggable={false}
+          onError={() => props.onError()}
+          onLoad={(event) => {
+            const image = event.currentTarget
+            setState({ width: image.naturalWidth, height: image.naturalHeight })
+            props.onInfo({ width: image.naturalWidth, height: image.naturalHeight })
+            measure()
+          }}
+          onClick={() => {
+            if (!state.overflow && state.zoom === "fit") return
+            setState("zoom", state.zoom === "fit" ? "actual" : "fit")
+          }}
+        />
+      </div>
+    </div>
+  )
+}
+
+function ArtifactVideo(props: MediaProps) {
+  const url = createBlobUrl(() => props.content)
+  return (
+    <div data-slot="artifact-stage" data-zoom="fit" class="relative min-h-0 flex-1 overflow-hidden">
+      <div class="absolute inset-0 flex items-center justify-center p-6">
+        <video
+          data-slot="artifact-media"
+          class="w-full bg-black"
+          controls
+          preload="metadata"
+          playsinline
+          onError={() => props.onError()}
+          src={url()}
+          onLoadedMetadata={(event) => {
+            const video = event.currentTarget
+            props.onInfo({ width: video.videoWidth, height: video.videoHeight, duration: video.duration })
+          }}
+        />
+      </div>
+    </div>
+  )
+}
+
+function ArtifactAudio(props: MediaProps) {
+  const url = createBlobUrl(() => props.content)
+  return (
+    <div data-slot="artifact-stage" class="relative min-h-0 flex-1 overflow-auto">
+      <div class="absolute inset-0 flex items-center justify-center p-6">
+        <div class="flex w-full max-w-lg flex-col items-center gap-5 rounded-xl border border-v2-border-border-muted bg-v2-background-bg-base px-8 py-8 shadow-[var(--v2-elevation-raised)]">
+          <div class="flex size-14 items-center justify-center rounded-full bg-v2-background-bg-layer-02">
+            <FileIcon node={{ path: props.path, type: "file" }} class="size-7" />
+          </div>
+          <div class="max-w-full truncate text-14-medium text-text-strong">{getFilename(props.path)}</div>
+          <audio
+            class="w-full"
+            onError={() => props.onError()}
+            controls
+            preload="metadata"
+            src={url()}
+            onLoadedMetadata={(event) => props.onInfo({ duration: event.currentTarget.duration })}
+          />
+        </div>
+      </div>
+    </div>
+  )
+}
+
+function ArtifactFrame(props: { path: string; content: FileContent; kind: "pdf" | "html" }) {
+  const url = createBlobUrl(() => props.content)
+  // PDF Open Parameters: start with the thumbnail pane closed and the page fitted to the pane width.
+  const src = () => (props.kind === "pdf" ? `${url()}#navpanes=0&view=FitH` : url())
+  return (
+    <iframe
+      class="block h-full w-full flex-1 border-0 bg-white"
+      title={getFilename(props.path)}
+      src={src()}
+      // The PDF viewer is Chromium's own and does not run in a sandboxed frame. HTML runs as an
+      // opaque origin: no app storage, cookies, or credentialed requests reach it.
+      sandbox={props.kind === "html" ? "allow-scripts allow-popups allow-forms allow-modals" : undefined}
+      referrerPolicy="no-referrer"
+    />
+  )
+}
+
+function ArtifactMarkdown(props: { path: string; text: string; cacheKey?: string }) {
+  const parent = useMarkdown()
+  const artifacts = useArtifactOpener()
+  // getDirectory yields "/" for a root-level file, which would make relative links absolute.
+  const dir = createMemo(() => (props.path.includes("/") || props.path.includes("\\") ? getDirectory(props.path) : ""))
+  // Absolute references bypass the file's directory; relative ones resolve against it.
+  const resolve = (href: string) => (/^([a-z]:)?\//i.test(href) ? href : (resolveArtifactPath(dir(), href) ?? href))
+  return (
+    <MarkdownProvider
+      readImage={(src, signal) => parent?.readImage?.(resolve(src), signal) ?? Promise.resolve(undefined)}
+      openLocalFile={(href) => artifacts.open(href, dir())}
+    >
+      <div class="mx-auto w-full max-w-3xl px-8 py-6">
+        <Markdown text={props.text} cacheKey={props.cacheKey} class="select-text" />
+      </div>
+    </MarkdownProvider>
+  )
+}
+
+/** Mermaid sources render through the same fenced-block pipeline the timeline uses. */
+function ArtifactMermaid(props: { text: string; cacheKey?: string }) {
+  return (
+    <div class="mx-auto w-full max-w-4xl px-8 py-6">
+      <Markdown text={`\`\`\`mermaid\n${props.text}\n\`\`\``} cacheKey={props.cacheKey} class="select-text" />
+    </div>
+  )
+}
+
+function ArtifactTable(props: { path: string; text: string; onInfo: (info: ArtifactInfo) => void }) {
+  const language = useLanguage()
+  const parsed = createMemo(() => parseDelimited(props.text, props.path.toLowerCase().endsWith(".tsv") ? "\t" : ","))
+  createEffect(() => props.onInfo({ rows: parsed().total, columns: parsed().columns }))
+  // Pad the header to the widest row so no data column is dropped.
+  const header = () => Array.from({ length: parsed().columns }, (_, index) => parsed().rows[0]?.[index] ?? "")
+  const body = () => parsed().rows.slice(1)
+  return (
+    <div class="min-h-0 flex-1 overflow-auto">
+      <table data-slot="artifact-table" class="min-w-full text-13-regular text-text-base">
+        <thead>
+          <tr>
+            <th data-index />
+            <For each={header()}>{(cell) => <th>{cell}</th>}</For>
+          </tr>
+        </thead>
+        <tbody>
+          <For each={body()}>
+            {(row, index) => (
+              <tr>
+                <td data-index>{index() + 1}</td>
+                <For each={header()}>{(_, column) => <td>{row[column()] ?? ""}</td>}</For>
+              </tr>
+            )}
+          </For>
+        </tbody>
+      </table>
+      <Show when={parsed().total > parsed().rows.length}>
+        <div class="px-4 py-3 text-12-regular text-text-weak">
+          {language.t("file.view.table.truncated", { shown: parsed().rows.length - 1, total: parsed().total - 1 })}
+        </div>
+      </Show>
+    </div>
+  )
+}
+
+const specimenSizes = [12, 16, 24, 40, 64]
+
+function ArtifactFont(props: { path: string; content: FileContent }) {
+  const language = useLanguage()
+  const url = createBlobUrl(() => props.content)
+  const family = createMemo(() => `artifact-${Math.random().toString(36).slice(2)}`)
+  createEffect(() => {
+    const face = new FontFace(family(), `url(${url()})`)
+    document.fonts.add(face)
+    void face.load().catch(() => undefined)
+    onCleanup(() => document.fonts.delete(face))
+  })
+  return (
+    <div class="min-h-0 flex-1 overflow-auto">
+      <div class="mx-auto flex w-full max-w-3xl flex-col gap-6 px-8 py-8" style={{ "font-family": `"${family()}"` }}>
+        <div class="text-text-strong" style={{ "font-size": "56px", "line-height": "1.1" }}>
+          {getFilename(props.path).replace(/\.[^.]+$/, "")}
+        </div>
+        <div class="break-all text-text-base" style={{ "font-size": "22px", "line-height": "1.4" }}>
+          ABCDEFGHIJKLMNOPQRSTUVWXYZ
+          <br />
+          abcdefghijklmnopqrstuvwxyz
+          <br />
+          0123456789 !?&@#%(){}[]
+        </div>
+        <div class="flex flex-col gap-3 border-t border-v2-border-border-muted pt-6">
+          <For each={specimenSizes}>
+            {(size) => (
+              <div class="flex items-baseline gap-4">
+                <span
+                  class="w-8 shrink-0 text-12-regular text-text-faint tabular-nums"
+                  style={{ "font-family": "var(--font-family-mono)" }}
+                >
+                  {size}
+                </span>
+                <span class="text-text-base" style={{ "font-size": `${size}px`, "line-height": "1.25" }}>
+                  {language.t("file.view.fontSample")}
+                </span>
+              </div>
+            )}
+          </For>
+        </div>
+      </div>
+    </div>
+  )
+}
+
+function ArtifactBinary(props: { path: string; size: string }) {
+  const language = useLanguage()
+  return (
+    <div data-slot="artifact-stage" class="relative min-h-0 flex-1">
+      <div class="absolute inset-0 flex flex-col items-center justify-center gap-3 p-6 text-center">
+        <FileIcon node={{ path: props.path, type: "file" }} class="size-8 text-text-weak" />
+        <div class="text-14-medium text-text-strong">{getFilename(props.path)}</div>
+        <div class="text-13-regular text-text-weak">{language.t("file.view.binary", { size: props.size })}</div>
+      </div>
+    </div>
+  )
+}

packages/app/src/session/files/file-tabs.tsx

@@ -1,4 +1,4 @@
-import { createEffect, createMemo, createSignal, Match, on, onCleanup, Switch } from "solid-js"
+import { createEffect, createMemo, createSignal, Match, on, onCleanup, Show, Switch } from "solid-js"
 import { createStore } from "solid-js/store"
 import { Dynamic } from "solid-js/web"
 import { makeEventListener } from "@solid-primitives/event-listener"
@@ -11,8 +11,9 @@ import { LineCommentOverflowIcon } from "@opencode/ui/line-comment"
 import { Menu } from "@opencode/ui/menu"
 import { Tabs } from "@opencode/ui/tabs"
 import { ScrollView } from "@opencode/ui/scroll-view"
-import { showToast } from "@/shell/notifications/toast"
 import { selectionFromLines, useFile, type FileSelection, type SelectedLineRange } from "@/workspaces/files/model"
+import { artifactKind } from "@/workspaces/files/artifact"
+import { ArtifactView } from "@/session/files/artifact-view"
 import { useComments } from "@/composer/comments"
 import { useLanguage } from "@/runtime/i18n/language"
 import { useComposerState } from "@/composer/persistence"
@@ -205,6 +206,11 @@ export function SessionFileView(props: SessionFileViewProps) {
   })
   const contents = createMemo(() => state()?.content?.content ?? "")
   const cacheKey = createMemo(() => sampledChecksum(contents()))
+  // Plain text keeps the code view; every other kind is rendered by ArtifactView.
+  const artifact = createMemo(() => {
+    const content = state()?.content
+    return content?.type === "binary" || artifactKind(path() ?? "") !== "text"
+  })
   const selectedLines = createMemo<SelectedLineRange | null>(() => {
     const p = path()
     if (!p) return null
@@ -433,39 +439,42 @@ export function SessionFileView(props: SessionFileViewProps) {
         }}
         search={search}
         class="select-text"
-        media={{
-          mode: "auto",
-          path: path(),
-          current: state()?.content,
-          onLoad: scrollSync.queueRestore,
-          onError: (args: { kind: "image" | "audio" | "svg" }) => {
-            if (args.kind !== "svg") return
-            showToast({
-              variant: "error",
-              title: language.t("toast.file.loadFailed.title"),
-            })
-          },
-        }}
+        // Media and previews have their own viewers below; the code view only ever shows text.
+        media={{ mode: "off" }}
       />
     </div>
   )
 
+  // The code view scrolls inside ScrollView so line state and scroll position persist per tab.
+  const codeView = (source: string) => (
+    <ScrollView class="min-h-0 flex-1" viewportRef={scrollSync.setViewport} onScroll={scrollSync.handleScroll}>
+      {renderFile(source)}
+    </ScrollView>
+  )
+
   const content = () => (
-    <div class="mt-3 relative h-full min-h-0">
-      <ScrollView class="h-full" viewportRef={scrollSync.setViewport} onScroll={scrollSync.handleScroll}>
-        <Switch>
-          <Match when={state()?.loaded}>{renderFile(contents())}</Match>
-          <Match when={state()?.loading}>
-            <div class="px-6 py-4 text-text-weak">{language.t("common.loading")}…</div>
-          </Match>
-          <Match when={state()?.notFound ? state()?.name : undefined}>
-            {(name) => (
-              <div class="px-6 py-4 text-text-weak">{language.t("file.error.notFound", { name: name() })}</div>
-            )}
-          </Match>
-          <Match when={state()?.error}>{(err) => <div class="px-6 py-4 text-text-weak">{err()}</div>}</Match>
-        </Switch>
-      </ScrollView>
+    <div class="mt-3 relative h-full min-h-0 flex flex-col">
+      <Switch>
+        <Match when={state()?.loaded ? state()?.content : undefined}>
+          {(value) => (
+            <Show when={artifact()} fallback={codeView(value().content)}>
+              <ArtifactView
+                path={path() ?? ""}
+                content={value()}
+                cacheKey={cacheKey()}
+                source={codeView(value().content)}
+              />
+            </Show>
+          )}
+        </Match>
+        <Match when={state()?.loading}>
+          <div class="px-6 py-4 text-text-weak">{language.t("common.loading")}…</div>
+        </Match>
+        <Match when={state()?.notFound ? state()?.name : undefined}>
+          {(name) => <div class="px-6 py-4 text-text-weak">{language.t("file.error.notFound", { name: name() })}</div>}
+        </Match>
+        <Match when={state()?.error}>{(err) => <div class="px-6 py-4 text-text-weak">{err()}</div>}</Match>
+      </Switch>
     </div>
   )
 

packages/app/src/session/files/open-artifact.tsx

@@ -0,0 +1,105 @@
+import { createEffect, onCleanup, type ParentProps } from "solid-js"
+import { createSimpleContext } from "@opencode/ui/context"
+import { MarkdownProvider, useMarkdown } from "@opencode/session-ui/context/markdown"
+import { useBrowserAttachments } from "@/session/browser/attachments"
+import type { SessionModel } from "@/session/model"
+import { useFile } from "@/workspaces/files/model"
+import { artifactKind, resolveArtifactPath } from "@/workspaces/files/artifact"
+import { encodeFilePath } from "@/workspaces/files/path"
+import { useWorkspaceLocation } from "@/workspaces/location"
+import { useServer } from "@/runtime/server/current"
+import { ServerConnection } from "@/runtime/server/registry"
+import { useSessionLayout } from "@/session/session-layout"
+import { createOpenSessionFileTab } from "@/session/helpers"
+import type { createSessionBrowser } from "@/session/browser/model"
+
+/** Routes local links in timeline markdown to the artifact opener while keeping image loading. */
+export function ArtifactMarkdownProvider(props: ParentProps) {
+  const markdown = useMarkdown()
+  const artifacts = useArtifactOpener()
+  return (
+    <MarkdownProvider readImage={markdown?.readImage} openLocalFile={(path) => artifacts.open(path)}>
+      {props.children}
+    </MarkdownProvider>
+  )
+}
+
+/**
+ * Opens files the agent references as side-panel tabs, inside or outside the workspace, or as
+ * a browser tab for HTML when the desktop can load the file directly.
+ */
+export const { use: useArtifactOpener, provider: ArtifactOpenerProvider } = createSimpleContext({
+  name: "ArtifactOpener",
+  init: (props: { session: SessionModel; browser: ReturnType<typeof createSessionBrowser> }) => {
+    const file = useFile()
+    const server = useServer()
+    const location = useWorkspaceLocation()
+    const attachments = useBrowserAttachments()
+    const { tabs, view } = useSessionLayout()
+
+    const root = () => location().directory.replaceAll("\\", "/").replace(/\/+$/, "")
+
+    /**
+     * Turn a link into a path `useFile` can load: workspace-relative when it is under the root,
+     * otherwise absolute. Relative links resolve against `base`; ones that climb past the root
+     * become absolute too, so a `../../shared/report.pdf` still opens.
+     */
+    const resolve = (href: string, base?: string) => {
+      // Agents cite locations as path:line or path:line:col; the file is what opens.
+      const value = href.replaceAll("\\", "/").replace(/:\d+(?::\d+)?$/, "")
+      if (/^[a-z]:\//i.test(value) || value.startsWith("/")) return file.normalize(value)
+      const relative = resolveArtifactPath(base ?? "", value)
+      if (relative !== undefined) return file.normalize(relative)
+      // Climbing past the workspace root: resolve from the referencing folder's absolute location.
+      const dir = base ? `${root()}/${base.replace(/\/+$/, "")}` : root()
+      return file.normalize(resolveArtifactPath(dir, value) ?? value)
+    }
+
+    const showTab = createOpenSessionFileTab({
+      normalizeTab: (tab) => tab,
+      openTab: (tab) => tabs().open(tab),
+      pathFromTab: file.pathFromTab,
+      loadFile: () => undefined,
+      openReviewPanel: () => {
+        if (!view().reviewPanel.opened()) view().reviewPanel.open()
+      },
+      setActive: (tab) => tabs().setActive(tab),
+    })
+
+    // Inline paths are guessed from text, so confirm the file exists before a tab appears for it.
+    const openTab = (path: string) => {
+      void file.load(path).then(() => {
+        if (file.get(path)?.loaded) showTab(file.tab(path))
+      })
+    }
+
+    // The desktop's own sidecar shares this disk, and its browser pane accepts file:// URLs inside the
+    // session workspace only. Forwarded loopback servers do not qualify, matching the desktop policy.
+    const canOpenInBrowser = (path?: string) =>
+      ServerConnection.builtin(server.conn) &&
+      props.browser.available() &&
+      props.browser.attached() &&
+      (path === undefined || !file.absolute(path))
+
+    const openInBrowser = (path: string) => {
+      props.browser.command({ type: "tabs.open", url: `file://${encodeFilePath(`${root()}/${path}`)}` })
+    }
+
+    /** Open `href` as referenced from `base` (a workspace-relative directory, "" for the root). */
+    const open = (href: string, base?: string) => {
+      const path = resolve(href, base)
+      if (!path) return
+      if (artifactKind(path) === "html" && canOpenInBrowser(path)) return openInBrowser(path)
+      openTab(path)
+    }
+
+    // The agent's browser.preview tool arrives through the desktop browser pane attachment.
+    createEffect(() => {
+      const sessionID = props.session.identity.sessionID()
+      if (!sessionID) return
+      onCleanup(attachments.onPreview(server, sessionID, (path) => open(path)))
+    })
+
+    return { canOpenInBrowser, openInBrowser, open }
+  },
+})

packages/app/src/session/files/session-file-browser-tab.tsx

@@ -173,7 +173,9 @@ export function SessionFileBrowserTab(props: {
           <SessionFilePanelV2Empty>
             <div class="flex flex-col items-center gap-2 text-center text-text-weak">
               <Icon name="file-tree" size="large" class="mb-2" />
-              <div class="text-[13px] font-medium leading-[13px] text-text-strong">{language.t("command.file.open")}</div>
+              <div class="text-[13px] font-medium leading-[13px] text-text-strong">
+                {language.t("command.file.open")}
+              </div>
               <div class="h-5 text-13-regular leading-5">{language.t("session.files.selectToOpen")}</div>
             </div>
           </SessionFilePanelV2Empty>

packages/app/src/session/files/session-side-panel.tsx

@@ -37,6 +37,7 @@ import { useSettings } from "@/settings/model"
 import { createFileTabListSync } from "@/session/files/file-tab-scroll"
 import {
   SESSION_OPEN_FILE_TAB,
+  SESSION_BTW_TAB,
   isSessionBrowserTab,
   sessionBrowserTab,
   createOpenSessionFileTab,
@@ -74,6 +75,7 @@ export function SessionSidePanel(props: {
   size: Sizing
   stacked?: boolean
   browser: ReturnType<typeof createSessionBrowser>
+  btwPanel: () => JSX.Element
 }) {
   const layout = useLayout()
   const settings = useSettings()
@@ -227,7 +229,7 @@ export function SessionSidePanel(props: {
   })
   const fileBrowserVisible = createMemo(() => {
     const active = activeTab()
-    return active !== "review" && active !== "context" && active !== "empty" && !isSessionBrowserTab(active)
+    return active === SESSION_OPEN_FILE_TAB || active === activeFileTab()
   })
   const openFileKeybind = createMemo(() => command.keybindParts("file.open"))
   const openBrowserKeybind = createMemo(() => command.keybindParts("browser.open"))
@@ -385,6 +387,14 @@ export function SessionSidePanel(props: {
                                   />
                                 }
                               >
+                                <Match when={tab === SESSION_BTW_TAB}>
+                                  <SortableTab tab={tab} index={tabs().all().indexOf(tab)} onTabClose={tabs().close}>
+                                    <div class="flex items-center gap-1.5">
+                                      <Icon name="bubble-5" size="small" />
+                                      <span>{language.t("session.tab.btw")}</span>
+                                    </div>
+                                  </SortableTab>
+                                </Match>
                                 <Match when={isSessionBrowserTab(tab)}>
                                   <Show when={props.browser.tabs().find((item) => sessionBrowserTab(item.id) === tab)}>
                                     {(item) => (
@@ -583,6 +593,12 @@ export function SessionSidePanel(props: {
                         </Tabs.Content>
                       </Show>
 
+                      <Show when={activeTab() === SESSION_BTW_TAB}>
+                        <Tabs.Content value={SESSION_BTW_TAB} class="flex h-full min-h-0 flex-col overflow-hidden">
+                          {props.btwPanel()}
+                        </Tabs.Content>
+                      </Show>
+
                       <Show when={props.browser.opened()}>
                         <div
                           id={browserTabPanelID}

packages/app/src/session/files/tab.tsx

@@ -1,6 +1,8 @@
 import { children, createMemo, Show } from "solid-js"
 import type { JSX } from "solid-js"
 import { useSortable } from "@dnd-kit/solid/sortable"
+import { Icon } from "@opencode/ui/icon"
+import { IconButton } from "@opencode/ui/icon-button"
 import { Keybind } from "@opencode/ui/keybind"
 import { Tooltip } from "@opencode/ui/tooltip"
 import { Tabs } from "@opencode/ui/tabs"
@@ -69,9 +71,19 @@ export function SortableTab(props: {
               placement="bottom"
               gutter={10}
             >
-              <Tabs.CloseButton
-                class="h-5 w-5"
-                onClick={() => props.onTabClose(props.tab)}
+              <IconButton
+                size="small"
+                variant="ghost-muted"
+                onPointerDown={(event) => {
+                  event.preventDefault()
+                  event.stopPropagation()
+                }}
+                onClick={(event) => {
+                  event.preventDefault()
+                  event.stopPropagation()
+                  props.onTabClose(props.tab)
+                }}
+                icon={<Icon name="xmark-small" />}
                 aria-label={language.t("common.closeTab")}
               />
             </Tooltip>

packages/app/src/session/helpers.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, test } from "bun:test"
 import { createMemo, createRoot } from "solid-js"
 import { createStore } from "solid-js/store"
 import {
+  SESSION_BTW_TAB,
   SESSION_BROWSER_TAB,
   sessionBrowserTab,
   SESSION_OPEN_FILE_TAB,
@@ -236,6 +237,24 @@ describe("createSessionTabs", () => {
     })
   })
 
+  test("exposes the BTW tab without treating it as a file tab", () => {
+    createRoot((dispose) => {
+      const tabs = createMemo(() => ({ active: () => SESSION_BTW_TAB, all: () => [SESSION_BTW_TAB] }))
+      const result = createSessionTabs({
+        tabs,
+        pathFromTab: () => undefined,
+        normalizeTab: (tab) => tab,
+      })
+
+      expect(result.panelTabs()).toEqual([SESSION_BTW_TAB])
+      expect(result.openedTabs()).toEqual([])
+      expect(result.activeTab()).toBe(SESSION_BTW_TAB)
+      expect(result.activeFileTab()).toBeUndefined()
+      expect(result.closableTab()).toBe(SESSION_BTW_TAB)
+      dispose()
+    })
+  })
+
   test("exposes one browser tab without treating it as a file tab", () => {
     createRoot((dispose) => {
       const tabs = createMemo(() => ({ active: () => SESSION_BROWSER_TAB, all: () => [SESSION_BROWSER_TAB] }))

packages/app/src/session/helpers.ts

@@ -2,10 +2,11 @@ import { batch, createMemo, onCleanup, onMount, type Accessor } from "solid-js"
 import { createStore } from "solid-js/store"
 import { makeEventListener } from "@solid-primitives/event-listener"
 import { same } from "@/runtime/persistence/equality"
-import { isSessionBrowserTab, SESSION_OPEN_FILE_TAB } from "@/shell/state/session-tabs"
+import { isSessionBrowserTab, SESSION_BTW_TAB, SESSION_OPEN_FILE_TAB } from "@/shell/state/session-tabs"
 
 export {
   SESSION_BROWSER_TAB,
+  SESSION_BTW_TAB,
   SESSION_OPEN_FILE_TAB,
   sessionBrowserTab,
   isSessionBrowserTab,
@@ -63,13 +64,17 @@ export const createSessionTabs = (input: TabsInput) => {
     { equals: same },
   )
   const openedTabs = createMemo(
-    () => panelTabs().filter((tab) => tab !== SESSION_OPEN_FILE_TAB && !isSessionBrowserTab(tab)),
+    () =>
+      panelTabs().filter(
+        (tab) => tab !== SESSION_OPEN_FILE_TAB && tab !== SESSION_BTW_TAB && !isSessionBrowserTab(tab),
+      ),
     emptyTabs,
     { equals: same },
   )
   const activeTab = createMemo(() => {
     const active = input.tabs().active()
     if (active === "context") return active
+    if (active === SESSION_BTW_TAB) return active
     if (active === SESSION_OPEN_FILE_TAB && openFileOpen()) return active
     if (active && isSessionBrowserTab(active) && browser()) return active
     if (active === "review" && review()) return active
@@ -89,6 +94,7 @@ export const createSessionTabs = (input: TabsInput) => {
   const closableTab = createMemo<string | undefined>(() => {
     const active = activeTab()
     if (active === "context") return active
+    if (active === SESSION_BTW_TAB) return active
     if (active === SESSION_OPEN_FILE_TAB && openFileOpen()) return active
     if (active && isSessionBrowserTab(active) && browser()) return active
     if (!openedTabs().includes(active)) return

packages/app/src/session/model.ts

@@ -137,6 +137,7 @@ export function useSessionModel() {
       tabs: layout.tabs,
       view: layout.view,
       tabKey: layout.tabKey,
+      sessionKey: layout.sessionKey,
     },
     ownership: createSessionOwnership(layout.sessionKey),
     tabs: {

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

@@ -155,6 +155,9 @@ export function createSessionReview(input: {
   const count = () => diffs().length
   const hasChanges = () => count() > 0
   const ready = () => {
+    // A project without VCS never enables vcsQuery, so its status stays "pending" forever.
+    const project = input.session.project()
+    if (project && !project.vcs) return true
     if (mode() === "git" || mode() === "branch") return !vcsQuery.isPending
     return true
   }

packages/app/src/session/review/view.tsx

@@ -14,6 +14,8 @@ import { ReviewPanel } from "./panel"
 import { SessionReviewTab } from "./review-tab"
 import type { ChangeMode, SessionReviewModel } from "./model"
 import type { createSessionBrowser } from "../browser/model"
+import type { SessionBtwModel } from "../btw/model"
+import { SessionBtwPanel } from "../btw/panel"
 
 const MobilePanelDrawer = lazy(async () => {
   const { MobilePanelDrawer } = await import("@/shell/mobile-panel-drawer")
@@ -127,6 +129,7 @@ export function SessionMobileReview(props: { review: SessionReviewModel }) {
 export function SessionDesktopReview(props: {
   review: SessionReviewModel
   browser: ReturnType<typeof createSessionBrowser>
+  btw: SessionBtwModel
   present?: boolean
 }) {
   return (
@@ -153,6 +156,7 @@ export function SessionDesktopReview(props: {
         size={props.review.screen.size}
         stacked={props.review.screen.side.layout().stacked}
         browser={props.browser}
+        btwPanel={() => <SessionBtwPanel btw={props.btw} />}
       />
     </Suspense>
   )
@@ -249,7 +253,7 @@ function ReviewTitle(props: { review: SessionReviewModel }) {
 function ReviewEmpty(props: { review: SessionReviewModel; loadingClass: string }) {
   const language = useLanguage()
   const loading = () => (props.review.mode() === "git" || props.review.mode() === "branch") && !props.review.ready()
-  const noGit = () => props.review.mode() === "turn" && props.review.noGit()
+  const noGit = () => props.review.noGit()
   const text = () => {
     if (props.review.mode() === "git") return language.t("session.review.noUncommittedChanges")
     if (props.review.mode() === "branch") return language.t("session.review.noBranchChanges")
@@ -282,7 +286,7 @@ function ReviewEmpty(props: { review: SessionReviewModel; loadingClass: string }
 function ReviewPanelEmpty(props: { review: SessionReviewModel }) {
   const language = useLanguage()
   const loading = () => (props.review.mode() === "git" || props.review.mode() === "branch") && !props.review.ready()
-  const noGit = () => props.review.mode() === "turn" && props.review.noGit()
+  const noGit = () => props.review.noGit()
   return (
     <Switch>
       <Match when={loading()}>

packages/app/src/session/screen.tsx

@@ -38,6 +38,8 @@ import { SessionReviewToggle } from "./header/session-header-actions"
 import { createAnimatedPresence } from "@/runtime/animated-presence"
 import { createSessionBrowser } from "./browser/model"
 import { createTimelineCache } from "./timeline/cache"
+import { ArtifactMarkdownProvider, ArtifactOpenerProvider } from "./files/open-artifact"
+import { createSessionBtw } from "./btw/model"
 
 const SessionMobileFiles = lazy(async () => {
   const { SessionMobileFiles } = await import("./files/session-mobile-files")
@@ -50,14 +52,27 @@ const SessionSummaryPanel = lazy(async () => {
 })
 
 export function SessionScreen(props: { session: SessionModel }) {
+  // The timeline cache captures its owner when created, so link handling must be provided above it.
+  const browser = createSessionBrowser(props.session)
+  return (
+    <ArtifactOpenerProvider session={props.session} browser={browser}>
+      <ArtifactMarkdownProvider>
+        <SessionScreenContent session={props.session} browser={browser} />
+      </ArtifactMarkdownProvider>
+    </ArtifactOpenerProvider>
+  )
+}
+
+function SessionScreenContent(props: { session: SessionModel; browser: ReturnType<typeof createSessionBrowser> }) {
   const session = props.session
+  const browser = props.browser
   const server = useServer()
   const detailsProject = createMemo(() => {
     const info = session.data.info()
     return info ? projectForSession(info, server.ctx.sync.data.project) : undefined
   })
   const isDesktop = session.isDesktop
-  const browser = createSessionBrowser(session)
+  const btw = createSessionBtw(session)
   const screen = createSessionScreenLayout(session)
   const timeline = createSessionTimelineInteraction(session)
   const timelineSearch = createTimelineSearchController({
@@ -438,7 +453,12 @@ export function SessionScreen(props: { session: SessionModel }) {
                         setStore("sideReviewPresent", false)
                       }}
                     >
-                      <SessionDesktopReview review={review} browser={browser} present={store.sideReviewPresent} />
+                      <SessionDesktopReview
+                        review={review}
+                        browser={browser}
+                        btw={btw}
+                        present={store.sideReviewPresent}
+                      />
                     </div>
                   </Show>
                 </div>

packages/app/src/settings/settings.css

@@ -1102,10 +1102,6 @@
   padding-block: 20px;
 }
 
-.settings-server-connection .settings-servers-lead {
-  gap: 4px;
-}
-
 .settings-servers-row:not(:last-child) {
   padding-bottom: 16px;
   margin-bottom: 16px;

packages/app/src/shell/commands/command.tsx

@@ -88,11 +88,12 @@ export interface CommandOption {
   category?: string
   keybind?: KeybindConfig
   slash?: string
+  slashArguments?: boolean
   suggested?: boolean
   disabled?: boolean
   hidden?: boolean
   when?: (event: KeyboardEvent) => boolean
-  onSelect?: (source?: "palette" | "keybind" | "slash") => void
+  onSelect?: (source?: "palette" | "keybind" | "slash", input?: string) => void | Promise<void>
   onHighlight?: () => (() => void) | void
 }
 
@@ -389,9 +390,9 @@ export const { use: useCommand, provider: CommandProvider } = createSimpleContex
       return map
     })
 
-    const run = (id: string, source?: CommandSource) => {
+    const run = (id: string, source?: CommandSource, input?: string) => {
       const option = optionMap().get(id)
-      option?.onSelect?.(source)
+      return option?.onSelect?.(source, input)
     }
 
     const showPalette = () => {
@@ -420,7 +421,7 @@ export const { use: useCommand, provider: CommandProvider } = createSimpleContex
       if (!option) return
       event.preventDefault()
       event.stopPropagation()
-      option.onSelect?.("keybind")
+      void option.onSelect?.("keybind")
     }
 
     onMount(() => {
@@ -454,8 +455,8 @@ export const { use: useCommand, provider: CommandProvider } = createSimpleContex
 
     return {
       register,
-      trigger(id: string, source?: CommandSource) {
-        run(id, source)
+      trigger(id: string, source?: CommandSource, input?: string) {
+        return run(id, source, input)
       },
       keybind(id: string) {
         const config = keybindConfig(id)

packages/app/src/shell/commands/palette.ts

@@ -166,7 +166,7 @@ export function createCommandPaletteModel(props: { filesOnly?: () => boolean; on
     state.cleanup = undefined
     dialog.close()
     if (item.type === "command") {
-      item.option?.onSelect?.("palette")
+      void item.option?.onSelect?.("palette")
       return
     }
     if (item.type === "session") {

packages/app/src/shell/state/layout.test.ts

@@ -96,7 +96,7 @@ describe("layout persistence", () => {
   test("keeps scoped state and salvages valid tab entries", () => {
     const key = "local\u0000L3Byb2plY3Q/session"
     const value = decode({
-      sessionTabs: { old: { all: ["old"] }, [key]: { all: ["a", null, "a", "b"], active: 12 } },
+      sessionTabs: { old: { all: ["old"] }, [key]: { all: ["a", null, "a", "b", "btw"], active: "btw" } },
       sessionView: { old: { scroll: {} }, [key]: { scroll: {}, reviewOpen: ["a", null, "b"] } },
     })
     expect(value.sessionTabs).toEqual({ [key]: { all: ["a", "b"], active: undefined } })

packages/app/src/shell/state/layout.tsx

@@ -18,7 +18,7 @@ import type { ProjectAvatarVariant } from "@opencode/ui/project-avatar"
 import { SessionStateKey } from "@/runtime/server/scope"
 import { createSessionKeyReader, ensureSessionKey, pruneSessionKeys } from "./helpers"
 import { requireServerKey } from "@/shell/routes/session"
-import { closeSessionTab, openSessionTab, previewSessionTab, type SessionTabs } from "./session-tabs"
+import { closeSessionTab, openSessionTab, previewSessionTab, SESSION_BTW_TAB, type SessionTabs } from "./session-tabs"
 
 export { createSessionKeyReader, ensureSessionKey, pruneSessionKeys }
 
@@ -97,8 +97,9 @@ const normalizeSessionTabList = (path: ReturnType<typeof createPathHelpers> | un
 const normalizeStoredSessionTabs = (key: string, tabs: SessionTabs) => {
   const path = sessionPath(key)
   return {
-    all: normalizeSessionTabList(path, tabs.all),
-    active: tabs.active ? normalizeSessionTab(path, tabs.active) : tabs.active,
+    all: normalizeSessionTabList(path, tabs.all).filter((tab) => tab !== SESSION_BTW_TAB),
+    active:
+      tabs.active === SESSION_BTW_TAB ? undefined : tabs.active ? normalizeSessionTab(path, tabs.active) : tabs.active,
   }
 }
 

packages/app/src/shell/state/session-tabs.ts

@@ -1,5 +1,6 @@
 export const SESSION_OPEN_FILE_TAB = "open-file"
 export const SESSION_BROWSER_TAB = "browser"
+export const SESSION_BTW_TAB = "btw"
 export const sessionBrowserTab = (tabID: string) => `${SESSION_BROWSER_TAB}:${tabID}`
 export const isSessionBrowserTab = (tab: string | undefined) =>
   !!tab && (tab === SESSION_BROWSER_TAB || tab.startsWith(`${SESSION_BROWSER_TAB}:`))

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

@@ -9,7 +9,8 @@
   justify-content: center;
 }
 
-[data-titlebar-tab] {
+[data-titlebar-tab],
+[data-titlebar-tab-action] {
   --tab-base: var(--v2-background-bg-deep);
   --tab-overlay: transparent;
   background: linear-gradient(var(--tab-overlay), var(--tab-overlay)), var(--tab-base);
@@ -68,6 +69,14 @@
   --tab-overlay: var(--v2-overlay-simple-overlay-pressed);
 }
 
+[data-titlebar-tab-action]:is(:hover, :focus-visible) {
+  --tab-overlay: var(--v2-overlay-simple-overlay-hover);
+}
+
+[data-titlebar-tab-action]:is(:active, [data-state="pressed"]) {
+  --tab-overlay: var(--v2-overlay-simple-overlay-pressed);
+}
+
 [data-titlebar-tab]:is(:hover, [data-state="pressed"]) [data-slot="tab-close"] {
   background: linear-gradient(var(--tab-overlay), var(--tab-overlay)), var(--tab-base);
 }

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

@@ -276,7 +276,7 @@ export function TabNavItem(props: {
             "overflow-hidden text-clip whitespace-nowrap": !editing(),
             "select-text": editing(),
           }}
-          contenteditable={editing() ? true : undefined}
+          contenteditable={editing() ? "plaintext-only" : undefined}
           onDblClick={openRename}
           onKeyDown={(event) => {
             event.stopPropagation()

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

@@ -298,7 +298,7 @@ export function TitlebarTabStrip(props: {
                   : [new PointerActivationConstraints.Distance({ value: 4 })],
               preventActivation: (event) =>
                 isTabCloseTarget(event.target) ||
-                (event.target instanceof Element && !!event.target.closest('[contenteditable="true"]')),
+                (event.target instanceof Element && !!event.target.closest("[contenteditable]")),
             }),
           ]}
           modifiers={[

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

@@ -351,9 +351,10 @@ export function Titlebar(props: {
               >
                 <button
                   type="button"
+                  data-titlebar-tab-action
                   data-action="vertical-tabs-home"
                   data-state={layout.route().type === "home" ? "pressed" : undefined}
-                  class="group mb-1 flex h-7 w-full shrink-0 items-center gap-1.5 rounded-[6px] ps-1.5 pe-2 text-[13px] leading-4 text-v2-text-text-faint hover:bg-v2-background-bg-layer-02 hover:text-v2-text-text-base data-[state=pressed]:bg-v2-background-bg-layer-02 data-[state=pressed]:text-v2-text-text-base"
+                  class="group mb-1 flex h-7 w-full shrink-0 items-center gap-1.5 rounded-[6px] ps-1.5 pe-2 text-[13px] leading-4 text-v2-text-text-faint hover:text-v2-text-text-base data-[state=pressed]:text-v2-text-text-base"
                   onClick={toggleHome}
                   aria-label={language.t("home.title")}
                   aria-pressed={layout.route().type === "home"}
@@ -650,8 +651,9 @@ export function Titlebar(props: {
                             {homeButton(true)}
                             <button
                               type="button"
+                              data-titlebar-tab-action
                               data-action="vertical-tabs-new-session"
-                              class="group flex h-7 w-full shrink-0 items-center gap-1.5 rounded-[6px] ps-1.5 pe-2 text-[13px] leading-4 text-v2-text-text-faint hover:bg-v2-background-bg-layer-02 hover:text-v2-text-text-base"
+                              class="group flex h-7 w-full shrink-0 items-center gap-1.5 rounded-[6px] ps-1.5 pe-2 text-[13px] leading-4 text-v2-text-text-faint hover:text-v2-text-text-base"
                               onClick={openNewTab}
                               aria-label={language.t("command.session.new")}
                             >

packages/app/src/workspaces/files/artifact.test.ts

@@ -0,0 +1,118 @@
+import { describe, expect, test } from "bun:test"
+import {
+  artifactKind,
+  bytesToBase64,
+  contentBytes,
+  fileContentFromBytes,
+  MAX_MEDIA_BYTES,
+  parseDelimited,
+  resolveArtifactPath,
+} from "./artifact"
+
+describe("artifactKind", () => {
+  test.each([
+    ["shot.PNG", "image"],
+    ["logo.svg", "svg"],
+    ["song.mp3", "audio"],
+    ["demo.mp4", "video"],
+    ["clip.webm", "video"],
+    ["paper.pdf", "pdf"],
+    ["out/index.html", "html"],
+    ["README.md", "markdown"],
+    ["flow.mmd", "mermaid"],
+    ["data.csv", "table"],
+    ["data.tsv", "table"],
+    ["Inter.woff2", "font"],
+    ["src/app.ts", "text"],
+    ["Makefile", "text"],
+    [".env", "text"],
+    ["archive.tar.gz", "text"],
+  ] as const)("classifies %s as %s", (path, kind) => {
+    expect(artifactKind(path)).toBe(kind)
+  })
+})
+
+describe("fileContentFromBytes", () => {
+  test("keeps media as base64 with a mime type", () => {
+    const content = fileContentFromBytes("a.png", new Uint8Array([137, 80, 78, 71]))
+    expect(content).toEqual({ type: "binary", content: "iVBORw==", encoding: "base64", mimeType: "image/png" })
+  })
+
+  test("decodes text and svg with a mime type", () => {
+    expect(fileContentFromBytes("a.svg", new TextEncoder().encode("<svg/>"))).toEqual({
+      type: "text",
+      content: "<svg/>",
+      mimeType: "image/svg+xml",
+    })
+    expect(fileContentFromBytes("a.ts", new TextEncoder().encode("const a = 1"))).toEqual({
+      type: "text",
+      content: "const a = 1",
+      mimeType: undefined,
+    })
+  })
+
+  test("keeps only the size of media above the cap", () => {
+    const content = fileContentFromBytes("big.mp4", new Uint8Array(MAX_MEDIA_BYTES + 1))
+    expect(content).toEqual({ type: "binary", content: "", size: MAX_MEDIA_BYTES + 1 })
+  })
+
+  test("marks unknown binaries without keeping bytes", () => {
+    expect(fileContentFromBytes("a.bin", new Uint8Array([1, 0, 2]))).toEqual({ type: "binary", content: "", size: 3 })
+  })
+
+  test("encodes large buffers in chunks", () => {
+    const bytes = new Uint8Array(70_000).fill(65)
+    expect(bytesToBase64(bytes)).toBe(Buffer.from(bytes).toString("base64"))
+  })
+})
+
+describe("contentBytes", () => {
+  test("recovers byte counts from base64 and text", () => {
+    expect(contentBytes({ type: "binary", content: "iVBORw==", encoding: "base64" })).toBe(4)
+    expect(contentBytes({ type: "binary", content: "iVBORwA=", encoding: "base64" })).toBe(5)
+    expect(contentBytes({ type: "text", content: "héllo" })).toBe(6)
+  })
+})
+
+describe("parseDelimited", () => {
+  test("handles quotes, embedded delimiters, newlines, and CRLF", () => {
+    const parsed = parseDelimited('name,note\r\n"Smith, J","says ""hi""\nand more"\nplain,\n', ",")
+    expect(parsed.rows).toEqual([
+      ["name", "note"],
+      ["Smith, J", 'says "hi"\nand more'],
+      ["plain", ""],
+    ])
+    expect(parsed.total).toBe(3)
+    expect(parsed.columns).toBe(2)
+  })
+
+  test("counts rows past the limit without keeping them", () => {
+    const parsed = parseDelimited("a\tb\n1\t2\n3\t4\n5\t6", "\t", 2)
+    expect(parsed.rows).toHaveLength(2)
+    expect(parsed.total).toBe(4)
+  })
+})
+
+describe("resolveArtifactPath", () => {
+  test.each([
+    ["docs", "guide.md", "docs/guide.md"],
+    ["docs", "./img/a.png", "docs/img/a.png"],
+    ["docs/api", "../index.md", "docs/index.md"],
+    ["", "src/app.ts", "src/app.ts"],
+    ["docs", "sub\\win.md", "docs/sub/win.md"],
+    ["", "docs/guide.md", "docs/guide.md"],
+    ["/tmp/notes/", "../out/a.pdf", "/tmp/out/a.pdf"],
+    ["C:/tmp/notes/", "img.png", "C:/tmp/notes/img.png"],
+    ["/repo", "../shared/report.pdf", "/shared/report.pdf"],
+  ])("resolves %s + %s", (base, href, expected) => {
+    expect(resolveArtifactPath(base, href)).toBe(expected)
+  })
+
+  test.each([
+    ["docs", "../../etc/passwd"],
+    ["", "../x"],
+    ["docs", "/abs/path"],
+  ])("rejects %s + %s", (base, href) => {
+    expect(resolveArtifactPath(base, href)).toBeUndefined()
+  })
+})

packages/app/src/workspaces/files/artifact.ts

@@ -0,0 +1,211 @@
+import type { FileContent } from "@/runtime/server/types"
+
+export type ArtifactKind =
+  | "image"
+  | "svg"
+  | "audio"
+  | "video"
+  | "pdf"
+  | "html"
+  | "markdown"
+  | "mermaid"
+  | "table"
+  | "font"
+  | "text"
+
+const mimes = new Map([
+  ["png", "image/png"],
+  ["jpg", "image/jpeg"],
+  ["jpeg", "image/jpeg"],
+  ["gif", "image/gif"],
+  ["webp", "image/webp"],
+  ["avif", "image/avif"],
+  ["bmp", "image/bmp"],
+  ["ico", "image/x-icon"],
+  ["tif", "image/tiff"],
+  ["tiff", "image/tiff"],
+  ["heic", "image/heic"],
+  ["svg", "image/svg+xml"],
+  ["mp3", "audio/mpeg"],
+  ["wav", "audio/wav"],
+  ["ogg", "audio/ogg"],
+  ["oga", "audio/ogg"],
+  ["m4a", "audio/mp4"],
+  ["aac", "audio/aac"],
+  ["flac", "audio/flac"],
+  ["opus", "audio/ogg"],
+  ["weba", "audio/webm"],
+  ["mp4", "video/mp4"],
+  ["m4v", "video/mp4"],
+  ["webm", "video/webm"],
+  ["mov", "video/quicktime"],
+  ["ogv", "video/ogg"],
+  ["mkv", "video/x-matroska"],
+  ["pdf", "application/pdf"],
+  ["html", "text/html"],
+  ["htm", "text/html"],
+  ["md", "text/markdown"],
+  ["markdown", "text/markdown"],
+  ["mdx", "text/markdown"],
+  ["mmd", "text/vnd.mermaid"],
+  ["mermaid", "text/vnd.mermaid"],
+  ["csv", "text/csv"],
+  ["tsv", "text/tab-separated-values"],
+  ["ttf", "font/ttf"],
+  ["otf", "font/otf"],
+  ["woff", "font/woff"],
+  ["woff2", "font/woff2"],
+])
+
+export function artifactExtension(path: string) {
+  const name = path.split(/[\\/]/).pop() ?? ""
+  const index = name.lastIndexOf(".")
+  if (index <= 0) return ""
+  return name.slice(index + 1).toLowerCase()
+}
+
+export function artifactMime(path: string) {
+  return mimes.get(artifactExtension(path))
+}
+
+export function artifactKind(path: string): ArtifactKind {
+  const mime = artifactMime(path)
+  if (!mime) return "text"
+  if (mime === "image/svg+xml") return "svg"
+  if (mime === "application/pdf") return "pdf"
+  if (mime === "text/html") return "html"
+  if (mime === "text/markdown") return "markdown"
+  if (mime === "text/vnd.mermaid") return "mermaid"
+  if (mime === "text/csv" || mime === "text/tab-separated-values") return "table"
+  if (mime.startsWith("image/")) return "image"
+  if (mime.startsWith("audio/")) return "audio"
+  if (mime.startsWith("font/")) return "font"
+  return "video"
+}
+
+/** Kinds whose bytes are kept as base64 so media elements can play them without a text round trip. */
+const binaryKinds = new Set<ArtifactKind>(["image", "audio", "video", "pdf", "font"])
+
+/** Text files never contain NUL; a NUL in the first 8 KiB marks an unknown binary. */
+function isBinaryBytes(bytes: Uint8Array) {
+  return bytes.subarray(0, 8192).includes(0)
+}
+
+export function bytesToBase64(bytes: Uint8Array) {
+  const parts: string[] = []
+  for (let index = 0; index < bytes.length; index += 0x8000) {
+    parts.push(String.fromCharCode(...bytes.subarray(index, index + 0x8000)))
+  }
+  return btoa(parts.join(""))
+}
+
+/** Media above this stays a placeholder: base64 encoding on the main thread and the LRU budget both suffer. */
+export const MAX_MEDIA_BYTES = 25 * 1024 * 1024
+
+export function fileContentFromBytes(path: string, bytes: Uint8Array): FileContent {
+  const kind = artifactKind(path)
+  const mimeType = artifactMime(path)
+  if (binaryKinds.has(kind)) {
+    if (bytes.length > MAX_MEDIA_BYTES) return { type: "binary", content: "", size: bytes.length }
+    return { type: "binary", content: bytesToBase64(bytes), encoding: "base64", mimeType }
+  }
+  // Unknown binaries keep no bytes: the viewer only shows a placeholder for them.
+  if (kind === "text" && isBinaryBytes(bytes)) return { type: "binary", content: "", size: bytes.length }
+  return { type: "text", content: new TextDecoder().decode(bytes), mimeType }
+}
+
+/** Approximate on-disk size of loaded content. */
+export function contentBytes(content: FileContent) {
+  if (content.size !== undefined) return content.size
+  if (content.encoding === "base64") {
+    const padding = content.content.endsWith("==") ? 2 : content.content.endsWith("=") ? 1 : 0
+    return Math.floor((content.content.length * 3) / 4) - padding
+  }
+  return new TextEncoder().encode(content.content).length
+}
+
+/**
+ * Parse RFC 4180 style delimited text. Quoted fields may contain the delimiter, newlines, and
+ * doubled quotes. Rows beyond `limit` are counted but not returned.
+ */
+export function parseDelimited(text: string, delimiter: string, limit = 1000) {
+  const rows: string[][] = []
+  let row: string[] = []
+  let field = ""
+  let quoted = false
+  let total = 0
+  const endRow = () => {
+    row.push(field)
+    field = ""
+    const blank = row.length === 1 && row[0] === ""
+    if (!blank) {
+      total++
+      if (rows.length < limit) rows.push(row)
+    }
+    row = []
+  }
+  for (let index = 0; index < text.length; index++) {
+    const char = text[index]!
+    if (quoted) {
+      if (char !== '"') {
+        field += char
+        continue
+      }
+      if (text[index + 1] === '"') {
+        field += '"'
+        index++
+        continue
+      }
+      quoted = false
+      continue
+    }
+    if (char === '"' && field === "") {
+      quoted = true
+      continue
+    }
+    if (char === delimiter) {
+      row.push(field)
+      field = ""
+      continue
+    }
+    if (char === "\r") continue
+    if (char === "\n") {
+      endRow()
+      continue
+    }
+    field += char
+  }
+  if (field !== "" || row.length > 0) endRow()
+  const columns = rows.reduce((max, current) => Math.max(max, current.length), 0)
+  return { rows, total, columns }
+}
+
+/** Build a blob URL from loaded content. Callers revoke it when the viewer unmounts. */
+export function blobUrlFromContent(content: FileContent) {
+  const type = content.mimeType ?? "application/octet-stream"
+  if (content.encoding !== "base64") return URL.createObjectURL(new Blob([content.content], { type }))
+  const raw = atob(content.content)
+  const bytes = Uint8Array.from(raw, (char) => char.charCodeAt(0))
+  return URL.createObjectURL(new Blob([bytes], { type }))
+}
+
+/**
+ * Resolve a relative link against a directory. A relative base yields a workspace-relative path and
+ * an absolute base an absolute one; undefined when the link climbs past the base's root.
+ */
+export function resolveArtifactPath(base: string, href: string) {
+  const target = href.replaceAll("\\", "/")
+  if (target.startsWith("/")) return undefined
+  const dir = base.replaceAll("\\", "/")
+  const segments = [...dir.split("/").filter(Boolean)]
+  for (const segment of target.split("/")) {
+    if (!segment || segment === ".") continue
+    if (segment !== "..") {
+      segments.push(segment)
+      continue
+    }
+    if (segments.length === 0) return undefined
+    segments.pop()
+  }
+  return `${dir.startsWith("/") ? "/" : ""}${segments.join("/")}`
+}

packages/app/src/workspaces/files/model.tsx

@@ -5,11 +5,12 @@ import { createSimpleContext } from "@opencode/ui/context"
 import { showToast } from "@/shell/notifications/toast"
 import { useParams } from "@solidjs/router"
 import { base64Encode } from "@opencode/util/encode"
-import { getFilename } from "@opencode/util/path"
+import { getDirectory, getFilename } from "@opencode/util/path"
 import { useWorkspaceLocation } from "@/workspaces/location"
 import { useLanguage } from "@/runtime/i18n/language"
 import { useLayout } from "@/shell/state/layout"
 import { createPathHelpers } from "./path"
+import { fileContentFromBytes } from "./artifact"
 import {
   approxBytes,
   evictContentLru,
@@ -185,14 +186,17 @@ export const { use: useFile, provider: FileProvider } = createSimpleContext({
 
       setLoading(file)
 
+      // Files outside the workspace are read from their own directory, like markdown images.
+      // The trailing separator from getDirectory keeps "/" and "C:/" valid, like readLocalImage.
+      const request = path.absolute(file)
+        ? { path: getFilename(file), location: { directory: getDirectory(file) } }
+        : { path: file, location: { directory } }
       const promise = serverSDK.api.file
-        .read({ path: file, location: { directory } })
+        .read(request)
         .then((data) => {
           if (scope() !== directory) return
-          const content = { type: "text" as const, content: new TextDecoder().decode(data) }
+          const content = fileContentFromBytes(file, data)
           setLoaded(file, content)
-
-          if (!content) return
           touchFileContent(file, approxBytes(content))
           evictContent(new Set([file]))
         })
@@ -281,6 +285,7 @@ export const { use: useFile, provider: FileProvider } = createSimpleContext({
     return {
       ready: () => view().ready(),
       normalize: path.normalize,
+      absolute: path.absolute,
       tab: path.tab,
       pathFromTab: path.pathFromTab,
       tree: {

packages/app/src/workspaces/files/path.test.ts

@@ -21,6 +21,24 @@ describe("file path helpers", () => {
     expect(path.normalize("c:\\repo\\src\\app.ts")).toBe("src\\app.ts")
   })
 
+  test("keeps files outside the workspace absolute and round-trips them through tabs", () => {
+    const posix = createPathHelpers(() => "/repo")
+    expect(posix.normalize("/tmp/out/report.pdf")).toBe("/tmp/out/report.pdf")
+    expect(posix.absolute("/tmp/out/report.pdf")).toBe(true)
+    expect(posix.absolute("src/app.ts")).toBe(false)
+    expect(posix.tab("/tmp/out/report.pdf")).toBe("file:///tmp/out/report.pdf")
+    expect(posix.pathFromTab("file:///tmp/out/report.pdf")).toBe("/tmp/out/report.pdf")
+    expect(posix.normalize("/repository/x.ts")).toBe("/repository/x.ts")
+
+    const windows = createPathHelpers(() => "C:\\repo")
+    expect(windows.normalize("C:\\tmp\\font.ttf")).toBe("C:\\tmp\\font.ttf")
+    expect(windows.normalize("file:///C:/tmp/font.ttf")).toBe("C:/tmp/font.ttf")
+    expect(windows.absolute("C:/tmp/font.ttf")).toBe(true)
+    expect(windows.tab("C:/tmp/font.ttf")).toBe("file:///C:/tmp/font.ttf")
+    expect(windows.pathFromTab("file:///C:/tmp/font.ttf")).toBe("C:/tmp/font.ttf")
+    expect(windows.pathFromTab("file:///C:/repo/src/app.ts")).toBe("src/app.ts")
+  })
+
   test("normalizes Windows directory separators", () => {
     const path = createPathHelpers(() => "C:\\repo")
     expect(path.normalizeDir("frontend\\")).toBe("frontend")

packages/app/src/workspaces/files/path.ts

@@ -105,7 +105,11 @@ export function createPathHelpers(scope: () => string) {
   const normalize = (input: string) => {
     const root = scope()
 
-    let path = unquoteGitPath(decodeFilePath(stripQueryAndHash(stripFileProtocol(input))))
+    // file:///C:/dir becomes /C:/dir once the protocol is gone; restore the drive form.
+    let path = unquoteGitPath(decodeFilePath(stripQueryAndHash(stripFileProtocol(input)))).replace(
+      /^[/\\]([A-Za-z]:)/,
+      "$1",
+    )
 
     // Separator-agnostic prefix stripping for Cygwin/native Windows compatibility
     // Only case-insensitive on Windows (drive letter or UNC paths)
@@ -116,20 +120,21 @@ export function createPathHelpers(scope: () => string) {
       canonPath.startsWith(canonRoot) &&
       (canonRoot.endsWith("/") || canonPath === canonRoot || canonPath[canonRoot.length] === "/")
     ) {
-      // Slice from original path to preserve native separators
-      path = path.slice(root.length)
+      // Slice from original path to preserve native separators, then drop the separator itself.
+      path = path.slice(root.length).replace(/^[/\\]/, "")
     }
 
     if (path.startsWith("./") || path.startsWith(".\\")) {
       path = path.slice(2)
     }
 
-    if (path.startsWith("/") || path.startsWith("\\")) {
-      path = path.slice(1)
-    }
+    // An absolute path that is not under the root stays absolute; it is a file outside the workspace.
     return path
   }
 
+  /** Whether a normalized path points outside the workspace root. */
+  const absolute = (path: string) => /^[A-Za-z]:[/\\]/.test(path) || path.startsWith("/") || path.startsWith("\\\\")
+
   const tab = (input: string) => {
     const path = normalize(input)
     return `file://${encodeFilePath(path)}`
@@ -149,6 +154,7 @@ export function createPathHelpers(scope: () => string) {
 
   return {
     normalize,
+    absolute,
     tab,
     pathFromTab,
     normalizeDir,

packages/app/vite.js

@@ -1,4 +1,5 @@
 import { readFileSync } from "node:fs"
+import { createRequire } from "node:module"
 import solidPlugin from "vite-plugin-solid"
 import tailwindcss from "@tailwindcss/vite"
 import { fileURLToPath } from "url"
@@ -17,6 +18,24 @@ if (tailwindGenerate && typeof tailwindHotUpdate === "function") {
   }
 }
 
+// The markdown worker imports these directly, so they are served unbundled to keep worker startup
+// stable. Vite applies `exclude` to every import inside a pre-bundle too, which would leave a bare
+// `import "marked"` in mermaid's chunk that the browser cannot resolve from this package.
+const workerDeps = ["@shikijs/stream", "marked", "marked-shiki", "remend"]
+
+/** @type {import("rolldown").Plugin} */
+const bundleNestedWorkerDeps = {
+  name: "opencode-desktop:bundle-nested-worker-deps",
+  resolveId(id, importer) {
+    if (!importer || !workerDeps.includes(id) || !importer.includes("node_modules")) return
+    try {
+      return createRequire(importer).resolve(id)
+    } catch {
+      return
+    }
+  },
+}
+
 export const channel = (() => {
   const raw = process.env.OPENCODE_CHANNEL
   if (raw === "local" || raw === "dev" || raw === "beta" || raw === "prod") return raw
@@ -44,8 +63,9 @@ export default [
           format: "es",
         },
         optimizeDeps: {
-          exclude: ["@shikijs/stream", "marked", "marked-shiki", "remend"],
+          exclude: workerDeps,
           include: ["@opencode/session-ui > mermaid", "@opencode/session-ui > mermaid > katex"],
+          rolldownOptions: { plugins: [bundleNestedWorkerDeps] },
         },
       }
     },

packages/cli/package.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/package.json",
   "name": "@opencode/cli",
-  "version": "2.0.10",
+  "version": "2.0.12",
   "type": "module",
   "license": "MIT",
   "bin": {

packages/cli/script/service-smoke.ts

@@ -55,7 +55,7 @@ try {
   if ((await pluginIDs(info.url, headers)).includes("smoke")) throw new Error("Smoke plugin existed before creation")
   const plugin = path.join(root, ".opencode", "plugins", "smoke.ts")
   await fs.writeFile(plugin, pluginSource())
-  await waitForPlugin(info.url, headers)
+  await waitForPlugin(info.url, headers, plugin)
 
   const unauthorizedInfo = await fetch(new URL("/api/info", info.url), {
     signal: AbortSignal.timeout(5_000),
@@ -139,7 +139,13 @@ async function waitForReady(url: string, headers: HeadersInit) {
 }
 
 function exitsWithin(process: Bun.Subprocess, milliseconds: number) {
-  return Promise.race([process.exited.then(() => true), Bun.sleep(milliseconds).then(() => false)])
+  return new Promise<boolean>((resolve) => {
+    const timeout = setTimeout(() => resolve(false), milliseconds)
+    process.exited.then(() => {
+      clearTimeout(timeout)
+      resolve(true)
+    })
+  })
 }
 
 function pluginSource() {
@@ -159,11 +165,15 @@ async function pluginIDs(url: string, headers: HeadersInit) {
   )
 }
 
-async function waitForPlugin(url: string, headers: HeadersInit) {
+async function waitForPlugin(url: string, headers: HeadersInit, plugin: string) {
   const deadline = Date.now() + 10_000
+  let attempt = 0
   while (Date.now() < deadline) {
     if ((await pluginIDs(url, headers)).includes("smoke")) return
     await Bun.sleep(25)
+    // Native watchers may coalesce a single creation edge. Keep changing valid source so
+    // the smoke proves that a later native event is delivered.
+    if (++attempt % 10 === 0) await fs.writeFile(plugin, `${pluginSource()}// watcher retry ${attempt}\n`)
   }
   throw new Error("Compiled service did not discover the created plugin")
 }

packages/cli/src/commands/handlers/upgrade.ts

@@ -5,34 +5,77 @@ import { Runtime } from "../../framework/runtime"
 import { Updater } from "../../services/updater"
 import { handlePromptErrors } from "../../ui/prompt"
 import { OPENCODE_VERSION } from "../../version"
+import { stripVTControlCharacters } from "node:util"
 
 export default Runtime.handler(
   Commands.commands.upgrade,
-  Effect.fn("cli.upgrade")(function* (input) {
-    intro("Upgrade")
-    const updater = yield* Updater.Service
-    const method = Option.getOrUndefined(input.method) ?? (yield* updater.method())
-    if (!method)
-      return yield* Effect.fail(
-        new Error("Could not detect the installation method. Pass --method to choose how to upgrade OpenCode."),
+  Effect.fn("cli.upgrade")(
+    function* (input) {
+      intro("Upgrade")
+      const updater = yield* Updater.Service
+      const method = Option.getOrUndefined(input.method) ?? (yield* updater.method())
+      if (!method)
+        return yield* Effect.fail(
+          new Error("Could not detect the installation method. Pass --method to choose how to upgrade OpenCode."),
+        )
+
+      log.info(`Using method: ${method}`)
+      const target = Option.getOrUndefined(input.target) ?? (yield* updater.latest())
+      const version = target.trim().replace(/^v/, "")
+      if (version === OPENCODE_VERSION) {
+        log.warn(`OpenCode upgrade skipped: ${version} is already installed`)
+        outro("Done")
+        return
+      }
+
+      log.info(`From ${OPENCODE_VERSION} → ${version}`)
+      const progress = spinner()
+      progress.start("Upgrading...")
+      yield* updater.upgrade(method, target).pipe(
+        Effect.tap(() => Effect.sync(() => progress.stop("Upgrade complete"))),
+        Effect.tapCause(() => Effect.sync(() => progress.stop("Upgrade failed", 1))),
       )
-
-    log.info(`Using method: ${method}`)
-    const target = Option.getOrUndefined(input.target) ?? (yield* updater.latest())
-    const version = target.trim().replace(/^v/, "")
-    if (version === OPENCODE_VERSION) {
-      log.warn(`OpenCode upgrade skipped: ${version} is already installed`)
       outro("Done")
-      return
-    }
-
-    log.info(`From ${OPENCODE_VERSION} → ${version}`)
-    const progress = spinner()
-    progress.start("Upgrading...")
-    yield* updater.upgrade(method, target).pipe(
-      Effect.tap(() => Effect.sync(() => progress.stop("Upgrade complete"))),
-      Effect.tapCause(() => Effect.sync(() => progress.stop("Upgrade failed", 1))),
-    )
-    outro("Done")
-  }, handlePromptErrors),
+    },
+    (effect) =>
+      handlePromptErrors(
+        effect.pipe(
+          Effect.mapError((error) =>
+            error instanceof Updater.UpgradeError ? new Error(formatUpgradeError(error), { cause: error }) : error,
+          ),
+        ),
+      ),
+  ),
 )
+
+function formatUpgradeError(error: Updater.UpgradeError) {
+  const clean = (value: string) => stripVTControlCharacters(value).replaceAll("\r", "").trim()
+  const line = (value: string) => clean(value).replace(/\s+/g, " ")
+  const detail = wrap(clean(error.detail), Math.max(24, (process.stdout.columns ?? 80) - 7)).join("\n")
+  return [
+    line(error.title),
+    "",
+    detail,
+    ...(error.command ? ["", field("Command", line(error.command))] : []),
+    field("Retry", line(error.retry)),
+  ].join("\n")
+}
+
+function field(label: string, value: string) {
+  const prefix = label.padEnd(9)
+  const width = Math.max(24, Math.min(61, (process.stdout.columns ?? 80) - prefix.length - 10))
+  const lines = wrap(value, width)
+  return lines.map((line, index) => `${index === 0 ? prefix : " ".repeat(prefix.length)}${line}`).join("\n")
+}
+
+function wrap(value: string, width: number) {
+  return value.split("\n").flatMap((source) => {
+    if (source.length <= width) return [source]
+    return source.split(/\s+/).reduce<string[]>((result, word) => {
+      const index = result.length - 1
+      if (index < 0 || result[index].length + word.length + 1 > width) result.push(word)
+      else result[index] += ` ${word}`
+      return result
+    }, [])
+  })
+}

packages/cli/src/config/config.ts

@@ -7,7 +7,7 @@ import { produce, type Draft } from "immer"
 import { applyEdits, modify, parse, type ParseError } from "jsonc-parser"
 import path from "path"
 import { ConfigMigration } from "./migrate"
-import { Info, SchemaURL } from "./schema"
+import { Info, normalizeLegacyTabs, SchemaURL } from "./schema"
 
 export * from "./schema"
 
@@ -119,7 +119,7 @@ function merge(...values: readonly (Info | undefined)[]) {
   return Option.getOrElse(
     decode(
       values.reduce<Record<string, unknown>>(
-        (result, value) => mergeRecords(result, value ?? {}),
+        (result, value) => mergeRecords(result, normalizeLegacyTabs(value) ?? {}),
         {},
       ),
     ),

packages/cli/src/config/schema.ts

@@ -8,3 +8,11 @@ export const Info = Schema.Struct({
   ...Config.Info.fields,
 })
 export type Info = Schema.Schema.Type<typeof Info>
+
+export function normalizeLegacyTabs(info: Info | undefined) {
+  if (info?.tabs?.enabled === undefined) return info
+  const tabs = { ...info.tabs }
+  tabs.mode ??= tabs.enabled ? "on" : "off"
+  delete tabs.enabled
+  return { ...info, tabs }
+}

packages/cli/src/index.ts

@@ -1,7 +1,8 @@
 #!/usr/bin/env bun
 
 import { NodeRuntime, NodeServices } from "@effect/platform-node"
-import { Effect } from "effect"
+import { Cause, Effect } from "effect"
+import { getErrorReported } from "effect/Runtime"
 import { Commands } from "./commands/commands"
 import { Runtime } from "./framework/runtime"
 import { Observability } from "@opencode/util/observability"
@@ -130,5 +131,15 @@ Effect.gen(function* () {
   Effect.provide(NodeServices.layer),
   Effect.scoped,
   Effect.tap(() => Effect.sync(() => process.exit(process.exitCode ?? 0))),
-  NodeRuntime.runMain,
+  // runMain's default reporter logs the fatal cause to stdout. Write it to stderr instead: the
+  // desktop and `Service.ensure` only capture stderr from `serve --service`, so this is the only
+  // channel through which a startup failure's reason reaches the user.
+  Effect.tapCause((cause) =>
+    Effect.sync(() => {
+      if (Cause.hasInterruptsOnly(cause)) return
+      if (!getErrorReported(Cause.squash(cause))) return
+      process.stderr.write(Cause.pretty(cause) + "\n")
+    }),
+  ),
+  NodeRuntime.runMain({ disableErrorReporting: true }),
 )

packages/cli/src/services/updater.ts

@@ -5,7 +5,9 @@ import { Context, Duration, Effect, FileSystem, Layer, Option, Ref, Schema } fro
 import { ChildProcess } from "effect/unstable/process"
 import { parse, type ParseError } from "jsonc-parser"
 import path from "node:path"
+import { stripVTControlCharacters } from "node:util"
 import { action, parseReleaseVersion, type Policy } from "./updater-action"
+import { errorMessage } from "../util/error"
 
 export const methods = ["curl", "npm", "pnpm", "bun", "yarn", "vp", "brew"] as const
 
@@ -13,10 +15,82 @@ export type Method = (typeof methods)[number]
 export type RunResult = { readonly type: "available" | "installed"; readonly version: string }
 export type CheckResult = RunResult | { readonly type: "unavailable"; readonly message: string }
 
+export class UpgradeError extends Error {
+  readonly title: string
+  readonly detail: string
+  readonly command?: string
+  readonly retry: string
+
+  constructor(
+    input: {
+      readonly title: string
+      readonly detail: string
+      readonly command?: string
+      readonly retry: string
+    },
+    options?: ErrorOptions,
+  ) {
+    super(input.detail, options)
+    this.name = "UpgradeError"
+    this.title = input.title
+    this.detail = input.detail
+    this.command = input.command
+    this.retry = input.retry
+  }
+}
+
 const decodeVpPackages = Schema.decodeUnknownOption(
   Schema.fromJsonString(Schema.Array(Schema.Struct({ name: Schema.String }))),
 )
 
+const installNames: Record<Method, string> = {
+  curl: "The OpenCode installer",
+  npm: "npm",
+  pnpm: "pnpm",
+  bun: "Bun",
+  yarn: "Yarn",
+  vp: "Vite+",
+  brew: "Homebrew",
+}
+
+function conciseDetail(input: string) {
+  const lines = stripVTControlCharacters(input)
+    .trim()
+    .replaceAll("\r", "\n")
+    .split("\n")
+    .map((line) => line.trimEnd())
+    .filter((line) => line.trim().length > 0)
+  const tail = lines.slice(-12).join("\n")
+  const clipped = tail.length > 2_000
+  const detail = clipped ? `…${tail.slice(-1_999)}` : tail
+  if (!detail) return
+  if (lines.length <= 12 && !clipped) return detail
+  return `${detail}\n\nOutput shortened to the last 12 lines.`
+}
+
+function errorDetail(cause: unknown): string {
+  if (cause instanceof AppProcess.AppProcessError) {
+    const stderr = conciseDetail(cause.stderr ?? "")
+    if (stderr) return stderr
+    if (cause.cause !== undefined) return errorDetail(cause.cause)
+    return cause.message
+  }
+  if (cause instanceof Error) {
+    const detail = cause.cause === undefined ? undefined : errorDetail(cause.cause)
+    if (!detail || detail === cause.message) return cause.message
+    return `${cause.message}: ${detail}`
+  }
+  return errorMessage(cause)
+}
+
+function resultDetail(result: { code: number; stdout: string; stderr: string }) {
+  return (
+    conciseDetail(result.stderr) ??
+    conciseDetail(result.stdout) ??
+    `The command exited with code ${result.code} without any error output.`
+  )
+}
+
 export interface Interface {
   readonly run: (onInstall?: (version: string) => void) => Effect.Effect<RunResult | undefined>
   readonly check: () => Effect.Effect<CheckResult | undefined, Error>
@@ -24,9 +98,9 @@ export interface Interface {
   readonly method: () => Effect.Effect<Method | undefined>
   readonly latest: () => Effect.Effect<string, Error>
   readonly upgrade: (method: Method, version: string) => Effect.Effect<void, Error>
-  readonly removal: (method: Method) =>
-    | { readonly command: ReadonlyArray<string>; readonly run: Effect.Effect<void, Error> }
-    | undefined
+  readonly removal: (
+    method: Method,
+  ) => { readonly command: ReadonlyArray<string>; readonly run: Effect.Effect<void, Error> } | undefined
 }
 
 export class Service extends Context.Service<Service, Interface>()("@opencode/cli/Updater") {}
@@ -89,7 +163,6 @@ const make = Effect.gen(function* () {
           stdout: result.stdout.toString("utf8"),
           stderr: result.stderr.toString("utf8"),
         })),
-        Effect.orElseSucceed(() => ({ code: 1, stdout: "", stderr: "" })),
       )
   })
 
@@ -119,7 +192,11 @@ const make = Effect.gen(function* () {
     ]
     const results = yield* Effect.forEach(
       checks,
-      (check) => exec(check.command).pipe(Effect.map((result) => ({ check, result }))),
+      (check) =>
+        exec(check.command).pipe(
+          Effect.orElseSucceed(() => ({ code: 1, stdout: "", stderr: "" })),
+          Effect.map((result) => ({ check, result })),
+        ),
       { concurrency: "unbounded" },
     )
     return results.find((result) => {
@@ -144,11 +221,7 @@ const make = Effect.gen(function* () {
     return {
       command,
       run: exec(command, "5 minutes").pipe(
-        Effect.flatMap((result) =>
-          result.code === 0
-            ? Effect.void
-            : Effect.fail(new Error(result.stderr.trim() || `Failed to uninstall with ${method}`)),
-        ),
+        Effect.flatMap((result) => (result.code === 0 ? Effect.void : Effect.fail(new Error(resultDetail(result))))),
       ),
     }
   }
@@ -163,14 +236,44 @@ const make = Effect.gen(function* () {
             signal: AbortSignal.any([signal, AbortSignal.timeout(10_000)]),
           },
         ),
-      catch: (cause) => new Error("Failed to check for updates", { cause }),
+      catch: (cause) =>
+        new UpgradeError(
+          {
+            title: "Could not check for OpenCode updates",
+            detail: errorDetail(cause),
+            retry: "Check your network, then run opencode upgrade again.",
+          },
+          { cause },
+        ),
     })
-    if (!response.ok) return yield* Effect.fail(new Error(`Update check failed with status ${response.status}`))
+    if (!response.ok)
+      return yield* Effect.fail(
+        new UpgradeError({
+          title: "Could not check for OpenCode updates",
+          detail: `The update service returned HTTP ${response.status}.`,
+          retry: "Try again in a few minutes.",
+        }),
+      )
     const data: { version: string; metadata?: { package?: string } } = yield* Effect.tryPromise({
       try: () => response.json(),
-      catch: (cause) => new Error("Failed to read update information", { cause }),
+      catch: (cause) =>
+        new UpgradeError(
+          {
+            title: "Could not read the OpenCode update information",
+            detail: errorDetail(cause),
+            retry: "Try again in a few minutes.",
+          },
+          { cause },
+        ),
     })
-    if (!data.metadata?.package) return yield* Effect.fail(new Error("Update information did not include a package"))
+    if (!data.metadata?.package)
+      return yield* Effect.fail(
+        new UpgradeError({
+          title: "Could not read the OpenCode update information",
+          detail: "The update service returned incomplete release information.",
+          retry: "Try again in a few minutes.",
+        }),
+      )
     return { package: data.metadata.package, version: data.version }
   })
 
@@ -185,6 +288,40 @@ const make = Effect.gen(function* () {
       fs.remove(directory, { recursive: true, force: true }).pipe(Effect.ignore),
     )
 
+  const runUpgrade = (input: {
+    readonly method: Method
+    readonly command: string[]
+    readonly displayCommand?: string[]
+    readonly title?: string
+    readonly retry?: string
+  }) => {
+    const failure = (detail: string, cause?: unknown) =>
+      new UpgradeError(
+        {
+          title: input.title ?? `${installNames[input.method]} could not install OpenCode`,
+          detail,
+          command: (input.displayCommand ?? input.command).join(" "),
+          retry: input.retry ?? "Fix the issue above, then run opencode upgrade again.",
+        },
+        cause === undefined ? undefined : { cause },
+      )
+    return exec(input.command, "5 minutes").pipe(
+      Effect.flatMap((result) =>
+        result.code === 0 ? Effect.succeed(result) : Effect.fail(failure(resultDetail(result))),
+      ),
+      Effect.mapError((cause) =>
+        cause instanceof UpgradeError
+          ? cause
+          : failure(
+              cause instanceof AppProcess.AppProcessError && cause.stderr === undefined && cause.cause === undefined
+                ? `Failed to update with ${input.method}`
+                : errorDetail(cause),
+              cause,
+            ),
+      ),
+    )
+  }
+
   const upgrade = Effect.fnUntraced(function* (method: Method, input: string) {
     if (!parseReleaseVersion(input)) return yield* Effect.fail(new Error(`Invalid version: ${input}`))
     const version = input.trim().replace(/^v/, "")
@@ -212,31 +349,54 @@ const make = Effect.gen(function* () {
           ? ["vp", "install", "-g", "--force", target]
           : ["vp", "update", "-g", target],
     }
-    const result = yield* Effect.scoped(
+    yield* Effect.scoped(
       Effect.gen(function* () {
         if (method === "bun") {
           // Bun does not prune old versions from its shared package cache.
           yield* fs.makeDirectory(global.cache, { recursive: true })
           const cache = yield* temporaryDirectory("update-")
-          return yield* exec(["bun", "install", "--global", "--trust", "--cache-dir", cache, target], "5 minutes")
+          return yield* runUpgrade({
+            method,
+            command: ["bun", "install", "--global", "--trust", "--cache-dir", cache, target],
+            displayCommand: ["bun", "install", "--global", "--trust", target],
+          })
         }
         if (method === "curl") {
           yield* fs.makeDirectory(global.cache, { recursive: true })
           const directory = yield* temporaryDirectory("update-")
           const installer = path.join(directory, "install")
-          const download = yield* exec(
-            ["curl", "-fsSL", "-o", installer, "https://opencode.ai/v2/install"],
-            "5 minutes",
-          )
-          if (download.code !== 0) return download
-          return yield* exec(["bash", installer, "--version", version, "--no-modify-path"], "5 minutes")
+          yield* runUpgrade({
+            method,
+            command: ["curl", "-fsSL", "-o", installer, "https://opencode.ai/v2/install"],
+            displayCommand: ["curl", "-fsSL", "https://opencode.ai/v2/install"],
+            title: "Could not download the OpenCode installer",
+            retry: "Check your network, then run opencode upgrade again.",
+          })
+          return yield* runUpgrade({
+            method,
+            command: ["bash", installer, "--version", version, "--no-modify-path"],
+            displayCommand: ["opencode", "upgrade", version, "--method", "curl"],
+            title: "The OpenCode installer failed",
+          })
         }
-        if (method === "brew") return yield* exec(["brew", "upgrade", packageName], "5 minutes")
-        return yield* exec(commands[method], "5 minutes")
+        if (method === "brew") return yield* runUpgrade({ method, command: ["brew", "upgrade", packageName] })
+        return yield* runUpgrade({ method, command: commands[method] })
       }),
-    ).pipe(Effect.mapError((cause) => new Error(`Failed to update with ${method}`, { cause })))
-    if (result.code === 0) return
-    return yield* Effect.fail(new Error(result.stderr.trim() || `Failed to update with ${method}`))
+    ).pipe(
+      Effect.mapError((cause) =>
+        cause instanceof UpgradeError
+          ? cause
+          : new UpgradeError(
+              {
+                title: "Could not prepare the OpenCode upgrade",
+                detail: errorDetail(cause),
+                retry: "Fix the issue above, then run opencode upgrade again.",
+              },
+              { cause },
+            ),
+      ),
+      Effect.asVoid,
+    )
   })
 
   const inspect = Effect.fnUntraced(function* () {

packages/cli/test/config.test.ts

@@ -78,7 +78,7 @@ test("merges inline CLI config content over the global config", async () => {
   await Bun.write(
     file,
     JSON.stringify({
-      tabs: { enabled: true, scope: "global" },
+      tabs: { mode: "on", scope: "global" },
       keybinds: { "app.exit": "ctrl+q" },
       plugins: ["global"],
       animations: true,
@@ -105,7 +105,7 @@ test("merges inline CLI config content over the global config", async () => {
       }),
     )
 
-    expect(result.loaded.tabs).toEqual({ enabled: false, scope: "global" })
+    expect(result.loaded.tabs).toEqual({ mode: "off", scope: "global" })
     expect(result.loaded.keybinds).toEqual({ "app.exit": "ctrl+q", "help.show": false })
     expect(result.loaded.plugins).toEqual(["inline"])
     expect(result.updated).toMatchObject({ animations: false, mouse: false })
@@ -116,6 +116,26 @@ test("merges inline CLI config content over the global config", async () => {
   }
 })
 
+test("reads the legacy tabs toggle without rewriting it", async () => {
+  await using directory = await tmpdir()
+  const file = path.join(directory.path, "cli.json")
+  await Bun.write(file, JSON.stringify({ tabs: { enabled: false } }))
+
+  const config = await run(
+    directory.path,
+    Effect.gen(function* () {
+      const service = yield* Config.Service
+      expect((yield* service.get()).tabs).toEqual({ mode: "off" })
+      return yield* service.update((draft) => {
+        draft.animations = false
+      })
+    }),
+  )
+
+  expect(config.tabs).toEqual({ mode: "off" })
+  expect(await Bun.file(file).json()).toEqual({ tabs: { enabled: false }, animations: false })
+})
+
 test("migrates tui and kv config into cli.json", async () => {
   await using directory = await tmpdir()
   await Bun.write(

packages/client/package.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/package.json",
   "name": "@opencode/client",
-  "version": "2.0.10",
+  "version": "2.0.12",
   "type": "module",
   "license": "MIT",
   "repository": {

packages/codemode/AGENTS.md

@@ -6,6 +6,8 @@
 - Tool schemas are the model-facing Interface. Keep arguments minimal and natural to the operation; never add unrelated IDs as ambient capability tokens.
 - State model-visible diagnostics, logs, tool descriptions, and instructions directly. The execution context is already clear; do not repeat `Code Mode` or `CodeMode` unless the distinction is necessary.
 - When interpreter behavior or support changes, update `interpreter-support.md` and direct tests in the same PR.
+- Program values are `Value` (`src/interpreter/objects.ts`); host values are `unknown` and are copied in at the boundaries (`fromHost`, `fromJson`). Do not widen program-facing signatures back to `unknown`.
+- A built-in kind of object is one `Obj` subclass (`Wrapper` for host-backed data such as Date or Map, `Opaque` for machinery such as functions and promises) that overrides `tag`, `toString`, `toPrimitive`, `inspect`, `toHost`, and `iterator` as needed. Do not add `instanceof` ladders over the built-in classes elsewhere; ask the object.
 
 ## OpenAPI
 

packages/codemode/interpreter-support.md

@@ -24,7 +24,7 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
       and Map, RegExp, and generators serialize as `{}`. A bare `undefined` result is `null`.
       Tool results come back the way `JSON.parse(JSON.stringify(result))` would. The table, where a value cannot
       be JSON but what the program meant is clear: a promise is awaited (a rejection fails the program), a Set
-      crosses as an array, a URLSearchParams as its query string, an Error as `{ name, message, ...own }`, a
+      crosses as an array, a URLSearchParams as its query string, an Error as `{ name, message, ...own enumerable }`, a
       Uint8Array is rejected with a hint to encode as text, and own `__proto__` keys are dropped so merging tool
       inputs or results cannot replace a prototype. In-program `JSON.stringify` keeps JS behavior except for the
       Error form and a promise, which is a `TypeError` with an await hint rather than a silent `{}`.
@@ -38,8 +38,11 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
       10,000,000 elements (`Array(n)`, `length =`, `Array.from`, `split`, `matchAll`, `concat`, `flat`; below the JS
       maximum of 2^32 - 1), and 10,000 pending promises at once. Exceeding one throws a `RangeError`. A single regular
       expression match can still run long on a pathological pattern; the host regex engine has no interrupt hook.
-- [ ] Strict-mode early errors: duplicate parameter names, `yield` as an identifier, and a trailing comma after a
-      rest parameter are accepted unless the program itself begins with `"use strict"`.
+- [x] A trailing comma after a rest parameter is a syntax error, with or without `"use strict"`.
+- [x] A program that begins with `"use strict"` rejects `yield` as an identifier and duplicate parameter names at
+      parse time. Without it, `yield` is an ordinary binding.
+- [ ] Duplicate parameter names in non-strict code throw when the function is called, instead of binding the last
+      parameter as JavaScript does.
 
 ## Values and literals
 
@@ -53,7 +56,7 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] `NaN` and `Infinity` globals.
 - [ ] BigInt literals and in-interpreter BigInt arithmetic; BigInt remains invalid at JSON-like host boundaries.
 - [ ] Arbitrary Symbol primitive values and symbol-keyed properties. The confined `Symbol.iterator` and
-      `Symbol.asyncIterator` keys are available only for custom iterator protocols.
+      `Symbol.asyncIterator` keys are available only for the iterator protocols.
 - [ ] Tagged-template calls.
 - [ ] Getter and setter definitions in object literals.
 
@@ -84,7 +87,6 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] Destructuring reads through the prototype chain like member access: `const { constructor } = error` and
       `const { slice } = values` find the inherited built-in.
 - [ ] Member expressions as `for...in` targets (`for (x.y in obj)`).
-- [ ] `IteratorClose` during destructuring should throw a `TypeError` when `return()` yields a non-object.
 
 ## Statements and control flow
 
@@ -92,9 +94,10 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] `if`/`else` and conditional expressions.
 - [x] `switch`, including default clauses and fallthrough.
 - [x] `for`, `while`, and `do...while`.
-- [x] `for...of` over arrays, strings, Maps, Sets, URLSearchParams, Headers, custom synchronous iterators, and
-      confined synchronous generators. Abrupt completion invokes the iterator's optional `return()`.
-- [x] `for...in` over own keys of plain objects, arrays, strings, and tool references; other values iterate nothing.
+- [x] `for...of` over arrays, strings, Maps, Sets, URLSearchParams, Headers, Uint8Arrays, built-in iterators, custom
+      synchronous iterators, and confined synchronous generators. Abrupt completion invokes the iterator's optional `return()`.
+- [x] `for...in` over own keys of plain objects, arrays, strings, and tool references. `null`, `undefined`, and other
+      non-objects iterate nothing. An un-awaited promise throws rather than iterating.
 - [x] Unlabeled `break` and `continue`.
 - [x] `try`, `catch`, optional catch bindings, and `finally`.
 - [x] `throw` with arbitrary values.
@@ -108,7 +111,8 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 ## Functions and callbacks
 
 - [x] Function declarations, function expressions, and arrow functions.
-- [x] Synchronous and `async` functions.
+- [x] Synchronous and `async` functions. A line break between `function` and the name is allowed, as in JavaScript;
+      a line break between `async` and `function` is not an async function.
 - [x] Closures, recursion, default parameters, rest parameters, and destructured parameters.
 - [x] A call depth limit of 10000: deeper nesting throws a catchable `RangeError: Maximum call stack size exceeded`
       at the overflowing call instead of running until the timeout. Callbacks invoked by built-ins count below the
@@ -120,8 +124,8 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] `Boolean`, `Number`, `String`, `parseInt`, `parseFloat`, `isFinite`, `isNaN`, and URI helpers as callbacks.
 - [x] Built-in method references as callbacks, such as `values.map(Math.abs)`, `records.map(JSON.stringify)`,
       `items.forEach(console.log)`, and `Promise.resolve(-1).then(Math.abs)`. Extra callback arguments a built-in
-      does not consume are ignored, like JS; consumed arguments stay strictly validated (`Math.floor` still rejects a
-      string). A detached method loses its receiver, as in JS: `values.filter("abc".includes)` is a `TypeError`
+      does not consume are ignored, like JS, and consumed arguments coerce, like JS (`"3.7".replace(/\d\.\d/,
+    Math.floor)` is `"3"`). A detached method loses its receiver, as in JS: `values.filter("abc".includes)` is a `TypeError`
       because `includes` is called without a string `this`.
 - [x] Constructors work as callbacks with JS call semantics: `Error` types construct (`messages.map(Error)`),
       and new-requiring constructors (`Map`, `Set`, `URL`, `URLSearchParams`, `Headers`, `Promise`) throw a `TypeError`,
@@ -141,11 +145,13 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
       assignments, object literal keys, and destructuring or parameter defaults.
 - [x] Built-in functions are objects too, with `name` and `length` (`Math.max.length === 2`,
       `Array.prototype.push.name === "push"`).
-- [ ] A named function expression's name is not bound inside its own body.
-- [ ] Redeclaring a function in the same scope is rejected; in JavaScript the last declaration wins.
-- [ ] A line terminator between `async function` and the function name.
-- [ ] Generator and async generator functions evaluate parameter defaults and destructuring at the first `next()`
-      rather than at the call, so their errors are not thrown synchronously.
+- [x] A named function expression's name is bound read-only inside its own body; assigning to it throws a
+      `TypeError`, as in strict mode.
+- [x] Redeclaring a function in the same scope, or alongside a `var`, is allowed: the last declaration wins.
+- [x] Generator functions have their own `prototype` (inheriting the shared generator prototype), so
+      `g() instanceof g` holds. Plain functions have none, since they cannot construct.
+- [x] Generator and async generator functions bind parameters (defaults, destructuring) at the call and defer only the
+      body to the first `next()`, so a bad argument throws synchronously from the call site, as in JS.
 - [x] Synchronous and async generator declarations/expressions, `yield`, and `yield*`, including lazy bodies,
       `next(value)`, `return(value)`, `throw(value)`, exhaustion, promise adoption, async request ordering,
       `try`/`catch`/`finally`, and sync/async iterator symbols. Async `yield*` awaits values while adapting a sync
@@ -158,7 +164,8 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
       rejected by every synchronous consumer.
 - [x] Synchronous iterator acquisition and result validation follow `IteratorClose` boundaries: consumer errors and
       intentional early stops invoke `return()`, acquisition/`next()` failures do not, and an original consumer error
-      wins over a cleanup failure. Async iterator consumption remains limited to `for await...of` and async `yield*`.
+      wins over a cleanup failure. A generator's `return()` is an intentional stop, so a `return()` that throws or
+      yields a non-object surfaces from it as a `TypeError`. Async iterator consumption remains limited to `for await...of` and async `yield*`.
 - [x] Portable generator protocol coverage is adapted from pinned Test262 cases for suspended-start, suspended-yield,
       and completed states; sync and async `next`/`return`/`throw`; finally yields and completion overrides; rejected
       yielded promises; mixed async request queues; sync and async `yield*` forwarding; malformed methods/results;
@@ -180,7 +187,8 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
       on any other value throws a catchable `TypeError` naming the callee: other built-in functions such as `Number`
       say `new` is unsupported and point at the plain call, user-defined functions report the constructor gap below,
       and non-callable values are not constructors. Error constructors take the ES2022 options object, so
-      `new Error(message, { cause })` installs a non-enumerable `cause` when the option is present.
+      `new Error(message, { cause })` installs a non-enumerable `cause` when the option is present. `Error.isError`
+      is true for every Error value.
 - [x] Arithmetic operators: `+`, `-`, `*`, `/`, `%`, and `**`.
 - [x] Equality and ordering: `==`, `!=`, `===`, `!==`, `<`, `<=`, `>`, and `>=`.
 - [x] Bitwise operators: `&`, `|`, `^`, `~`, `<<`, `>>`, and `>>>`.
@@ -191,13 +199,14 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] Plain, arithmetic, bitwise, and logical assignment operators.
 - [x] Property deletion on plain data objects and arrays, including computed and optional forms; deleting an array index
       creates a hole without changing its length. Deleting a non-configurable property (`length`) or
-      assigning a read-only one (`Math.PI`, `fn.name`) throws a `TypeError`, as in strict mode.
+      assigning a read-only one (`Math.PI`, `fn.name`) throws a `TypeError`, as in strict mode. `delete` of a
+      non-reference (`delete 0`, `delete f()`) evaluates the operand and is `true`; `delete x` on a variable throws.
 - [ ] Operators, `switch` discriminants, template interpolation, and coercion helpers such as `String` and `isNaN`
       applied to functions and namespaces; JavaScript coerces them, the interpreter rejects non-data operands.
 - [ ] ToPrimitive on object operands: operators, `Error(message)`, `Date` arguments, and `parseInt` radix should call
       `valueOf`/`toString` in spec order and surface their throws.
-- [ ] Property keys follow ToPropertyKey: `x[null]`, `x[true]`, and objects (via `toString`) become string keys; only
-      strings and numbers are accepted.
+- [x] Property keys follow ToPropertyKey: `x[null]`, `x[true]`, and objects (via their built-in string form) become
+      string keys.
 
 ## Promises and tools
 
@@ -233,6 +242,10 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
       resolving with the promise itself rejects with a `TypeError`. Resolver callables work anywhere callbacks are
       accepted, including `.then`/`.catch` handlers and collection callbacks, and vanish at the data boundary like
       any function.
+- [x] `Promise.withResolvers()`: the same promise and resolver callables as the constructor, as a `{ promise, resolve,
+reject }` object.
+- [x] `Promise.try(fn, ...args)`: calls `fn` synchronously; a throw rejects, a return fulfils, and a returned promise or
+      thenable is adopted.
 - [x] Recursive assimilation of objects with an own callable `then` field across `Promise.resolve`, combinators,
       constructors, reactions, `finally`, `await`, and async returns. Thenable methods run deferred, receive
       first-call-wins resolve/reject functions, and ignore throws after settlement. Inherited/accessor `then` fields
@@ -253,7 +266,9 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
       not construct.
 - [x] `Object()` and `new Object()` return `{}` for nullish arguments and pass objects through unchanged;
       primitive wrapper objects (`Object(1)`) are rejected explicitly.
-- [x] Computed property names and object spread.
+- [x] Computed property names and object spread. Any value works as a key (ToPropertyKey): strings, numbers, and the
+      two confined symbols as themselves, everything else as its string form (`o[null]` is `o["null"]`, `o[{}]` is
+      `o["[object Object]"]`), in reads, writes, literals, `in`, and destructuring.
 - [x] `Object.keys`, `Object.values`, `Object.entries`, `Object.hasOwn`, `Object.assign`, and `Object.fromEntries`, with
       synchronous iterator support for `fromEntries`. Sources follow ToObject: strings enumerate by index, other
       primitives and wrappers contribute nothing, and `null`/`undefined` throw. `Object.assign` accepts array
@@ -270,8 +285,9 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] `Object.is` for supported data values.
 - [x] `Object.groupBy` over finite collections and custom synchronous iterators/generators, with string-key coercion
       and plain-object results.
-- [x] `Object.prototype` methods on values: `toString` (`"[object Array]"`), `toLocaleString`, `valueOf`,
-      `hasOwnProperty`, `isPrototypeOf`, and `propertyIsEnumerable`.
+- [x] `Object.prototype` methods on values: `toString` (`"[object Array]"`, `"[object Map]"`, `"[object Promise]"`, and so
+      on for every built-in kind, as JS reports through `Symbol.toStringTag`), `toLocaleString` (calls the value's
+      `toString`, as in JS), `valueOf`, `hasOwnProperty`, `isPrototypeOf`, and `propertyIsEnumerable`.
 
 ## Arrays
 
@@ -285,9 +301,14 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
       `lastIndexOf`.
 - [x] Aggregation: `reduce` and `reduceRight`.
 - [x] Ordering: `sort`, `toSorted`, `reverse`, and `toReversed`.
-- [x] Access/copying: `at`, `slice`, `concat`, `flat`, `with`, and `join`.
+- [x] Access/copying: `at`, `slice`, `concat`, `flat`, `with`, `join`, and `toLocaleString` (each element's
+      `toLocaleString`, holes and nullish elements as empty strings).
 - [x] Mutation: `push`, `pop`, `shift`, `unshift`, `splice`, `fill`, and `copyWithin`.
-- [x] Materialized iteration helpers: `keys`, `values`, and `entries` return arrays rather than iterators.
+- [x] `keys`, `values`, `entries`, and `[Symbol.iterator]` (the same function as `values`) return live iterator objects
+      with `next()` and `[Symbol.iterator]`, as in JS. Iterator objects are opaque references: they print as
+      `[opaque reference]`, serialize to `{}`, and cannot be passed to extensions. Every built-in collection iterator
+      shares one prototype. JavaScript gives each collection its own; the difference is not observable here because
+      `Object.getPrototypeOf` is not exposed.
 - [x] `length`, numeric indexing, index assignment, spread, and `for...of`.
 - [x] The `thisArg` argument of `Array.from` is accepted and ignored, like JS arrows.
 - [x] `Array.prototype.toSpliced`.
@@ -298,15 +319,17 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] Assigning `length` to truncate or extend an array; invalid lengths throw `RangeError`.
 - [x] Non-index own properties on arrays (`arr.foo = 1`, `arr.constructor = null`). They are excluded from the JSON
       form, like `JSON.stringify`.
-- [ ] Argument coercion for `indexOf`, `lastIndexOf`, `includes`, `fill`, `flat`, `copyWithin`, and the `join`
-      separator: JavaScript applies ToIntegerOrInfinity/ToString (including `valueOf`, strings, and `undefined`), the
-      interpreter requires numbers and strings; `includes()`/`indexOf()` with no argument should search for
-      `undefined`.
-- [ ] Iterator objects from `keys`, `values`, and `entries` with a live `next()`.
+- [x] Numeric arguments coerce as in JS (ToIntegerOrInfinity): `indexOf(x, "1")`, `slice("1", "3")`, `at(null)`,
+      `flat(1.9)`, `with(1.5, v)`, `Math.max("3", "2")`, `parseInt("11", "2")`, `(1.5).toFixed("2")`,
+      `String.fromCharCode("65")`, and the Uint8Array equivalents. `join(sep)` and `JSON.parse(text)` apply ToString
+      (`join(null)` is `"1null2"`, `JSON.parse(123)` is `123`). `Array.from({ length: "2" })` applies ToLength; a
+      promise source still throws with an `await` hint rather than JS's silent `[]`. A program object's own
+      `valueOf`/`toString` is not consulted yet (see ToPrimitive above).
 
 ## Strings
 
-- [x] Case/normalization: `toLowerCase`, `toUpperCase`, `normalize`.
+- [x] Case/normalization: `toLowerCase`, `toUpperCase`, `normalize`, and the `toLocaleLowerCase`/`toLocaleUpperCase`
+      aliases, which ignore their locale argument and apply the default Unicode casing.
 - [x] Trimming: `trim`, `trimStart`, and `trimEnd`, plus the Annex B `trimLeft` and `trimRight` aliases.
 - [x] Searching/tests: `includes`, `startsWith`, `endsWith`, `indexOf`, `lastIndexOf`, and `search`.
 - [x] Slicing/access: `slice`, `substring`, Annex B `substr`, `at`, `charAt`, `charCodeAt`, and `codePointAt`.
@@ -314,7 +337,7 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] Regular-expression integration: `match`, materialized `matchAll`, `replace`, `replaceAll`, `split`, and `search`.
 - [x] `localeCompare`; locale and options arguments are currently ignored.
 - [x] `isWellFormed` and `toWellFormed`.
-- [x] `toString`, `length`, numeric indexing, spread, and `for...of` by Unicode code point.
+- [x] `toString`, `length`, numeric indexing, spread, `for...of`, and `[Symbol.iterator]` by Unicode code point.
 - [x] Static `String.fromCharCode` and `String.fromCodePoint`.
 - [x] Native argument coercion for supported String methods; for example, `includes(1)` and `slice("1")` coerce like
       native JS, `split(undefined)` returns the whole string, and `includes`/`startsWith`/`endsWith` reject regular
@@ -330,7 +353,8 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] Coercion functions: `Number`, `parseInt`, and `parseFloat`.
 - [x] Number predicates/parsers: `Number.isInteger`, `Number.isFinite`, `Number.isNaN`, `Number.isSafeInteger`,
       `Number.parseInt`, and `Number.parseFloat`.
-- [x] Number formatting: `toFixed`, `toPrecision`, `toExponential`, `toString`, and `valueOf`.
+- [x] Number formatting: `toFixed`, `toPrecision`, `toExponential`, `toString`, `valueOf`, and `toLocaleString`, which
+      always formats as `en-US` (`"1,234.5"`) so output does not depend on the host.
 - [x] Number constants: `MAX_SAFE_INTEGER`, `MIN_SAFE_INTEGER`, `MAX_VALUE`, `MIN_VALUE`, `EPSILON`, `NaN`,
       `POSITIVE_INFINITY`, and `NEGATIVE_INFINITY`.
 - [x] Math constants: `PI`, `E`, `LN2`, `LN10`, `LOG2E`, `LOG10E`, `SQRT2`, and `SQRT1_2`.
@@ -343,7 +367,8 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
       use their epoch time) and reject opaque runtime references as data errors.
 - [x] Unknown static members on global namespaces and on `Number`/`String`/the coercion functions read as `undefined`
       for feature detection. Calling any undefined value reports a native-style `TypeError` naming the callee, for
-      example `Math.sum is not a function.` Unknown `Promise` statics keep their descriptive error.
+      example `Math.sum is not a function.` or `search(...).catch is not a function.` Unknown `Promise` statics keep
+      their descriptive error.
 - [x] `Math.sumPrecise` over finite collections and custom synchronous iterators/generators, rejecting non-number
       elements without coercion.
 - [x] Global coercing `isFinite` and `isNaN`; opaque runtime references reject as data errors, like `Number(...)`.
@@ -357,7 +382,8 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] `JSON.stringify` function and array replacers. Function replacers receive `(key, value)` in preorder, including
       the root, but no `this` holder. Array replacers preserve requested property order, deduplicate names, coerce
       number primitives, and ignore non-string/non-number entries. Primitive wrapper entries remain unsupported.
-- [x] Captured `console.log`, `console.info`, `console.debug`, `console.warn`, and `console.error`.
+- [x] Captured `console.log`, `console.info`, `console.debug`, `console.warn`, and `console.error`. An Error prints as
+      `Error.prototype.toString` would show it (`Error: boom`), wherever it appears in the logged value.
 - [x] Captured `console.dir` and `console.table`.
 
 ## Date
@@ -377,6 +403,8 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
       `TimeClip` behavior.
 - [x] `Date.prototype.toUTCString` and its `toGMTString` alias.
 - [x] `toDateString` and `toTimeString` in the host's local timezone.
+- [x] `toLocaleString`, `toLocaleDateString`, and `toLocaleTimeString` always format as `en-US` in UTC
+      (`"1/1/1970, 12:00:00 AM"`) so output does not depend on the host.
 - [x] Native one-argument Date coercion for supported values, including booleans, null, arrays, and plain objects.
 - [ ] Date setters and multi-argument construction coerce object arguments through `valueOf`/`toString` and surface
       their throws.
@@ -398,14 +426,30 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] Match `indices` metadata for the `d` flag, including named groups on `exec`, `match`, and `matchAll` results.
 - [x] `RegExp.escape`.
 
+## Iterator
+
+- [x] `Iterator.prototype.map`, `filter`, `take`, `drop`, and `flatMap` on any iterator or generator: lazy, one source
+      step per result, closing the source when a callback throws, on early `return()`, or when `for...of` or
+      destructuring finishes with it early. Once done or closed a helper stays done, and a callback that re-enters its
+      own helper is a `TypeError`. `take`/`drop` coerce their count and reject `NaN` or negative counts with a
+      `RangeError`; `flatMap` callbacks must return an iterable or iterator, not a string.
+- [x] `Iterator.prototype.reduce`, `toArray`, `forEach`, `some`, `every`, and `find`, closing the source on early exit.
+- [x] `Iterator.from(value)` returns iterators and generators as they are, and wraps strings, iterables, and objects
+      with a `next` method. `Iterator` itself is abstract: calling or constructing it is a `TypeError`.
+- [x] Helpers and `Iterator.from` wrappers have `return()`; collection iterators (`array.values()`) do not, as in JS,
+      so an early exit from them leaves them where they were.
+- [ ] `Iterator.concat`, `Iterator.zip`, and `Iterator.zipKeyed` (stage 3 proposals).
+
 ## Map and Set
 
 - [x] Static `Map.groupBy` over finite collections and custom synchronous iterators/generators, preserving key identity.
 - [x] `new Map()` from synchronous iterables of entries.
-- [x] Map `get`, `set`, `has`, `delete`, `clear`, `size`, and `forEach`.
+- [x] Map `get`, `set`, `has`, `delete`, `clear`, `size`, `forEach`, `getOrInsert`, and `getOrInsertComputed`.
+      `forEach` is live: entries deleted during the walk are skipped and entries added are visited, as in JS.
 - [x] `new Set()` from synchronous iterables.
 - [x] Set `add`, `has`, `delete`, `clear`, `size`, and `forEach`.
-- [x] Materialized `keys`, `values`, and `entries` arrays for Map and Set.
+- [x] Live `keys`, `values`, `entries`, and `[Symbol.iterator]` iterators for Map and Set; a Set-like operand's `keys()`
+      may return any iterator or an array.
 - [x] Spread, `for...of`, `Array.from`, and `Object.fromEntries` integration.
 - [x] Map and Set values serialize to `{}` at host/JSON boundaries.
 - [x] Set composition and relation methods: `union`, `intersection`, `difference`, `symmetricDifference`, `isSubsetOf`,
@@ -421,8 +465,9 @@ ultimate source of truth. Upstream test262 files run verbatim from `test/test262
 - [x] Writable URL fields except `origin`.
 - [x] `new URLSearchParams()` from query strings, data objects, synchronous iterables of pairs, and URLSearchParams.
 - [x] URLSearchParams `append`, `delete`, `get`, `getAll`, `has`, `set`, `sort`, `forEach`, `keys`, `values`,
-      `entries`, `toString`, and `size`.
-- [x] URL values serialize to their href; URLSearchParams serialize to `{}`.
+      `entries`, `[Symbol.iterator]`, `toString`, and `size`.
+- [x] URL values are their href in `JSON.stringify` and at the host boundary. URLSearchParams are `{}` in
+      `JSON.stringify` and their query string at the host boundary.
 
 ## Uint8Array
 
@@ -434,7 +479,8 @@ with a hint to encode as text first (`TextDecoder`, `toBase64`, `toHex`).
 - [x] Index reads and writes with JS byte semantics: values wrap modulo 256, out-of-range writes are ignored, indexes
       cannot be deleted. `length` is a prototype accessor, so `Object.keys` lists only indexes.
 - [x] `at`, `slice`, `subarray` (a view on the same bytes), `set`, `fill`, `reverse`, `indexOf`, `lastIndexOf`,
-      `includes`, `join`, `toString`, `toBase64`, `toHex`, and materialized `keys`, `values`, and `entries` arrays.
+      `includes`, `join`, `toString`, `toBase64`, `toHex`, and live `keys`, `values`, `entries`, and `[Symbol.iterator]`
+      iterators.
 - [x] Spread, destructuring, `for...of`, `yield*`, `Array.from`, and `new Set(bytes)`. `Array.isArray` is false.
 - [x] String coercion joins with commas; `JSON.stringify` gives `{"0":1,...}`; `console.log` prints
       `Uint8Array(n) [...]`.
@@ -450,8 +496,8 @@ with a hint to encode as text first (`TextDecoder`, `toBase64`, `toHex`).
       `fatal` and `ignoreBOM` options; `decode` takes a Uint8Array or nothing.
 - [x] `new Headers()` from records, synchronous iterables of pairs, and Headers, wrapping the host's `Headers`: names
       fold to lowercase, values are normalized and combined, and invalid names or values throw a `TypeError`.
-- [x] Headers `append`, `delete`, `get`, `getSetCookie`, `has`, `set`, `forEach`, `keys`, `values`, and `entries`;
-      iteration is live and sorted by name, with `set-cookie` values kept apart.
+- [x] Headers `append`, `delete`, `get`, `getSetCookie`, `has`, `set`, `forEach`, `keys`, `values`, `entries`, and
+      `[Symbol.iterator]`; iteration is live and sorted by name, with `set-cookie` values kept apart.
 - [x] Headers serialize to a `{ name: value }` object in JSON, in results, and in tool arguments.
 - [ ] `Request`, `Response`, and `Blob`.
 - [ ] `crypto.subtle` and `TextDecoder` streaming or non-UTF-8 encodings.
@@ -466,7 +512,8 @@ Nothing is exposed unless a host provides it; extension calls are not tool calls
 - [x] Every value crossing in either direction is converted, never shared: plain objects and arrays are copied,
       `Date`, `RegExp`, `URL`, `URLSearchParams`, `Headers`, `Map`, `Set`, and `Uint8Array` become fresh copies with
       their contents converted (a host `ArrayBuffer` comes in as a `Uint8Array`; other typed arrays cannot come out),
-      errors cross as errors with their name and message, and a `__proto__` key is dropped. Functions, generators,
+      errors cross as errors with their name, message, `cause`, and own enumerable data, and a `__proto__` key is
+      dropped. Functions, generators,
       un-awaited promises, and symbols cannot be passed in; a class instance, a symbol, or a BigInt cannot come out.
 - [x] A host function inside a result becomes a program function whose calls cross the same way, so a result can
       carry methods (`res.json()`) whose host closures keep the host state. Diagnostics name it by its path
@@ -491,8 +538,10 @@ Nothing is exposed unless a host provides it; extension calls are not tool calls
 - [x] `AggregateError` with the `(errors, message?)` signature and an own `errors` array, constructed directly or by
       an all-rejected `Promise.any`; direct construction accepts custom synchronous iterators and generators.
 - [x] Error `name`/`message`, error inheritance through `instanceof`, and plain-data serialization. `message` is an own
-      non-enumerable property and `name` is inherited, as in JS, so `Object.keys(err)` is `[]` while the host still
-      receives `{ name, message }`. Errors have no `stack`; the diagnostic carries the source location instead.
+      non-enumerable property and `name` is inherited, as in JS, so `Object.keys(err)` is `[]` for a plain error. The
+      result boundary still emits `{ name, message, ...own enumerable }`, so a field such as `code` crosses. `cause` is
+      non-enumerable: an extension Error carries it, and this JSON form does not. Errors have no `stack`; the diagnostic
+      carries a 1-based line and column in the submitted source instead.
 - [x] `instanceof` against any constructor with a `prototype`, including every built-in and `Function`.
 - [x] Catchable user throws, runtime failures raised during interpreted evaluation, awaited tool failures, and awaited
       tool-call-limit failures; parse/compile failures, cooperative timeout, and output bounding remain outside program
@@ -501,8 +550,9 @@ Nothing is exposed unless a host provides it; extension calls are not tool calls
       short orientation to the supported subset; this matrix is the full reference.
 - [x] Model-visible host failure messages and underlying causes, including output-validation errors.
 - [x] Caught errors do not distinguish user throws, interpreter failures, and tool failures; a program sees one
-      Error-shaped value with `name` and `message` in `catch`, rejection handlers, and `Promise.allSettled` reasons.
-      This is deliberate: the program should handle a failure the same way regardless of where it originated.
+      Error-shaped value in `catch`, rejection handlers, and `Promise.allSettled` reasons. It always has `name` and
+      `message`, plus `cause` and own data when the failure carried them. This is deliberate: the program should
+      handle a failure the same way regardless of where it originated.
 - [x] Failures raised by the interpreter are `TypeError`s unless JavaScript names them otherwise (`RangeError`,
       `ReferenceError`, `SyntaxError`, `URIError`), so `e instanceof TypeError` and `e.constructor === TypeError`
       hold. Unsupported syntax reached at runtime is a `SyntaxError`; awaited tool failures stay plain `Error`.

packages/codemode/package.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/package.json",
   "name": "@opencode/codemode",
-  "version": "2.0.10",
+  "version": "2.0.12",
   "description": "Effect-native confined code execution over schema-described tools",
   "type": "module",
   "license": "MIT",

packages/codemode/src/data.ts

@@ -15,6 +15,7 @@ import {
   Obj,
   PromiseObj,
   record,
+  type Value,
   SetObj,
   URLSearchParamsObj,
   HeadersObj,
@@ -23,14 +24,14 @@ import { typeofValue } from "./interpreter/references.js"
 
 export type Json = Schema.Json
 
-type Replacer<R> = (args: Array<unknown>) => Effect.Effect<unknown, unknown, R>
+type Replacer<R> = (args: Array<Value>) => Effect.Effect<Value, unknown, R>
 
 /**
  * What `JSON.stringify` would serialize for a program value, as host JSON: `toJSON` is honored, functions and
  * `undefined` vanish, non-finite numbers become null, and everything else is copied. Two departures from JS
  * so a mistake is not a silent `{}`: an Error serializes as `{ name, message, ...own }`, and a promise throws.
  */
-export const toJson = <R>(ctx: Interpreter<R>, value: unknown, replacer?: Replacer<R>) =>
+export const toJson = <R>(ctx: Interpreter<R>, value: Value, replacer?: Replacer<R>) =>
   walk(ctx, value, replacer, false)
 
 /**
@@ -38,11 +39,11 @@ export const toJson = <R>(ctx: Interpreter<R>, value: unknown, replacer?: Replac
  * awaited, a Set crosses as an array, a URLSearchParams as its query string, a Uint8Array asks to be encoded as
  * text first, and a `__proto__` key is dropped so host code can never receive one.
  */
-export const toBoundary = <R>(ctx: Interpreter<R>, value: unknown) => walk(ctx, value, undefined, true)
+export const toBoundary = <R>(ctx: Interpreter<R>, value: Value) => walk(ctx, value, undefined, true)
 
 const walk = <R>(
   ctx: Interpreter<R>,
-  value: unknown,
+  value: Value,
   replacer: Replacer<R> | undefined,
   boundary: boolean,
 ): Effect.Effect<Json | undefined, unknown, R> => {
@@ -104,7 +105,7 @@ const walk = <R>(
 }
 
 /** Host JSON as program values: objects and arrays are copied, primitives pass through. */
-export const fromJson = <R>(ctx: Interpreter<R>, value: unknown): unknown => {
+export const fromJson = <R>(ctx: Interpreter<R>, value: Json | undefined): Value => {
   if (value === null || typeof value !== "object") return value
   if (Array.isArray(value))
     return new Arr(