Merge origin/master into worktree/archive-agent-notes-20260726

# Conflicts:
#	.agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.i18n.yaml
#	.agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.md
#	.agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.zh.md

packages/llm/llm/src/adapter-failure.ts

@@ -47,8 +47,10 @@ export function markLlmAdapterFailure(
   const error = value instanceof Error
     ? value as Error & { code?: string }
     : new HarnessError(String(value), 'UNKNOWN', { cause: value })
-  const carried = error instanceof HarnessError ? ownFailureSnapshot(error) : undefined
-  const failure = carried !== undefined && carried.code === error.code ? carried : Object.freeze({
+  // Cross-package copies preserve own data but not class identity. Trust the
+  // carried facts only when both own properties agree after validation.
+  const carried = ownFailureSnapshot(error)
+  const failure = carried !== undefined && carried.code === ownErrorCode(error) ? carried : Object.freeze({
     message: errorMessage(error),
     code: harnessErrorCode(error),
   })
@@ -56,6 +58,16 @@ export function markLlmAdapterFailure(
   return error
 }
 
+/** Read a foreign error's own data-backed `code` without invoking accessors. */
+function ownErrorCode(error: Error): unknown {
+  try {
+    const descriptor = Object.getOwnPropertyDescriptor(error, 'code')
+    return descriptor !== undefined && 'value' in descriptor ? descriptor.value : undefined
+  } catch (_sdkPropertyTrap) {
+    return undefined
+  }
+}
+
 /** Snapshot an own data property without invoking an SDK-defined accessor. */
 function ownFailureSnapshot(error: Error): LlmFailure | undefined {
   try {

packages/llm/llm/tests/service.spec.ts

@@ -291,6 +291,34 @@ describe('LlmService', () => {
     expect(facts).not.toBe(carried)
   })
 
+  it('keeps validated failure facts across package copies with matching own codes', async () => {
+    const original = Object.assign(new Error('provider busy'), {
+      code: 'RATE_LIMIT',
+      failure: {
+        message: 'provider busy',
+        code: 'RATE_LIMIT',
+        status: 429,
+        providerRetryAfterMs: 1_500,
+        requestId: 'req-cross-copy',
+      },
+    })
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    ctx.llm.registerAdapter(['test-provider'], new ThrowingAdapter(original))
+
+    const stream = ctx.llm.stream({ provider: 'test-provider', model: 'test-model', messages: [] })
+    await expect((async () => {
+      for await (const _chunk of stream) { /* drain */ }
+    })()).rejects.toBe(original)
+    expect(llmFailureOf(stream, original)).toEqual({
+      message: 'provider busy',
+      code: 'RATE_LIMIT',
+      status: 429,
+      providerRetryAfterMs: 1_500,
+      requestId: 'req-cross-copy',
+    })
+  })
+
   it('keeps an unknown SDK Error exact without trusting its private code or accessors', async () => {
     const original = Object.assign(new Error('socket closed'), { code: 'ECONNRESET' })
     Object.defineProperty(original, 'failure', {
@@ -324,6 +352,64 @@ describe('LlmService', () => {
     expect(llmFailureOf(stream, original)).toEqual({ message: 'LLM adapter failed', code: 'UNKNOWN' })
   })
 
+  it('keeps an SDK Error exact without trusting accessor-backed carried facts', async () => {
+    const original = Object.assign(new Error('busy'), {
+      failure: { message: 'busy', code: 'SERVER', status: 503 },
+    })
+    Object.defineProperty(original, 'code', {
+      get() { throw new Error('SDK code accessor must not escape') },
+    })
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    ctx.llm.registerAdapter(['test-provider'], new ThrowingAdapter(original))
+    const stream = ctx.llm.stream({ provider: 'test-provider', model: 'test-model', messages: [] })
+
+    await expect((async () => {
+      for await (const _chunk of stream) { /* drain */ }
+    })()).rejects.toBe(original)
+    expect(llmFailureOf(stream, original)).toEqual({ message: 'busy', code: 'UNKNOWN' })
+  })
+
+  it('does not trust carried facts matched only by an inherited code', async () => {
+    class InheritedCodeError extends Error {
+      get code(): string { return 'SERVER' }
+    }
+    const original = Object.assign(new InheritedCodeError('busy'), {
+      failure: { message: 'busy', code: 'SERVER', status: 503 },
+    })
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    ctx.llm.registerAdapter(['test-provider'], new ThrowingAdapter(original))
+    const stream = ctx.llm.stream({ provider: 'test-provider', model: 'test-model', messages: [] })
+
+    await expect((async () => {
+      for await (const _chunk of stream) { /* drain */ }
+    })()).rejects.toBe(original)
+    expect(llmFailureOf(stream, original)).toEqual({ message: 'busy', code: 'UNKNOWN' })
+  })
+
+  it('keeps an SDK Error exact when code descriptor inspection is trapped', async () => {
+    const target = Object.assign(new Error('busy'), {
+      code: 'SERVER',
+      failure: { message: 'busy', code: 'SERVER', status: 503 },
+    })
+    const original = new Proxy(target, {
+      getOwnPropertyDescriptor(value, property) {
+        if (property === 'code') throw new Error('SDK code descriptor trap')
+        return Reflect.getOwnPropertyDescriptor(value, property)
+      },
+    })
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    ctx.llm.registerAdapter(['test-provider'], new ThrowingAdapter(original))
+    const stream = ctx.llm.stream({ provider: 'test-provider', model: 'test-model', messages: [] })
+
+    await expect((async () => {
+      for await (const _chunk of stream) { /* drain */ }
+    })()).rejects.toBe(original)
+    expect(llmFailureOf(stream, original)).toEqual({ message: 'busy', code: 'UNKNOWN' })
+  })
+
   it('falls back safely when SDK objects trap failure inspection or expose malformed facts', async () => {
     const propertyTrap = new Proxy(new HarnessError('descriptor trapped', 'SERVER'), {
       getOwnPropertyDescriptor(target, property) {