fix(user-interaction): reject ask_user_question from delegated subagents

packages/ui/tool-ask-user/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/ui/tool-ask-user/README.md
-README.md: 8e779f4025c20cd200344efb7cb8cd6bc09ba64d
-README.zh.md: acaffec0764404a0e0e842ffc2b4efdee8869c4f
+README.md: d7866ff018ebfed5afbf105b1a20714490bdb818
+README.zh.md: 18a1c8e9f958c174fc34f26a572d88b6c031d7f9

packages/ui/tool-ask-user/README.md

@@ -54,4 +54,5 @@ Append-only; newly visible content follows the reusable request prefix and does
 ## Known Limitations and Deferred Work
 
 - **A pending question blocks the tool call until the human answers** — the tool declares no `timeout-policy` budget; cancellation rides the turn's `exec.signal` only.
+- **Delegated subagents cannot ask the user** — `ask_user_question` rejects calls from a delegated subagent with `DELEGATED_CALLER`; a child that needs a decision must delegate the question to the top-level agent.
 - **Native answers render as JSON text** — the canonical value remains structured, but the model-facing result uses compact JSON rather than a richer content-block vocabulary.

packages/ui/tool-ask-user/README.zh.md

@@ -54,4 +54,5 @@
 ## 已知限制与暂缓事项
 
 - **待处理问题会阻塞工具调用，直至用户作答**：该工具未声明 `timeout-policy` 预算；取消仅沿用当前轮次的 `exec.signal`。
+- **委托的子代理不能向用户提问**：`ask_user_question` 会以 `DELEGATED_CALLER` 拒绝来自委托子代理的调用；需要决策的子代理必须把问题转交给顶层代理。
 - **Native 回答渲染为 JSON 文本**：规范值仍为结构化数据，但模型侧结果使用紧凑 JSON，而非更丰富的内容块词汇。

packages/ui/tool-ask-user/tests/tool-ask-user.spec.ts

@@ -2,6 +2,7 @@ import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
 import { CallId } from '@deepseek-ai/dsh-llm'
 import type { Agent } from '@deepseek-ai/dsh-agent'
+import SessionStore from '@deepseek-ai/dsh-session'
 import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
 import ToolRegistry from '@deepseek-ai/dsh-tools'
 import UserInteractionService, { type AskUserQuestionRequest } from '@deepseek-ai/dsh-user-interaction'
@@ -201,6 +202,7 @@ describe('ask_user_question tool', () => {
 
   it('passes optional header and agent through to the user-interaction request', async () => {
     const ctx = await setup()
+    await ctx.plugin(SessionStore)
     const seen: AskUserQuestionRequest[] = []
     ctx.userInteraction.registerProvider({
       async ask(request) {
@@ -208,7 +210,8 @@ describe('ask_user_question tool', () => {
         return { answers: [{ id: 'continue', selected: ['ok'] }] }
       },
     })
-    const agent = { id: 'main' } as unknown as Agent
+    const session = ctx.sessions.create(undefined, { meta: { delegationDepth: 0 } })
+    const agent = { session } as unknown as Agent
 
     const result = await ctx.tools.execute({
       signal: testToolSignal,
@@ -238,6 +241,34 @@ describe('ask_user_question tool', () => {
     })
   })
 
+  it('rejects a delegated subagent with a structured DELEGATED_CALLER error', async () => {
+    const ctx = await setup()
+    await ctx.plugin(SessionStore)
+    const seen: AskUserQuestionRequest[] = []
+    ctx.userInteraction.registerProvider({
+      async ask(request) {
+        seen.push(request)
+        return { answers: [{ id: 'continue', selected: ['ok'] }] }
+      },
+    })
+    const session = ctx.sessions.create(undefined, { meta: { delegationDepth: 1 } })
+    const agent = { session } as unknown as Agent
+
+    const result = await ctx.tools.execute({
+      signal: testToolSignal,
+      callId: CallId('ask-delegated'),
+      name: 'ask_user_question',
+      arguments: { questions: [{ id: 'continue', question: 'Continue?' }] },
+      agent,
+    })
+
+    expect(result).toMatchObject({
+      isError: true,
+      error: { info: { name: 'UserInteractionError', code: 'DELEGATED_CALLER' } },
+    })
+    expect(seen).toHaveLength(0)
+  })
+
   it('returns a structured error for empty question batches', async () => {
     const ctx = await setup()