diff --git a/src/__tests__/queryMissingToolUseRecovery.test.ts b/src/__tests__/queryMissingToolUseRecovery.test.ts
index 4dab1c2a1..2cefda122 100644
--- a/src/__tests__/queryMissingToolUseRecovery.test.ts
+++ b/src/__tests__/queryMissingToolUseRecovery.test.ts
@@ -99,7 +99,7 @@ describe('query missing tool_use recovery', () => {
         observedPrompts.push(messages)
         if (callCount === 1) {
           yield createAssistantMessage(
-            [{ type: 'text', text: '现在调用 TaskUpdate 标记完成。' }],
+            [{ type: 'text', text: '现在调用工具继续处理。' }],
             'tool_use',
           )
           return
@@ -141,4 +141,110 @@ describe('query missing tool_use recovery', () => {
       'Your previous response ended with stop_reason=tool_use',
     )
   })
+
+  test('surfaces an error immediately for missing task tool use', async () => {
+    const toolUseContext = createToolUseContext()
+
+    let callCount = 0
+    const yielded: unknown[] = []
+    const deps = {
+      uuid: () => 'query-chain-id',
+      microcompact: async (messages: unknown[]) => ({ messages }),
+      autocompact: async () => ({
+        compactionResult: undefined,
+        consecutiveFailures: 0,
+      }),
+      callModel: async function* () {
+        callCount += 1
+        yield createAssistantMessage(
+          [{ type: 'text', text: '让我查看任务列表确认状态更新成功：' }],
+          'tool_use',
+        )
+      },
+    }
+
+    const generator = query({
+      messages: [
+        createUserMessage({
+          content: '使用 TaskUpdate 更新任务状态',
+        }),
+      ],
+      systemPrompt: asSystemPrompt([]),
+      userContext: {},
+      systemContext: {},
+      canUseTool: async (_tool, input) => ({
+        behavior: 'allow',
+        updatedInput: input,
+      }),
+      toolUseContext,
+      querySource: 'sdk',
+      maxTurns: 3,
+      deps: deps as never,
+    })
+
+    let next = await generator.next()
+    while (!next.done) {
+      yielded.push(next.value)
+      next = await generator.next()
+    }
+
+    expect(next.value.reason).toBe('model_error')
+    expect(callCount).toBe(1)
+    expect(JSON.stringify(yielded)).toContain(
+      'Task tool call failed: the model ended with stop_reason=tool_use',
+    )
+  })
+
+  test('surfaces an error when generic missing tool_use recovery fails', async () => {
+    const toolUseContext = createToolUseContext()
+
+    let callCount = 0
+    const yielded: unknown[] = []
+    const deps = {
+      uuid: () => 'query-chain-id',
+      microcompact: async (messages: unknown[]) => ({ messages }),
+      autocompact: async () => ({
+        compactionResult: undefined,
+        consecutiveFailures: 0,
+      }),
+      callModel: async function* () {
+        callCount += 1
+        yield createAssistantMessage(
+          [{ type: 'text', text: '现在调用工具继续处理。' }],
+          'tool_use',
+        )
+      },
+    }
+
+    const generator = query({
+      messages: [
+        createUserMessage({
+          content: '使用工具继续处理',
+        }),
+      ],
+      systemPrompt: asSystemPrompt([]),
+      userContext: {},
+      systemContext: {},
+      canUseTool: async (_tool, input) => ({
+        behavior: 'allow',
+        updatedInput: input,
+      }),
+      toolUseContext,
+      querySource: 'sdk',
+      maxTurns: 3,
+      deps: deps as never,
+    })
+
+    let next = await generator.next()
+    while (!next.done) {
+      yielded.push(next.value)
+      next = await generator.next()
+    }
+
+    expect(next.value.reason).toBe('model_error')
+    expect(callCount).toBe(2)
+    expect(JSON.stringify(yielded)).toContain(
+      'Model response error: the model indicated it wanted to call a tool',
+    )
+  })
 })
diff --git a/src/query.ts b/src/query.ts
index 79c63c251..348d3426e 100644
--- a/src/query.ts
+++ b/src/query.ts
@@ -205,8 +205,26 @@ function isMissingToolUseResponse(msg: Message | undefined): boolean {
   return !content.some(block => block.type === 'tool_use')
 }
 
+function isTaskRelatedMissingToolUseResponse(
+  msg: Message | undefined,
+): boolean {
+  if (!isMissingToolUseResponse(msg)) return false
+  if (msg?.type !== 'assistant') return false
+  const content = msg.message?.content
+  if (!Array.isArray(content)) return false
+  const text = content
+    .filter(block => block.type === 'text')
+    .map(block => block.text)
+    .join('\n')
+  return /Task(Create|Update|List|Get)|\btask(s)?\b|任务/.test(text)
+}
+
 const MISSING_TOOL_USE_RECOVERY_MESSAGE =
   'Your previous response ended with stop_reason=tool_use but did not include a tool_use block. Continue by issuing the missing tool call now. If the user asked to update task state, call TaskUpdate with the appropriate taskId and status; do not just describe the action.'
+const MISSING_TOOL_USE_FAILURE_MESSAGE =
+  'Model response error: the model indicated it wanted to call a tool, but no tool call was provided after retry. The requested action did not run.'
+const TASK_TOOL_USE_FAILURE_MESSAGE =
+  'Task tool call failed: the model ended with stop_reason=tool_use but did not provide the required task tool call. The requested task action did not run.'
 
 export type QueryParams = {
   messages: Message[]
@@ -1371,6 +1389,14 @@ async function* queryLoop(
         return { reason: 'completed' }
       }
 
+      if (isTaskRelatedMissingToolUseResponse(lastMessage)) {
+        const error = new Error(TASK_TOOL_USE_FAILURE_MESSAGE)
+        yield createAssistantAPIErrorMessage({
+          content: TASK_TOOL_USE_FAILURE_MESSAGE,
+        })
+        return { reason: 'model_error', error }
+      }
+
       if (
         isMissingToolUseResponse(lastMessage) &&
         state.transition?.reason !== 'missing_tool_use_recovery'
@@ -1401,6 +1427,16 @@ async function* queryLoop(
         state = next
         continue
       }
+      if (
+        isMissingToolUseResponse(lastMessage) &&
+        state.transition?.reason === 'missing_tool_use_recovery'
+      ) {
+        const error = new Error(MISSING_TOOL_USE_FAILURE_MESSAGE)
+        yield createAssistantAPIErrorMessage({
+          content: MISSING_TOOL_USE_FAILURE_MESSAGE,
+        })
+        return { reason: 'model_error', error }
+      }
 
       const stopHookResult = yield* handleStopHooks(
         messagesForQuery,
diff --git a/src/utils/messages.ts b/src/utils/messages.ts
index dc583e06c..aab561801 100644
--- a/src/utils/messages.ts
+++ b/src/utils/messages.ts
@@ -395,7 +395,7 @@ export const NO_RESPONSE_REQUESTED = 'No response requested.'
 // reject any payload containing it — placeholder satisfies pairing structurally
 // but the content is fake, which poisons training data if submitted.
 export const SYNTHETIC_TOOL_RESULT_PLACEHOLDER =
-  '[Tool result missing due to internal error]'
+  'Tool execution failed: the model requested a tool call, but no tool result was recorded. The requested task action did not complete successfully.'
 
 // Prefix used by UI to detect classifier denials and render them concisely
 const AUTO_MODE_REJECTION_PREFIX =