diff --git a/web/src/engine/templateMatch.ts b/web/src/engine/templateMatch.ts
index d589e9f2..67ed3d67 100644
--- a/web/src/engine/templateMatch.ts
+++ b/web/src/engine/templateMatch.ts
@@ -3,6 +3,7 @@ import { DeliverableItem } from '../types/workbench';
 const READ_ONLY_INTENT =
   /(?:总结|概括|查看|看看|展示|读取|介绍|解释|分析|评价|检查|查询|当前状态|进度|谁在编辑|是否在编辑)/;
 const WRITE_INTENT =
+  // 弱写动词（整理/梳理/汇总等）故意不含：走聊天通道，由后端阶段感知 + 确认门禁引导。
   /(?:开始|编写|编制|生成|起草|创建|撰写|重写|更新|修改|完善|补充|刷新|重做|改写)/;
 const CURRENT_DOC_DEIXIS = /当前受控文档|当前文档|本文件|这份文档|本文档|本受控文档/;
 
diff --git a/web/src/hooks/useTaskRunAttempts.test.ts b/web/src/hooks/useTaskRunAttempts.test.ts
index 580dae47..d4fdf54e 100644
--- a/web/src/hooks/useTaskRunAttempts.test.ts
+++ b/web/src/hooks/useTaskRunAttempts.test.ts
@@ -5,6 +5,7 @@ import { isBlockedGovernanceStatus } from '../lib/blockedGovernanceCopy';
 import {
   buildFailedTaskErrorInfo,
   buildNetworkErrorInfo,
+  isTaskStageDegradeCode,
   readRemoteTaskRun,
 } from '../lib/taskRunErrorInfo';
 
@@ -22,6 +23,15 @@ test('chat and task attempts live in one hook', () => {
   assert.equal(hook.includes('chatWindow.allMessages.find'), true);
   assert.equal(hook.includes('buildFailedTaskErrorInfo'), true);
   assert.equal(hook.includes('buildCancelledTaskErrorInfo'), true);
+  assert.equal(hook.includes('isTaskStageDegradeCode'), true);
+  assert.equal(hook.includes('改由对话确认引导'), true);
+});
+
+test('stage unresolved and not-in-active-stage degrade to chat once', () => {
+  assert.equal(isTaskStageDegradeCode('TASK_SCOPE_UNRESOLVED'), true);
+  assert.equal(isTaskStageDegradeCode('DOC_TASK_NOT_IN_ACTIVE_STAGE'), true);
+  assert.equal(isTaskStageDegradeCode('DOC_BUSY'), false);
+  assert.equal(isTaskStageDegradeCode(''), false);
 });
 
 test('failed run with error_message surfaces TASK_FAILED not NETWORK_ERROR', () => {
diff --git a/web/src/hooks/useTaskRunAttempts.ts b/web/src/hooks/useTaskRunAttempts.ts
index 82bcc5b6..c09ec1a6 100644
--- a/web/src/hooks/useTaskRunAttempts.ts
+++ b/web/src/hooks/useTaskRunAttempts.ts
@@ -29,6 +29,7 @@ import {
   buildFailedTaskErrorInfo,
   buildInterruptedTaskErrorInfo,
   buildNetworkErrorInfo,
+  isTaskStageDegradeCode,
   readRemoteTaskRun,
 } from '../lib/taskRunErrorInfo';
 import {
@@ -790,6 +791,27 @@ export function useTaskRunAttempts(input: TaskRunAttemptsInput) {
           ? Number((_err as { httpStatus?: number }).httpStatus)
           : undefined;
       const errMeta = _err as { errorCode?: string; detail?: string; message?: string };
+      // 阶段/作用域未解析：降级聊天一次，由后端意图确认引导，替代仅弹错误气泡。
+      if (
+        mode === 'run' &&
+        attemptIndex === 0 &&
+        isTaskStageDegradeCode(errMeta.errorCode) &&
+        task.userMessage?.trim()
+      ) {
+        settled = true;
+        patchAsst({
+          status: 'pending',
+          livePhaseLabel: '改由对话确认引导…',
+          errorInfo: undefined,
+          taskRequest: undefined,
+          content: '',
+        });
+        taskRunStream.setThinking(sessionId, false);
+        runStreamAttempt(task.userMessage.trim(), asstId, 0, {
+          clientTurnId: task.clientTurnId,
+        });
+        return;
+      }
       failOrRetry(
         buildNetworkErrorInfo(httpStatus, {
           errorCode: errMeta.errorCode,
diff --git a/web/src/lib/taskRunErrorInfo.ts b/web/src/lib/taskRunErrorInfo.ts
index ece1444c..328f14c3 100644
--- a/web/src/lib/taskRunErrorInfo.ts
+++ b/web/src/lib/taskRunErrorInfo.ts
@@ -35,6 +35,11 @@ const fatalDenialCopy: Record<string, string> = {
   TASK_SCOPE_UNRESOLVED: '无法定位该文档任务的工作流阶段，请检查任务名或联系管理员',
 };
 
+/** 任务直通道失败后应降级到聊天确认引导的错误码（仅降级一次，防循环）。 */
+export function isTaskStageDegradeCode(code: string | undefined | null): boolean {
+  return code === 'TASK_SCOPE_UNRESOLVED' || code === 'DOC_TASK_NOT_IN_ACTIVE_STAGE';
+}
+
 export function buildNetworkErrorInfo(
   httpStatus?: number,
   opts?: { errorCode?: string; detail?: string },