diff --git a/app/(chat)/api/chat/route.ts b/app/(chat)/api/chat/route.ts
index e1971a923..e95340dc8 100644
--- a/app/(chat)/api/chat/route.ts
+++ b/app/(chat)/api/chat/route.ts
@@ -1,10 +1,11 @@
 import { isExplicitDestructiveIntent } from "@/lib/ai/canvas-agent-runtime/capability-access";
 import { inferVideoTaskRequirements } from "@/lib/ai/canvas-agent-runtime/video-protocol";
 import { createLogger } from "@/lib/observability/logger";
+import { trackRuntimeWork } from "@/lib/observability/active-work";
 import { geolocation } from "@vercel/functions";
 import {
   convertToModelMessages,
-  createUIMessageStream,
+  createUIMessageStream as createAiUIMessageStream,
   generateText,
   smoothStream,
   stepCountIs,
@@ -426,6 +427,8 @@ import {
 } from "./_lib/video-models";
 
 const chatApiLogger = createLogger("chat.route");
+const createUIMessageStream: typeof createAiUIMessageStream = (options) =>
+  createAiUIMessageStream({ ...options, execute: (writer) => trackRuntimeWork(() => options.execute(writer)) });
 
 const INTERNAL_IMAGE_GENERATION_FAILURE_PATTERN =
   /生成图片失败|图片生成失败|未找到图片数据|未解析到图片|模型未返回生成图片|图片数据不可用|未返回可用图片/i;
@@ -443,13 +446,13 @@ function assertGeneratedImageMarkdownHasImage(markdown: string, modelLabel: stri
   throw new Error(`${modelLabel} 未返回可用图片：${reason.slice(0, 160)}`);
 }
 
-function getPublicImageGenerationErrorText(error: unknown) {
+function getPublicImageGenerationErrorText(error: unknown, requestId: string) {
   const message = error instanceof Error ? error.message : String(error || "");
   const publicMessage = getUserFacingImageGenerationErrorMessage(error);
   if (!message || (publicMessage === message && INTERNAL_IMAGE_GENERATION_FAILURE_PATTERN.test(message))) {
-    return "图片生成失败，请稍后重试";
+    return `图片生成失败，请稍后重试。若连续失败，请联系管理员。\n\n请求编号：${requestId}`;
   }
-  return publicMessage;
+  return `${publicMessage}\n\n请求编号：${requestId}`;
 }
 
 
@@ -9630,9 +9633,10 @@ export async function POST(request: Request) {
             
             // 如果故障转移也失败，返回错误消息
             const errorMessageId = generateUUID();
+            const errorText = getPublicImageGenerationErrorText(error, errorMessageId);
             writeAssistantTextChunk(
               writer,
-              "图片生成失败，请稍后重试",
+              errorText,
               "gemini:error",
               errorMessageId,
             );
@@ -9652,7 +9656,7 @@ export async function POST(request: Request) {
                     id: errorMessageId,
                     chatId: id,
                     role: "assistant",
-                    parts: [{ type: "text", text: "图片生成失败，请稍后重试" }],
+                    parts: [{ type: "text", text: errorText }],
                     attachments: [],
                     createdAt: new Date(),
                     videoStorageStatus: null,
@@ -10332,7 +10336,7 @@ export async function POST(request: Request) {
             
             // 返回错误消息
             const errorMessageId = generateUUID();
-            const errorText = getPublicImageGenerationErrorText(error);
+            const errorText = getPublicImageGenerationErrorText(error, errorMessageId);
             writeAssistantTextChunk(
               writer,
               errorText,
@@ -10772,9 +10776,10 @@ export async function POST(request: Request) {
           } catch (error) {
             chatApiLogger.error("[Chat API] Volcano Vision generation error:", error);
             const errorMessageId = generateUUID();
+            const errorText = getPublicImageGenerationErrorText(error, errorMessageId);
             writeAssistantTextChunk(
               writer,
-              "图片生成失败，请稍后重试",
+              errorText,
               "volcano:error",
               errorMessageId,
             );
@@ -10794,7 +10799,7 @@ export async function POST(request: Request) {
                     id: errorMessageId,
                     chatId: id,
                     role: "assistant",
-                    parts: [{ type: "text", text: "图片生成失败，请稍后重试" }],
+                    parts: [{ type: "text", text: errorText }],
                     attachments: [], // 必须提供 attachments 字段
                     createdAt: new Date(),
                     videoStorageStatus: null,
@@ -11702,7 +11707,7 @@ export async function POST(request: Request) {
             chatApiLogger.error("[Chat API] OpenAI-compatible image model generation error:", error);
 
             const errorMessageId = generateUUID();
-            const errorText = getPublicImageGenerationErrorText(error);
+            const errorText = getPublicImageGenerationErrorText(error, errorMessageId);
 
             dataStream.write({
               type: "data-appendMessage",
diff --git a/app/api/canvas/[id]/capabilities/route.ts b/app/api/canvas/[id]/capabilities/route.ts
index 9507c77d9..f146da491 100644
--- a/app/api/canvas/[id]/capabilities/route.ts
+++ b/app/api/canvas/[id]/capabilities/route.ts
@@ -8,6 +8,7 @@ import { getCanvasCapabilityManifest } from "@/lib/canvas/capabilities/registry"
 import { executeCanvasCapabilityRuntime } from "@/lib/canvas/capabilities/runtime";
 import { getCanvasCapabilityTask } from "@/lib/canvas/capabilities/task-store";
 import { CanvasAgentMutationError } from "@/lib/canvas/agent-mutations";
+import { formatRequestFailure, getRequestFailureDetails } from "@/lib/request-error";
 
 export const dynamic = "force-dynamic";
 export const maxDuration = 600;
@@ -39,7 +40,8 @@ export async function GET(
       { status: 404 }
     );
   }
-  return NextResponse.json({ success: true, task });
+  const failure = task.status === "failed" ? getRequestFailureDetails(task.error) : undefined;
+  return NextResponse.json({ success: true, task: { ...task, failure, error: failure ? formatRequestFailure(failure, task.id) : task.error } });
 }
 
 export async function POST(
@@ -51,9 +53,11 @@ export async function POST(
     return NextResponse.json({ success: false, error: "未登录" }, { status: 401 });
   }
 
+  let requestId: string | undefined;
   try {
     const { id } = await params;
     const command = canvasCapabilityClientCommandSchema.parse(await request.json());
+    requestId = command.requestId;
     const result = await executeCanvasCapabilityRuntime({
       command,
       projectId: id,
@@ -67,8 +71,9 @@ export async function POST(
       error instanceof CanvasCapabilityRuntimeError ||
       error instanceof CanvasAgentMutationError
     ) {
+      const failure = getRequestFailureDetails(error);
       return NextResponse.json(
-        { success: false, error: error.message, code: error.code },
+        { success: false, error: formatRequestFailure(failure, requestId), code: error.code, failure, requestId },
         { status: error.status }
       );
     }
@@ -82,9 +87,9 @@ export async function POST(
         { status: 400 }
       );
     }
-    const message = error instanceof Error ? error.message : "执行画布能力失败";
+    const failure = getRequestFailureDetails(error, "执行画布能力失败");
     return NextResponse.json(
-      { success: false, error: message },
+      { success: false, error: formatRequestFailure(failure, requestId), failure, requestId },
       { status: 500 }
     );
   }
diff --git a/app/api/canvas/generate/image/route.ts b/app/api/canvas/generate/image/route.ts
index 5060327d3..835f4a6a5 100644
--- a/app/api/canvas/generate/image/route.ts
+++ b/app/api/canvas/generate/image/route.ts
@@ -2,6 +2,7 @@ import { executeCanvasImageResponse } from "@/lib/canvas/generate-image-response
 import { NextResponse } from "next/server";
 import { auth } from "@/app/(auth)/auth";
 import { getCanvasImageTaskForUser } from "@/lib/canvas/image-task-queue";
+import { formatRequestFailure, getRequestFailureDetails } from "@/lib/request-error";
 
 export const maxDuration = 1200;
 
@@ -23,13 +24,15 @@ export async function GET(request: Request) {
       return NextResponse.json({ success: false, error: "任务不存在" }, { status: 404 });
     }
 
+    const failure = task.status === "failed" ? getRequestFailureDetails(task.error) : undefined;
     return NextResponse.json({
       success: true,
       task: {
         id: task.id,
         status: task.status,
         attempts: task.attempts,
-        error: task.error || null,
+        error: failure ? formatRequestFailure(failure, task.id) : null,
+        failure,
         result: task.result || null,
         createdAt: task.createdAt,
         startedAt: task.startedAt,
diff --git a/lib/canvas/capabilities/runtime.ts b/lib/canvas/capabilities/runtime.ts
index 84ab4da92..ff5a61dc9 100644
--- a/lib/canvas/capabilities/runtime.ts
+++ b/lib/canvas/capabilities/runtime.ts
@@ -14,13 +14,16 @@ import { getCanvasCapability } from "@/lib/canvas/capabilities/registry";
 import { enqueueCanvasCapabilityExecution } from "@/lib/canvas/capabilities/task-queue";
 import {
   createOrRecoverCanvasCapabilityTask,
-  MAX_CANVAS_CAPABILITY_TASK_ATTEMPTS,
+  getCanvasCapabilityTask,
+  heartbeatCanvasCapabilityTask,
   markCanvasCapabilityTaskFailed,
   markCanvasCapabilityTaskRunning,
   markCanvasCapabilityTaskSucceeded,
 } from "@/lib/canvas/capabilities/task-store";
 import { applyCanvasOperationPlan } from "@/lib/canvas/agent-mutations";
 import type { CanvasOperationPlan } from "@/types/canvas/agent-protocol";
+import { formatRequestFailure, getRequestFailureDetails } from "@/lib/request-error";
+import { trackRuntimeWork } from "@/lib/observability/active-work";
 
 export type CanvasCapabilityRuntimeResult = {
   clientCommand?: CanvasCapabilityClientCommand;
@@ -58,9 +61,11 @@ function serializeTask(task: {
   status: string;
   version: number;
 }) {
+  const failure = task.status === "failed" ? getRequestFailureDetails(task.error) : undefined;
   return {
     attempts: task.attempts,
-    error: task.error,
+    error: failure ? formatRequestFailure(failure, task.id) : task.error,
+    failure,
     id: task.id,
     requestId: task.requestId,
     result: task.result,
@@ -69,6 +74,13 @@ function serializeTask(task: {
   };
 }
 
+function storedTaskResult(task: Parameters<typeof serializeTask>[0], mode: "headless" | "interactive"): CanvasCapabilityRuntimeResult {
+  const result = task.status === "succeeded" && task.result && typeof task.result === "object"
+    ? task.result as Omit<CanvasCapabilityRuntimeResult, "task">
+    : { mode };
+  return { ...result, task: serializeTask(task) };
+}
+
 function buildMediaOperationPlan(params: {
   command: CanvasCapabilityClientCommand;
   mediaResults: CanvasCapabilityMediaResult[];
@@ -211,11 +223,7 @@ export async function executeCanvasCapabilityRuntime(params: {
   });
 
   if (task.status === "succeeded") {
-    const storedResult =
-      task.result && typeof task.result === "object"
-        ? (task.result as Omit<CanvasCapabilityRuntimeResult, "task">)
-        : ({ mode: "headless" } as const);
-    return { ...storedResult, task: serializeTask(task) };
+    return storedTaskResult(task, "headless");
   }
   if (task.status === "running") {
     return {
@@ -225,15 +233,8 @@ export async function executeCanvasCapabilityRuntime(params: {
       task: serializeTask(task),
     };
   }
-  if (
-    task.status === "failed" &&
-    task.attempts >= MAX_CANVAS_CAPABILITY_TASK_ATTEMPTS
-  ) {
-    throw new CanvasCapabilityRuntimeError(
-      task.error || "画布能力任务超过最大重试次数",
-      409,
-      "CANVAS_CAPABILITY_RETRY_EXHAUSTED"
-    );
+  if (task.status === "failed") {
+    return { mode: "headless", task: serializeTask(task) };
   }
 
   const shouldRunHeadlessly = shouldExecuteCanvasCapabilityHeadlessly({
@@ -241,7 +242,9 @@ export async function executeCanvasCapabilityRuntime(params: {
     command,
   });
   if (!shouldRunHeadlessly) {
-    task = await markCanvasCapabilityTaskRunning(task.id);
+    const claimed = await markCanvasCapabilityTaskRunning(task.id);
+    if (!claimed) return storedTaskResult((await getCanvasCapabilityTask({ requestId: command.requestId, userId: params.userId, projectId: params.projectId })) || task, "interactive");
+    task = claimed;
     const result = {
       mode: "interactive" as const,
       clientCommand: command,
@@ -250,10 +253,18 @@ export async function executeCanvasCapabilityRuntime(params: {
     return { ...result, task: serializeTask(task) };
   }
 
-  return enqueueCanvasCapabilityExecution({
+  const heartbeat = setInterval(() => {
+    void heartbeatCanvasCapabilityTask(task.id).catch((error) => {
+      console.warn("[Canvas Capability] Task heartbeat failed:", error);
+    });
+  }, 30_000);
+  try {
+    return await trackRuntimeWork(() => enqueueCanvasCapabilityExecution({
     projectId: params.projectId,
     execute: async () => {
-      task = await markCanvasCapabilityTaskRunning(task.id);
+      const claimed = await markCanvasCapabilityTaskRunning(task.id);
+      if (!claimed) return storedTaskResult((await getCanvasCapabilityTask({ requestId: command.requestId, userId: params.userId, projectId: params.projectId })) || task, "headless");
+      task = claimed;
       try {
         const projectRevision = context.project.updatedAt.toISOString();
         const mutationPlan = buildMutationOperationPlan({
@@ -299,5 +310,8 @@ export async function executeCanvasCapabilityRuntime(params: {
         throw error;
       }
     },
-  });
+    }));
+  } finally {
+    clearInterval(heartbeat);
+  }
 }
diff --git a/lib/canvas/capabilities/task-store.ts b/lib/canvas/capabilities/task-store.ts
index db96249bb..9fa17eb3c 100644
--- a/lib/canvas/capabilities/task-store.ts
+++ b/lib/canvas/capabilities/task-store.ts
@@ -1,11 +1,11 @@
-import { and, eq, lt, sql } from "drizzle-orm";
+import { and, eq, inArray, lt, sql } from "drizzle-orm";
 
 import type { CanvasCapabilityClientCommand } from "@/lib/canvas/capabilities/client-command";
 import { db } from "@/lib/db";
 import { canvasCapabilityTask } from "@/lib/db/schema";
 
 const STALE_RUNNING_TASK_MS = 15 * 60 * 1000;
-export const MAX_CANVAS_CAPABILITY_TASK_ATTEMPTS = 3;
+const INTERRUPTED_TASK_MESSAGE = "任务执行中断，结果尚未确认。请先查看画布和历史记录，或联系管理员核对原任务，避免重复处理。";
 
 export type CanvasCapabilityTaskResult = Record<string, unknown>;
 
@@ -25,7 +25,25 @@ export async function getCanvasCapabilityTask(params: {
       )
     )
     .limit(1);
-  return task || null;
+  if (!task) return null;
+  const staleBefore = new Date(Date.now() - STALE_RUNNING_TASK_MS);
+  if (["pending", "running"].includes(task.status) && task.updatedAt < staleBefore) {
+    const [interrupted] = await db.update(canvasCapabilityTask).set({
+      status: "failed",
+      error: INTERRUPTED_TASK_MESSAGE,
+      completedAt: new Date(),
+      updatedAt: new Date(),
+    }).where(and(
+      eq(canvasCapabilityTask.id, task.id),
+      inArray(canvasCapabilityTask.status, ["pending", "running"]),
+      lt(canvasCapabilityTask.updatedAt, staleBefore),
+    )).returning();
+    if (interrupted) return interrupted;
+    const [latest] = await db.select().from(canvasCapabilityTask)
+      .where(eq(canvasCapabilityTask.id, task.id)).limit(1);
+    return latest || task;
+  }
+  return task;
 }
 
 export async function createOrRecoverCanvasCapabilityTask(params: {
@@ -42,6 +60,7 @@ export async function createOrRecoverCanvasCapabilityTask(params: {
       capabilityId: params.command.capabilityId,
       source: params.command.source,
       request: params.command,
+      updatedAt: new Date(),
     })
     .onConflictDoNothing({ target: canvasCapabilityTask.requestId });
 
@@ -50,59 +69,19 @@ export async function createOrRecoverCanvasCapabilityTask(params: {
     userId: params.userId,
     projectId: params.projectId,
   };
-  let task = await getCanvasCapabilityTask(taskLookup);
+  const task = await getCanvasCapabilityTask(taskLookup);
   if (!task) {
     throw new Error("无法创建画布能力任务");
   }
 
-  const staleBefore = new Date(Date.now() - STALE_RUNNING_TASK_MS);
-  if (
-    task.status === "failed" &&
-    task.attempts < MAX_CANVAS_CAPABILITY_TASK_ATTEMPTS
-  ) {
-    await db
-      .update(canvasCapabilityTask)
-      .set({
-        status: "pending",
-        error: null,
-        completedAt: null,
-        updatedAt: new Date(),
-      })
-      .where(eq(canvasCapabilityTask.id, task.id));
-  } else if (
-    task.status === "running" &&
-    task.updatedAt < staleBefore &&
-    task.attempts < MAX_CANVAS_CAPABILITY_TASK_ATTEMPTS
-  ) {
-    await db
-      .update(canvasCapabilityTask)
-      .set({
-        status: "pending",
-        error: "恢复超时的执行中任务",
-        updatedAt: new Date(),
-      })
-      .where(
-        and(
-          eq(canvasCapabilityTask.id, task.id),
-          lt(canvasCapabilityTask.updatedAt, staleBefore)
-        )
-      );
-  } else if (task.status === "running" && task.updatedAt < staleBefore) {
-    await db
-      .update(canvasCapabilityTask)
-      .set({
-        status: "failed",
-        error: "画布能力任务超过最大重试次数",
-        completedAt: new Date(),
-        updatedAt: new Date(),
-      })
-      .where(eq(canvasCapabilityTask.id, task.id));
-  }
-
-  task = (await getCanvasCapabilityTask(taskLookup)) || task;
   return task;
 }
 
+export async function heartbeatCanvasCapabilityTask(taskId: string) {
+  await db.update(canvasCapabilityTask).set({ updatedAt: new Date() })
+    .where(and(eq(canvasCapabilityTask.id, taskId), inArray(canvasCapabilityTask.status, ["pending", "running"])));
+}
+
 export async function markCanvasCapabilityTaskRunning(taskId: string) {
   const now = new Date();
   const [task] = await db
@@ -115,11 +94,10 @@ export async function markCanvasCapabilityTaskRunning(taskId: string) {
       error: null,
       updatedAt: now,
     })
-    .where(eq(canvasCapabilityTask.id, taskId))
+    .where(and(eq(canvasCapabilityTask.id, taskId), eq(canvasCapabilityTask.status, "pending")))
     .returning();
 
-  if (!task) throw new Error("画布能力任务不存在");
-  return task;
+  return task || null;
 }
 
 export async function markCanvasCapabilityTaskSucceeded(
diff --git a/lib/canvas/generate-image-response.ts b/lib/canvas/generate-image-response.ts
index 0762ef2be..09f85b7db 100644
--- a/lib/canvas/generate-image-response.ts
+++ b/lib/canvas/generate-image-response.ts
@@ -10,7 +10,7 @@ import { generateCanvasImage, type CanvasGenerateImageRequest } from "@/lib/canv
 import { getPointsSystemConfig } from "@/lib/db/queries";
 import { prepareFeaturePointsCharge } from "@/lib/points/feature-charge";
 import { getImageToolCreditCost, type ImageToolCreditFeature } from "@/lib/points/config";
-import { getUserFacingImageGenerationErrorMessage } from "@/lib/request-error";
+import { getUserFacingImageGenerationErrorMessage, getRequestFailureDetails } from "@/lib/request-error";
 
 interface GenerateImageRequest extends CanvasGenerateImageRequest {
   async?: boolean;
@@ -121,7 +121,7 @@ export async function executeCanvasImageResponse(body: GenerateImageRequest, use
   } catch (error) {
     console.error("[Canvas Generate Image] Error:", error);
     return NextResponse.json(
-      { success: false, error: getUserFacingImageGenerationErrorMessage(error),
+      { success: false, error: getUserFacingImageGenerationErrorMessage(error), failure: getRequestFailureDetails(error),
         ...(error instanceof ProviderTaskUncertainError ? { code: "PROVIDER_TASK_UNCERTAIN" } : {}) },
       { status: error instanceof ProviderTaskUncertainError ? 503 : 500 },
     );
diff --git a/lib/canvas/image-task-queue.ts b/lib/canvas/image-task-queue.ts
index 8c926fd4f..e5cdde04a 100644
--- a/lib/canvas/image-task-queue.ts
+++ b/lib/canvas/image-task-queue.ts
@@ -38,6 +38,7 @@ import {
 } from "@/lib/agents/detail-replacement-batch";
 import { executeDetailReplacementBatch } from "@/lib/agents/detail-replacement-batch-runner";
 import { getUserFacingImageGenerationErrorMessage } from "@/lib/request-error";
+import { trackRuntimeWork } from "@/lib/observability/active-work";
 
 type CanvasImageTaskStatus =
   | "waiting"
@@ -328,7 +329,7 @@ async function markStaleDatabaseRunningTasksFailed() {
     .update(canvasImageTask)
     .set({
       status: "failed",
-      error: "图片生成任务已超时，请重新发起生成",
+      error: "图片任务执行中断或等待超时，结果尚未确认。请先查看原任务和历史记录，联系管理员核对，避免重复生成。",
       completedAt,
       updatedAt: completedAt,
     })
@@ -383,7 +384,7 @@ async function runSingleTask(entry: PendingTaskEntry) {
       }
     }
     const runningTimeoutMs = getCanvasImageRunningTimeoutMs(request);
-    const execution: Promise<CanvasImageTaskResult> = isStyleProTaskRequest(request)
+    const execution: Promise<CanvasImageTaskResult> = trackRuntimeWork<CanvasImageTaskResult>(() => isStyleProTaskRequest(request)
       ? executeStyleProTask({
           request,
           userId: String(task.userId || entry.userId),
@@ -412,7 +413,7 @@ async function runSingleTask(entry: PendingTaskEntry) {
               ownerKey,
               request: imageRequest,
             });
-          })();
+          })());
     const heartbeat = isDetailReplacementBatchRequest(request)
       ? setInterval(() => {
           void db.update(canvasImageTask).set({ updatedAt: new Date() })
@@ -426,7 +427,7 @@ async function runSingleTask(entry: PendingTaskEntry) {
     try {
       result = await withCanvasImageTaskExecutionTimeout(
         execution,
-        runningTimeoutMs,
+        Math.max(runningTimeoutMs, LOCAL_ACTIVE_RUNNING_HARD_TIMEOUT_MS),
         entry.taskId
       );
     } finally {
@@ -751,7 +752,7 @@ export async function getCanvasImageTaskForUser(params: {
 
     if (shouldMarkStale) {
       const staleBefore = new Date(now - runningTimeoutMs);
-      const timeoutMessage = "图片生成任务已超时，请重新发起生成";
+      const timeoutMessage = "图片任务执行中断或等待超时，结果尚未确认。请先查看原任务和历史记录，联系管理员核对，避免重复生成。";
       const completedAt = new Date();
       const [timedOutTask] = await db
         .update(canvasImageTask)
diff --git a/lib/client/canvas-toolbar-capability.ts b/lib/client/canvas-toolbar-capability.ts
index b3980057d..431d71350 100644
--- a/lib/client/canvas-toolbar-capability.ts
+++ b/lib/client/canvas-toolbar-capability.ts
@@ -1,6 +1,40 @@
 import type { CanvasCapabilityClientCommand } from "@/lib/canvas/capabilities/client-command";
 import { mergeCanvasSnapshots } from "@/lib/video-canvas/merge-snapshot";
 import { useCanvasStore } from "@/store/canvas";
+import { formatRequestFailure, getRequestFailureDetails } from "@/lib/request-error";
+
+async function requestCapabilityResult(command: CanvasCapabilityClientCommand) {
+  const endpoint = `/api/canvas/${command.projectId}/capabilities`;
+  let payload: any = null;
+  try {
+    const response = await fetch(endpoint, {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify(command),
+    });
+    payload = await response.json().catch(() => null);
+    if (payload?.success === false || (!response.ok && ![502, 503, 504, 524].includes(response.status))) {
+      throw Object.assign(new Error(payload?.error || "图片处理请求未通过"), { confirmedRejection: true });
+    }
+    if (!response.ok) payload = null;
+  } catch (error) {
+    if ((error as { confirmedRejection?: boolean })?.confirmedRejection) throw error;
+  }
+  const deadline = Date.now() + 20 * 60 * 1000;
+  while (Date.now() < deadline) {
+    const task = payload?.task;
+    if (task?.status === "succeeded") return payload;
+    if (task?.status === "failed") throw new Error(task.error || "图片处理失败，请联系管理员核对任务结果");
+    await new Promise(resolve => setTimeout(resolve, 1500));
+    try {
+      const response = await fetch(`${endpoint}?requestId=${encodeURIComponent(command.requestId)}`, { cache: "no-store", signal: AbortSignal.timeout(12_000) });
+      payload = response.ok ? await response.json() : null;
+    } catch {
+      payload = null;
+    }
+  }
+  throw new Error(formatRequestFailure(getRequestFailureDetails({ providerOutcomeUnknown: true }), command.requestId));
+}
 
 /** Runs after the editor has saved and while its save queue is reserved. */
 export async function executeCanvasToolbarCapability(
@@ -10,15 +44,7 @@ export async function executeCanvasToolbarCapability(
   const before = useCanvasStore.getState();
   if (before.projectId !== projectId) throw new Error("画布已切换，请重新选择图片");
   const base = JSON.stringify({ canvasData: before.getCanvasState() });
-  const response = await fetch(`/api/canvas/${projectId}/capabilities`, {
-    method: "POST",
-    headers: { "Content-Type": "application/json" },
-    body: JSON.stringify(command),
-  });
-  const payload = await response.json().catch(() => ({}));
-  if (!response.ok || payload?.success !== true) {
-    throw new Error(payload?.error || "图片处理失败");
-  }
+  await requestCapabilityResult(command);
 
   const projectResponse = await fetch(`/api/canvas/${projectId}`);
   const result = await projectResponse.json();
diff --git a/lib/jobs/image-archive-job.ts b/lib/jobs/image-archive-job.ts
index b62d2a94a..10ce21f32 100644
--- a/lib/jobs/image-archive-job.ts
+++ b/lib/jobs/image-archive-job.ts
@@ -1,5 +1,6 @@
 import { preparePendingImageDownloads } from "@/lib/storage/image-download-preparation";
 import "server-only";
+import { trackRuntimeWork } from "@/lib/observability/active-work";
 
 import { archiveTemporaryImage } from "@/lib/storage/image-archive";
 import {
@@ -26,6 +27,7 @@ function getBatchSize() {
 }
 
 export async function runImageArchiveJob() {
+  return trackRuntimeWork(async () => {
   const batchSize = getBatchSize();
   console.log(`[ImageArchiveJob] Start image archive job (batchSize=${batchSize})`);
 
@@ -125,4 +127,5 @@ export async function runImageArchiveJob() {
     downloadTasks,
     pendingDownloads: await hasPendingImageDownloads(),
   };
+  });
 }
diff --git a/lib/observability/active-work.ts b/lib/observability/active-work.ts
new file mode 100644
index 000000000..8e5f3c093
--- /dev/null
+++ b/lib/observability/active-work.ts
@@ -0,0 +1,23 @@
+import "server-only";
+import { unlinkSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+
+const state = globalThis as typeof globalThis & { __aiChatbotActiveWork?: number };
+const path = join(process.platform === "win32" ? tmpdir() : "/tmp", `ai-chatbot-active-work-${process.pid}.json`);
+
+function update(delta: number) {
+  state.__aiChatbotActiveWork = (state.__aiChatbotActiveWork || 0) + delta;
+  try {
+    writeFileSync(path, JSON.stringify({ pid: process.pid, active: state.__aiChatbotActiveWork }), { mode: 0o600 });
+  } catch (error) {
+    try { unlinkSync(path); } catch {}
+    console.warn("[Active Work] Failed to record running work:", error);
+  }
+}
+
+/** Includes generation that continues after the client connection closes. */
+export async function trackRuntimeWork<T>(execute: () => T | Promise<T>): Promise<T> {
+  update(1);
+  try { return await execute(); } finally { update(-1); }
+}
diff --git a/lib/request-error.ts b/lib/request-error.ts
index 3a060050f..c18c23167 100644
--- a/lib/request-error.ts
+++ b/lib/request-error.ts
@@ -189,14 +189,6 @@ export function isGatewayResponseTimeout(error: unknown): boolean {
     /\bHTTP\s*524\b|\b524\s*:\s*A timeout occurred\b|Error code\s*524\b/i.test(getRequestErrorText(error));
 }
 
-function getPublicGatewayErrorMessage(error: unknown): string | null {
-  if (isGatewayResponseTimeout(error)) {
-    return "模型服务响应超时（HTTP 524），生成结果尚未确认。请先查看历史记录，避免重复提交。";
-  }
-  const message = getRequestErrorMessage(error);
-  return message ? getGatewayErrorPageMessage(message) : null;
-}
-
 export function isProviderBalanceError(error: unknown): boolean {
   const message = getRequestErrorText(error);
   return PROVIDER_BALANCE_PATTERNS.some((pattern) => pattern.test(message));
@@ -221,19 +213,74 @@ export function isRateLimitError(error: unknown): boolean {
     RATE_LIMIT_PATTERNS.some((pattern) => pattern.test(message));
 }
 
+export type RequestFailureDetails = {
+  code: string;
+  message: string;
+  recommendation: string;
+  outcome: "failed" | "unknown";
+};
+
+export function getRequestFailureDetails(
+  error: unknown,
+  fallbackMessage = "请求未能完成",
+): RequestFailureDetails {
+  const text = getRequestErrorText(error);
+  const status = getRequestErrorStatus(error);
+  const detail = (code: string, message: string, recommendation: string, outcome: "failed" | "unknown" = "failed") =>
+    ({ code, message, recommendation, outcome });
+  if (isGatewayResponseTimeout(error)) {
+    return detail("RESULT_UNCONFIRMED", "模型服务响应超时（HTTP 524），生成结果尚未确认。", "请先查看历史记录，避免重复提交。", "unknown");
+  }
+  if ((isRecord(error) && error.providerOutcomeUnknown === true) || /结果(?:尚)?未确认|结果暂未确认|request_outcome_unknown|任务执行中断|may still be running/i.test(text)) {
+    return detail("RESULT_UNCONFIRMED", "任务结果尚未确认，可能仍在处理。", "请先查看原任务或历史记录；持续没有结果时联系管理员，避免重复生成。", "unknown");
+  }
+  if (isProviderBalanceError(error)) {
+    return detail("PROVIDER_BALANCE_EXHAUSTED", "图片服务商线路余额或额度不足，与您的积分余额无关。", "请切换可用模型或联系管理员处理线路额度。");
+  }
+  if (isRateLimitError(error)) {
+    return detail("RATE_LIMITED", "当前请求过于频繁。", "请稍后重试，避免连续点击；模型线路限流时可切换其他可用模型。");
+  }
+  if (/content.?polic|moderation|safety|policy_rejected|内容(?:敏感|审核|限制)|不能生成像那样|不能生成那样|违规/i.test(text)) {
+    return detail("CONTENT_POLICY_REJECTED", "模型服务因内容审核限制拒绝了本次请求。", "请调整描述或参考图中的受限内容后再提交；重复提交相同内容通常无法解决。");
+  }
+  if (/上传到存储桶失败|存储.*失败|归档.*失败|archive.*failed|storage.*failed/i.test(text)) {
+    return detail("RESULT_STORAGE_FAILED", "处理结果保存失败，生成结果可能已经存在。", "请保留当前页面并联系管理员提供请求编号，先不要重复生成。", "unknown");
+  }
+  if (/参考图.*(?:下载失败|不可|失效)|无法获取图片|图片(?:源文件|链接).*不可|获取图片.*失败|get image url failed/i.test(text)) {
+    return detail("SOURCE_IMAGE_UNAVAILABLE", "请求中的图片无法读取，链接可能已失效或没有访问权限。", "请重新上传原图后再提交；若原图仍可打开，请联系管理员检查取图服务。");
+  }
+  if (/版本冲突|画布.*(?:更新|过期)|CANVAS_REVISION_CONFLICT|stale.canvas/i.test(text)) {
+    return detail("CANVAS_REVISION_CONFLICT", "画布已更新，本次保存与当前版本冲突。", "请先重新同步画布，再继续操作，避免覆盖较新的修改。");
+  }
+  if (/no_eligible_route|service_unavailable|service_rejected|channel.*unavailable|暂无可用服务|未配置.*模型|没有可用.*(?:模型|通道)|通道.*(?:不可用|未通过)|鉴权/i.test(text)) {
+    return detail("PROVIDER_UNAVAILABLE", "当前模型服务或通道暂不可用。", "请切换其他可用模型；若多个模型都失败，请联系管理员检查服务配置。");
+  }
+  if (/neither a task ID nor output URLs|已完成.*未取回|completed without.*output/i.test(text)) {
+    return detail("RESULT_UNCONFIRMED", "模型服务没有返回可读取的任务结果，生成状态尚未确认。", "请保留当前任务并联系管理员核对，避免重复生成。", "unknown");
+  }
+  if (/service_error|upstream_server_error|excessive system load|generate(?: image)? failed/i.test(text)) {
+    return detail("PROVIDER_EXECUTION_FAILED", "模型服务未能完成本次处理。", "请稍后重试；若连续失败，请切换模型或联系管理员，并提供请求编号。");
+  }
+  if (/timeout|timed out|超时|fetch failed|ECONNRESET|ECONNREFUSED|failed to fetch|networkerror|load failed|network request failed/i.test(text) || [502, 504].includes(status || 0)) {
+    return detail("RESULT_UNCONFIRMED", "请求连接中断或等待超时，任务结果尚未确认。", "请先查看原任务或历史记录，避免重复提交；持续没有结果时联系管理员。", "unknown");
+  }
+  if (/generate(?: image)? failed|generation failed|upstream_server_error|service_error|excessive system load|未返回可用图片|任务FAILED/i.test(text) || (status !== null && status >= 500)) {
+    return detail("PROVIDER_EXECUTION_FAILED", "模型服务未能完成本次处理。", "请稍后重试；若连续失败，请切换模型或联系管理员，并提供请求编号。");
+  }
+  const message = getRequestErrorMessage(error);
+  return detail("REQUEST_FAILED", message && !/^\s*</.test(message) ? message : fallbackMessage, "");
+}
+
+export function formatRequestFailure(details: RequestFailureDetails, requestId?: string) {
+  const text = [details.message, details.recommendation].filter(Boolean).join("");
+  return requestId ? `${text}\n\n请求编号：${requestId}` : text;
+}
+
 export function getUserFacingImageGenerationErrorMessage(
   error: unknown,
   fallbackMessage = "图片生成失败，请稍后重试",
 ) {
-  const gatewayMessage = getPublicGatewayErrorMessage(error);
-  if (gatewayMessage) return gatewayMessage;
-  if (isProviderBalanceError(error)) {
-    return "图片服务商线路余额或额度不足，请切换模型或联系管理员；与您的积分余额无关。";
-  }
-  if (isRateLimitError(error)) {
-    return "图片服务请求过于频繁，请稍后重试或切换模型。";
-  }
-  return getRequestErrorMessage(error) || fallbackMessage;
+  return formatRequestFailure(getRequestFailureDetails(error, fallbackMessage));
 }
 
 export function getFriendlyRateLimitMessage(
@@ -251,15 +298,12 @@ export function getUserFacingRequestErrorMessage(
     rateLimitMessage?: string;
   }
 ) {
-  const gatewayMessage = getPublicGatewayErrorMessage(error);
-  if (gatewayMessage) return gatewayMessage;
-  if (isProviderBalanceError(error)) {
-    return "模型服务商线路余额或额度不足，请切换模型或联系管理员。";
-  }
   if (isRateLimitError(error)) {
     return getFriendlyRateLimitMessage(options?.rateLimitMessage);
   }
 
+  const failure = getRequestFailureDetails(error, fallbackMessage);
+  if (failure.code !== "REQUEST_FAILED") return formatRequestFailure(failure);
   const message = getRequestErrorMessage(error);
   if (!message) {
     return fallbackMessage;
diff --git a/playwright.helpers.config.ts b/playwright.helpers.config.ts
index 4d4f7855e..c949b6a34 100644
--- a/playwright.helpers.config.ts
+++ b/playwright.helpers.config.ts
@@ -3,6 +3,9 @@ import { defineConfig } from "@playwright/test";
 export default defineConfig({
   testDir: "./tests",
   testMatch: [
+    /routes\/runtime-active-work\.test\.ts/,
+    /routes\/canvas-capability-task-recovery\.test\.ts/,
+    /routes\/canvas-toolbar-capability\.test\.ts/,
     /routes\/agent-project-recovery\.test\.ts/,
     /routes\/admin-media-loading\.test\.ts/,
     /routes\/video-canvas-production\.test\.ts/,
diff --git a/proxy.ts b/proxy.ts
index 22c0f8fc9..897f8b0bd 100644
--- a/proxy.ts
+++ b/proxy.ts
@@ -43,6 +43,7 @@ const manualIpBlockCache = new Map<
 >();
 
 function isHighFrequencyReadApi(pathname: string, method: string) {
+  if (method === "POST" && /^\/api\/canvas\/[^/]+\/image-archives$/.test(pathname)) return true;
   if (method === "GET" && pathname === "/api/canvas/download-zip-task") return true;
   if (method !== "GET") return false;
   if (/^\/api\/canvas\/[^/]+\/detail-archives$/.test(pathname)) return true;
@@ -668,7 +669,20 @@ export async function proxy(request: NextRequest, event: NextFetchEvent) {
         }
       );
     }
-  } else if (isHighFrequencyReadApi(pathname, request.method)) {
+    } else if (request.method === "POST" && /^\/api\/canvas\/[^/]+\/image-archives$/.test(pathname)) {
+      const token = await resolveToken();
+      const identifier = typeof token?.sub === "string" && token.sub
+        ? `user:${token.sub}:image-archives`
+        : `ip:${clientIP}:image-archives`;
+      const result = checkRateLimitByIdentifier(identifier, rateLimiters.uiPolling);
+      if (!result.allowed) {
+        const retryAfter = Math.max(1, Math.ceil((result.resetTime - Date.now()) / 1000));
+        return withAccessLog(NextResponse.json(
+          { error: "图片状态查询过于频繁，请稍后再查看", retryAfter },
+          { status: 429, headers: { "Retry-After": String(retryAfter) } },
+        ), { outcome: "rate_limited", severity: "watch", reasons: ["图片归档状态查询限流"] });
+      }
+    } else if (isHighFrequencyReadApi(pathname, request.method)) {
     const pollingRateLimit = checkRateLimit(request, rateLimiters.uiPolling);
     if (!pollingRateLimit.allowed) {
       console.warn(`[Security] UI polling rate limit exceeded for IP: ${clientIP}`, {
diff --git a/tests/routes/canvas-capability-task-recovery.test.ts b/tests/routes/canvas-capability-task-recovery.test.ts
new file mode 100644
index 000000000..6eaab31c9
--- /dev/null
+++ b/tests/routes/canvas-capability-task-recovery.test.ts
@@ -0,0 +1,65 @@
+import { expect, test } from "@playwright/test";
+import { serverLoader } from "../helpers/canvas-download-server-loader";
+
+function harness(status = "running") {
+  let now = 2_000_000;
+  const row: any = { id: "task-a", requestId: "request-a", userId: "user-a", projectId: "project-a", status, attempts: status === "pending" ? 0 : 1, updatedAt: new Date(now - 16 * 60_000), error: null };
+  const matches = (predicate: any): boolean => !predicate || (predicate[0] === "and" ? predicate.slice(1).every(matches)
+    : predicate[0] === "eq" ? row[predicate[1]] === predicate[2]
+    : predicate[0] === "lt" ? row[predicate[1]] < predicate[2]
+    : predicate[2].includes(row[predicate[1]]));
+  const db = {
+    select: () => ({ from: () => ({ where: (p: any) => ({ limit: async () => matches(p) ? [{ ...row }] : [] }) }) }),
+    insert: () => ({ values: () => ({ onConflictDoNothing: async () => undefined }) }),
+    update: () => ({ set: (values: any) => ({ where: (p: any) => {
+      const apply = () => {
+        if (!matches(p)) return [];
+        for (const [key, value] of Object.entries(values)) row[key] = key === "attempts" ? row.attempts + 1 : value;
+        return [{ ...row }];
+      };
+      const result = apply();
+      return Object.assign(Promise.resolve(result), { returning: async () => result });
+    } }) }),
+  };
+  const columns = Object.fromEntries(["id", "requestId", "userId", "projectId", "status", "updatedAt", "attempts"].map(k => [k, k]));
+  const store = serverLoader({
+    "@/lib/db": { db }, "@/lib/db/schema": { canvasCapabilityTask: columns },
+    "drizzle-orm": { eq: (...v: any[]) => ["eq", ...v], lt: (...v: any[]) => ["lt", ...v], inArray: (...v: any[]) => ["in", ...v], and: (...v: any[]) => ["and", ...v], sql: () => "increment" },
+    Date: class extends Date { constructor(value?: any) { super(value ?? now); } static now() { return now; } },
+  })("lib/canvas/capabilities/task-store.ts");
+  const lookup = { requestId: "request-a", userId: "user-a", projectId: "project-a" };
+  return { row, store, lookup, advance: (ms: number) => { now += ms; } };
+}
+
+test("a stale task stops reporting running without authorizing another execution", async () => {
+  const h = harness();
+  const task = await h.store.getCanvasCapabilityTask(h.lookup);
+  expect(task.status).toBe("failed");
+  expect(task.error).toContain("结果尚未确认");
+  const repeated = await h.store.createOrRecoverCanvasCapabilityTask({ ...h.lookup, command: { requestId: "request-a" } });
+  expect(repeated.status).toBe("failed");
+  expect(repeated.attempts).toBe(1);
+});
+
+test("heartbeats keep a legitimate long-running task active beyond fifteen minutes", async () => {
+  const h = harness();
+  await h.store.heartbeatCanvasCapabilityTask("task-a");
+  h.advance(14 * 60_000);
+  await h.store.heartbeatCanvasCapabilityTask("task-a");
+  h.advance(14 * 60_000);
+  expect((await h.store.getCanvasCapabilityTask(h.lookup)).status).toBe("running");
+  expect(h.row.attempts).toBe(1);
+});
+
+test("only the pending task can be claimed and a duplicate claim cannot run again", async () => {
+  const h = harness("pending");
+  expect(await h.store.markCanvasCapabilityTaskRunning("task-a")).toMatchObject({ status: "running", attempts: 1 });
+  expect(await h.store.markCanvasCapabilityTaskRunning("task-a")).toBeNull();
+  expect(h.row.attempts).toBe(1);
+});
+
+test("another user cannot inspect or change a stale task", async () => {
+  const h = harness();
+  expect(await h.store.getCanvasCapabilityTask({ ...h.lookup, userId: "user-b" })).toBeNull();
+  expect(h.row.status).toBe("running");
+});
diff --git a/tests/routes/canvas-toolbar-capability.test.ts b/tests/routes/canvas-toolbar-capability.test.ts
index c5d7d72ee..907502d19 100644
--- a/tests/routes/canvas-toolbar-capability.test.ts
+++ b/tests/routes/canvas-toolbar-capability.test.ts
@@ -47,7 +47,7 @@ test("merges the result with edits made while processing and advances the save r
   globalThis.fetch = (async (url) => {
     if (String(url).endsWith("/capabilities")) {
       useCanvasStore.getState().moveNode("source", { x: 50, y: 80 });
-      return Response.json({ success: true });
+      return Response.json({ success: true, task: { status: "succeeded" } });
     }
     return Response.json({ success: true, data: {
       updatedAt: "r2", canvasData: { nodes: [node("source"), node("result")], edges: [] },
@@ -67,12 +67,31 @@ test("a provider failure is shown without reloading or changing the canvas", asy
   expect(useCanvasStore.getState().canvasRevision).toBe("r1");
 });
 
+test("a lost submission response polls the original task and never resubmits", async () => {
+  const requests: { method: string; url: string }[] = [];
+  const originalSetTimeout = globalThis.setTimeout;
+  let polls = 0;
+  globalThis.setTimeout = ((fn: () => void) => originalSetTimeout(fn, 0)) as typeof setTimeout;
+  globalThis.fetch = (async (url, init) => {
+    requests.push({ method: init?.method || "GET", url: String(url) });
+    if (init?.method === "POST") throw new TypeError("fetch failed");
+    if (String(url).includes("/capabilities?")) return Response.json({ success: true, task: { status: ++polls === 1 ? "running" : "succeeded" } });
+    return Response.json({ success: true, data: { updatedAt: "r2", canvasData: { nodes: [node("source"), node("result")], edges: [] } } });
+  }) as typeof fetch;
+  const submitted = command();
+  try { await executeCanvasToolbarCapability(submitted); } finally { globalThis.setTimeout = originalSetTimeout; }
+  expect(requests.filter(r => r.method === "POST")).toHaveLength(1);
+  expect(requests.filter(r => r.url.includes("/capabilities?"))).toHaveLength(2);
+  expect(requests.filter(r => r.url.includes("/capabilities?")).every(r => r.url.includes(encodeURIComponent(submitted.requestId)))).toBe(true);
+  expect(useCanvasStore.getState().nodes.map(n => n.id)).toEqual(["source", "result"]);
+});
+
 test("switching projects during processing does not load the old result into the new project", async () => {
   globalThis.fetch = (async (url) => {
     if (String(url).endsWith("/capabilities")) {
       useCanvasStore.getState().setProject("project-b");
       useCanvasStore.getState().loadCanvas({ nodes: [node("other") as any], edges: [] });
-      return Response.json({ success: true });
+      return Response.json({ success: true, task: { status: "succeeded" } });
     }
     return Response.json({ success: true, data: { updatedAt: "r2", canvasData: { nodes: [node("result")], edges: [] } } });
   }) as typeof fetch;
@@ -104,7 +123,7 @@ test("a result merge conflict retains both the local edit and its original revis
   globalThis.fetch = (async (url) => {
     if (String(url).endsWith("/capabilities")) {
       useCanvasStore.getState().moveNode("source", { x: 50, y: 80 });
-      return Response.json({ success: true });
+      return Response.json({ success: true, task: { status: "succeeded" } });
     }
     return Response.json({ success: true, data: { updatedAt: "r2", canvasData: {
       nodes: [{ ...node("source"), position: { x: 200, y: 80 } }, node("result")], edges: [],
diff --git a/tests/routes/image-provider-error-classification.test.ts b/tests/routes/image-provider-error-classification.test.ts
index 5e3d93e71..8dff2cae6 100644
--- a/tests/routes/image-provider-error-classification.test.ts
+++ b/tests/routes/image-provider-error-classification.test.ts
@@ -2,11 +2,32 @@ import { expect, test } from "@playwright/test";
 import {
   getUserFacingImageGenerationErrorMessage,
   getUserFacingRequestErrorMessage,
+  getRequestFailureDetails,
+  formatRequestFailure,
   getGatewayErrorPageMessage,
   isGatewayResponseTimeout,
   isProviderBalanceError,
   isRateLimitError,
 } from "@/lib/request-error";
+
+test("known provider and platform failures explain their cause and next action", () => {
+  for (const [message, code, next] of [
+    ["We are sorry, this prompt may violate our content policies", "CONTENT_POLICY_REJECTED", "调整描述"],
+    ["The channel is temporarily unavailable", "PROVIDER_UNAVAILABLE", "切换其他"],
+    ["generate image failed", "PROVIDER_EXECUTION_FAILED", "稍后重试"],
+    ["excessive system load", "PROVIDER_EXECUTION_FAILED", "稍后重试"],
+    ["get image url failed", "SOURCE_IMAGE_UNAVAILABLE", "重新上传"],
+    ["图片上传到存储桶失败", "RESULT_STORAGE_FAILED", "不要重复生成"],
+    ["任务执行中断，结果尚未确认", "RESULT_UNCONFIRMED", "避免重复生成"],
+  ]) {
+    const failure = getRequestFailureDetails(new Error(message));
+    expect(failure.code).toBe(code);
+    expect(failure.recommendation).toContain(next);
+    expect(formatRequestFailure(failure, "request-123")).toContain("请求编号：request-123");
+  }
+  expect(getRequestFailureDetails({ providerOutcomeUnknown: true, message: "content policy" }).outcome).toBe("unknown");
+  expect(getRequestFailureDetails(new Error("图片上传到存储桶失败")).outcome).toBe("unknown");
+});
 import { isImageModelBalanceBlocked, resolveConfiguredImageBalanceFallback } from "@/lib/ai/runtime/image-balance";
 import { serverLoader } from "../helpers/canvas-download-server-loader";
 
diff --git a/tests/routes/runtime-active-work.test.ts b/tests/routes/runtime-active-work.test.ts
new file mode 100644
index 000000000..795f49384
--- /dev/null
+++ b/tests/routes/runtime-active-work.test.ts
@@ -0,0 +1,19 @@
+import { expect, test } from "@playwright/test";
+import { serverLoader } from "../helpers/canvas-download-server-loader";
+
+test("release draining includes background work until its original promise settles", async () => {
+  const counts: number[] = [];
+  const work = serverLoader({
+    "node:fs": { writeFileSync: (_path: string, text: string) => counts.push(JSON.parse(text).active), unlinkSync() {} },
+  })("lib/observability/active-work.ts");
+  let finish!: () => void;
+  const original = new Promise<void>(resolve => { finish = resolve; });
+  const pending = work.trackRuntimeWork(() => original);
+  await work.trackRuntimeWork(async () => "another request");
+  expect(counts).toEqual([1, 2, 1]);
+  finish();
+  await pending;
+  expect(counts).toEqual([1, 2, 1, 0]);
+  await expect(work.trackRuntimeWork(async () => { throw new Error("expected failure"); })).rejects.toThrow("expected failure");
+  expect(counts.at(-1)).toBe(0);
+});