fix(agents): retain provider details from prompt rejection

packages/cli/src/serve/agent-host-client.test.ts

@@ -9,6 +9,7 @@ import * as fs from 'node:fs/promises';
 import os from 'node:os';
 import path from 'node:path';
 import { describe, expect, it, vi } from 'vitest';
+import type { HostRunResult } from '@qwen-code/qwen-code-core';
 import type { AcpSessionBridge } from './acp-session-bridge.js';
 import { isRevocation, startAgentHostConnection } from './agent-host-client.js';
 
@@ -44,6 +45,83 @@ describe('isRevocation', () => {
   });
 });
 
+it('returns the provider detail when sendPrompt rejects with a JSON-RPC error', async () => {
+  const workspaceCwd = await fs.mkdtemp(path.join(os.tmpdir(), 'pr12582-f7-'));
+  let result: HostRunResult | undefined;
+  let pickups = 0;
+  const bridge = {
+    listWorkspaceSessions: () => [],
+    spawnOrAttach: vi.fn().mockResolvedValue({}),
+    async *subscribeEvents() {},
+    getSessionStatsStatus: vi.fn().mockResolvedValue({ models: {} }),
+    sendPrompt: vi.fn().mockRejectedValue({
+      code: -32603,
+      message: 'Internal error',
+      data: { details: '400 PR12582_PROVIDER_400_READABLE_CAUSE' },
+    }),
+    closeSession: vi.fn().mockResolvedValue({}),
+  } as unknown as AcpSessionBridge;
+  vi.stubEnv('QWEN_HOME', workspaceCwd);
+  vi.stubGlobal(
+    'fetch',
+    vi.fn(async (url: string, init?: RequestInit) => {
+      if (url.endsWith('/enroll')) {
+        return Response.json({ host: { id: 'host-test' }, secret: 'secret' });
+      }
+      if (url.endsWith('/pickup')) {
+        if (++pickups > 1) {
+          return Response.json(
+            { error: 'Invalid Agent Host credential.' },
+            { status: 401 },
+          );
+        }
+        return Response.json({
+          assignment: {
+            agent: { id: 'agent-test', name: 'test' },
+            threadId: 'thread-test',
+            runId: 'run-test',
+            attempt: 1,
+            lease: { leaseId: 'lease-test' },
+            prompt: 'Read the fixture.',
+          },
+        });
+      }
+      if (url.endsWith('/result')) {
+        result = JSON.parse(init?.body as string) as HostRunResult;
+      }
+      if (url.endsWith('/heartbeat')) {
+        return Response.json({ lease: { leaseId: 'lease-test' } });
+      }
+      return Response.json({ ok: true });
+    }),
+  );
+  try {
+    await startAgentHostConnection({
+      bridge,
+      serverUrl: 'http://127.0.0.1:18583',
+      workspaceId: 'ws-test',
+      workspaceCwd,
+      enrollmentToken: 'test-token',
+    });
+    await vi.waitFor(() => expect(pickups).toBe(2));
+    expect(result).toMatchObject({
+      status: 'failed',
+      error: '400 PR12582_PROVIDER_400_READABLE_CAUSE',
+    });
+    expect(bridge.sendPrompt).toHaveBeenCalledOnce();
+    expect(bridge.closeSession).toHaveBeenCalledOnce();
+    await vi.waitFor(async () => {
+      expect(await fs.readdir(path.join(workspaceCwd, 'agent-hosts'))).toEqual(
+        [],
+      );
+    });
+  } finally {
+    vi.unstubAllGlobals();
+    vi.unstubAllEnvs();
+    await fs.rm(workspaceCwd, { recursive: true, force: true });
+  }
+});
+
 it('retains a saved credential when rejoining sees only bare bearer 401s', async () => {
   const qwenDir = await fs.mkdtemp(path.join(os.tmpdir(), 'pr12582-f1-'));
   const serverUrl = 'http://127.0.0.1:18582';

packages/cli/src/serve/agent-host-client.ts

@@ -9,6 +9,7 @@ import * as fs from 'node:fs/promises';
 import os from 'node:os';
 import path from 'node:path';
 import { setTimeout as delay } from 'node:timers/promises';
+import { extractErrorMessage } from '@qwen-code/acp-bridge/bridge';
 import type {
   HostRunAssignment,
   HostRunResult,
@@ -491,14 +492,8 @@ async function executeAssignment(
       );
       if (turn?.promptId === promptId) {
         if (turn.state === 'error' || turn.state === 'cancelled') {
-          const message = turn.error?.message;
-          // A provider failure can arrive as the JSON-RPC error object
-          // itself; stringifying the field keeps the real cause on the wire
-          // instead of "[object Object]".
           throw new Error(
-            typeof message === 'string' && message
-              ? message
-              : (JSON.stringify(turn.error) ?? 'Managed Agent cancelled.'),
+            extractErrorMessage(turn.error ?? 'Managed Agent cancelled.'),
           );
         }
         if (turn.state === 'completed') {
@@ -843,7 +838,7 @@ async function connectAgentHost(
                 error instanceof Error && error.message === 'not_leasable'
                   ? 'cancelled'
                   : 'failed',
-              error: error instanceof Error ? error.message : String(error),
+              error: extractErrorMessage(error),
             };
           }
           await returnResult(