feat(mcp): 增强MCP服务器异常处理和错误描述

- 添加_iter_leaf_exceptions函数用于处理嵌套异常组
- 实现_describe_mcp_exception函数提供详细的MCP服务器错误信息
- 改进connect_mcp_servers中的错误处理，使用更精确的错误描述
- 在日志记录中包含更具体的错误详情

feat(outlook): 优化Outlook集成异常处理

- 添加_iter_leaf_exceptions函数用于异常处理
- 创建_coerce_outlook_mcp_exception函数统一异常转换
- 改进_call_outlook_mcp_tool中的异常捕获和处理
- 对认证令牌获取和MCP调用添加专门的超时和HTTP错误处理

feat(web): 改进Web会话定时任务结果记录

- 实现_record_cron_result_for_web_session函数
- 为Web模式下的独立定时任务执行结果提供持久化存储
- 支持将定时任务响应消息添加到目标会话中
- 确保前端可以显示定时任务执行结果

app-instance/backend/nanobot/agent/tools/mcp.py

@@ -19,6 +19,37 @@ from nanobot.agent.tools.base import Tool
 from nanobot.agent.tools.registry import ToolRegistry
 
 
+def _iter_leaf_exceptions(exc: BaseException) -> list[BaseException]:
+    if isinstance(exc, BaseExceptionGroup):
+        leaves: list[BaseException] = []
+        for sub_exc in exc.exceptions:
+            leaves.extend(_iter_leaf_exceptions(sub_exc))
+        return leaves
+    return [exc]
+
+
+def _describe_mcp_exception(exc: BaseException, *, server_name: str, url: str | None = None) -> str:
+    leaves = _iter_leaf_exceptions(exc)
+    target = f" ({url})" if url else ""
+
+    for leaf in leaves:
+        if isinstance(leaf, httpx.TimeoutException):
+            return f"MCP server '{server_name}' timed out while waiting for a response{target}"
+        if isinstance(leaf, httpx.ConnectError):
+            return f"MCP server '{server_name}' is unreachable{target}"
+        if isinstance(leaf, httpx.HTTPStatusError):
+            return f"MCP server '{server_name}' returned HTTP {leaf.response.status_code}{target}"
+        if isinstance(leaf, httpx.HTTPError):
+            detail = str(leaf).strip() or leaf.__class__.__name__
+            return f"MCP server '{server_name}' HTTP error{target}: {detail}"
+
+    detail_source = leaves[0] if leaves else exc
+    detail = str(detail_source).strip() or detail_source.__class__.__name__
+    if isinstance(exc, BaseExceptionGroup):
+        return f"MCP server '{server_name}' failed: {detail_source.__class__.__name__}: {detail}"
+    return detail
+
+
 class MCPToolWrapper(Tool):
     """把单个 MCP server tool 包装成 nanobot Tool。"""
 
@@ -340,7 +371,12 @@ async def connect_mcp_servers(
             )
         except Exception as e:
             # 单个 server 失败不影响其他 server 继续连；错误写进 report 供 UI 展示。
+            error_detail = _describe_mcp_exception(
+                e,
+                server_name=name,
+                url=str(getattr(cfg, "url", "") or "").strip() or None,
+            )
             report[name]["status"] = "error"
-            report[name]["last_error"] = str(e)
+            report[name]["last_error"] = error_detail
-            logger.error("MCP server '{}': failed to connect: {}", name, e)
+            logger.error("MCP server '{}': failed to connect: {}", name, error_detail)
     return report

app-instance/backend/nanobot/web/outlook.py

@@ -31,6 +31,38 @@ class OutlookIntegrationError(RuntimeError):
     """Raised when the Outlook integration backend is unavailable or misconfigured."""
 
 
+def _iter_leaf_exceptions(exc: BaseException) -> list[BaseException]:
+    if isinstance(exc, BaseExceptionGroup):
+        leaves: list[BaseException] = []
+        for sub_exc in exc.exceptions:
+            leaves.extend(_iter_leaf_exceptions(sub_exc))
+        return leaves
+    return [exc]
+
+
+def _coerce_outlook_mcp_exception(exc: BaseException, *, url: str) -> OutlookIntegrationError:
+    if isinstance(exc, OutlookIntegrationError):
+        return exc
+
+    leaves = _iter_leaf_exceptions(exc)
+    for leaf in leaves:
+        if isinstance(leaf, httpx.TimeoutException):
+            return OutlookIntegrationError(f"Outlook MCP 请求超时：{url}")
+        if isinstance(leaf, httpx.ConnectError):
+            return OutlookIntegrationError(f"Outlook MCP 无法连接：{url}")
+        if isinstance(leaf, httpx.HTTPStatusError):
+            return OutlookIntegrationError(f"Outlook MCP 返回 HTTP {leaf.response.status_code}：{url}")
+        if isinstance(leaf, httpx.HTTPError):
+            detail = str(leaf).strip() or leaf.__class__.__name__
+            return OutlookIntegrationError(f"Outlook MCP 网络错误：{detail}")
+
+    detail_source = leaves[0] if leaves else exc
+    detail = str(detail_source).strip() or detail_source.__class__.__name__
+    return OutlookIntegrationError(
+        f"Outlook MCP 调用失败：{detail_source.__class__.__name__}: {detail}"
+    )
+
+
 @dataclass(frozen=True)
 class OutlookDefaults:
     """Default values exposed to the web setup form."""
@@ -187,18 +219,27 @@ async def _call_outlook_mcp_tool(
     from mcp import ClientSession, types
     from mcp.client.streamable_http import streamable_http_client
 
+    url = _outlook_mcp_url(config)
     backend_id = _require_backend_identity(config)
     client = _authz_client(config)
+    try:
         token_response = await client.issue_token(
             client_id=config.backend_identity.client_id,
             client_secret=config.backend_identity.client_secret,
             audience=f"mcp:{OUTLOOK_SERVER_ID}",
             scopes=scopes or ["list_tools", f"tool:{tool_name}"],
         )
+    except httpx.TimeoutException as exc:
+        raise OutlookIntegrationError("AuthZ token 请求超时。") from exc
+    except httpx.HTTPError as exc:
+        detail = str(exc).strip() or exc.__class__.__name__
+        raise OutlookIntegrationError(f"AuthZ token 获取失败：{detail}") from exc
+
     access_token = str(token_response.get("access_token") or "").strip()
     if not access_token:
         raise OutlookIntegrationError("Failed to obtain an Outlook MCP access token.")
 
+    try:
         async with AsyncExitStack() as stack:
             http_client = await stack.enter_async_context(
                 httpx.AsyncClient(
@@ -208,11 +249,13 @@ async def _call_outlook_mcp_tool(
                 )
             )
             read, write, _ = await stack.enter_async_context(
-            streamable_http_client(_outlook_mcp_url(config), http_client=http_client)
+                streamable_http_client(url, http_client=http_client)
             )
             session = await stack.enter_async_context(ClientSession(read, write))
             await session.initialize()
             result = await session.call_tool(tool_name, arguments=arguments)
+    except Exception as exc:  # noqa: BLE001
+        raise _coerce_outlook_mcp_exception(exc, url=url) from exc
 
     parts: list[str] = []
     for block in result.content:

app-instance/backend/nanobot/web/server.py

@@ -540,6 +540,40 @@ def _infer_cron_route_from_session_key(session_key: str | None) -> tuple[str | N
     return channel, chat_id
 
 
+def _record_cron_result_for_web_session(
+    *,
+    session_manager: SessionManager,
+    job: CronJob,
+    result: CronExecutionResult,
+) -> str | None:
+    """Persist standalone web cron output so the frontend can surface it."""
+    target_session_key = _resolve_cron_session_key(job)
+    if not target_session_key.startswith("web:"):
+        return None
+
+    # agent_turn jobs already write their own history via AgentLoop.process_direct().
+    if job.payload.kind == "agent_turn":
+        return target_session_key
+
+    # reminder/system_event jobs bypass the agent loop, so standalone web mode
+    # must append the final message into the target session explicitly.
+    if job.payload.kind != "system_event" or not job.payload.deliver or not result.response:
+        return None
+
+    session = session_manager.get_or_create(target_session_key)
+    session.add_message(
+        "assistant",
+        result.response,
+        metadata={
+            "source": "cron",
+            "job_id": job.id,
+            "job_name": job.name,
+        },
+    )
+    session_manager.save(session)
+    return target_session_key
+
+
 # ============================================================================
 # App factory
 # ============================================================================
@@ -635,8 +669,12 @@ def create_app(
                 default_channel="web",
                 default_chat_id="default",
             )
-            target_session_key = _resolve_cron_session_key(job)
+            target_session_key = _record_cron_result_for_web_session(
-            if job.payload.kind == "agent_turn" and target_session_key.startswith("web:"):
+                session_manager=session_manager,
+                job=job,
+                result=result,
+            )
+            if target_session_key:
                 await websocket_broadcaster.broadcast({
                     "type": "session_updated",
                     "session_id": target_session_key,