fix: reconnect MCP client on terminated session (#8694)

* fix: reconnect MCP client on terminated session

* Update astrbot/core/agent/mcp_client.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* Update mcp_client.py

---------

Co-authored-by: Weilong Liao <37870767+Soulter@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

astrbot/core/agent/mcp_client.py

@@ -13,7 +13,7 @@ import httpx
 from tenacity import (
     before_sleep_log,
     retry,
-    retry_if_exception_type,
+    retry_if_exception,
     stop_after_attempt,
     wait_exponential,
 )
@@ -93,6 +93,10 @@ _DENIED_DOCKER_ARGS = frozenset(
     }
 )
 _STDIO_ALLOWLIST_ENV = "ASTRBOT_MCP_STDIO_ALLOWED_COMMANDS"
+_MCP_RECONNECT_ERROR_MESSAGES = (
+    "session terminated",
+    "session was terminated",
+)
 
 try:
     import anyio
@@ -121,6 +125,13 @@ except (ModuleNotFoundError, ImportError):
         )
 
 
+def _is_mcp_reconnect_error(exc: BaseException) -> bool:
+    if "anyio" in globals() and isinstance(exc, anyio.ClosedResourceError):
+        return True
+    message = str(exc).lower()
+    return any(marker in message for marker in _MCP_RECONNECT_ERROR_MESSAGES)
+
+
 def _prepare_config(config: dict) -> dict:
     """Prepare configuration, handle nested format"""
     if config.get("mcpServers"):
@@ -635,7 +646,7 @@ class MCPClient:
         """
 
         @retry(
-            retry=retry_if_exception_type(anyio.ClosedResourceError),
+            retry=retry_if_exception(_is_mcp_reconnect_error),
             stop=stop_after_attempt(2),
             wait=wait_exponential(multiplier=1, min=1, max=3),
             before_sleep=before_sleep_log(logger, logging.WARNING),
@@ -651,9 +662,15 @@ class MCPClient:
                     arguments=arguments,
                     read_timeout_seconds=read_timeout_seconds,
                 )
-            except anyio.ClosedResourceError:
+            except Exception as exc:
+                if not _is_mcp_reconnect_error(exc):
+                    raise
+
                 logger.warning(
-                    f"MCP tool {tool_name} call failed (ClosedResourceError), attempting to reconnect..."
+                    "MCP tool %s call failed (%s: %s), attempting to reconnect...",
+                    tool_name,
+                    type(exc).__name__,
+                    exc,
                 )
                 # Attempt to reconnect
                 await self._reconnect()

tests/unit/test_mcp_client_reconnect.py

@@ -0,0 +1,103 @@
+from datetime import timedelta
+
+import anyio
+import pytest
+from tenacity import wait_none
+
+from astrbot.core.agent import mcp_client
+
+
+class FlakyMcpSession:
+    def __init__(self, first_error: Exception | None = None) -> None:
+        self.calls = 0
+        self.first_error = first_error or RuntimeError("Session terminated")
+
+    async def call_tool(
+        self,
+        *,
+        name: str,
+        arguments: dict,
+        read_timeout_seconds: timedelta,
+    ) -> dict[str, object]:
+        self.calls += 1
+        if self.calls == 1:
+            raise self.first_error
+        return {
+            "name": name,
+            "arguments": arguments,
+            "timeout": read_timeout_seconds.total_seconds(),
+        }
+
+
+@pytest.mark.parametrize(
+    ("error", "expected"),
+    [
+        (RuntimeError("Session terminated"), True),
+        (RuntimeError("SESSION TERMINATED"), True),
+        (RuntimeError("session was terminated"), True),
+        (anyio.ClosedResourceError(), True),
+        (RuntimeError("business flow terminated normally"), False),
+        (RuntimeError("terminated"), False),
+    ],
+)
+def test_mcp_reconnect_error_detection_is_narrow(
+    error: BaseException, expected: bool
+) -> None:
+    assert mcp_client._is_mcp_reconnect_error(error) is expected
+
+
+@pytest.mark.asyncio
+async def test_call_tool_reconnects_on_session_terminated(monkeypatch) -> None:
+    monkeypatch.setattr(mcp_client, "wait_exponential", lambda **_: wait_none())
+
+    client = mcp_client.MCPClient()
+    session = FlakyMcpSession()
+    reconnects = 0
+
+    async def reconnect() -> None:
+        nonlocal reconnects
+        reconnects += 1
+        client.session = session
+
+    client.session = session
+    client._reconnect = reconnect
+
+    result = await client.call_tool_with_reconnect(
+        tool_name="lookup",
+        arguments={"url": "https://example.com"},
+        read_timeout_seconds=timedelta(seconds=5),
+    )
+
+    assert result == {
+        "name": "lookup",
+        "arguments": {"url": "https://example.com"},
+        "timeout": 5.0,
+    }
+    assert session.calls == 2
+    assert reconnects == 1
+
+
+@pytest.mark.asyncio
+async def test_call_tool_does_not_reconnect_on_business_error(monkeypatch) -> None:
+    monkeypatch.setattr(mcp_client, "wait_exponential", lambda **_: wait_none())
+
+    client = mcp_client.MCPClient()
+    session = FlakyMcpSession(first_error=ValueError("business logic failed"))
+    reconnects = 0
+
+    async def reconnect() -> None:
+        nonlocal reconnects
+        reconnects += 1
+
+    client.session = session
+    client._reconnect = reconnect
+
+    with pytest.raises(ValueError, match="business logic failed"):
+        await client.call_tool_with_reconnect(
+            tool_name="lookup",
+            arguments={"url": "https://example.com"},
+            read_timeout_seconds=timedelta(seconds=5),
+        )
+
+    assert session.calls == 1
+    assert reconnects == 0