Don't crash agent on MCP server disconnected

Author: Kludex

pydantic_ai_slim/pydantic_ai/mcp.py

@@ -110,8 +110,11 @@ async def list_tools(self) -> list[mcp_types.Tool]:
         - We don't cache tools as they might change.
         - We also don't subscribe to the server to avoid complexity.
         """
-        async with self:  # Ensure server is running
-            result = await self._client.list_tools()
+        try:
+            async with self:  # Ensure server is running
+                result = await self._client.list_tools()
+        except anyio.get_cancelled_exc_class():
+            return []
         return result.tools
 
     async def direct_call_tool(
@@ -206,6 +209,7 @@ async def __aenter__(self) -> Self:
                 self._read_stream, self._write_stream = await self._exit_stack.enter_async_context(
                     self.client_streams()
                 )
+
                 client = ClientSession(
                     read_stream=self._read_stream,
                     write_stream=self._write_stream,