Prevent MCP ClientSession hang (grll#35)

* Prevent MCP ClientSession hang

Per https://modelcontextprotocol.io/specification/draft/basic/lifecycle#timeouts

"Implementations SHOULD establish timeouts for all sent requests, to prevent hung connections and resource exhaustion. When the request has not received a success or error response within the timeout period, the sender SHOULD issue a cancellation notification for that request and stop waiting for a response.

SDKs and other middleware SHOULD allow these timeouts to be configured on a per-request basis."

* Update core.py

* Update core.py

* Update core.py

* Update based on PR comments

* Update core.py

Co-authored-by: Guillaume Raille <guillaume.raille@gmail.com>

---------

Co-authored-by: Guillaume Raille <guillaume.raille@gmail.com>

Author: njbrake

src/mcpadapt/core.py

@@ -8,6 +8,7 @@
 import threading
 from abc import ABC, abstractmethod
 from contextlib import AsyncExitStack, asynccontextmanager
+from datetime import timedelta
 from functools import partial
 from typing import Any, AsyncGenerator, Callable, Coroutine
 
@@ -71,6 +72,7 @@ def async_adapt(
 @asynccontextmanager
 async def mcptools(
     serverparams: StdioServerParameters | dict[str, Any],
+    client_session_timeout_seconds: float | timedelta | None = 5,
 ) -> AsyncGenerator[tuple[ClientSession, list[mcp.types.Tool]], None]:
     """Async context manager that yields tools from an MCP server.
 
@@ -81,6 +83,7 @@ async def mcptools(
         serverparams: Parameters passed to either the stdio client or sse client.
             * if StdioServerParameters, run the MCP server using the stdio protocol.
             * if dict, assume the dict corresponds to parameters to an sse MCP server.
+        client_session_timeout_seconds: Timeout for MCP ClientSession calls
 
     Yields:
         A tuple of (MCP Client Session, list of MCP tools) available on the MCP server.
@@ -98,8 +101,18 @@ async def mcptools(
             f"Invalid serverparams, expected StdioServerParameters or dict found `{type(serverparams)}`"
         )
 
+    timeout = None
+    if isinstance(client_session_timeout_seconds, float):
+        timeout = timedelta(seconds=client_session_timeout_seconds)
+    elif isinstance(client_session_timeout_seconds, timedelta):
+        timeout = client_session_timeout_seconds
+
     async with client as (read, write):
-        async with ClientSession(read, write) as session:
+        async with ClientSession(
+            read,
+            write,
+            timeout,
+        ) as session:
             # Initialize the connection and get the tools from the mcp server
             await session.initialize()
             tools = await session.list_tools()