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Title: fix(streamable_http): expose session_idle_timeout and don't reap active sessions by BuildWithAbid · Pull Request #2510 · modelcontextprotocol/python-sdk · GitHub

Open Graph Title: fix(streamable_http): expose session_idle_timeout and don't reap active sessions by BuildWithAbid · Pull Request #2510 · modelcontextprotocol/python-sdk

X Title: fix(streamable_http): expose session_idle_timeout and don't reap active sessions by BuildWithAbid · Pull Request #2510 · modelcontextprotocol/python-sdk

Description: Closes #2455 Fixes both problems described in the issue: Problem 1: session_idle_timeout not exposed by streamable_http_app() StreamableHTTPSessionManager(...) accepted session_idle_timeout, but neither Server.streamable_http_app(...) nor MCPServer.streamable_http_app(...) did. So the canonical high-level API could not configure a supported session-manager feature. This PR threads session_idle_timeout: float | None = None through both wrappers and forwards it to the underlying StreamableHTTPSessionManager. Problem 2: active requests cancelled by the idle timeout The previous logic reset the deadline only at the start of each incoming request. A handler whose work outlived session_idle_timeout would be cancelled mid-flight; the client waited until session termination instead of receiving the tool result. Replaced the deadline-bumping logic with a per-transport in-flight counter and a _suspend_idle_timeout() async context manager: on entry: idle_active_requests += 1. If this is the first concurrent request, set idle_scope.deadline = math.inf. on exit: idle_active_requests -= 1. If this was the last in-flight request, restore now + session_idle_timeout. Both the new-session and existing-session code paths now wrap transport.handle_request(...) with _suspend_idle_timeout, so the deadline is suspended for the lifetime of every request. Test plan All in tests/server/test_streamable_http_manager.py: test_session_idle_timeout_passthrough_lowlevel — verifies the kwarg propagates from Server.streamable_http_app() to the manager. test_session_idle_timeout_passthrough_mcpserver — same for MCPServer.streamable_http_app(). test_suspend_idle_timeout_sets_deadline_inf_then_restores — direct unit test of the helper: deadline is inf during the request, finite (≈ now + timeout) after. test_suspend_idle_timeout_only_restores_after_last_concurrent_request — nested suspensions keep the deadline at inf until the outermost exit; counter logic correctness. test_suspend_idle_timeout_no_op_without_timeout — helper is inert when no timeout is configured. test_long_running_request_outlives_idle_timeout — regression for problem 2: end-to-end via httpx.ASGITransport + Client, a tool whose handler sleeps 4× the timeout still completes successfully. test_idle_session_reaped_after_request_completes — the session is still reaped once the request finishes, so existing reaping behavior is preserved. Local results: ``` tests/server/test_streamable_http_manager.py 18 passed tests/server/ + tests/shared/test_streamable_http.py 542 passed ruff check + ruff format clean pyright 0 errors, 0 warnings ``` Notes No public API removed — session_idle_timeout is a new kwarg with the same None default everywhere. The validation guards (session_idle_timeout > 0, mutually exclusive with stateless) still live on StreamableHTTPSessionManager.__init__ and continue to raise correctly when invoked through either wrapper.

Open Graph Description: Closes #2455 Fixes both problems described in the issue: Problem 1: session_idle_timeout not exposed by streamable_http_app() StreamableHTTPSessionManager(...) accepted session_idle_timeout, but ne...

X Description: Closes #2455 Fixes both problems described in the issue: Problem 1: session_idle_timeout not exposed by streamable_http_app() StreamableHTTPSessionManager(...) accepted session_idle_timeout, but ne...

Opengraph URL: https://github.com/modelcontextprotocol/python-sdk/pull/2510

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