Keep HTTP health checks responsive during tool calls

[ChiragAgg5k]

Summary

• Offload hosted HTTP MCP tool execution to an AnyIO worker thread so synchronous Appwrite SDK, docs search, context, and upload work cannot block the ASGI event loop.
• Add a regression test proving a blocking HTTP tool call does not prevent the event loop from waking promptly.

Testing

• uv run python -m unittest tests.unit.test_server -v
• uv run python -m unittest discover -s tests/unit -v
• uv run --group dev ruff check src/mcp_server_appwrite/server.py tests/unit/test_server.py
• uv run --group dev black --check src/mcp_server_appwrite/server.py tests/unit/test_server.py
• uv run --group dev pyright

[greptile-apps]

Greptile Summary

This PR keeps the ASGI event loop responsive during HTTP MCP tool calls by offloading synchronous Appwrite SDK work to an anyio worker thread, and fixes a concurrent-access bug in ResultStore that was exposed by the change.

• server.py: Introduces _execute_public_tool_for_transport; for the HTTP transport it calls to_thread.run_sync(..., abandon_on_cancel=True) so blocking SDK/docs/upload calls cannot stall /healthz or other in-flight requests.
• operator.py: Adds threading.Lock to ResultStore.get, list, and save, preventing iterator-mutation crashes when the event loop and a worker thread access the store concurrently.
• Tests: New ResultStoreTests validates concurrent safety under ThreadPoolExecutor, and test_http_tool_execution_does_not_block_event_loop proves the event loop is free within 100 ms while a 200 ms blocking call runs in a thread.

Confidence Score: 5/5

Safe to merge — the thread offload and ResultStore locking are both correct and directly validated by new tests.

The core change is well-scoped: to_thread.run_sync with abandon_on_cancel=True correctly frees the event loop, the positional-arg forwarding to execute_public_tool matches its signature, and the new lock in ResultStore closes the iterator-mutation window without introducing deadlock risk. Both previous review concerns are fully addressed and covered by targeted regression tests.

No files require special attention.

Important Files Changed

Filename	Overview
src/mcp_server_appwrite/server.py	Adds _execute_public_tool_for_transport helper that offloads HTTP tool execution to an anyio worker thread with abandon_on_cancel=True, keeping the ASGI event loop free during blocking SDK calls.
src/mcp_server_appwrite/operator.py	Adds threading.Lock to ResultStore covering get, list, and save, making the store safe for concurrent access from worker threads.
tests/unit/test_operator.py	Adds ResultStoreTests with a concurrent save+list thread-safety regression test using ThreadPoolExecutor; correctly verifies no size overflow and no iterator crash.
tests/unit/test_server.py	Adds test_http_tool_execution_does_not_block_event_loop which uses a 200ms blocking operator to prove the event loop remains free within 100ms while the task is still pending.
pyproject.toml	Adds anyio>=4.0.0 as an explicit runtime dependency (it was previously transitively pulled via mcp[cli] but not declared).

_{Reviews (2): Last reviewed commit: "Address HTTP tool offload review feedbac..." | Re-trigger Greptile}