fix(mcp): gate SSE session until initialize completes - #2234
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SSE /mcp/messages POSTs could reach ServerSession before the handshake finished, causing -32602 "Received request before initialization was complete". Mirror the WebSocket init_done latch in the bridge so later frames wait for the initialize result. Co-authored-by: Zsanz3 <Zsanz3@users.noreply.github.com>
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Fixes #2233
Problem
MCP SSE could accept concurrent POSTs (e.g.
tools/call) beforeinitializefinished, which surfaces as-32602 Received request before initialization was complete. WebSocket already had aninit_donelatch; SSE did not.Fix
In
deploy/docker/mcp_bridge.py, add_run_with_init_gatefor SSE sessions: allow the first frame (initialize) immediately, wait for the server's first write (initialize result) to setinit_done, then feed later messages into the read stream. Bridge-only latch — does not patch the upstream MCP SDK race.Test
tests/test_issue_2233_mcp_sse.py— source-shape check plus anyio behavior coverage for the gate.Does not touch #2226.