fix: bump SDK to 1.26.0, fix tools_call scenario#134
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SDK 1.26.0 made Protocol.connect() throw if already connected to a transport. The tools_call scenario was calling server.connect(transport) on every request with the same Server instance, which now throws. Fixed by adding proper session management: each initialize request creates a new Server + Transport pair, and subsequent requests are routed to the correct transport via the mcp-session-id header.
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The else branch was returning 400 for both missing-session and invalid/stale-session cases. The MCP spec requires 404 for invalid session IDs and 400 only for non-initialization requests without any session ID.
Instead of adding session management, simply create a new Server instance per request. This preserves the original stateless design while fixing the SDK 1.26.0 Protocol.connect() restriction.
pcarleton
changed the title
felixweinberger
approved these changes
Feb 5, 2026
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SDK 1.26.0 made
Protocol.connect()throw if already connected to a transport. Thetools_callscenario was callingserver.connect(transport)on every request with the sameServerinstance, which now throws.Fixed by adding proper protocol management: each initialize request creates a new Server + Transport pair.