fix(everything-server): route sampling/elicitation requests over the originating tool-call stream - #414
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…sendRequest Tool handlers issued sampling/createMessage and elicitation/create via mcpServer.server.request(), which carries no relatedRequestId. The SDK's Streamable HTTP transport routes such requests to the standalone GET SSE stream; if the client hasn't opened it yet, the request is silently parked in the event store and the scenario times out after 60s. Switch test_sampling, test_elicitation, test_elicitation_sep1034_defaults, and test_elicitation_sep1330_enums to the handler's extra.sendRequest(), which sets relatedRequestId so the request rides the originating tools/call POST SSE stream. Fixes #407 Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Qz5WunPTnDHVot4C2J6sFz
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pcarleton
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Jul 27, 2026
pcarleton
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July 27, 2026 11:00
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Requested by Paul Carleton · Slack thread
Before: scenarios that exercise server-initiated requests against the everything-server (
tools-call-sampling,tools-call-elicitation,elicitation-sep1034-defaults,elicitation-sep1330-enums) could intermittently hang and fail with a ~60s request timeout. Whenever the tool handler ran before the client had opened the standaloneGET /mcpSSE stream (easy to hit with any added latency, e.g. a proxy in front of the server), the server'ssampling/createMessage/elicitation/createrequest was silently parked in the event store and never delivered.After: those scenarios complete deterministically. The server→client request is delivered on the SSE stream of the originating
tools/callPOST, which is guaranteed to be open for the duration of the handler, so it no longer matters whether or when the client opens the standalone GET stream.How: the four tool handlers in
examples/servers/typescript/everything-server.ts(test_sampling,test_elicitation,test_elicitation_sep1034_defaults,test_elicitation_sep1330_enums) issued their server→client requests viamcpServer.server.request(...), which carries norelatedRequestId— the SDK's Streamable HTTP transport routes such messages to the standalone GET stream, and silently stores-and-returns if that stream isn't connected. They now use the handler'sextra.sendRequest(...), which setsrelatedRequestIdto the in-flight tool-call id so the SDK associates the request with the open POST response stream. Schemas, result handling, and error handling are unchanged.Verification:
npm run typecheck,npm run lint,npm run build,npm test(442 tests) all pass.tools/call test_samplingwithout ever openingGET /mcphangs on the unpatched server (request never delivered) and succeeds on the patched one (request arrives on the POST SSE stream).Fixes #407
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https://claude.ai/code/session_01Qz5WunPTnDHVot4C2J6sFz
Generated by Claude Code