fix: use negotiated protocol version in server-sse-polling raw requests - #416
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The server-sse-polling scenario hard-coded mcp-protocol-version: 2025-11-25 on its raw tools/call POST and Last-Event-ID reconnection GET instead of the version negotiated during initialize — the same bug class as #412. A server that enforces the negotiated session version rejects those requests once it negotiates any other version. Read transport.protocolVersion after client.connect() and use it for both raw request headers, falling back to the run's spec version, mirroring the sse-multiple-streams fix (#415). Add a regression test whose fixture server down-negotiates to 2025-06-18 and 400s any request whose MCP-Protocol-Version header does not match, so a fix that hard-codes the latest version cannot pass. Follow-up to #415. Co-Authored-By: Claude <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_0178cz8nAyFRHQyq9cg2XgZz
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Enforce session id alongside protocol version in the fixture, record Last-Event-ID presence per GET so the SDK's automatic standalone GET cannot satisfy the reconnect assertion, normalize the header type instead of casting, return a descriptive 400 body on the GET path, add Allow to 405s, use the spec-shaped empty-data priming event, and read sessionId via the SDK's public getter in the scenario. Co-Authored-By: Claude <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_0178cz8nAyFRHQyq9cg2XgZz
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Review follow-ups on the session-termination change: - terminateSessionRaw: abort the DELETE after 5s so a wedged server cannot stall suite teardown. - terminateSessionBestEffort: shared SDK-path teardown helper that delegates to terminateSessionRaw with the transport's negotiated protocol version, so the socket is truly released at the bound and the version-mismatch 400 on strict servers (the failure mode of issue modelcontextprotocol#79) goes away. Used by connectToServer close() and both SSE scenarios, replacing their inline try/catch blocks. - lifecycle.ts: the raw session-id probe and its teardown DELETE now use ctx.specVersion instead of a hardcoded 2025-11-25, matching the negotiated-version convention from modelcontextprotocol#415/modelcontextprotocol#416. - Add sdk-client.test.ts regression tests asserting close() sends a DELETE with the issued session ID (and none without one), so a bad future merge cannot silently drop the fix.
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#316) * fix: send HTTP DELETE to terminate server sessions after each scenario The conformance test harness opened sessions against servers under test but never issued an HTTP DELETE to terminate them, leaving a dangling session on the server after each scenario. This violates the "hermetic" expectation called out in the Streamable HTTP transport spec. - `connection/sdk-client.connectToServer` now calls `transport.terminateSession()` before `client.close()`. A 405 response (DELETE not supported) is tolerated because the spec allows the server to refuse. - A new `terminateSessionRaw` helper handles scenarios that bypass the SDK client and open sessions via raw `fetch` (`lifecycle.ts`, `http-standard-headers.ts`). - `sse-polling.ts` and `sse-multiple-streams.ts`, which manage their own transport, now terminate the session in their existing `finally` block before closing the client. - `lifecycle.test.ts` gains two cases asserting that DELETE is sent with the issued session ID and that no DELETE is sent when the server did not assign one. Verified manually against `examples/servers/typescript/everything-server.ts` that running a server scenario now causes the server to log `Received session termination request for session <id>`. Fixes #79 Signed-off-by: Satoshi Ito <satoshi.ito.tf@hitachi.com> * Use negotiated protocol version for teardown DELETE and bound it Review follow-ups on the session-termination change: - terminateSessionRaw: abort the DELETE after 5s so a wedged server cannot stall suite teardown. - terminateSessionBestEffort: shared SDK-path teardown helper that delegates to terminateSessionRaw with the transport's negotiated protocol version, so the socket is truly released at the bound and the version-mismatch 400 on strict servers (the failure mode of issue #79) goes away. Used by connectToServer close() and both SSE scenarios, replacing their inline try/catch blocks. - lifecycle.ts: the raw session-id probe and its teardown DELETE now use ctx.specVersion instead of a hardcoded 2025-11-25, matching the negotiated-version convention from #415/#416. - Add sdk-client.test.ts regression tests asserting close() sends a DELETE with the issued session ID (and none without one), so a bad future merge cannot silently drop the fix. --------- Signed-off-by: Satoshi Ito <satoshi.ito.tf@hitachi.com> Co-authored-by: Paul Carleton <paulc@anthropic.com>
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- Adapt run() to the RunContext signature introduced in modelcontextprotocol#318. - Send the protocol version the server negotiated in the initialize result on follow-up requests instead of hardcoding 2025-11-25, falling back to the requested spec version (the sse-multiple-streams pattern from modelcontextprotocol#415/modelcontextprotocol#416). Parsing the initialize body is bounded by a 5s timeout, and every fetch shares one AbortController aborted when the scenario ends, so a server answering with a never-ending SSE stream can neither hang the run nor leak a held-open connection. - Fail the scenario when initialize itself fails; previously a broken server (401/500) was reported as stateless and passed. - Check the initialized notification response and fail when it is rejected, emitting SKIPPED placeholders for the lifecycle checks so per-check aggregation keeps its rows. - Report unexpected DELETE statuses as WARNING instead of FAILURE (the spec never pins a success status for session termination). - Treat 404 on DELETE as an already-terminated session only when the follow-up request confirms the session is gone; a 404 from a server whose session still responds (likely no DELETE route) is a WARNING with the 404 check skipped, rather than a misattributed failure. - Exclude the scenario from the draft spec version via removedIn: sessions were removed entirely by SEP-2575.
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…322) * feat: add session-lifecycle conformance scenario for streamable HTTP This commits a `server-session-lifecycle` scenario that verifies the server honors the two RFC 2119 statements the Streamable HTTP transport spec places on session termination: 1. After receiving an HTTP DELETE bearing the issued Mcp-Session-Id, the server accepts it (2xx) or signals that explicit termination is not supported (405). 2. Subsequent requests bearing the terminated session ID MUST get HTTP 404 Not Found. The scenario inlines a raw `fetch` initialize/terminate/probe flow so the DELETE is the test action (not background cleanup). Stateless servers that never issue a session ID are reported as INFO, and the lifecycle checks are SKIPPED. Servers that return 405 on DELETE skip both checks without flagging a failure — the spec allows servers to refuse explicit termination. Refs #79 Signed-off-by: Satoshi Ito <satoshi.ito.tf@hitachi.com> * fix: address review feedback on session-lifecycle scenario - Adapt run() to the RunContext signature introduced in #318. - Send the protocol version the server negotiated in the initialize result on follow-up requests instead of hardcoding 2025-11-25, falling back to the requested spec version (the sse-multiple-streams pattern from #415/#416). Parsing the initialize body is bounded by a 5s timeout, and every fetch shares one AbortController aborted when the scenario ends, so a server answering with a never-ending SSE stream can neither hang the run nor leak a held-open connection. - Fail the scenario when initialize itself fails; previously a broken server (401/500) was reported as stateless and passed. - Check the initialized notification response and fail when it is rejected, emitting SKIPPED placeholders for the lifecycle checks so per-check aggregation keeps its rows. - Report unexpected DELETE statuses as WARNING instead of FAILURE (the spec never pins a success status for session termination). - Treat 404 on DELETE as an already-terminated session only when the follow-up request confirms the session is gone; a 404 from a server whose session still responds (likely no DELETE route) is a WARNING with the 404 check skipped, rather than a misattributed failure. - Exclude the scenario from the draft spec version via removedIn: sessions were removed entirely by SEP-2575. --------- Signed-off-by: Satoshi Ito <satoshi.ito.tf@hitachi.com> Co-authored-by: Paul Carleton <paulc@anthropic.com>
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Requested by Paul Carleton · Slack thread
Before
The
server-sse-pollingscenario initialized through the SDK'sStreamableHTTPClientTransportbut hard-codedmcp-protocol-version: 2025-11-25on its two raw follow-up requests — thetools/call test_reconnectionPOST and theLast-Event-IDreconnection GET. Against a stateful server that enforces the version negotiated during initialize, those requests are rejected the moment the negotiated version is anything other than2025-11-25: the 400 on the POST is misreported as "server does not implement test_reconnection tool" (WARNING) and the scenario ends before testing any polling behavior. This is the same bug class as #412, fixed forserver-sse-multiple-streamsin #415.After
Both raw requests carry the version actually negotiated during initialize, so version-enforcing servers get their SSE polling behavior genuinely exercised. Servers that don't enforce the version are unaffected.
How
In
src/scenarios/server/sse-polling.ts, afterclient.connect(transport)the scenario reads the SDK transport's publicprotocolVersiongetter intonegotiatedProtocolVersion(alongside the session-id extraction, now via the publicsessionIdgetter) and uses it for themcp-protocol-versionheader on the raw POST and reconnection GET, falling back to the run'sspecVersionif the transport exposes none — mirroring the merged #415 pattern exactly.src/scenarios/server/sse-polling.test.tsadds regression coverage with a hardened fixture: the fixture server down-negotiates every initialize to2025-06-18regardless of the proposed version, records each follow-up request'sMCP-Protocol-Versionheader (and, for GETs,Last-Event-IDpresence, so the SDK's automatic standalone GET cannot satisfy the reconnect assertion), and 400s any version or session-id mismatch — so a wrong fix that hard-codes the latest version cannot pass. The fixture serves a spec-shaped priming event (id + empty data) then closes the stream without the tool result, forcing the scenario down theLast-Event-IDreconnection GET path so both fixed sites are exercised. Verified the test fails against the previous scenario code with either site regressed individually. A second test pins that the fixture rejects the supported-but-non-negotiated latest version.Also verified end-to-end against the in-repo everything-server (
examples/servers/typescript) on this branch:server-sse-pollingpasses 3/3 (priming event, retry field, disconnect-resume), so lenient servers see no behavior change.Follow-up to #415; same bug class as #412.