fix: send HTTP DELETE to terminate server sessions after each scenario#316
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pugsatoshi wants to merge 1 commit into
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fix: send HTTP DELETE to terminate server sessions after each scenario#316pugsatoshi wants to merge 1 commit into
pugsatoshi wants to merge 1 commit into
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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. - `client-helper.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 modelcontextprotocol#79 Signed-off-by: Satoshi Ito <satoshi.ito.tf@hitachi.com>
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This pull request makes server-targeting scenarios issue an HTTP DELETE to terminate the MCP session before closing the
client, so that each scenario leaves the server under test in a hermetic state. The fix lands in the shared
connectToServerhelper plus a newterminateSessionRawfor scenarios that bypass the SDK transport. A follow-up PR willadd a dedicated
session-lifecyclescenario that exercises the second half of the issue (servers MUST return 404 forrequests on a terminated session ID).
Motivation and Context
Fixes #79.
The Streamable HTTP transport spec says clients SHOULD send an HTTP DELETE with the
Mcp-Session-Idheader to explicitly terminate a session when they no longer need it.The conformance harness never did this — every scenario opened a session via
initialize, ran its checks, and let the server hold onto the dangling session.For real servers that gate resources by active session (in-memory state, connection slots, etc.), this is observable as drift between conformance runs.
How Has This Been Tested?
npm run check— typecheck + lint pass.npm run test— 173/173 tests pass.lifecycle.test.tsgains two new cases asserting that DELETE is sent with the issuedexamples/servers/typescript/everything-server.ts:$ PORT=3010 npx tsx examples/servers/typescript/everything-server.ts
$ npx tsx src/index.ts server --url http://localhost:3010/mcp --scenario tools-call-simple-text
Running client scenario 'tools-call-simple-text' against server: http://localhost:3010/mcp
Checks:
2026-05-21T10:23:18.394Z [tools-call-simple-text] SUCCESS Tool returns simple text content
Test Results:
Passed: 1/1, 0 failed, 0 warnings
The everything-server now logs
Received session termination request for session <id>for every scenario, which was previously absent.Breaking Changes
None
Types of changes
Checklist
Additional context