fix: replay request SSE responses after disconnect

[he-yufeng]

Summary

• persist request-scoped SSE events even after closeSSEStream() detaches the active controller
• avoid throwing when the terminal response is safely stored for replay
• add a regression test that closes a POST SSE stream, completes the tool while disconnected, and replays the final response through Last-Event-ID

To verify

• pnpm --filter @modelcontextprotocol/node test -- streamableHttp.test.ts -t closeSSE
• pnpm --filter @modelcontextprotocol/server test -- streamableHttp.test.ts
• pnpm --filter @modelcontextprotocol/server typecheck
• pnpm --filter @modelcontextprotocol/node typecheck
• pnpm --filter @modelcontextprotocol/server lint
• pnpm --filter @modelcontextprotocol/node lint
• pnpm --filter @modelcontextprotocol/server build
• pnpm --filter @modelcontextprotocol/node build
• git diff --check

[changeset-bot]

🦋 Changeset detected

Latest commit: 68a6acf

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@modelcontextprotocol/node	Patch
@modelcontextprotocol/server	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pkg-pr-new]

Open in StackBlitz

@modelcontextprotocol/client

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/client@2207

@modelcontextprotocol/codemod

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/codemod@2207

@modelcontextprotocol/server

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/server@2207

@modelcontextprotocol/server-legacy

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/server-legacy@2207

@modelcontextprotocol/express

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/express@2207

@modelcontextprotocol/fastify

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/fastify@2207

@modelcontextprotocol/hono

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/hono@2207

@modelcontextprotocol/node

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/node@2207

commit: 68a6acf

[he-yufeng]

Added a changeset for @modelcontextprotocol/node and @modelcontextprotocol/server as patch releases. Validation for this follow-up: git diff --check; verified the changeset frontmatter and package names against packages/middleware/node/package.json and packages/server/package.json. The previous CI run was already green; this push only adds release metadata.

[he-yufeng]

Rebased on current main and force-pushed the branch.

Validated locally:

• pnpm install
• pnpm changeset status --since upstream/main (@modelcontextprotocol/node and @modelcontextprotocol/server patch)
• pnpm --filter @modelcontextprotocol/server typecheck
• pnpm --filter @modelcontextprotocol/server lint
• pnpm --filter @modelcontextprotocol/node typecheck
• pnpm --filter @modelcontextprotocol/node lint
• pnpm --filter @modelcontextprotocol/node exec vitest run test/streamableHttp.test.ts (75 passed)
• git diff --check upstream/main..HEAD

The pre-push hook also completed the repo-wide build, typecheck, and lint steps successfully.