fix(mcp): reinitialize expired HTTP sessions

[lurenjia534]

Related Issue

Resolve #2380

Problem

After a Streamable HTTP MCP server restarted, its old session id could remain attached to the client transport. A tool retry then sent the same expired id again instead of establishing a new session, so the server repeatedly returned Unknown session id.

What changed

• Recognize a terminated session only when a sessionful Streamable HTTP transport receives the specification-defined HTTP 404 or the reported HTTP 400 / JSON-RPC -32600 response with an explicit invalid-session and reinitialize message.
• Reinitialize the affected server and retry the interrupted tool call exactly once.
• Make manual, RPC, OAuth, and automatic recovery callers join one reconnect attempt per server.
• Resolve the current client before each call so existing tool wrappers remain valid after reconnect.
• Never transparently replay a call that fails only with ConnectionClosed, because its server-side outcome is unknown and replaying could duplicate side effects.
• Preserve the original session error alongside reconnect diagnostics, and allow an aborted caller to stop waiting without cancelling the shared reconnect.
• Exercise real in-process Streamable HTTP sessions as well as concurrency, abort, failed-reconnect, and false-positive cases.

Validation

• Before/after real Streamable HTTP E2E on the exact upstream base
  691ec4679ea19d6be8ac18f359088384ed3e446d and fixed
  e03fd73a947bf34668059ff694ece2566e539f8c: the added invalid-session
  scenario failed on upstream with the server's Unknown session id
  response, then passed unchanged after the fix by establishing a replacement
  session and retrying the interrupted call once.
• pnpm --filter @moonshot-ai/agent-core exec vitest run test/mcp/client-http.test.ts test/mcp/connection-manager.test.ts test/mcp/tool-manager-mcp.test.ts — 93 passed
• pnpm --filter @moonshot-ai/agent-core exec vitest run — 4,133 passed, 30 skipped, 3 expected failures, 1 todo
• pnpm --filter @moonshot-ai/agent-core typecheck
• pnpm --filter @moonshot-ai/agent-core build
• pnpm --filter @moonshot-ai/kimi-code typecheck
• pnpm --filter @moonshot-ai/kimi-code build
• node apps/kimi-code/dist/main.mjs --version
• pnpm exec oxlint --type-aware --quiet
• git diff --check

Checklist

• I have read the CONTRIBUTING document.
• I have linked a related issue, or explained the problem above.
• I have added tests that prove my feature works.
• Ran gen-changesets skill, or this PR needs no changeset.
• Ran gen-docs skill, or this PR needs no doc update.

[changeset-bot]

🦋 Changeset detected

Latest commit: e03fd73

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

This PR includes changesets to release 1 package

Name	Type
@moonshot-ai/kimi-code	Patch

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commit: e03fd73

[lurenjia534]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. 🎉

Reviewed commit: e03fd73a94

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