[diegomura]

Problem

MCP subscriptions/listen requests return 200 and hold a notification stream open until Vercel's 10-second timeout. A live request reproduced this at approximately 10.5 seconds. The SDK advertises tool-list changes by default, although this site's documentation tools do not change during an invocation.

Change

Disable the tools.listChanged capability and set maxSubscriptions: 0 so subscription attempts receive an immediate JSON error. Keep normal MCP tool calls and legacy protocol support unchanged.

Validation

• Five regression tests pass, covering capability discovery, subscription rejection, legacy tool listing, searches, and GET rejection. The first two tests failed before the fix.
• Site TypeScript check passes after generating Next.js route types.
• Run tests from apps/site with Node 22: node ../../node_modules/vitest/vitest.mjs run --root . --config ../../vitest.config.js 'app/api/mcp/[transport]/route.test.ts'.

Production logs identify Copilot CLI among timed-out requests but do not expose their MCP method. After deployment, verify that /mcp timeout rate and billed duration fall; this reproduces and fixes the subscription timeout, but does not establish that every observed timeout had that cause.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated
react-pdf	Error		Oct 20, 2026 10:19pm UTC

[changeset-bot]

⚠️ No Changeset found

Latest commit: 20d350d

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

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