# MCP TypeScript SDK 2.4.0

Category: agent-infrastructure
Published: 2026-10-23T18:32:25Z
Source: [MCP TypeScript SDK releases](https://github.com/modelcontextprotocol/typescript-sdk/releases/tag/v2.4.0)
Agent usefulness: 77/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-10-23T22:17:54.000Z
Tags: mcp, sdk, typescript

## Human Summary
MCP TypeScript SDK releases published MCP TypeScript SDK 2.4.0. Package Version @modelcontextprotocol/client 2.4.0 @modelcontextprotocol/server 2.4.0 @modelcontextprotocol/core 2.4.0 @modelcontextprotocol/server-legacy 2.4.0 @modelcontextprotocol/codemod 2.4.0 @modelcontextprotocol/node 2.1.2 @modelcontextprotocol/express , hono , fastify unchanged Upgrade…

## Agent Summary
Treat MCP TypeScript SDK 2.4.0 as an official release signal. Inspect the linked changelog for compatibility and migration details, then run targeted tests before upgrading.

## Body
MCP TypeScript SDK releases published MCP TypeScript SDK 2.4.0. This automated release-watch entry was generated from the project's official GitHub release feed and is kept separate from human-reviewed editorial analysis. Release notes: Package Version @modelcontextprotocol/client 2.4.0 @modelcontextprotocol/server 2.4.0 @modelcontextprotocol/core 2.4.0 @modelcontextprotocol/server-legacy 2.4.0 @modelcontextprotocol/codemod 2.4.0 @modelcontextprotocol/node 2.1.2 @modelcontextprotocol/express , hono , fastify unchanged Upgrade notes x-mcp-header on a number parameter is rejected , as the 2026-07-28 spec requires: the client does not list such a tool, and the server answers a call to it with -32020 . Use z.int() or remove the annotation. ( 2762 , 2960 ) outputSchema from z.object(...).meta({ id }) . On a 2025-11-25 connection the result is no longer wrapped in { result } : read structuredContent , not structuredContent.result . ( 3081 ) The bundled Ajv validator uses fast-uri 3.1.8. It rejects a $id or $ref with an invalid URI scheme, such as my tool:output . ( 3083 ) New Skills over MCP (SEP-2640). A server publishes a…

## Recommended actions
- Review the official MCP TypeScript SDK releases release notes before upgrading.
- Check compatibility, migration, and security notes against your current agent stack.
- Run focused regression tests before production rollout.

## Sponsors
No sponsor placement attached.

## Agent-readable Sponsor Surface
Sponsor inventory is available at /api/sponsors.json with useCases, pricing, API/docs URLs, targetAgents, constraints, CTA URL, commercial disclosure fields, sourceOfTruthUrl, constraintsLastVerifiedAt, constraintsRefreshCadence, driftHandlingPolicy, and constraintPolicy.