{"generatedAt":"2026-10-27T13:07:44.092Z","canonicalUrl":"https://agentbreakwatch.com/p/mcp-server-ts-v2","llmsTxtUrl":"https://agentbreakwatch.com/p/mcp-server-ts-v2/llms.txt","categoryHub":{"slug":"agent-sdks","title":"AI Agent SDKs & Frameworks Breaking-Change Index","url":"https://agentbreakwatch.com/c/agent-sdks"},"tldrVerdict":"MCP TypeScript SDK v2 Server (@modelcontextprotocol/server) is currently at v2.4.0 on NPM (published 2026-10-23), with a 90-day Stability Score of 78/100 (B) and HIGH schema drift risk. v2 split of @modelcontextprotocol/sdk. 2.4.0 rejects x-mcp-header on number parameters (error -32020, per the 2026-07-28 spec), stops wrapping outputSchema results from z.object().meta({ id }) in { result } on 2025-11-25 connections, and its bundled Ajv rejects $id or $ref values with an invalid URI scheme.","package":{"slug":"mcp-server-ts-v2","packageName":"@modelcontextprotocol/server","registry":"npm","kind":"sdk","subcategory":"MCP Core SDK","displayName":"MCP TypeScript SDK v2 Server","vendor":"Model Context Protocol","githubRepo":"modelcontextprotocol/typescript-sdk","breakingSummary":"v2 split of @modelcontextprotocol/sdk. 2.4.0 rejects x-mcp-header on number parameters (error -32020, per the 2026-07-28 spec), stops wrapping outputSchema results from z.object().meta({ id }) in { result } on 2025-11-25 connections, and its bundled Ajv rejects $id or $ref values with an invalid URI scheme.","schemaDriftRisk":"high","affectedSymbols":["McpServer","registerTool","outputSchema","structuredContent","x-mcp-header"],"migrationBefore":"import { McpServer } from \"@modelcontextprotocol/sdk/server/mcp.js\";\n// client code read structuredContent.result","migrationAfter":"import { McpServer } from \"@modelcontextprotocol/server\";\n// on 2025-11-25 connections read structuredContent directly\n// use z.int() for any parameter annotated with x-mcp-header","description":"Model Context Protocol implementation for TypeScript - Server package","latestVersion":"2.4.0","latestPublishedAt":"2026-10-23T18:20:13.773Z","recentVersions":[{"version":"2.4.0","publishedAt":"2026-10-23T18:20:13.773Z"},{"version":"2.3.1","publishedAt":"2026-10-05T11:52:39.322Z"},{"version":"2.3.0","publishedAt":"2026-10-02T17:48:29.517Z"},{"version":"2.2.0","publishedAt":"2026-09-28T19:09:46.736Z"},{"version":"2.1.0","publishedAt":"2026-09-23T15:45:32.276Z"},{"version":"2.0.0","publishedAt":"2026-07-27T23:55:22.239Z"}],"releasesLast90d":5,"dependenciesCount":2,"license":"Apache-2.0","registryUrl":"https://www.npmjs.com/package/@modelcontextprotocol/server","githubUrl":"https://github.com/modelcontextprotocol/typescript-sdk","installCommand":"npm install @modelcontextprotocol/server@2.4.0","stabilityScore":78,"stabilityGrade":"B"}}