ui shadcn@4.23.0

Version 4.23.0 of the shadcn command-line tool, which installs components from the shadcn/ui library, moves its built-in MCP server to version 2 of the MCP TypeScript SDK. That server is what lets an AI assistant browse, search and install components from registries directly into a project. According to the release notes, the shadcn mcp command now serves MCP protocol 2026-07-28 as well as earlier versions. That July revision of the Model Context Protocol lets each request carry what is needed to handle it instead of relying on a persistent session, so clients built for it can now talk to shadcn's server. The pull request says the server still accepts the 2025 initialize handshake older clients use, and adds an integration test that connects with both the 2025-11-25 and 2026-07-28 protocol versions.

The breaking part affects developers who import the server in their own code rather than running the command. The shadcn/mcp export is now an McpServer object, and a new createServer() export returns a fresh instance for each connection. Code that called setRequestHandler on the old Server export should switch to registerTool, or reach the underlying low-level server through server.server.setRequestHandler. The pull request says connecting a transport works as before, and lists two smaller behavior changes: tool input schemas move from JSON Schema draft-07 to 2020-12, which drops the additionalProperties: false setting, and calling an unknown tool now returns a -32602 protocol error instead of a tool result marked as an error.