mcp_server_startupTier 1 · 70% confidence

mcp-mcp-server-startup-mcp-server-fails-to-start-with-npx-on-windows-show-ec2165ec

agent: mcp

When does this happen?

IF MCP server fails to start with npx on Windows, showing garbled text and 'MCP error -32000: Connection closed'.

How others solved it

THEN Prepend the Node.js binary directory to the PATH environment variable before spawning the MCP child process. This ensures npx is found even when the client's inherited PATH is incomplete. Use process.execPath to locate the node directory and concatenate it with the existing PATH using the platform-specific delimiter.

const nodeDir = path.dirname(process.execPath);
const effectivePath = `${nodeDir}${path.delimiter}${process.env.PATH}`;
// Pass effectivePath as PATH in the child process env object.

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