Step 1. Start a server up in the terminal
uvx mcp-server-fetch
Step 2. Initialize it by copy and pasting this JSON-RPC invocation (and hit return)
{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"protocolVersion":"2025-03-26","capabilities":{"sampling":{},"roots":{"listChanged":true}},"clientInfo":{"name":"mcp-inspector","version":"0.12.0"}}}
Step 3. Notify the server that it's now initialized