mcp-explorer exposes MCP server contracts

Simon Willison's mcp-explorer is a Python CLI that lists an HTTP MCP server's tools, inspects full schemas, calls a named tool, and checks stateless and legacy compatibility. Why it matters: An MCP endpoint can look usable until a tool schema, capability, or protocol mode disagrees with the client. This puts those contracts in a terminal before an agent is given the endpoint.

Try this: Run `mcp-explorer doctor` against one non-production MCP URL, then inspect the JSON schema for its most privileged tool before connecting an agent.