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I couldn't find a great CLI tool for interactively probing an MCP server, so I had Codex help build mcp-explorer — a stateless Python CLI that needs no installation and runs via uvx against any MCP endpoint.
Because no good CLI existed for interactively probing MCP servers, Simon had Codex help him build mcp-explorer, a stateless Python CLI that works via uvx without installation — demonstrated against Ade Oshineye's agentic-mermaid.dev demo MCP server. ✦ AI generated
Simon Willison · Simon Willison's Weblog · 2026-07-31 · original ↗
I couldn't find a great CLI tool for interactively probing an MCP server, so I had Codex help build my own. mcp-explorer is the result. It's a stateless Python CLI tool, so you don't even need to install it to try it out - it works with uvx like this: uvx mcp-explorer list https://agentic-mermaid.dev/mcp
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gives example → The 2026-07-28 stateless MCP specification (MCP 2.0) is the most significant change to the Model Context Protocol since it first launched, and it has reignited my interest in a protocol that had been eclipsed by Skills and by agent harnesses with terminal and curl access.Simon Willison · Simon Willison's Webloggives example → Giving an agent a shell environment with internet access is fraught with risk and requires a strong driving model, whereas MCP tools are easier to audit and control and are simple enough that smaller laptop models can drive them, and the stateless spec greatly cuts client and server implementation complexity.Simon Willison · Simon Willison's Weblogprovides context → MCP lets a host application route a user request through an embedded MCP client to the correct MCP server, which executes the tool call and returns a structured response the agent uses to continue reasoning.ByteByteGo · ByteByteGo Newsletter