Open-source MCP Master Tester: npx-run any MCP server with a tool-definition linter
simplymanas · reddit · 2026-11-05
The author open-sourced MCP Master Tester (MIT), a local web UI to see exactly what a client sees from your MCP servers and test them quickly. Run with npx mcp-master-tester.
- Works with stdio, Streamable HTTP, and SSE transports;
- Auto-generated forms for every tool;
- A lint tab flags weak tool definitions (missing descriptions, untyped fields);
- Full JSON-RPC log with timings.
Feedback and contributions welcome; the author also asks what lint rules others would add.
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