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MCP Tool Schema Validator

Validate Model Context Protocol tool definitions before you ship them.

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About the MCP Tool Schema Validator

Paste a single MCP tool, an array of tools or a whole tools/list response and get every problem listed: illegal names, missing inputSchema, OpenAI-style parameters used by mistake, untyped properties, required fields that don't exist, missing descriptions and duplicate tool names.

Examples

Wrong key

JSON{ "name": "search", "parameters": {} }

Output

YAMLtool.parameters: MCP uses inputSchema, not parameters

Keyboard shortcuts

  • Copy the main outputCtrl / ⌘ + Shift + C
  • Download the resultCtrl / ⌘ + S
  • Share this toolCtrl / ⌘ + Shift + S
  • Reset the inputsAlt + R
  • Open the tool search paletteCtrl / ⌘ + K

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Frequently asked questions

Version 1.0.0 · Updated 2026-08-14 · Runs entirely in your browser