MCP Tool Schema Validator
Validate Model Context Protocol tool definitions before you ship them.
MCP tool definition
Paste a tool, an array of tools, or a tools/list response
Validation
- tool.inputSchema.properties.limit
Add a description so the model fills this argument correctly
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
{ "name": "search", "parameters": {} }Output
tool.parameters: MCP uses inputSchema, not parametersKeyboard 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