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
Related tools
AI Tool Schema Builder
AI & LLM
Build function-calling schemas for OpenAI, Claude, Gemini, MCP and the AI SDK.
AI Tool Schema Converter
AI & LLM
Convert function-calling schemas between OpenAI, Anthropic, Gemini and MCP.
JSON Schema to AI Tool Schema
AI & LLM
Wrap any JSON Schema into a ready-to-use function-calling tool.
LLM Structured Output Validator
AI & LLM
Check that a model's JSON reply matches your JSON Schema.
MCP Tool Schema Generator
AI & LLM
Generate an MCP, OpenAI or Anthropic tool schema from example arguments.
AI Dataset Deduplicator
AI & LLM
Remove exact and near-duplicate rows from fine-tuning datasets.
Frequently asked questions
Version 1.0.0 · Updated 2026-08-14 · Runs entirely in your browser