MCP Tool Schema Validator
Validate MCP tool definitions and verify `inputSchema` before deployment
MCP Tool Definition
Formatted Definition
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Frequently Asked Questions
It checks that your tool definition is valid JSON, confirms the required top-level fields are present, validates the embedded `inputSchema`, and reports both errors and warnings about the MCP shape.
No. It validates the JSON definition locally in your browser. It does not connect to a running MCP server or any third-party API.
Typical issues include missing `name`, a non-object `inputSchema`, invalid JSON Schema inside `inputSchema`, non-boolean annotation hints, and definitions that omit a useful description.
Yes. Paste the entire MCP tool definition, not only the `inputSchema`. The validator is designed to inspect the full object.