MCP Tool Schema Validator

Validate MCP tool names, descriptions, input schemas, output schemas, required fields, and strictness before shipping a server.

Tools

Errors

Warnings

MCP tools JSON

Schema findings

Tool definitions pass all checks.

Private by default: this tool runs entirely in your browser. Nothing you paste is uploaded to Execute.Online.

About MCP Tool Schema Validator Online

Validate Model Context Protocol tool definitions, names, descriptions, inputSchema, outputSchema, required properties, and strictness locally.

How to use MCP Tool Validator

1Paste one tool, a tool array, or an object containing tools.
2Review errors that make the schema invalid.
3Review warnings about descriptions and strictness.
4Update the server definition and validate again.

Frequently Asked Questions

What is an MCP tool definition?

An MCP tool definition gives a model a name, description, JSON Schema input contract, and optional structured output contract for invoking server functionality.

What schema problems are detected?

The validator checks object schemas, required fields, missing properties, duplicate names, risky name characters, descriptions, and additionalProperties declarations.

Does this connect to my MCP server?

No. It validates pasted JSON locally and makes no network connection to the server.

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