MCP Server Validator

Validate MCP tool definitions: name, description, inputSchema, required properties, outputSchema, and annotations. Structural checks in your browser.

Introduction

MCP Server Validator is a free, browser-based utility in our AI Tools collection. Paste an MCP-style tool definition (or tools array) and get a clear pass/warning/error report for JSON structure, name, description, inputSchema, required properties, outputSchema, and annotations. Runs entirely in your browser. MCP Server Validator helps you catch structural mistakes in Model Context Protocol tool definitions before you wire them into a server. It checks valid JSON, object shape, tool name and description, inputSchema type/properties/required consistency, and optional outputSchema and annotations. It is a practical structural validator — not a claim of full MCP specification certification. See the official MCP documentation for protocol requirements, and use JSON Schema Generator when you need to draft an inputSchema from a sample payload. Everything runs locally in your browser — inputs stay on your device, with no account or upload required. Highlights include validate single tools or tools arrays.

Features

Validate single tools or tools arrays
inputSchema structure and required-field checks
Optional outputSchema and annotations checks
Pass / warning / error report with paths
Format JSON, example, and copy report

How to use

1
Paste a tool object, a tools array, or { "tools": [...] }.
2
Click Validate (or rely on live checks) and review errors vs warnings.
3
Fix paths called out in the report, then re-validate.

Example

Simple tool

Input

{"name":"get_user","description":"Get user information","inputSchema":{"type":"object","properties":{"userId":{"type":"string"}},"required":["userId"]}}

Output

✓ Valid JSON
✓ Tool name present
✓ Description present
✓ inputSchema valid
⚠ outputSchema not provided

Benefits

Run MCP Validator entirely in the browser with no signup or installation.
Keep sensitive sample data private — processing never leaves your device.
Validate single tools or tools arrays
inputSchema structure and required-field checks
Optional outputSchema and annotations checks
Pair it with JSON Schema and JSON Schema when your workflow needs adjacent utilities.

FAQs

No. It validates common structural requirements for tool definitions (name, description, inputSchema, etc.). Protocol transport, capabilities, and server lifecycle are out of scope.

A single tool object, an array of tools, or an object with a tools array.

See https://modelcontextprotocol.io/docs for the Model Context Protocol specification and guides.

No. Validation runs locally in your browser.

Yes. MCP Validator on EverydayDevTools is free, with no account, watermarks, or usage caps for normal interactive use.

No. MCP Validator runs in your browser. Your input is processed locally and is not sent to EverydayDevTools servers.

Paste an MCP-style tool definition (or tools array) and get a clear pass/warning/error report for JSON structure, name, description, inputSchema, required properties, outputSchema, and annotations. Runs entirely in your browser. It fits everyday ai tools tasks when you want a fast local utility instead of installing a CLI or opening a heavy IDE feature.

Core capabilities include: Validate single tools or tools arrays; inputSchema structure and required-field checks; Optional outputSchema and annotations checks; Pass / warning / error report with paths.