MCP tool schema validator
Paste an MCP tools/list response, choose a tool, and validate sample tools/call arguments against its input schema. Everything runs locally.
Paste a tools/list response to inspect available MCP tools.
What is MCP schema validation?
Model Context Protocol tools describe their inputs with JSON Schema. Before wiring a connector into a client, you can validate that the tool list has the expected shape and that sample call arguments match the selected tool schema.
This validator is intentionally offline. It helps debug schemas, examples, and captured payloads without asking for server URLs, credentials, or authorization headers.
FAQ
Does this connect to my MCP server? +
No. This is an offline validator for pasted MCP payloads. It does not make network requests, open SSE streams, run stdio servers, or handle OAuth.
What does it validate? +
It checks common JSON-RPC envelope fields, extracts tools from a tools/list response, verifies required MCP tool metadata, and validates sample tools/call arguments against the selected tool's inputSchema.
Is it safe to paste tokens or headers? +
You should not paste secrets into any browser tool. This validator does not send data to a server, but it is designed for schemas and sample arguments rather than credentials.
Which schema format is supported? +
MCP tool input schemas are JSON Schema objects. This tool validates them with Ajv and supports common JSON Schema keywords, formats, required fields, enums, arrays, nested objects, and additionalProperties.
Why not test live MCP connections? +
A universal browser-only MCP connection tester would fail for many real servers because of CORS, OAuth redirects, auth headers, and stdio transport limits. Offline validation is deterministic and works on a static site.
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