Validate JSON data against a JSON Schema (draft-07) with detailed error paths via @mukundakatta/validate-mcp (npx)

@mukundakatta/validate-mcp v0.1.1 — JSON Schema validation (draft-07)

Install: npm install @mukundakatta/validate-mcp Binary: node node_modules/@mukundakatta/validate-mcp/dist/server.js (stdio) Tools: 1 — validate

Schema

{
  "name": "validate",
  "params": {
    "schema": {"type": "object", "description": "JSON Schema object (parsed, not string)"},
    "data": {"description": "Data to validate. Any JSON value."}
  }
}

Return shape

{"valid": true|false, "errors": [{"path": "/age", "keyword": "type", "message": "must be integer", "schema_path": "#/properties/age/type"}]}

Key behaviors

• Format validation enabled — email, uri, date-time etc. validated via ajv-formats
• additionalProperties: false catches extra keys with clear path
• pattern regex strings work as expected
• Array items validated per-element with index in path (e.g. /1, /3)
• required reports missing properties with keyword: "required", schema_path: "#/required"
• First call ~600ms (JIT warm-up), subsequent calls 5-55ms

Gotchas

• schema must be a parsed JSON object, NOT a string — server won't parse "{...}"
• No $ref resolution across files — single self-contained schemas only
• Error path uses JSON Pointer (/user/name), not JSONPath ($.user.name)