API Contract Validator MCP Server

by lazymac2x Your server? Claim it

answering

API Contract Validator is answering right now. Last checked 11 min ago. It exposes 5 tools. Last commit 11 Apr 2026.

Cloudflare Workers MCP server: api-contract-validator

Uptime history 47 days of history

47 days agonow

100.0%

Uptime 24h

91 of 91 checks

Tools

read from the server

173 ms

Response time

average over 24h

Stars

last commit 11 Apr 2026

Nothing serious here today

Today is the operative word: we check API Contract Validator every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 11 min ago.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add api-contract-validator --transport http https://api.lazy-mac.com/api-contract-validator/mcp

~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "api-contract-validator": {
      "url": "https://api.lazy-mac.com/api-contract-validator/mcp"
    }
  }
}

~/.codex/config.toml

[mcp_servers.api-contract-validator]
url = "https://api.lazy-mac.com/api-contract-validator/mcp"

.cursor/mcp.json

{
  "mcpServers": {
    "api-contract-validator": {
      "url": "https://api.lazy-mac.com/api-contract-validator/mcp"
    }
  }
}

.vscode/mcp.json

{
  "mcpServers": {
    "api-contract-validator": {
      "url": "https://api.lazy-mac.com/api-contract-validator/mcp"
    }
  }
}

Available tools 5

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

breaking

check_breaking_changes

Compare two OpenAPI spec versions to detect breaking changes: removed paths/operations, new required parameters, removed response codes, operationId renames.

diff

diff_request_response

Compare a real HTTP request/response against an OpenAPI spec contract. Returns per-field violations.

generate

generate_mock_from_spec

Generate mock response data from an OpenAPI spec. Uses examples, defaults, formats, and type heuristics.

lint

lint_api_schema

Lint an API spec for quality and best practice compliance. Rules: operation-id-kebab-case, response-success-required, tags-defined, no-empty-description, security-defined.

validate

validate_openapi_spec

Validate an OpenAPI 3.x or AsyncAPI spec JSON. Returns structural errors, missing required fields, and warnings.

Endpoints

URL	Transport	State	Latency	Checked
https://api.lazy-mac.com/api-contract-validator/mcp	streamable-http	answering	171 ms	11 min ago

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API Contract Validator — questions

Answers built from our own checks of this server.

What can API Contract Validator do?

It exposes 5 tools, read directly from the server on our last check. Among them: check_breaking_changes, diff_request_response, generate_mock_from_spec, lint_api_schema, validate_openapi_spec. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →

Is API Contract Validator working right now?

We send a real MCP handshake every 15 minutes. Over the last 24 hours 91 of 91 checks got a reply (100.0%), average response time 173 ms. The bar chart above shows every period we have measured.

How do I connect API Contract Validator?

Copy the ready config from this page — we generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each with the file path that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.

Does API Contract Validator need an API key?

No. API Contract Validator completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 5 of them are readable on this page. This is what we observed, not what the docs claim.

How fast is API Contract Validator?

It answers our handshake in 173 ms on average, which is faster than 72% of all working MCP servers we measure. The comparison comes from our own checks across the whole registry, every 15 minutes.

Is API Contract Validator open source?

We cannot say either way: written in JavaScript and 0 stars on GitHub, but we could not determine the licence, and without one the code is not open source by default.