Api Contract Validator

io.github.lazymac2xPublished by GitHub account lazymac2xv1.0.0Updated Oct 25, 2026

Cloudflare Workers MCP server: api-contract-validator

VerifiedStreamable HTTPWeb executableDeveloper ToolsData & Analytics

Overview

AI-generated overview

A remote MCP server that lets an assistant validate, lint, diff and mock OpenAPI or AsyncAPI specs and check them for breaking changes.

What you can do
Validate OpenAPI 3.x or AsyncAPI spec JSON, returning structural errors, missing required fields and warnings. Compare a real HTTP request/response against a spec contract and get per-field violations. Lint a spec against quality rules such as kebab-case operation IDs, required success responses, defined tags, non-empty descriptions and defined security. Generate mock response data from a spec using examples, defaults, formats and type heuristics. Compare two spec versions to detect breaking changes such as removed paths, new required parameters, removed response codes and renamed operation IDs.
When to use it
Useful when reviewing or maintaining API specifications: checking a spec before publishing, verifying that live traffic matches the contract, enforcing lint conventions, producing mock responses for testing, or judging whether a spec change breaks existing clients.
Requirements
A remote endpoint at over streamable HTTP; no packages, environment variables, headers or authentication are declared. Network access to that endpoint is needed.
Before you install
Specs and request/response data you submit are sent to a third-party hosted service, so avoid including secrets or sensitive payloads. The tools are read-only analysis and generation; no writes or deletions are described.

Installation

In SourceWeft

  1. Open Api Contract Validator in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/io.github.lazymac2x%2Fapi-contract-validator/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

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

README

This repository has no README.

Tools

5

validate_openapi_spec

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

Parametersspecrequiredstrict

diff_request_response

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

Parametersspecrequiredrequestrequiredresponse

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.

Parametersspecrequiredrules

generate_mock_from_spec

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

ParameterspathspecrequiredmethodstatusCode

check_breaking_changes

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

Parametersspec_newrequiredspec_oldrequired

Version history

1
  1. v1.0.0LatestSep 16, 2026

Score

75% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listedRequired15 pts
  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts

    Declare a GitHub repository with a README, or serve resource_documentation in the OAuth protected-resource metadata.

  • License10 pts

    Declare a license in the repository or the registry entry.