MCP server de api-contract-guardian

API Contract Guardian

Monitor OpenAPI schema diffs between git branches, detect breaking changes, generate migration guides, and block CI pipelines on contract violations. |

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Why API Contract Guardian?

Real-world scenarios:

• CI/CD gating: Block PRs that introduce breaking API changes — catch them before merge, not after deploy
• API version upgrades: When bumping v1 → v2, generate a migration guide for consumers automatically
• Microservice contract enforcement: Ensure service boundaries respect their OpenAPI contracts across deploys
• Client SDK regeneration: Know exactly what changed so SDK clients can be updated with confidence

Installation

Note: api-contract-guardian is not yet on public PyPI. Use one of the methods below.

Install the latest version directly from GitHub:

pip install git+https://github.com/Coding-Dev-Tools/api-contract-guardian.git

Or install via Homebrew (macOS/Linux):

brew tap Coding-Dev-Tools/tap
brew install api-contract-guardian

Or install via Scoop (Windows):

scoop bucket add Coding-Dev-Tools https://github.com/Coding-Dev-Tools/scoop-bucket
scoop install api-contract-guardian

npm (Node.js wrapper — publishing pending):

# Not yet available — install via pip instead

Then run: api-contract-guardian --help

Quick Start

# Compare two spec files
api-contract-guardian check spec-v1.yaml spec-v2.yaml

# Generate migration guide
api-contract-guardian migrate spec-v1.yaml spec-v2.yaml --output MIGRATION.md

# CI gating (exits non-zero on breaking changes)
api-contract-guardian check spec-v1.yaml spec-v2.yaml

For machine-readable output, use --format yaml or --format json.

Example commands:

api-contract-guardian check spec-v1.yaml spec-v2.yaml --format yaml --output contract-diff.yaml

api-contract-guardian migrate spec-v1.yaml spec-v2.yaml --format json --output MIGRATION.json

Features

• Breaking Change Detection: Identifies removed endpoints, changed types, renamed fields, removed properties, and more
• Migration Guide Generation: Produces human-readable markdown migration guides
• Multiple Output Formats: Rich (terminal), JSON, YAML, or Markdown for diff and migrate; Rich, JSON, or YAML for check
• CI Gating: Exits with non-zero code when breaking changes are detected
• OpenAPI 3.x Support: Full support for OpenAPI 3.0.x and 3.1.x specs
• Git Branch Diffing: Compare specs between branches, tags, or commits
• File Comparison: Compare two local spec files directly

Breaking Changes Detected

Category	Example
Removed endpoint	DELETE /users/{id} removed
Removed property	email removed from User schema
Changed type	age changed from integer to string
Required property added	phone now required in User
Renamed field	name renamed to fullName
Response format changed	200 response type changed
Endpoint auth changed	security dropped from DELETE /admin (now public) or a new scheme required

CI/CD Integration

# Fail the build if breaking changes are detected
api-contract-guardian check spec-v1.yaml spec-v2.yaml || echo "Breaking API changes found!"

Pricing

API Contract Guardian is one of eleven tools in the Revenue Holdings suite. One license covers all CLI tools.

Plan	Price	Best For
Free	$0	Individual devs, OSS — CLI only, 1 spec comparison
ACG Individual	$19/mo ($15 billed annually)	Professional devs — unlimited specs, CI/CD gating
Suite (all 11 tools)	$49/mo ($39 billed annually)	Full Revenue Holdings toolkit — 40% savings
Team	$79/mo ($63 billed annually)	Up to 5 devs — shared dashboards, alerts, run history
Enterprise	Custom	SSO, RBAC, compliance reports, dedicated support

🔹 No lock-in: CLI works fully offline on the free tier — no telemetry, no phone-home. 🔹 Annual billing: Save 20%.

Per-Tier Features

Feature	Free	ACG	Suite	Team	Enterprise
CLI: diff, check, migrate	✓	✓	✓	✓	✓
Unlimited spec comparisons	—	✓	✓	✓	✓
CI/CD gating	—	✓	✓	✓	✓
Migration guide generation	—	✓	✓	✓	✓
Custom rules / policies	—	✓	✓	✓	✓
Team dashboard	—	—	—	✓	✓
Compliance reports	—	—	—	—	✓
RBAC	—	—	—	—	✓
SSO / SAML / OIDC	—	—	—	—	✓
Priority support	Community	24h	24h	8h	Dedicated

License

MIT

Install

api-contract-guardian is a Python CLI and is not on public PyPI:

pip install git+https://github.com/Coding-Dev-Tools/api-contract-guardian.git

For development: pip install -e .

Test

pytest tests/