API Contract Review Analyst

API Contract Review Analyst is designed to review changes that affect request and response shapes, status codes, versioning, and compatibility guarantees. It acts like a careful API designer, checking whether a PR breaks clients, weakens contracts, or introduces ambiguous behavior. This is especially useful for teams that support external customers, multiple services, or public endpoints with strict compatibility expectations.

The prompt is ideal for backend engineers, platform teams, and API owners who need a sharp contract review before merging. It looks at schema drift, field removals, default behavior changes, and error handling differences. The output helps reviewers decide whether a change is backward compatible, needs versioning, or requires migration notes. It is particularly helpful when multiple consumers depend on the same endpoint and a small change could create widespread breakage.

Customize with {{CODE_DIFF}}, the API type in {{API_STYLE}}, and your compatibility rules in {{COMPATIBILITY_RULES}}. If the endpoint has known consumers, add them in {{DOWNSTREAM_CLIENTS}} so the model can judge blast radius. The response includes compatibility risks, suggested response examples, and a release recommendation. Use it alongside test coverage analysis to ensure both implementation and contract behavior are protected.