Breaking Change Detector

What this skill does

This skill directs the agent to compare two versions of a codebase, API schema, or interface definition and systematically identify every change that could break existing callers. It classifies each change by severity, explains why it is breaking, and provides a concrete migration hint so consumers know exactly what they need to update.

Use this before publishing a new package version, before deploying an API change that existing clients depend on, or during a code review to catch unintended contract changes.

How to use

Claude Code / Cline

Copy this file to .agents/skills/breaking-change-detector/SKILL.md in your project root.

Then ask:

• "Use the Breaking Change Detector skill to compare the old and new versions of our API."
• "I changed src/auth/index.ts. Use the Breaking Change Detector skill to find any breaking changes."

Provide: the old version (paste, file path, or git ref) and the new version.