API Versioning Skill

Phase 1 — Discovery

Ask only what isn't obvious from context:

Strategy already chosen? URL prefix (/v1/) vs. header (Accept: application/vnd.api+json;version=2) vs. query param — each has non-obvious tradeoffs (see below).
Who are the clients? Internal services (fast migration possible), third-party developers (long deprecation windows), or SDKs you own (can force upgrades). This dictates sunset timelines.
Existing traffic? If v1 is live, ask for any analytics on usage before deprecating. Never deprecate blind.
Monolith or microservices? Microservices complicate versioning — each service may be on a different version cycle.