Build, debug, and optimize Claude API / Anthropic SDK apps. Apps built with this skill include prompt caching by default. Also migrates existing Claude API code between model versions (4.6 → 4.7 → 4.8, Mythos Preview → Fable 5, retired-model replacements). Use for /oc-claude-api, "Anthropic SDK", "prompt caching", "cache hit rate", "tool use", "model migration", "extended thinking", "batch API", "files API", "memory", "citations".
