backend-engineering-workflow End-to-end backend engineering workflow for building backend services, creating, modifying, optimizing, debugging, testing, and documenting server endpoints, detecting backend risks, refactoring or rewriting backend code, and verifying server behavior. Use when the user asks to build a backend, create a server, implement backend features, add or adjust REST APIs, GraphQL resolvers, RPC handlers, controllers, routes, request validation, response schemas, authentication, authorization, pagination, filtering, sorting, OpenAPI/Swagger specs, backend integration tests, performance/error handling, database logic, or backend quality hardening. Do NOT use for frontend-only work, deployment-only tasks with no backend code change, database-only analysis with no service change, or high-level architecture discussion with no implementation.
Build, debug, and optimize Claude API / Anthropic SDK apps. Apps built with this skill should include prompt caching. Also handles migrating existing Claude API code between Claude model versions (4.5 → 4.6, 4.6 → 4.7, retired-model replacements). TRIGGER when: code imports `anthropic`/`@anthropic-ai/sdk`; user asks for the Claude API, Anthropic SDK, or Managed Agents; user adds/modifies/tunes a Claude feature (caching, thinking, compaction, tool use, batch, files, citations, memory) or model (Opus/Sonnet/Haiku) in a file; questions about prompt caching / cache hit rate in an Anthropic SDK project. SKIP: file imports `openai`/other-provider SDK, filename like `*-openai.py`/`*-generic.py`, provider-neutral code, general programming/ML.