Prefer defaulting and naked switches over if/else chains for shallow branching logic in Go. Use when writing or refactoring conditional logic with 1-3 branches.
Use when adding a cross-cutting concern (OTEL tracing, logging, metrics, caching, auth) to a business domain, creating files under business/domain/*/extensions/*, or adding the extension seam (ExtBusiness/Extension) to a *bus package.
Enforce primitive-at-edges / strong-types-in-Business layering and the toBus/fromBusResponse/toDB converter pattern. Use when writing, editing, or auditing Go files under app/*, business/domain/*, or .../stores/*db.
Service Diffguard: read-only PR review lenses for correctness, error visibility, comment truthfulness, test coverage, type/contract boundaries, and simplification across every language in this repo (Go, Vue/JS/SCSS, Rego, protobuf, SQL, Helm/YAML, shell). Use for PR review, pre-commit review, unstaged-diff review, or a targeted review of one of those aspects.
Apply modern Go syntax guidelines based on the project's Go version. Use whenever writing, editing, or reviewing Go (.go) code — not only when explicitly asked for guidelines.