Backend Systems Guidance

This is a composable overlay, not a standalone workflow. Use alongside the repo's implementation skill when the change touches backend code.

Choose activity independently from backend depth. A review request is read-only unless the user also asks for remediation; use the architecture and reliability rules as inspection criteria and report findings instead of changing code.

This is the canonical backend overlay in this repo. It extends the thin baseline backend-guidance overlay with stronger guidance for non-trivial service boundaries, repositories, reliability, and trust boundaries.

Prefer it over backend-guidance when the task includes new endpoints or consumers, multi-layer refactors, repository or transaction work, auth or trust-boundary logic, or backend review that needs explicit testing and reliability checks.