Engineering Loop

Own the change from a verified starting point to a reviewed result. Use one agent and this skill alone unless a specialist changes a material decision.

Establish the baseline

1. Read applicable AGENTS.md files and repository documentation.
2. Record the requested behavior, constraints, and observable done conditions.
3. Inspect the branch and working tree; preserve unrelated user-owned changes.
4. Identify repository-native validation and run the smallest safe baseline that separates pre-existing failures from task regressions.

For a long, cross-stack, or high-risk change, use the templates and failure rules in references/loop-contract.md. When a defect is intermittent, performance-related, difficult to reproduce, or resists the first evidence-driven pass, use references/hard-debugging.md.