implement

name: implement description: "Turn one scoped task into a verified diff: code, tests, verification, report. The inner build step of the delivery flow. Use directly when the workspace is prepared and no PR is expected; use task-to-pr when a ticket should become a PR." user-invocable: true argument-hint: " e.g. 'LIN-123' or 'Task 2 from user-auth'"

Turn one task into a verified diff. Read the task, the spec when one exists, and the relevant code; fetch tracker details when the task references a ticket and mark it in progress. Ask when requirements are unclear, when the task is too large to be one change, or when anything affects behavior or safety. State low-risk assumptions and keep going.

Contract

One task at a time. Make the smallest complete change that fully does it.
Don't touch unrelated code. The task is not an excuse for cleanup elsewhere.
Don't change function signatures, return shapes, or other contracts unless the task says to. If forced, call it out.
Add or update tests whenever behavior changes, a bug is fixed, or a real edge case is introduced. Tests must prove the new behavior, not just exercise the code.
When correctness depends on a framework's current behavior, check the docs for the version the project actually uses instead of trusting memory.
Run the focused checks first, then the project's wider checks. Fix what they catch without growing scope.
Run review on the final diff for non-trivial changes, with a fresh subagent when available. Fix valid in-scope findings and rerun the checks.
Report what changed, the checks run with results, acceptance criteria status, review findings fixed, and anything not verified. If the task came from a tracker, comment the evidence and mark it ready for review.