check

Run after any non-trivial change. Catches drift where you implemented something adjacent to the request but not the actual request.

When to use

• Multi-step tasks (3+ requirements)
• Tasks where the user gave specific constraints (file paths, function names, edge cases)
• After tool failures or pivots — make sure the original goal still holds

How

1. Quote the original request back, verbatim.
2. For each verb / requirement, mark: done, partial, missing.
3. For each partial or missing item, do the work now.
4. Only after the list is all done, stop.

Never claim a task is complete based on intent. Only based on verified state — files that exist, tests that pass, output that was actually produced.