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Use when implementing any feature or bugfix, before writing implementation code
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Based on SOC occupation classification
Use when doing any creative work — creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.
Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes
Use when you have a written implementation plan to execute with review checkpoints
Use when implementation is complete and all tests pass — guides completion by presenting structured options for merge, PR, or cleanup
Use when receiving code review feedback, before implementing suggestions — requires technical rigor and verification, not performative agreement
Use when completing tasks, implementing major features, or before merging to verify work meets requirements
| name | nobody-uses-tdd |
| description | Use when implementing any feature or bugfix, before writing implementation code |
Write the test first. Watch it fail. Write minimal code to pass.
Core principle: If you didn't watch the test fail, you don't know if it tests the right thing.
Violating the letter of the rules is violating the spirit of the rules.
NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST
Write code before the test? Delete it. Start over.
No exceptions:
Write one minimal test showing what should happen.
Run the test. Confirm:
Test passes? You're testing existing behavior. Fix the test.
Write the simplest code to pass the test. Nothing more.
Don't add features, refactor other code, or "improve" beyond the test.
Run the test. Confirm:
After green only. Remove duplication, improve names, extract helpers.
Keep tests green. Don't add behavior.
| Excuse | Reality |
|---|---|
| "Too simple to test" | Simple code breaks. Test takes 30 seconds. |
| "I'll test after" | Tests passing immediately prove nothing. |
| "Need to explore first" | Fine. Throw away exploration, start with TDD. |
| "Test hard = design unclear" | Listen to the test. Hard to test = hard to use. |
| "TDD will slow me down" | TDD is faster than debugging. |
| "Already manually tested" | Ad-hoc ≠ systematic. No record, can't re-run. |
| "Deleting X hours is wasteful" | Sunk cost fallacy. Keeping unverified code is debt. |
All of these mean: Delete code. Start over with TDD.
Never fix bugs without a test.