tracer-bullets
Installation
SKILL.md
Tracer Bullets
Build features as vertical slices through all layers, verifying each slice before starting the next. From The Pragmatic Programmer: get feedback as quickly as possible. Don't build horizontal layers in isolation (all endpoints, then all UI, then all tests). Build one thin vertical path, verify it works, then expand.
Skip for single-layer changes, one-file bug fixes, or work already decomposed into ordered vertical slices by a task tracker.
Quick Reference
| Principle | Practice |
|---|---|
| Vertical over horizontal | Build one slice through all layers, not one layer across all features |
| Verify before advancing | Tests pass, page renders, round-trip works before next slice |
| One slice per session | Each slice should be completable in a single agent session |
| First feature sets pattern | First CRUD establishes conventions; subsequent CRUDs go faster |
| Check before building | Task trackers may already decompose the work into slices |
| Skip when trivial | Single-layer work or proven patterns don't need this ceremony |