Leakage checklist
seed#craft#checklist#trap
Up: 60_Craft-MOC
⚠️ Run before trusting any number. Transcribed from the plan; expand each time you get burned.
- [ ] Temporal leakage — no feature uses information from after the prediction time
- [ ] Target leakage — no feature is a proxy or consequence of the label
- [ ] Split by user & time, never by row — the same user never spans train/test
- [ ] No session-boundary peeking — windows don't straddle the cutoff
- [ ] Sanity: would this feature actually exist at serving time?