This article explains drift budgets: a simple, absolute threshold that turns the DriftScore into an enforceable gate. It is for teams setting standards in CI and for leads who want a single number to govern by.
Overview
The DriftScore (DriftScore) runs from 0 to 100, where lower means less drift. A drift budget is the maximum DriftScore you are willing to accept. When a scan exceeds the budget, the run can fail, which makes the budget a clear, objective quality gate.
Setting a budget
Apply a budget on a scan with the --drift-budget flag:
vg scan --drift-budget 60
Here, a DriftScore at or under 60 is acceptable and a higher score signals the project has drifted beyond your tolerance.
Budgets vs. baselines
- A drift budget is an absolute ceiling on the DriftScore. It answers "how much total drift is allowed?"
- A baseline measures change from a snapshot. It answers "did this change make things worse?"
The two work well together: use a budget to cap total drift and a baseline with worsening checks to stop new regressions. For the relative approach, see:
vg scan --baseline .vibgrate/baseline.json --drift-worsening
Choosing a budget
Start with a budget near your current DriftScore so the build passes today, then tighten it over time as you reduce drift. A budget you can never meet gets ignored; a budget just below today's score creates steady, achievable pressure.
Related
See the DriftScore explainer for how the score is calculated, the baseline guides for relative gating, and the exit codes reference for wiring budgets into CI.