Setting a budget feels like control.
In reality, budgets only define how much damage is acceptable — not how to prevent it.
What Budget Limits Actually Do
Budgets:
- Track total spend
- Trigger alerts
- Stop usage after limits are exceeded
They do not:
- Evaluate individual requests
- Prevent large one-time costs
The Single-request Problem
A single request can:
- Use massive input
- Generate large output
- Consume the entire daily budget
Budgets react after this happens.
Why Granularity Matters
Effective control requires:
- Per-request limits
- Per-user limits
- Per-project limits
Granularity allows systems to stop unsafe actions early.
Combining Budgets with Request Guards
Budgets work best when combined with:
- Pre-flight cost estimation
- Max cost per request
- Rate limits
Budgets define boundaries.
Request guards enforce them.
Conclusion
Budgets are necessary but insufficient.
Without request-level enforcement, they offer visibility — not safety.
