Why your AI bill keeps growing (and it's not the model)
The bill grows because of what agents do, not what models cost: tool fan-out, retry loops, context bloat, and ungoverned vendors. The five growth drivers and the five levers.
Month over month, the AI line grows — and the model rate card didn't change. The growth is in what agents do. Five drivers, five levers.
The five growth drivers
Tool fan-out: more agents × more tools × more calls. Retry loops: the same failure billed repeatedly. Context bloat: long sessions re-sending growing contexts. Ungoverned vendors: tools and data bought without review. Autonomy: unattended agents spending without a human moment.
The five levers
Ceilings bound the total. Velocity limits kill the loops. Allowlists govern the vendors. Category budgets separate inference from tools from payments. Approvals add the human moment where it matters. Set the budget →
The pattern
None of this is model-choice. That's why rate shopping alone never fixes the bill — and why the spend shape matters more than the rate card.