Levee / Learn / AI agent cost controls
AI agent cost controls: budgets for tokens, tool calls and purchases
"Agent spend" means three different things. Controlling one doesn't control the others.
Short answer: AI agent costs split into model tokens, tool and API calls, and purchases with real money. Control tokens with per-run budgets, iteration caps and gateway limits. Control tool calls with rate limits and quotas. Control purchases with a human-approved mandate checked at payment authorization, outside the agent. Add alerts and a hard stop to each, because an agent that loops will not stop itself.
The three kinds of agent cost
1. Model tokens
Every reasoning step, retry and long context is billed by usage. This is the cost most teams notice first, because an agent that loops can burn through a month of budget in a night. It is billed by your model provider, so the control sits at the provider or a gateway in front of it.
2. Tool and API calls
Agents call search, data, code-execution and SaaS APIs, many of them metered. A runaway agent can hit a paid endpoint thousands of times. Control it with quotas and rate limits on each tool, ideally enforced by the tool or gateway rather than the agent.
3. Purchases with real money
Some agents buy things: SaaS seats, ads, travel, supplies, API credits. This is a different risk. Tokens are a usage bill, while a purchase is money leaving an account to a merchant. It needs a control that decides whether each payment matches what a person approved. See AI agent spend controls.
Controls that work for token and call costs
- Per-run budgets. A maximum token and call count for one task, after which the run stops.
- Iteration and depth caps. Limit loops, retries, sub-agents and context size.
- Per-key or per-project limits. Give each agent its own key so one agent can't consume the shared budget.
- Model routing. Send simple steps to cheaper models and reserve large models for hard ones.
- Caching. Reuse results for repeated calls.
- Alerts on anomalies. Notify on spend rate, not just monthly totals.
- Hard stops. A kill switch that ends the run, enforced outside the agent.
Why the control must sit outside the agent
An agent told to "stay under budget" is following a request, not a control. It can misjudge, be confused by its inputs or be steered by hostile text. Limits that matter should be enforced by a gateway, a provider setting or an authorization step the agent can't change. The same logic applies to money, as explained in how to stop an AI agent overspending.
A simple budget model
Give each agent task a ceiling for each kind of cost. For example: a token budget per run, a call quota per tool per day, and, if it can buy anything, a purchase mandate naming the purpose, merchants, total amount and end date. Review the three together, since a cheap token bill can sit beside an expensive purchase mistake.
Where Levee fits
Levee is the authorization layer for AI agent spend. Levee lets a human approve what an agent may spend, enforces it at the moment of card authorization, outside the agent, and keeps tamper-evident proof of every decision. It covers the third kind of cost, purchases, and does not meter tokens or API calls. Levee is not a card issuer and never holds or moves money. Cards are issued by a provider such as Airwallex. For how purchase controls compare, read AI agent spend control tools compared, and for the injection angle, limit the damage from prompt-injected purchases.
Frequently asked questions
What are AI agent cost controls?
They are the limits, budgets and alerts that keep an agent's spending predictable. They cover model usage (tokens), tool and API calls, and purchases such as cards or payments, and each kind is controlled in a different place.
How do I cap token spend for an AI agent?
Set per-run and per-day token budgets, cap loop iterations and context size, route routine steps to cheaper models, and alert on anomalies. Many LLM gateways and observability tools support budgets and alerts per key, team or project.
Why can an agent's costs spiral?
Agents loop, retry and call tools on their own. A bug, a vague goal or hostile input can multiply calls many times over. Without a hard stop outside the agent, nothing ends the run until a person notices the bill.
Are token budgets enough to control what an agent spends?
No. Token budgets control model usage only. When an agent can pay for things with a card or wallet, the purchases need a separate control that checks each payment against what a human approved.
Does Levee control token or LLM costs?
No. Levee does not meter model tokens. Levee is the authorization layer for agent purchases: it checks each card payment at authorization, outside the agent, against a human-approved mandate. Levee is not a card issuer and never holds or moves money.
Related
Levee is running a free design partner pilot for platforms putting AI agents in charge of spend.
Become a design partner