In short
Set a per-action cap, a recurring cap and an approval rule, and make sure they are checked by the system, not by the AI's own judgement. A limit the model can talk itself past is not a limit.
Why prompts are not limits
Telling an AI "don't spend more than $20" is a request, not a control. Models misread instructions and can be manipulated by content they read. Real limits are checked by software before money is committed.
The three limits to set
- Per-action limit: the most a single tool use can cost.
- Recurring limit: the most a monthly tool can cost.
- Approval rule: which actions wait for you before they happen.
Where to enforce them
Enforce limits where the cost is recorded. If the record refuses an entry above the limit, no part of the AI can exceed it.
Review regularly
Look at what was spent each week. Lower limits that are never reached; raise them only when a result justifies it.
How Maqron does it
Maqron checks per-action limits, balances and approvals inside its database before any tool cost is recorded. Usage credits are spent only on AI features inside Maqron and have no cash value.
Questions
Can an AI agent overspend if I set a limit in the prompt?
Yes. Prompt instructions can be ignored or overridden. Use limits enforced by the system that records the cost.
What is a good starting per-action limit?
Start low, around the price of the cheapest useful tool you expect the AI to use, and raise it only after reviewing results.