What is a Spend Cap?
A spend cap is a hard ceiling on what an agent may spend — per transaction, per day, or per month.
The kinds of caps
Per-transaction: the largest single purchase allowed.
Per-period: daily, weekly, or monthly ceilings.
Per-category: caps on inference, data, tools, payments.
Why caps matter
They bound the worst case — the audit log can't stop a runaway, a cap can.
The tuning loop
Set from actuals × 1.5, then tighten with audit-log data.
FAQ
What's a good starting cap?
Recent actuals × 1.5, then tighten.
Do caps slow agents?
No — they only stop spend beyond the budget.
Related
Stop the next $12,400 night.
One API call (or MCP tool) in front of every agent transaction — APPROVED, BLOCKED, or FLAGGED, deterministic, ~5 ms, fully logged.
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