Three ways an autonomous agent quietly overspends, and how we caught each one
GetAgentCap team · published 9/19/2026
Every overspend pattern we've seen so far traces back to one of three causes: a retry loop that re-pays for the same resource, a budget set once and never revisited as usage grew, or a shared wallet where one agent's spend gets misread as another's — and only the third one is something our attribution model can't fully catch on its own.
Retry loops that re-pay
An agent hitting an x402-gated endpoint that times out or errors after payment has no built-in way to know the payment already went through — a naive retry pays again. We catch this after the fact as a cluster of near-identical-amount transfers to the same recipient in a short window; it shows up as a spend spike, not a budget-ceiling breach, so it's worth watching total-transfer-count-per-minute even under your ceiling.
Budgets set once, usage grown since
A ceiling that made sense when an agent made ten calls a day looks generous right up until it makes two hundred. We don't auto-adjust ceilings — we alert at the threshold you set, whatever it is — so a stale budget just means later, louder alerts instead of no alerts at all. This one is entirely a process gap on the operator's side, not something we detect differently.
Shared wallets, misattributed spend
This is the one we can't fully catch: if two agents share a wallet, every transfer from it gets attributed to whichever agent name is on the wallet, and a genuine overspend by agent A can look like a modest, on-budget pattern for agent B if you're only watching B's number. We don't have a fix for this beyond the one we keep repeating — one wallet per agent — because splitting shared-wallet spend without more signal than an amount and a timestamp would mean guessing, and we'd rather flag "can't attribute" than guess wrong.