Scenario: The Overnight Runaway
It's 2:14 AM. An agent hits a rate limit, retries the purchase 40 times, buys compute from an unknown vendor, and tips an API into overage. You wake up to $12,400.
The sequence
2:14 — rate limit; retries begin.
2:15 — purchase from an unknown vendor.
2:31 — overage tier triggered.
9:03 — you find out from Stripe.
What happens with sipi.bot
Retry #11 exceeds the velocity limit → BLOCKED.
Unknown vendor not on the allowlist → BLOCKED.
$2,200 over the approval threshold → FLAGGED for review.
Time-of-day rule: overnight purchases wait for a human.
The rule set
Velocity limit + merchant allowlist + approval threshold + time-of-day rule.
The log you'd see
02:14:21 BLOCKED velocity limit (retry #11) $4,000 compute-vendor
02:15:03 BLOCKED merchant not on allowlist $6,200 unknown-gpu.ru
02:31:47 FLAGGED over approval threshold $2,200 api-overage
09:03:00 APPROVED (after human review) $150 approved-vendorOne clean log instead of one Stripe panic.
FAQ
Is this scenario real?
It's the founder story — the incident that inspired sipi.bot, documented in the blog and eval report.
Would a time-of-day rule block all overnight work?
Only unattended spend — set it to flag overnight purchases for review rather than hard-blocking.
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.
See plans — from $99/mo Try a live check