01
Paste the admin key
OpenAI organization admin, Anthropic org admin, or an OpenRouter management key. About two minutes. No SDK, no base URL, no proxy.
AI agent spend guard
Your AI bill has a bedtime.
Catch a runaway AI agent in minutes, not on your invoice. Built for indie devs and agencies who already ship agents and do not want another proxy in the path.
No card for the free tier. Prompts never touch BillCurfew.
No proxy. Requests still go straight to the provider.
No code change. Paste a management key. Leave the SDK alone.
No prompt access. We read usage and dollars, never the conversation.
Lights out, on a schedule you pick
02
Set a bedtime
A daily dollar cap per key, and a spike rule: if spend in M minutes jumps past N times the recent baseline, that’s a loop.
03
We knock, or we cut the lights
Email and Slack fire on the five-minute poll. Auto-kill is optional. OpenAI deletion is permanent and stays off until you say so.
The other tools sit in the request. We don’t.
Helicone, Portkey, Requesty, and LiteLLM earn their keep by being the path the prompt takes. That is useful for logs and routing. It is the wrong shape when the only job is “this agent is spending like it forgot to sleep.”
| Gateway / proxy | BillCurfew | |
|---|---|---|
| Sees prompts | Yes, that’s the product | No |
| Code or base URL change | Required | None |
| Stops the next token | Can, because it is in path | No — we act on the next poll |
| Kills a key the provider already issued | Usually no | Yes, with a confirm |
| Setup | SDK, proxy, or virtual key | Paste an admin key |
A free key, or a 14-day trial
Monthly USD. Checkout uses Stripe Tax code txcd_10103000 for SaaS. Stay on free if one key and email is enough.
Questions worth asking before you paste a key
Put the invoice on a curfew.
One provider, one key, email alerts. Upgrade when the roster grows.