Watch one customer hit the brake.

One customer, one monthly budget. Cheaper model at the threshold; BudgetExceededError at the cap, before the provider call.

ControlsCustomer settings

Customer ID

Monthly budget

USD / month

Downgrade at 80%

Requested model

gpt-5.5gpt-5.4claude-opus-4-8

Downgrade to

gpt-5.4-minigpt-5.4-nanoclaude-haiku-4-5

Request type

Chat message≈600–2.2k input tokensLong-context summary≈8k–24k input tokens

“Send 10” stops early at the first blocked request.

This monthguard.status()

$0.0000of $0.10

80%: cheaper model100%: blocked

Normal

Provider calls0

Blocked (never sent)0

Downgraded calls0

Remaining$0.10

You've hit this month's AI limit. Upgrade for more.Upgrade

Example UI on BudgetExceededError. Spend can end slightly above budget (checked before, recorded after each call).

Usage-event logonUsage(event) · newest first

No requests yet. Click “Send request”.

CodeUpdates with your settings

Free · MIT · npm install llmbrake

Try it in your app.

Same library, your real provider and your own store.