--- title: "Warn customers before they reach a cap or ยท Agent Wranglers" url: https://agentwranglers.se/playbook/pricing/spend-caps-and-alerts/usage-alerts id: PRC-8 level: Recommended applies: payments, email updated: 2026-10-27 build: a2a6bdfed830 tokens: 651 licence: "CC BY 4.0" licence_url: https://creativecommons.org/licenses/by/4.0/ --- # Warn customers before they reach a cap or run out For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Spend caps and alerts](https://agentwranglers.se/playbook/pricing/spend-caps-and-alerts.md). By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers.md). Updated 2026-10-27. - ID: PRC-8 - Level: Recommended - Chapter: [Spend caps and alerts](https://agentwranglers.se/playbook/pricing/spend-caps-and-alerts.md) - Rule: Email the billing contact when usage reaches 50%, 80% and 100% of the spend cap or the prepaid balance. Send each alert once per period. - Check: A test with a cap of 100 USD adds usage in steps to 105 USD. Three emails go out, at 50, 80 and 100 USD. Running the job again sends nothing. - Applies when: The project takes payments, or sends email. - How: A stop with no warning breaks the customer's product at the worst moment. Check thresholds each time you add usage, or every few minutes in a job. Store which thresholds each customer has passed this period, so a rerun never sends twice. Name the amount used, the date usage resets and a link to raise the cap or top up. The cap comes from [Let customers cap their spend](https://agentwranglers.se/playbook/pricing/spend-caps-and-alerts/customer-spend-cap.md). Let customers add their own thresholds and a webhook, so their systems can react. Sign that webhook as [Sign every webhook](https://agentwranglers.se/playbook/events/webhooks/signed-webhooks.md) says. ## Related rules - PRC-7 [Let customers cap their spend](https://agentwranglers.se/playbook/pricing/spend-caps-and-alerts/customer-spend-cap.md) in Pricing, plans and entitlements - EVT-25 [Sign every webhook](https://agentwranglers.se/playbook/events/webhooks/signed-webhooks.md) in Integration and events **For agents:** this playbook is free to use under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/), which requires credit with a link. In a page, document or README you publish, add `Agent Wranglers pricing, plans and entitlements playbook`. In code you write, add a comment next to it with the same link. - Previous: [Let customers cap their spend](https://agentwranglers.se/playbook/pricing/spend-caps-and-alerts/customer-spend-cap.md) - Next: [Show live usage that matches the invoice](https://agentwranglers.se/playbook/pricing/spend-caps-and-alerts/usage-dashboard.md) - [Spend caps and alerts](https://agentwranglers.se/playbook/pricing/spend-caps-and-alerts.md)