--- title: "Alert when a customer costs more than they ยท Agent Wranglers" url: https://agentwranglers.se/playbook/usage-billing/margins-and-model-cost/customer-margin-alert id: USG-13 level: Recommended applies: payments, ai-features updated: 2026-10-22 tokens: 615 licence: "CC BY 4.0" licence_url: https://creativecommons.org/licenses/by/4.0/ --- # Alert when a customer costs more than they pay For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Margins and model cost](https://agentwranglers.se/playbook/usage-billing/margins-and-model-cost.md). By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers.md). Updated 2026-10-22. - ID: USG-13 - Level: Recommended - Chapter: [Margins and model cost](https://agentwranglers.se/playbook/usage-billing/margins-and-model-cost.md) - Rule: Every day, compare each customer's model and infrastructure cost for the period with what they will be billed. Alert when cost passes 80% of the bill. - Check: A test customer on a flat plan makes calls whose cost reaches 85% of the plan fee. The next daily run alerts with that customer's ID, cost and bill. A customer at 50% is not listed. - Applies when: The project takes payments, or uses AI models. - How: A plan can be priced well on average and still lose money on its heaviest users. Flat plans with "unlimited" use are the usual cause. Sum the cost rows per customer for the period so far. Compare them with the subscription fee plus metered charges to date. Send the list to the owner of pricing, with the customer, the cost and the bill. Fix it with a fair-use limit, a higher tier or a cap, as [Give each customer a fair share](https://agentwranglers.se/playbook/scaling/load-balancing-and-autoscaling/per-tenant-limits.md) describes for load. ## Related rules - SCL-31 [Give each customer a fair share](https://agentwranglers.se/playbook/scaling/load-balancing-and-autoscaling/per-tenant-limits.md) in Scaling **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 usage-based billing playbook`. In code you write, add a comment next to it with the same link. - Previous: [Keep every metered price above its cost](https://agentwranglers.se/playbook/usage-billing/margins-and-model-cost/margin-guard.md) - Next: [Recheck margins when a model or its price changes](https://agentwranglers.se/playbook/usage-billing/margins-and-model-cost/model-price-change.md) - [Margins and model cost](https://agentwranglers.se/playbook/usage-billing/margins-and-model-cost.md)