AI products are moving from flat subscriptions to usage-based and outcome-based billing: per-resolution support agents, premium request quotas, per-token gateway billing. Every one of those numbers is produced by a meter, and the meter is usually the vendor's own. We spent the last month auditing the open-source side of that world — 110 tools that count tokens, track costs, or enforce budgets — and this post is the field report. The short version: 45+ verified bugs, five recurring families, ...