Scope usage. group_by is meter (default), key or account; from and to are dates or timestamps, to exclusive. Each row is a sum, with how many events went into it:
Under group_by=account, a row with group: null is project-level usage that belongs to no account. A key bound to one account only sees that account’s usage.

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Meters and prices

Channels, webhooks, the twin layer and MCP have no meter. Simulated (sandbox) numbers and their texts record no usage. Text tokens. Each agent reply in a conversation records two rows: tokens_in (input, including cached input) and tokens_out (output, including reasoning), priced from the model the reply ran on. An agent that runs on your own model key records the same rows at no charge, so you can still see how many tokens it used. Hosted agents. A live project’s agent records one agent_month when it is created and once in each later month it exists. Your monthly spend across all meters, and the cap that limits it, is on Billing and spend caps. No free tier. Usage needs a card on file. A project without one, sandbox included, records no usage because billable requests are refused first with 402 payment_method_required (see Billing). Live Pay as you go and Growth usage is sent to Stripe and billed monthly; sandbox usage is recorded here but not charged.