Usage and billing

Advisor calls run as a separate sub-inference billed at the advisor model's rates. Usage is reported in the usage.iterations[] array:

{
  "usage": {
    "input_tokens": 1760,
    "cache_read_input_tokens": 412,
    "cache_creation_input_tokens": 0,
    "output_tokens": 531,
    "iterations": [
      {
        "type": "message",
        "input_tokens": 412,
        "cache_read_input_tokens": 0,
        "cache_creation_input_tokens": 0,
        "output_tokens": 89
      },
      {
        "type": "advisor_message",
        "model": "claude-opus-5",
        "input_tokens": 823,
        "cache_read_input_tokens": 0,
        "cache_creation_input_tokens": 0,
        "output_tokens": 1612
      },
      {
        "type": "message",
        "input_tokens": 1348,
        "cache_read_input_tokens": 412,
        "cache_creation_input_tokens": 0,
        "output_tokens": 442
      }
    ]
  }
}

Top-level usage fields reflect executor tokens only. Advisor tokens are not rolled into the top-level totals because they are billed at a different rate. Iterations with type: "advisor_message" are billed at the advisor model's rates, and iterations with type: "message" are billed at the executor model's rates.

Every top-level usage field is the sum of that field across all executor iterations, including input_tokens, output_tokens, and cache_read_input_tokens. Because each executor iteration re-sends the growing conversation, later iterations' inputs include earlier iterations' output, so summed input_tokens exceeds the size of any single prompt. Use usage.iterations for a full per-iteration breakdown when building cost-tracking logic.

Advisor output is typically 400 to 700 text tokens, or 1,400 to 1,800 tokens total including thinking. The cost savings come from the advisor not generating your full final output. The executor does that at its lower rate.

The top-level max_tokens applies to executor output only. It does not bound advisor sub-inference tokens. To cap advisor output directly, set max_tokens on the tool definition. The advisor's tokens also do not draw from any task budget applied to the executor.

Priority Tier applies to each model independently. A Priority Tier commitment on the executor model does not extend to the advisor. Advisor calls run at Priority Tier only if your organization also holds a commitment on the advisor model.