# ToolCallUsage

> Tracon documentation. Tracon is a .NET package family that adds a control
> plane on Microsoft Agent Framework, published as NuGet packages that run
> inside your own ASP.NET Core application.
>
> Page: https://tracon.dev/http-api/schemas/toolcallusage/
> Summary: OpenAPI request or response schema for ToolCallUsage, including required fields, defaults, constraints, and linked nested types.

[← All HTTP schemas](/http-api/schemas/)

A non-token measurement and its cost: one tool call's, or one item a
workflow function node reported.

**Shape:** `object`

| Property | Required | Type | Description | Rules |
|---|---|---|---|---|
| `unit` | yes | `string` | The measurement unit. See ToolUsageUnits for known values. | — |
| `quantity` | yes | `number (double)` | The billed quantity. | pattern `^-?(?:0\\|[1-9]\d*)(?:\.\d+)?$` |
| `cost` | no | `number (double)` | The computed amount. Stays `null` if the configuration has no price for this tool — <strong>not</strong> zero. | pattern `^-?(?:0\\|[1-9]\d*)(?:\.\d+)?$` |
| `currency` | no | `string` | The currency of `Cost`. Comes from `Tracon:Pricing:Currency` for Tracon's own tools. | — |
| `isEstimated` | no | `boolean` | Whether the quantity was measured or estimated. | — |
| `provider` | no | `string` | The provider that did the work (for example `elevenlabs`), or `null` when the reporter does not name one. | — |
| `model` | no | `string` | The model that did the work (for example `eleven_multilingual_v2`), or `null` when the reporter does not name one. | — |