# ToolUsageUnits

> 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/api/tracon.toolusageunits/
> Summary: ToolUsageUnits: The known unit names for ToolCallUsage.Unit.

<div class="api-provenance">Namespace Tracon · Assembly <code>Tracon.Abstractions.dll</code></div>

The known unit names for [ToolCallUsage.Unit](/api/tracon.toolcallusage/#Tracon_ToolCallUsage_Unit).

```csharp
public static class ToolUsageUnits
```

<dl class="api-relations"><dt>Inheritance</dt><dd><a href="https://learn.microsoft.com/dotnet/api/system.object">object</a> ← <a href="/api/tracon.toolusageunits/">ToolUsageUnits</a></dd><dt>Inherited Members</dt><dd><a href="https://learn.microsoft.com/dotnet/api/system.object.gettype">object.GetType()</a>, <a href="https://learn.microsoft.com/dotnet/api/system.object.memberwiseclone">object.MemberwiseClone()</a>, <a href="https://learn.microsoft.com/dotnet/api/system.object.tostring">object.ToString()</a>, <a href="https://learn.microsoft.com/dotnet/api/system.object.equals#system-object-equals(system-object)">object.Equals(object?)</a>, <a href="https://learn.microsoft.com/dotnet/api/system.object.equals#system-object-equals(system-object-system-object)">object.Equals(object?, object?)</a>, <a href="https://learn.microsoft.com/dotnet/api/system.object.referenceequals">object.ReferenceEquals(object?, object?)</a>, <a href="https://learn.microsoft.com/dotnet/api/system.object.gethashcode">object.GetHashCode()</a></dd></dl>

## Remarks

The list is **not** closed: the field is free text, and a
tool may report its own unit. These constants only keep the names
Tracon's own tools use in one place.

## Fields

### <a id="Tracon_ToolUsageUnits_Calls"></a> Calls

Calls. Used when a provider bills a hosted tool, such as a web search, by the call.

```csharp
public const string Calls = "calls"
```

#### Field Value

 [string](https://learn.microsoft.com/dotnet/api/system.string)

### <a id="Tracon_ToolUsageUnits_Characters"></a> Characters

Characters. Used in text-to-speech generation.

```csharp
public const string Characters = "characters"
```

#### Field Value

 [string](https://learn.microsoft.com/dotnet/api/system.string)

### <a id="Tracon_ToolUsageUnits_Images"></a> Images

Generated images. Used when an image provider bills per image.

```csharp
public const string Images = "images"
```

#### Field Value

 [string](https://learn.microsoft.com/dotnet/api/system.string)

### <a id="Tracon_ToolUsageUnits_Seconds"></a> Seconds

Seconds. Used in speech-to-text conversion.

```csharp
public const string Seconds = "seconds"
```

#### Field Value

 [string](https://learn.microsoft.com/dotnet/api/system.string)

### <a id="Tracon_ToolUsageUnits_Tokens"></a> Tokens

Tokens. Used when an image provider bills image generation by output tokens, and by the knowledge search for
the input tokens of the query it embeds.

```csharp
public const string Tokens = "tokens"
```

#### Field Value

 [string](https://learn.microsoft.com/dotnet/api/system.string)