# TraconPreflightOptions

> 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.traconpreflightoptions/
> Summary: TraconPreflightOptions: Defines options for the pre-flight context-window check.

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

Defines options for the pre-flight context-window check.

```csharp
public sealed class TraconPreflightOptions
```

<dl class="api-relations"><dt>Inheritance</dt><dd><a href="https://learn.microsoft.com/dotnet/api/system.object">object</a> ← <a href="/api/tracon.traconpreflightoptions/">TraconPreflightOptions</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.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 check estimates prompt token count before a run starts and rejects the
call, with no model provider ever contacted, once the estimate exceeds the
model's context window. The estimate is approximate: counting a
prompt's tokens without the provider's own tokenizer can only approximate
the real count, and a wrong count either rejects a call that would have
succeeded or lets through one that would have failed.

**Disabled by default**: a false rejection stops a
working agent, and that risk must be opted into, not discovered in production.

## Constructors

### <a id="Tracon_TraconPreflightOptions__ctor"></a> TraconPreflightOptions\(\)

```csharp
public TraconPreflightOptions()
```

## Properties

### <a id="Tracon_TraconPreflightOptions_Enabled"></a> Enabled

Gets or sets whether the pre-flight context-window check runs.
Disabled by default.

```csharp
public bool Enabled { get; set; }
```

#### Property Value

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

### <a id="Tracon_TraconPreflightOptions_ReserveRatio"></a> ReserveRatio

Gets or sets the share of the context window kept free for the answer,
from 0 to 1. Defaults to 0.2 (20%).

```csharp
public double ReserveRatio { get; set; }
```

#### Property Value

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

#### Remarks

A fixed token count would need updating for every new model; a ratio
scales with the model's own window automatically.