# TraconOutputTruncatedException > 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.traconoutputtruncatedexception/ > Summary: TraconOutputTruncatedException: Thrown when the model stops at its output token limit before a structured (JSON) response is complete.
Namespace Tracon · Assembly Tracon.Abstractions.dll
Thrown when the model stops at its output token limit before a structured (JSON) response is complete. ```csharp public sealed class TraconOutputTruncatedException : TraconException, ISerializable ```
Inheritance
object ← Exception ← TraconException ← TraconOutputTruncatedException
Implements
ISerializable
Inherited Members
TraconException.ErrorType, Exception.GetBaseException(), Exception.ToString(), Exception.GetType(), Exception.TargetSite, Exception.Message, Exception.Data, Exception.InnerException, Exception.HelpLink, Exception.Source, Exception.HResult, Exception.StackTrace, object.GetType(), object.ToString(), object.Equals(object?), object.Equals(object?, object?), object.ReferenceEquals(object?, object?), object.GetHashCode()
## Remarks The run fails with error type `output_truncated`, classified as [RunErrorClass.OutputTruncated](/api/tracon.runerrorclass/). A cut-off JSON document cannot be parsed, and asking the model again with the same limit cuts it off again, so no structured-response repair turn runs. Raise [ModelBinding.MaxOutputTokens](/api/tracon.modelbinding/#Tracon_ModelBinding_MaxOutputTokens) instead. Detection lives in the same shared `IChatClient` decorator that detects a provider's content filter, so every provider that reports `ChatFinishReason.Length` gets the same behaviour. A plain-text response cut off the same way does not throw this exception; its run records a [RunEventCustomTypes.OutputTruncated](/api/tracon.runeventcustomtypes/#Tracon_RunEventCustomTypes_OutputTruncated) event instead. The message names the provider and the limit. It never carries the response text. ## Constructors ### TraconOutputTruncatedException\(\) Creates a new error. ```csharp public TraconOutputTruncatedException() ``` ### TraconOutputTruncatedException\(string\) Creates a new error. ```csharp public TraconOutputTruncatedException(string message) ``` #### Parameters `message` [string](https://learn.microsoft.com/dotnet/api/system.string) The error message. Must not carry the response text. ### TraconOutputTruncatedException\(string, Exception\) Creates a new error. ```csharp public TraconOutputTruncatedException(string message, Exception innerException) ``` #### Parameters `message` [string](https://learn.microsoft.com/dotnet/api/system.string) The error message. Must not carry the response text. `innerException` [Exception](https://learn.microsoft.com/dotnet/api/system.exception) The underlying error. ## Fields ### OutputTruncatedErrorType The stable value written to [TraconException.ErrorType](/api/tracon.traconexception/#Tracon_TraconException_ErrorType). ```csharp public const string OutputTruncatedErrorType = "output_truncated" ``` #### Field Value [string](https://learn.microsoft.com/dotnet/api/system.string) ## Properties ### ErrorType Gets the stable error type name written to the run record. ```csharp public override string ErrorType { get; } ``` #### Property Value [string](https://learn.microsoft.com/dotnet/api/system.string) #### Remarks Defaults to the full name of the exception type, so today's behaviour does not change. A derived type overrides this member when the record has to be machine readable — for example [TraconContentFilteredException](/api/tracon.traconcontentfilteredexception/) writes `content_filtered`. Reports and alert rules can rely on this stable name instead of an assembly name. The value is written to `RunError.Type` and **carries no secret**. ### MaxOutputTokens Gets the output token limit the request set, or [null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null) when the binding set none and the provider applied its own default. ```csharp public int? MaxOutputTokens { get; init; } ``` #### Property Value [int](https://learn.microsoft.com/dotnet/api/system.int32)? ### ProviderName Gets the provider whose model stopped at the limit, or [null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null) when unknown. ```csharp public string? ProviderName { get; init; } ``` #### Property Value [string](https://learn.microsoft.com/dotnet/api/system.string)?