# TraconProviderUnavailableException > 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.traconproviderunavailableexception/ > Summary: TraconProviderUnavailableException: Thrown when the circuit breaker has temporarily taken a model provider out of service.
Namespace Tracon · Assembly Tracon.Abstractions.dll
Thrown when the circuit breaker has temporarily taken a model provider out of service. ```csharp public sealed class TraconProviderUnavailableException : TraconException, ISerializable ```
Inheritance
object ← Exception ← TraconException ← TraconProviderUnavailableException
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 Thrown while the circuit is `Open`; **no request reaches the provider**. The circuit opens once consecutive failures pass `FailureThreshold`, and moves to half-open for a single trial after `BreakDuration`. ## Constructors ### TraconProviderUnavailableException\(\) Creates a new error. ```csharp public TraconProviderUnavailableException() ``` ### TraconProviderUnavailableException\(string\) Creates a new error. ```csharp public TraconProviderUnavailableException(string message) ``` #### Parameters `message` [string](https://learn.microsoft.com/dotnet/api/system.string) The error message. ### TraconProviderUnavailableException\(string, Exception\) Creates a new error. ```csharp public TraconProviderUnavailableException(string message, Exception innerException) ``` #### Parameters `message` [string](https://learn.microsoft.com/dotnet/api/system.string) The error message. `innerException` [Exception](https://learn.microsoft.com/dotnet/api/system.exception) The underlying error. ## Fields ### ProviderUnavailableErrorType The stable value written to [TraconException.ErrorType](/api/tracon.traconexception/#Tracon_TraconException_ErrorType). ```csharp public const string ProviderUnavailableErrorType = "provider_unavailable" ``` #### 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**. ### ProviderName Gets the name of the provider whose circuit is open. ```csharp public string? ProviderName { get; init; } ``` #### Property Value [string](https://learn.microsoft.com/dotnet/api/system.string)? ### RetryAfter Gets the time at which the circuit goes half-open and is retried. ```csharp public DateTimeOffset? RetryAfter { get; init; } ``` #### Property Value [DateTimeOffset](https://learn.microsoft.com/dotnet/api/system.datetimeoffset)?