# TraconSessionConflictException > 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.traconsessionconflictexception/ > Summary: TraconSessionConflictException: Thrown for the losing request when two concurrent first requests arrive for the same new session id.
Namespace Tracon · Assembly Tracon.Abstractions.dll
Thrown for the losing request when two concurrent first requests arrive for the same new session id. ```csharp public sealed class TraconSessionConflictException : TraconException, ISerializable ```
Inheritance
object ← Exception ← TraconException ← TraconSessionConflictException
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 while creating a new session, `AgentSessionManager.GetOrCreateSessionAsync` attempts an atomic insert through `ISessionStore.TryCreateAsync`. When a concurrent second request for the same id loses that attempt, it cannot know whether the winner's chat history provider has produced its conversation id yet — that id is produced only while the winner's first turn runs. Had the loser run its own turn anyway, it would have produced its own conversation id and the following save would have silently overwritten the winner's state; that was the actual defect. So the loser gets an explicit conflict error instead; a retry takes the normal (race-free) path and finds the winner's record already in place. ## Constructors ### TraconSessionConflictException\(\) Creates a new error. ```csharp public TraconSessionConflictException() ``` ### TraconSessionConflictException\(string\) Creates a new error. ```csharp public TraconSessionConflictException(string message) ``` #### Parameters `message` [string](https://learn.microsoft.com/dotnet/api/system.string) The error message. ### TraconSessionConflictException\(string, Exception\) Creates a new error. ```csharp public TraconSessionConflictException(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 ### SessionConflictErrorType The stable value written to [TraconException.ErrorType](/api/tracon.traconexception/#Tracon_TraconException_ErrorType). ```csharp public const string SessionConflictErrorType = "session_conflict" ``` #### 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**. ### SessionId Gets the id of the conflicting session. ```csharp public string? SessionId { get; init; } ``` #### Property Value [string](https://learn.microsoft.com/dotnet/api/system.string)?