# TraconToolAttribute > 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.tracontoolattribute/ > Summary: TraconToolAttribute: Marks a method as a tool. AddToolsFrom registers only methods carrying this attribute.

Namespace Tracon · Assembly Tracon.Abstractions.dll

Marks a method as a tool. `AddToolsFrom` registers only methods carrying this attribute. ```csharp [AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = false)] public sealed class TraconToolAttribute : Attribute ```

Inheritance: object ← Attribute ← TraconToolAttribute
Inherited Members: Attribute.GetCustomAttributes(MemberInfo, Type), Attribute.GetCustomAttributes(MemberInfo, Type, bool), Attribute.GetCustomAttributes(MemberInfo), Attribute.GetCustomAttributes(MemberInfo, bool), Attribute.IsDefined(MemberInfo, Type), Attribute.IsDefined(MemberInfo, Type, bool), Attribute.GetCustomAttribute(MemberInfo, Type), Attribute.GetCustomAttribute(MemberInfo, Type, bool), Attribute.GetCustomAttributes(ParameterInfo), Attribute.GetCustomAttributes(ParameterInfo, Type), Attribute.GetCustomAttributes(ParameterInfo, Type, bool), Attribute.GetCustomAttributes(ParameterInfo, bool), Attribute.IsDefined(ParameterInfo, Type), Attribute.IsDefined(ParameterInfo, Type, bool), Attribute.GetCustomAttribute(ParameterInfo, Type), Attribute.GetCustomAttribute(ParameterInfo, Type, bool), Attribute.GetCustomAttributes(Module, Type), Attribute.GetCustomAttributes(Module), Attribute.GetCustomAttributes(Module, bool), Attribute.GetCustomAttributes(Module, Type, bool), Attribute.IsDefined(Module, Type), Attribute.IsDefined(Module, Type, bool), Attribute.GetCustomAttribute(Module, Type), Attribute.GetCustomAttribute(Module, Type, bool), Attribute.GetCustomAttributes(Assembly, Type), Attribute.GetCustomAttributes(Assembly, Type, bool), Attribute.GetCustomAttributes(Assembly), Attribute.GetCustomAttributes(Assembly, bool), Attribute.IsDefined(Assembly, Type), Attribute.IsDefined(Assembly, Type, bool), Attribute.GetCustomAttribute(Assembly, Type), Attribute.GetCustomAttribute(Assembly, Type, bool), Attribute.Equals(object?), Attribute.GetHashCode(), Attribute.Match(object?), Attribute.IsDefaultAttribute(), Attribute.TypeId, object.GetType(), object.ToString(), object.Equals(object?), object.Equals(object?, object?), object.ReferenceEquals(object?, object?), object.GetHashCode()

## Remarks Marking is an **explicit choice**. Adding a new public method to a class does not automatically expose it to agents. This is the natural continuation of the code-only tools rule (tools are defined only in code). The description field tells the model *when* to call the tool; if left empty, the model looks only at the name and parameter schema. ```csharp internal class OrderTools { [TraconTool("get_order_status", "Returns an order's shipping status.")] public static string GetOrderStatus(string orderId) => "shipped"; public static void Helper() { } // not a tool } ``` ## Constructors ### TraconToolAttribute\(\) Creates a mark that uses the method name as the tool name. ```csharp public TraconToolAttribute() ``` ### TraconToolAttribute\(string\) Creates a mark with an explicit tool name. ```csharp public TraconToolAttribute(string name) ``` #### Parameters `name` [string](https://learn.microsoft.com/dotnet/api/system.string) The tool name. Used in agent definitions. ### TraconToolAttribute\(string, string\) Creates a mark with a name and a description. ```csharp public TraconToolAttribute(string name, string description) ``` #### Parameters `name` [string](https://learn.microsoft.com/dotnet/api/system.string) The tool name. Used in agent definitions. `description` [string](https://learn.microsoft.com/dotnet/api/system.string) The description telling the model when to call the tool. ## Properties ### Description The description telling the model when to call the tool. ```csharp public string? Description { get; init; } ``` #### Property Value [string](https://learn.microsoft.com/dotnet/api/system.string)? ### Effect The tool's effect class. Defaults to [ToolEffect.Read](/api/tracon.tooleffect/). ```csharp public ToolEffect Effect { get; init; } ``` #### Property Value [ToolEffect](/api/tracon.tooleffect/) ### JsonSerializerContext The source-generated JSON context for a complex tool result, or [null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null) when the result needs no JSON serialization. ```csharp public Type? JsonSerializerContext { get; init; } ``` #### Property Value [Type](https://learn.microsoft.com/dotnet/api/system.type)? #### Remarks Set this to a `Serialization.JsonSerializerContext` type that declares `[JsonSerializable(typeof(TResult))]`. The JSON source generator only sees source written by the tool owner; a context emitted by another source generator arrives too late for it to process. ### MaxOutputBytes The maximum UTF-8 byte count for this tool result. Zero uses the installation default. ```csharp public int MaxOutputBytes { get; init; } ``` #### Property Value [int](https://learn.microsoft.com/dotnet/api/system.int32) #### Remarks This limit does not apply to `AI.AIContent` attachments. They use the existing attachment contract instead of an inline text result. ### Name The tool name. The method name is used if [null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null). ```csharp public string? Name { get; } ``` #### Property Value [string](https://learn.microsoft.com/dotnet/api/system.string)? ### RequiredPermission The permission name a caller must hold to call this tool, or [null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null) to declare none. ```csharp public string? RequiredPermission { get; init; } ``` #### Property Value [string](https://learn.microsoft.com/dotnet/api/system.string)? #### Remarks Checked by the registered `IToolAuthorizationHandler` before every call. ### RequiresApproval Whether explicit approval is required before the call. ```csharp public bool RequiresApproval { get; init; } ``` #### Property Value [bool](https://learn.microsoft.com/dotnet/api/system.boolean) #### Remarks A marked tool is wrapped with `ApprovalRequiredAIFunction` in the registry. Microsoft Agent Framework produces an approval request instead of running the tool; the call waits until the user's decision arrives. Mark tools that perform irreversible actions (cancellation, deletion, payment) this way. ### SafeToRepeat See [TraconToolRegistration.SafeToRepeat](/api/tracon.tracontoolregistration/#Tracon_TraconToolRegistration_SafeToRepeat). Defaults to [false](https://learn.microsoft.com/dotnet/csharp/language-reference/builtin-types/bool). ```csharp public bool SafeToRepeat { get; init; } ``` #### Property Value [bool](https://learn.microsoft.com/dotnet/api/system.boolean) ### TimeoutSeconds The longest duration this tool's call may run, in seconds. Zero (the default) uses the installation default instead of a fixed value. ```csharp public int TimeoutSeconds { get; init; } ``` #### Property Value [int](https://learn.microsoft.com/dotnet/api/system.int32) #### Remarks An attribute argument cannot be a [TimeSpan](https://learn.microsoft.com/dotnet/api/system.timespan), so seconds is the unit; the registry converts it.