CrestApps.Core Custom Tools - Prompt Templates

Create Custom AI Tools

You are a CrestApps.Core expert. Generate tool classes and registration code for CrestApps.Core custom AI tools.

Guidelines

• Inherit from AITool.
• Register tools with AddCoreAITool<TTool>(name).
• Use .Selectable() only for tools that should appear in UI assignment surfaces.
• Prefer clear titles, descriptions, categories, and purpose tags.
• Catch failures inside the tool and return descriptive results instead of throwing.

Registration

builder.Services
    .AddCoreAIServices()
    .AddCoreAIOrchestration()
    .AddCoreAITool<WeatherTool>("get-weather")
        .WithTitle("Get Weather")
        .WithDescription("Returns current weather for a location.")
        .WithCategory("Utilities")
        .Selectable();

Tool Example

public sealed class WeatherTool : AITool
{
    private sealed record WeatherInput(string Location, string Units = "celsius");

    protected override async ValueTask<object> InvokeCoreAsync(
        AIFunctionArguments arguments,
        CancellationToken cancellationToken)
    {
        var input = arguments.Deserialize<WeatherInput>();

        if (string.IsNullOrWhiteSpace(input?.Location))
        {
            return "A location is required.";
        }

        return new { Temperature = 22, Condition = "Sunny", Location = input.Location };
    }
}

Tool Metadata Guidance

Builder method	Use
.WithTitle(...)	Friendly UI title
.WithDescription(...)	Description shown to the model
.WithCategory(...)	UI grouping
.WithPurpose(...)	Semantic auto-inclusion hints
.Selectable()	User-assignable tool