Interface IUnityMcpTool<TParams>

Generic interface for class-based MCP tools with strongly-typed parameters. Recommended for most tools as it provides automatic schema generation and type safety.

Namespace: Unity.AI.MCP.Editor.ToolRegistry
Assembly: Unity.AI.MCP.Editor.dll
Syntax
public interface IUnityMcpTool<TParams> where TParams : class
Type Parameters
Name Description
TParams

The strongly-typed parameter class or record. Must be a reference type with a parameterless constructor
Remarks

This interface automatically generates input schemas from the TParams type, eliminating the need for manual schema definition and parameter casting.

The parameter type should be a class or record with public properties decorated with McpDescriptionAttribute for better schema documentation.

Schema generation supports:

  • Primitive types (int, string, bool, etc.)
  • Enums (converted to string constraints)
  • Collections (arrays and lists)
  • Nested objects
  • Nullable types
  • Default values from property initializers

The class must have a parameterless constructor and be decorated with McpToolAttribute.

Examples
public class GreetParams
{
    [McpDescription("Name of person to greet", Required = true)]
    public string Name { get; set; }

    [McpDescription("Greeting style")]
    public string Style { get; set; } = "formal";
}

[McpTool("greet_person", "Greets a person with a message")]
public class GreetTool : IUnityMcpTool<GreetParams>
{
    public Task<object> ExecuteAsync(GreetParams parameters)
    {
        var greeting = parameters.Style == "formal"
            ? $"Good day, {parameters.Name}"
            : $"Hey {parameters.Name}!";

        return Task.FromResult<object>(new { message = greeting });
    }
}

Methods

ExecuteAsync(TParams)

Executes the tool asynchronously with strongly-typed parameters deserialized from the MCP client request.

Declaration
Task<object> ExecuteAsync(TParams parameters)
Parameters
Type Name Description
TParams parameters

Strongly-typed parameters deserialized from the MCP client request
Returns
Type Description
Task<object>

A task containing the tool execution result, which will be serialized to JSON. Can be an anonymous object, class instance, or primitive type
Remarks

Called on Unity's main thread. The parameters are automatically deserialized from JSON using Newtonsoft.Json with enum string conversion enabled. Return values are automatically serialized to JSON for the MCP response. For synchronous tools, return Task.FromResult(result).

Exceptions
Type Condition
Exception

Thrown exceptions are caught and returned as error responses to the MCP client