# Tool Categories Design
## Overview
Add category support to MCP tools for better organization in both the Unity Editor window and MCP protocol responses.
## Goals
1. Organize tools into collapsible foldouts in the MCPServerWindow
2. Expose categories in the MCP `tools/list` response for AI client discoverability
## Design
### 1. MCPToolAttribute Changes
Add optional `Category` property:
```csharp
[AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
public class MCPToolAttribute : Attribute
{
public string Name { get; }
public string Description { get; }
public string Category { get; set; } = "Uncategorized";
public MCPToolAttribute(string name, string description)
{
Name = name;
Description = description;
}
}
```
Usage:
```csharp
[MCPTool("scene_load", "Loads a scene", Category = "Scene")]
public static object Load(...) { }
```
### 2. ToolDefinition Changes
Add `category` field to protocol response:
```csharp
public class ToolDefinition
{
public string name;
public string description;
public string category; // NEW
public InputSchema inputSchema;
}
```
### 3. ToolRegistry Changes
- Expose `Category` property on `ToolInfo`
- Add `GetDefinitionsByCategory()` method for UI grouping
- Add `GetCategoryOrder()` for consistent sort order
- Update `ToDefinition()` to include category
### 4. MCPServerWindow Changes
- Replace flat tool list with collapsible foldouts per category
- Track foldout state in `Dictionary<string, bool>`
- Show tool count per category: "Scene (6)"
- Categories default to expanded
### 5. Category Assignments
| Category | Tools |
|----------|-------|
| Scene | scene_create, scene_load, scene_save, scene_get_active, scene_get_hierarchy, scene_screenshot |
| GameObject | gameobject_find, gameobject_manage |
| Component | component_manage |
| Asset | asset_manage, prefab_manage |
| Console | console_read |
| Tests | tests_run, tests_get_job |
| Editor | unity_refresh |
| Debug | test_echo, test_add, test_unity_info, test_list_scenes |
### 6. Sort Order
Categories appear in this order:
1. Scene
2. GameObject
3. Component
4. Asset
5. Console
6. Tests
7. Editor
8. Debug
9. Uncategorized (tools without explicit category)
## Files to Modify
1. `Editor/Attributes/MCPToolAttribute.cs` - Add Category property
2. `Editor/Core/MCPProtocol.cs` - Add category to ToolDefinition
3. `Editor/Core/ToolRegistry.cs` - Expose category, add grouping method
4. `Editor/UI/MCPServerWindow.cs` - Collapsible foldouts UI
5. `Editor/Tools/*.cs` - Add Category to all existing tools
## API Response Example
```json
{
"tools": [
{
"name": "scene_load",
"description": "Loads a scene by path or build index",
"category": "Scene",
"inputSchema": { ... }
},
{
"name": "gameobject_find",
"description": "Finds GameObjects by name, tag, layer...",
"category": "GameObject",
"inputSchema": { ... }
}
]
}
```
## Notes
- The MCP spec doesn't define `category`, but extra fields are allowed
- AI clients can use categories to group tools when presenting options
- Non-breaking additive change to the protocol
