# Changelog #30 - Scene Inspect Material Slots (TASK-014-10)

**Date:** 2025-11-27
**Version:** 1.9.9
**Phase:** Phase 7 - Introspection & Listing APIs
**Task:** TASK-014-10

---

## 📋 Summary

Implemented `scene_inspect_material_slots` tool - a scene-wide audit tool that provides a comprehensive view of material slot assignments across all objects. This tool complements per-object material queries by offering a holistic view ideal for clean-up workflows and identifying material issues before rendering or export.

---

## ✨ Features Added

### Domain Layer
- **`server/domain/tools/scene.py`**
  - Added `inspect_material_slots()` method to `ISceneTool` interface
  - Parameters: `material_filter: Optional[str]`, `include_empty_slots: bool`
  - Returns structured data with slot assignments, warnings, and statistics

### Application Layer
- **`server/application/tool_handlers/scene_handler.py`**
  - Implemented `inspect_material_slots()` RPC handler method
  - Validates and forwards requests to Blender

### Blender Addon Handler
- **`blender_addon/application/handlers/scene.py`**
  - Implemented `inspect_material_slots()` method
  - Iterates all objects with material slots in deterministic order
  - Collects slot data: object name, slot index, material name, empty status
  - Detects and reports warnings:
    - Empty slots (no material assigned)
    - Missing materials (referenced but not found in bpy.data.materials)
  - Supports filtering by material name
  - Returns summary statistics and detailed slot data

### MCP Adapter
- **`server/adapters/mcp/server.py`**
  - Added `@mcp.tool() scene_inspect_material_slots()`
  - Tagged: `[SCENE][SAFE][READ-ONLY]`
  - Formatted output with summary, warnings, and slot details (limited to first 20 for readability)
  - Includes full JSON data for programmatic access

### Registration
- **`blender_addon/__init__.py`**
  - Registered RPC endpoint: `scene.inspect_material_slots`

---

## 📊 Return Data Structure

```json
{
  "total_slots": 12,
  "assigned_slots": 10,
  "empty_slots": 2,
  "warnings": [
    "Cube[1]: Empty slot (no material assigned)",
    "Sphere[0]: Empty slot (no material assigned)"
  ],
  "slots": [
    {
      "object_name": "Cube",
      "object_type": "MESH",
      "slot_index": 0,
      "slot_name": "Material.001",
      "material_name": "Material.001",
      "is_empty": false
    },
    {
      "object_name": "Cube",
      "object_type": "MESH",
      "slot_index": 1,
      "slot_name": "Material.002",
      "material_name": null,
      "is_empty": true,
      "warnings": ["Empty slot (no material assigned)"]
    }
  ]
}
```

---

## 🧪 Testing

### Test File
- **`tests/test_scene_inspect_material_slots.py`**
  - `test_inspect_material_slots_basic()` - Basic audit with all slots
  - `test_inspect_material_slots_exclude_empty()` - Exclude empty slots
  - `test_inspect_material_slots_with_filter()` - Filter by material name
  - `test_inspect_material_slots_warnings()` - Verify warning detection

All tests include Blender availability checks and skip gracefully when Blender is not running.

---

## 📚 Documentation Updates

### Architecture Documentation
- **`_docs/SCENE_TOOLS_ARCHITECTURE.md`**
  - Added tool #15: `scene_inspect_material_slots`
  - Documented parameters, return structure, and usage examples

### Tools Summary
- **`_docs/AVAILABLE_TOOLS_SUMMARY.md`**
  - Added `scene_inspect_material_slots` to Scene Tools table
  - Added Material Tools section with `material_list` and `material_list_by_object`

### Task Tracking
- **`_docs/_TASKS/TASK-014-10_Scene_Inspect_Material_Slots.md`**
  - Marked as ✅ Done
  - Added completion date: 2025-11-27

---

## 🔧 Use Cases

1. **Pre-render audit**: Identify empty material slots that may cause rendering issues
2. **Material cleanup**: Find unused or duplicate material slots
3. **Export preparation**: Ensure all objects have proper material assignments
4. **Quality control**: Verify material consistency across scene
5. **Asset optimization**: Identify objects with excessive empty slots

---

## 💡 Key Implementation Details

- **Deterministic ordering**: Objects sorted alphabetically by name for diff-stable output
- **Warning system**: Automatic detection of empty slots and missing materials
- **Optional filtering**: Filter by specific material name for targeted audits
- **Performance**: Efficient iteration without mode switching or bmesh access
- **MCP output formatting**: Limited to 20 slots in summary view to prevent overwhelming output

---

## 🎯 Related Tools

- `scene_inspect_object` - Detailed single-object inspection including materials
- `material_list` - Lists all materials with shader parameters
- `material_list_by_object` - Lists material slots for specific object

---

**Status:** ✅ Complete
**Next:** TASK-014-11 (UV List Maps)
