## Unreal Engine MCP Tools

This project uses mcp-unreal for AI-driven Unreal Engine development. The following MCP tools are available:

### Workflow Guidelines

1. **Always check status first**: Call `status` to verify the editor and plugin connections before attempting editor operations.
2. **Look up docs before writing UE code**: Use `lookup_class` to get class references (inheritance, properties, functions) and `lookup_docs` for API patterns before writing C++ or Blueprint logic.
3. **Build-test cycle**: After editing C++ files, call `build_project` to compile, then `run_tests` to verify. Read build errors carefully — use `lookup_docs` to understand UE APIs.
4. **Actor workflow**: Use `get_level_actors` to discover existing actors, `spawn_actor` to create new ones, `move_actor` to position them, and `set_property`/`get_property` to read/write properties.
5. **Blueprint workflow**: Use `blueprint_query` with operation `list` to find Blueprints, then `list_variables`/`list_functions`/`list_nodes` to inspect them. Use `blueprint_modify` to make changes, and always `compile` after modifications.
6. **Material workflow**: Use `material_ops` with `create` to make new materials, `get_parameters` to inspect existing ones, and `set_parameter` or `set_texture` to modify them.
7. **Save your work**: The editor does not auto-save. After making changes, use `level_ops` with `save_level` or remind the user to save.
8. **PIE testing**: Use `pie_control` with operation `start` to begin a Play In Editor session, `status` to verify it started, and `stop` to end it. Use `capture_viewport` with `include_ui=true` during PIE to see the game view with HUD/menus. Use `player_control` to move the player pawn (`teleport`, `set_rotation`) or reposition the editor viewport camera (`get_camera`, `set_camera`).

### Tool Modes

- **Headless tools** (`build_project`, `run_tests`, `cook_project`, etc.) do NOT require the editor to be running. They invoke UnrealEditor-Cmd directly.
- **Editor tools** (actors, blueprints, materials, etc.) require the Unreal Editor to be open with the MCPUnreal plugin loaded.
- **Documentation tools** (`lookup_docs`, `lookup_class`) are always available — use them liberally.

### Object Paths

Many tools require UE object paths. The format is:
- Actor paths: `/Game/Maps/MapName.MapName:PersistentLevel.ActorName`
- Asset paths: `/Game/Folder/AssetName`
- Engine assets: `/Engine/BasicShapes/Cube`

Use `get_level_actors` to discover actor paths, and `search_assets` to find asset paths.

                                                    ┌───────────────────────┐
                                                    │   UE 5.7 Editor       │
                                                    │                       │
                                                    │  ┌─────────────────┐  │
                                                    │  │ Remote Control  │  │
                                              ┌────►│  │ API (port 30010)│  │
                                              │     │  │ (built-in)      │  │
                                              │     │  └─────────────────┘  │
┌──────────────┐    stdio     ┌──────────────┐│     │                       │
│  AI Coding   │   JSON-RPC   │              ││     │  ┌─────────────────┐  │
│    Agent     │◄────────────►│  mcp-unreal  │├────►│  │ MCPUnreal       │  │
│ (Claude Code │              │ (Go binary)  ││     │  │ Plugin (port    │  │
│  Cursor, etc)│              │              ││     │  │ 8090)           │  │
└──────────────┘              │ 49 tools     │┘     │  │ • Actors        │  │
                              │ doc index    │      │  │ • Blueprints    │  │
                              │              │      │  │ • Materials     │  │
                              │ ┌──────────┐ │      │  │ • PCG / GAS    │  │
                              │ │ Headless │ │      │  │ • Niagara       │  │
                              │ │ exec.Cmd │─┼──────│──│ • Mesh ops      │  │
                              │ └──────────┘ │      │  │ • Levels        │  │
                              │              │      │  └─────────────────┘  │
                              │ ┌──────────┐ │      │                       │
                              │ │ Bleve    │ │      └───────────────────────┘
                              │ │ Doc Index│ │
                              │ └──────────┘ │      ┌───────────────────────┐
                              │              │──────│ docs/                 │
                              └──────────────┘      │ ├── ue5.7/            │
                                                    │ ├── realtimemesh/     │
                                                    │ └── index.bleve       │
                                                    └───────────────────────┘

mcp-unreal --build-index

# Build
make build

# Run all tests with race detector
make test

# Go lint
make lint

# C++ format check (requires clang-format)
make cpp-fmt-check

# Run all checks (Go format, C++ format, vet, lint, tests)
make check

# Build the test project (first run ~2-5 min, incremental after)
make test-cpp-build

# Build and run all MCPUnreal.* automation tests
make test-cpp

# Install
go install github.com/remiphilippe/mcp-unreal/cmd/mcp-unreal@latest

# Build the documentation index
mcp-unreal --build-index

# Register with your AI coding tool (see Setup section below)

git clone https://github.com/remiphilippe/mcp-unreal.git
cd mcp-unreal
make build

curl http://localhost:30010/remote/info

cp -r plugin/ /path/to/YourProject/Plugins/MCPUnreal/

claude mcp add mcp-unreal -- /path/to/mcp-unreal

{
  "mcpServers": {
    "mcp-unreal": {
      "type": "stdio",
      "command": "/path/to/mcp-unreal",
      "env": {
        "MCP_UNREAL_PROJECT": "/path/to/MyProject/MyProject.uproject"
      }
    }
  }
}

{
  "mcpServers": {
    "mcp-unreal": {
      "command": "/path/to/mcp-unreal",
      "env": {
        "MCP_UNREAL_PROJECT": "/path/to/MyProject/MyProject.uproject"
      }
    }
  }
}

codex mcp add mcp-unreal -- /path/to/mcp-unreal

[mcp_servers.mcp-unreal]
command = "/path/to/mcp-unreal"
args = []
tool_timeout_sec = 120

[mcp_servers.mcp-unreal.env]
MCP_UNREAL_PROJECT = "/path/to/MyProject/MyProject.uproject"

{
  "servers": {
    "mcp-unreal": {
      "type": "stdio",
      "command": "/path/to/mcp-unreal",
      "env": {
        "MCP_UNREAL_PROJECT": "${workspaceFolder}"
      }
    }
  }
}

{
  "mcpServers": {
    "mcp-unreal": {
      "command": "/path/to/mcp-unreal",
      "env": {
        "MCP_UNREAL_PROJECT": "/path/to/MyProject/MyProject.uproject"
      }
    }
  }
}

{
  "mcpServers": {
    "mcp-unreal": {
      "command": "/path/to/mcp-unreal",
      "env": {
        "MCP_UNREAL_PROJECT": "/path/to/MyProject/MyProject.uproject"
      }
    }
  }
}

{
  "context_servers": {
    "mcp-unreal": {
      "command": "/path/to/mcp-unreal",
      "env": {
        "MCP_UNREAL_PROJECT": "/path/to/MyProject/MyProject.uproject"
      }
    }
  }
}

You: "Build the project, fix any errors, and run the tests"

Agent calls:
  1. status()                    → editor + plugin online
  2. build_project()             → finds 2 compile errors
  3. lookup_class("AActor")      → looks up the correct API
  4. (edits the C++ source)
  5. build_project()             → clean build
  6. run_tests(filter: "Game")   → 14/14 tests pass

You: "Add a Niagara fire effect to the torch actor"

Agent calls:
  1. get_level_actors(name_filter: "Torch")  → finds actor path
  2. lookup_class("UNiagaraComponent")       → checks API
  3. niagara_ops(operation: "spawn_system", system_path: "/Game/FX/NS_Fire", ...)
  4. niagara_ops(operation: "set_parameter", parameter_name: "SpawnRate", value: 50)

You: "Create a PCG scatter for placing rocks on the landscape"

Agent calls:
  1. lookup_docs("PCG scatter landscape")    → reads PCG docs
  2. pcg_ops(operation: "list_components")   → finds existing PCG actors
  3. spawn_actor(class: "Actor", name: "RockScatter")
  4. pcg_ops(operation: "add_node", node_type: "SurfaceSampler")
  5. pcg_ops(operation: "execute")           → generates rocks