Unity Devloop MCP
# unity-devloop-mcp
MCP server for the Unity **edit → compile → check** loop. An AI client (Claude Code, etc.) can read the editor state and console/compiler errors, trigger an asset refresh after editing scripts outside Unity, and run menu items — without you copying console output by hand.
Two parts:
| Part | Path | Role |
| --- | --- | --- |
| MCP server (Node, stdio) | `server/` | Exposes the tools below and forwards calls to the editor |
| Unity bridge (UPM, Editor-only) | `unity-package/` | Local HTTP listener on `127.0.0.1` that runs requests on the editor main thread |
The bridge listens only on `127.0.0.1` and only while the editor is open. Nothing is included in player builds.
## Tools
| Tool | Input | Result |
| --- | --- | --- |
| `unity_status` | — | project path, Unity version, active scene, build target, `isCompiling`, `isPlaying`, `isPaused` |
| `unity_console` | `limit` (default 100), `types` (`log,warning,error,exception,assert,compile-error,compile-warning`), `clear` | recent entries captured by the bridge (stack traces kept for errors/exceptions) |
| `unity_refresh` | — | runs `AssetDatabase.Refresh` (imports external file changes, starts recompilation) |
| `unity_execute_menu` | `path` | runs `EditorApplication.ExecuteMenuItem(path)` |
Console capture starts when the bridge loads, so entries from before the last script reload are not kept. Compiler errors are captured from `CompilationPipeline` and survive a failed compile (no reload happens on failure).
## Install
### 1. Unity package
Add to `Packages/manifest.json`:
```json
"com.shin0112.unity-devloop-mcp": "https://github.com/shin0112/unity-devloop-mcp.git?path=/unity-package"
```
or, for a local clone:
```json
"com.shin0112.unity-devloop-mcp": "file:C:/projects/unity-devloop-mcp/unity-package"
```
Menu: `Tools > Unity Devloop MCP > Status / Enable Bridge / Disable Bridge`.
### 2. MCP server (Claude Code)
From GitHub:
```bash
claude mcp add unity-devloop -- npx -y github:shin0112/unity-devloop-mcp
```
From a local clone:
```bash
cd C:/projects/unity-devloop-mcp && npm install
claude mcp add unity-devloop -- node C:/projects/unity-devloop-mcp/server/index.js
```
## Configuration
| Setting | Where | Default |
| --- | --- | --- |
| Port | EditorPrefs `Shin0112.UnityDevloopMcp.Port` (editor) and env `UNITY_DEVLOOP_PORT` (server) — keep them equal | `17890` |
| Request timeout | env `UNITY_DEVLOOP_TIMEOUT_MS` (server); the bridge waits up to 30 s for the main thread | `35000` |
## Notes
- Requests run on the editor main thread via `EditorApplication.update`. If the editor is unfocused and throttles updates, calls may be slow or time out.
- During a script reload the bridge restarts; calls fail briefly with "not reachable".
- `unity_execute_menu` can run any menu item. Only connect clients you trust.
## License
MIT
TDQS
Scored across 4 tools
Each tool targets a clearly distinct concern: reading editor state, reading console output, executing a menu action, and refreshing assets. There is no realistic confusion between them, as names and descriptions point to different resources and actions.
All tools share a consistent 'unity_' prefix, but the remainder mixes nouns (status, console) with verb phrases (execute_menu, refresh). It is still highly readable and predictable overall.
Four tools is a focused, reasonable scope for a lightweight editor bridge, though it sits at the thin end and could plausibly include one or two more operations (e.g., play mode control, test running).
The core dev loop is covered: inspect state, read console diagnostics, refresh/import external changes, and run arbitrary menu items as an escape hatch. Direct play mode toggle or test execution would round it out, but the menu escape hatch mitigates most gaps.