nodecode-unity

Unity: the project open in your editor — its tools, a call, and a whole change as one approved plan. A Nodecode rewrite of TakeshiTGAL/hermes-plugin-csharp-game-editor by TakeshiTGAL.

Get it

Tell the agent "add the unity cell", or run nodecode add nc://unity.

Set it up

The cell talks to MCP for Unity, the package that connects an open Unity editor to MCP clients. In the project:

Add the package in Unity: Window > Package Manager > + > Add package from git URL, and paste https://github.com/CoplayDev/unity-mcp.git?path=/MCPForUnity#v10.3.0.
Keep its transport on HTTP (its default) and press Start in Window > MCP for Unity. That window shows the address it listens on, usually http://127.0.0.1:8080/mcp.
Put that address in the unity section of /settings (or the page's Settings tab):

"unity": {
  "url": "http://127.0.0.1:8080/mcp",
  "timeout_seconds": 120,
  "plan_ttl_minutes": 10,
  "max_chars": 6000
}

url is the only required member. The endpoint has to be on this machine: MCP for Unity listens on loopback (the Start button in its window is what opens it), so a url that names another host is refused at start.

Nothing else is needed: no Unity Hub, no uv, no uvx, no Python. /unity with no argument shows which endpoint the cell is on and what the editor answers; (help :unity) is the model's guide to the tools.

Use it

Ask for what you want in the project — "what is in my scene?", "add a coin the player can collect", "run the EditMode tests" — and the model picks the tool. A change is planned first and runs on the second call:

Tool	Use
`unity_tools`	the editor's own tools and what each does
`unity_call`	one of them, with its arguments, right away
`unity_plan`	a whole change as steps; checks the paths and answers the plan with an id
`unity_apply`	runs the newest plan once, step by step, and stops at the first failure

;; the model does this, not you
(unity_plan "{\"steps\": [{\"tool\": \"manage_script\", \"arguments\": {\"path\": \"Assets/Scripts/Coin.cs\"}}, {\"tool\": \"manage_scene\", \"arguments\": {\"path\": \"Assets/Scenes/Main.unity\"}}]}")

The plan comes back in words, every step and its arguments, and nothing has run yet; unity_apply with its plan_id runs it. A plan is checked before it is kept: a path with .., a hidden file, a key or credential file, an absolute path, a delete of Assets, Packages or ProjectSettings, and the editor's own File/Quit are refused, with nothing sent to the editor. Only the newest plan can run, once, and it expires after plan_ttl_minutes.

From the keyboard, /unity shows the connection and /unity <word> lists the editor tools that word names.