AI assistants (MCP)

arxedit has a built-in MCP server. An AI assistant connected to it can look into the open level, show you things in the Scene view, and edit with you.

• Transport: Streamable HTTP at http://127.0.0.1:47630/mcp.
• It listens on this computer only, and only answers clients that give its token.
• Any MCP client can connect. It is tested with Claude Code.

Turn it on

The server is off by default.

1. Edit > Preferences...
2. Tick MCP server for AI assistants. Change the Port if 47630 is taken.
3. Save. It starts at once.

Under the port is the Token: every request must send it as Authorization: Bearer <token>, so that other programs on the computer can't edit through the editor. Copy puts it on the clipboard. New token makes another (on Save): connected clients then need the new one. Clients that can't send headers can use http://127.0.0.1:47630/mcp?token=<token>.

arxedit --mcp-port <port> on the command line also turns it on, at that port, with the same token. While a client is talking to it, the Scene view says MCP client connected at the bottom right.

Warning

A connected client can edit and save the open level, build and play. Every edit is one undo step (Ctrl+Z takes it back).

Claude Code

The release has a Claude Code plugin in editor/mcp/claude-code. It connects to the editor and adds a skill that tells Claude how to use the tools. In Claude Code, once:

/plugin marketplace add <path to editor/mcp/claude-code>
/plugin install arxedit@arxedit

The plugin reads the token from the environment variable ARXEDIT_MCP_TOKEN. Set it once with the token from Preferences, then start Claude Code again. On Windows, in a terminal:

setx ARXEDIT_MCP_TOKEN <token>

(setx applies to terminals opened after it.)

• With another port, set the environment variable ARXEDIT_MCP_PORT before starting Claude Code.
• Started the editor after Claude Code? Reconnect in /mcp.
• /mcp shows arxedit failed (HTTP 403): the token is old or wrong; arxedit isn't listed at all: ARXEDIT_MCP_TOKEN isn't set. Copy the token from Preferences again.

Without the plugin:

claude mcp add --transport http arxedit http://127.0.0.1:47630/mcp --header "Authorization: Bearer <token>"

Other clients

VS Code (.vscode/mcp.json):

{
  "servers": {
    "arxedit": {
      "type": "http",
      "url": "http://127.0.0.1:47630/mcp",
      "headers": { "Authorization": "Bearer <token>" }
    }
  }
}

Cursor (.cursor/mcp.json in a project, or ~/.cursor/mcp.json):

{
  "mcpServers": {
    "arxedit": {
      "url": "http://127.0.0.1:47630/mcp",
      "headers": { "Authorization": "Bearer <token>" }
    }
  }
}

Claude Desktop reaches local HTTP servers through the mcp-remote bridge (needs Node.js). In claude_desktop_config.json (Settings > Developer > Edit Config):

{
  "mcpServers": {
    "arxedit": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "http://127.0.0.1:47630/mcp", "--allow-http",
               "--header", "Authorization: Bearer <token>"]
    }
  }
}

What it can do

Tool	Does
status	Project, open level, counts, selection, camera, the last undo step
selection	What you selected, in detail (faces with uvs, edges, vertices, objects)
faces, edges, objects	Query the level: faces by room, texture or place; edges; entities, lights, fogs, paths, portals, rooms, materials
select	Selects and frames something, to show you
screenshot	The Scene view or the whole window, as an image
camera	Places the Scene view's camera
log	The Console
run	Edits. A Scene view action on the selection: extrude, doorway, make room, bridge, weld, paint, delete...
move	Edits. Moves, turns or scales the selection, as the gizmo
texture	Edits. Texture and uv placement of selected faces, surface flags
set	Edits. Values of an entity (Lua properties, components, ASL overrides), light, fog, path or portal
add	Edits. Adds an entity, light, fog, path, zone, portal or shape
undo	Undo or redo
problems	Runs the level checks
quest	Edits quest graphs; also reads a running quest and sends debug commands
graphs, graph_live	Animation graphs, and their live state during Play
editor	Save, Build, Play, Stop, rebuild navigation, new or open a level, open tabs, import files (any file on the computer an importer takes, by its path)