Holodeck

Holodeck is a large library of game-ready 3D assets (low-poly Synty-style prefabs, models, materials, textures and animations), plus the Playground: a live 3D editor where you say what you want — “build me a forest with a cabin and a campfire, at night” — and an AI agent builds it from the library while you watch. Think Star Trek holodeck meets the Unity editor.

Ways in

You want to… Use
Build scenes by talking or typing, in the browser Playground at https://arx.dev/playground
The same, inside the Unity editor with your real prefabs Unity client
Let Claude, Cursor or another AI tool build scenes MCP server at https://arx.dev/mcp
Script scenes, or run your own agent loop Playground API + tool reference
Search and download assets from code Asset library API
Run your own asset library and plug it in Host your own asset library

Every one of these drives the same scenes and the same tools. Build a forest from Claude over MCP and it appears live in the browser editor and in Unity at the same moment; nudge a tree in Unity and the browser sees it move.

How it fits together

 browser editor ─┐                       ┌─ Playground::Tools ── SceneOps ── scene (Postgres)
 Unity editor ───┼── REST /api/v1 ───────┤        ▲                             │
 scripts ────────┤                       │        │ same 14 tools               ▼
 Claude / MCP ───┴── POST /mcp ──────────┘   server agent (Grok)        live ops on ActionCable
                                                                        (/cable, PlaygroundChannel)
 asset library: this server's own, or any self-hosted library speaking the same API
  • Scenes are JSON: objects (library assets, primitives, lights, cameras), an environment (sky, ground, fog), a material library and settings (vendor lock).
  • Ops are the only way a scene changes — add, update, remove, env, material, … — whether they come from you, the agent or another client.
  • Tools are the agent’s verbs (search_assets, scatter_assets, place_asset, create_material, add_camera, …). They turn intent into ops.

Get an API key

Sign in, open Account → API keys (https://arx.dev/account?tab=api_keys), create a key and copy it (it’s shown once). Send it as Authorization: Bearer <key> to the API and MCP, or as ?token=<key> on the WebSocket.