pascal-mcp

Pascal — shared world

A 3D building world that anyone can edit through Claude. One world. CRDT-replicated. No central editor.

🌐 Live website: https://www.jogabysa.com 🔌 Live relay: wss://pascal-relay-deonmenezes.fly.dev 📦 Repo: https://github.com/deonmenezes/editor

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Try it (60 seconds)

Open https://www.jogabysa.com — you're now in the world. Orbit / zoom with the mouse. The status panel in the top-left shows the relay state and how many peers are online with you. Whatever's there was built by someone with the Pascal Claude plugin installed.

Build in it

Option A — Claude Code, two slash commands (recommended)

/plugin marketplace add deonmenezes/editor
/plugin install pascal-mcp@pascal-editor

Claude Code prompts you for the relay URL and room name (defaults work — just press enter). Restart and the pascal MCP server is live with the pascal-build skill auto-loaded. Now ask:

"Build me a small house with two windows, then export it as a glb."

Watch it appear on the website in real time.

Option B — Manual install (Claude Desktop, or any MCP client)

You need Claude Desktop and Node 18+.

git clone https://github.com/deonmenezes/editor.git
cd editor
bun install
bun run build

Add this to ~/.claude.json (Claude Code) or claude_desktop_config.json (Claude Desktop):

{
  "mcpServers": {
    "pascal": {
      "command": "node",
      "args": ["/absolute/path/to/editor/packages/mcp/dist/index.js"],
      "env": {
        "PASCAL_RELAY_URL": "wss://pascal-relay-deonmenezes.fly.dev",
        "PASCAL_ROOM": "pascal-shared-world"
      }
    }
  }
}

Restart Claude. Then ask:

"Build me a small house with two windows, then export it as a glb."

Watch it happen on the website in real time.

If you want, drop the agent-facing skill at .claude/skills/pascal-build.md into your own Claude config — it teaches the model how to use these tools well.

Host your own (20 minutes)

Step-by-step in ONBOARDING.md. Short version: deploy packages/relay to Fly.io (or any host with WebSocket support), deploy packages/web to Vercel, point the web's env at your relay, point your Claude plugin at it too.

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Architecture

   ┌──────────────────────────────────────────────────────┐
   │  Vercel-hosted website (packages/web)                │
   │  Next.js + React Three Fiber                         │
   │  Loads the world live, renders walls/roofs/slabs     │
   └────────────────────────────┬─────────────────────────┘
                                │ y-websocket
                                ▼
   ┌──────────────────────────────────────────────────────┐
   │  Relay (packages/relay) — on Fly.io                  │
   │  Stateless WebSocket router for CRDT messages        │
   │  Holds NO app state — every peer carries the doc     │
   └────────────────────────────▲─────────────────────────┘
                                │ y-websocket
   ┌────────────────────────────┴─────────────────────────┐
   │  Claude plugin (packages/mcp)                        │
   │  Each user's machine. Tools: wall_add, door_add, …   │
   │  Edits go straight into a shared Y.Doc               │
   └──────────────────────────────────────────────────────┘

The relay is the only centralized piece. It just routes encrypted CRDT messages between peers; turn it off and the doc still lives in everyone's local Y.Doc. Anyone can run their own relay, and the doc happily syncs to it.

Layout

Package	Role
packages/core	Zod schemas for nodes (wall, door, window, roof, …) — pure data
packages/mcp	Claude plugin. MCP stdio server backed by a Y.Doc
packages/relay	y-websocket relay. Stateless. Deploy anywhere
packages/web	Next.js + R3F viewer. Joins the swarm and renders 3D

MCP tools

Tool	Purpose
world_status	Connection state to the relay
scene_summary	Text tree of the current world (the model's "vision")
scene_clear	Wipe the shared scene back to defaults
wall_add	Add a wall — start and end are [x, z] floor coordinates
door_add / window_add	Add openings to a wall
roof_add	Single-segment roof on the level
node_delete	Delete nodes (cascades to descendants)
house_build	One-shot: rectangle + door + windows + gable roof
scene_export_glb	Export to a .glb you can open in Blender / model-viewer / VS Code
scene_save / scene_load	Local snapshot of the doc to JSON

Coordinate system: [x, z] on the floor plan, in metres. y=0 is the floor; positive y is up. glTF output is right-handed Y-up.

Limits called out honestly