Guides

Install the MCP

The r3ne MCP server lets Claude (or any MCP client) see your graph, add and wire nodes, write shaders and snapshot the output while R3NE is running. This guide takes you from zero to your first prompt in about five minutes.

Before you start

  • R3NE installed on a Mac with Apple silicon (macOS 14 or later).
  • Node.js 18 or newer. Check in Terminal with node -v. If it’s missing, install it from nodejs.org or with brew install node.
  • An MCP client: Claude Code (recommended), Claude Desktop, or Codex.

Option A — Claude Code (recommended)

In Claude Code the MCP comes as a plugin, together with two skills that teach Claude how R3NE works (nodes, shaders, 3D scenes). Nothing to clone or build.

  1. Open Claude Code (in the terminal with claude, or the Code tab of the Claude app).
  2. Add the R3NE plugin marketplace:
    /plugin marketplace add FranciscoOutonB/r3ne-app
  3. Install the plugin:
    /plugin install r3ne@r3ne-app
  4. Restart Claude Code so it starts the MCP server.
  5. Open R3NE. The MCP talks to the app on localhost:19780, which is only up while R3NE is running.
  6. Check the connection by asking:
    are you connected to r3ne?

Claude calls health and answers with the number of nodes and the frame rate of your open project.

To update later, run /plugin marketplace update r3ne-app and restart Claude Code.

Option B — Claude Desktop, Codex or another client

Other clients run the same server from a copy of the plugin repository. The server is already built, so there’s no npm install.

Download the repository and print the server’s path:

bash
git clone https://github.com/FranciscoOutonB/r3ne-app.git ~/r3ne-app
echo "$HOME/r3ne-app/mcp-server/dist/index.mjs"

Copy the path it prints, for example /Users/you/r3ne-app/mcp-server/dist/index.mjs. Client configs don’t expand ~, so always use the full path.

Claude Desktop

  1. In Claude Desktop open Settings → Developer → Edit Config. That opens ~/Library/Application Support/Claude/claude_desktop_config.json.
  2. Add the r3ne server with your path (keep any servers you already have inside mcpServers):
    json
    {
  "mcpServers": {
    "r3ne": {
      "command": "node",
      "args": ["/Users/you/r3ne-app/mcp-server/dist/index.mjs"]
    }
  }
}
  3. Quit Claude Desktop completely (⌘Q) and open it again. The r3ne tools show up in the tools menu of the chat.

Codex

Add this to ~/.codex/config.toml and start a new Codex session:

toml
[mcp_servers.r3ne]
command = "node"
args = ["/Users/you/r3ne-app/mcp-server/dist/index.mjs"]

Updating

bash
cd ~/r3ne-app && git pull

Then restart your client.

Your first prompt

With R3NE open, try:

Clear the canvas and build an audio-reactive kaleidoscope:
fractal noise into a kaleidoscope, a glow, and the bass of the
mic driving the zoom. Show me a snapshot when it's done.

Nodes appear on the canvas as Claude works, arranged left to right with the Output on the right. Everything it does can be undone with ⌘Z.

An R3NE node graph built by Claude: Audio In and Audio Bands driving a Neon Palette shader over Fractal Noise, with Kaleidoscope and Glow stacked under it and the Output on the right
A patch built from that prompt: audio drives the shader's zoom, the Post-FX stack sits under its source, and the Output is always on the right.

Troubleshooting

What you seeFix
“R3NE app is not running” or “fetch failed”Open R3NE and ask again. The MCP needs the app running.
The r3ne tools never appearRestart the client after installing. In Claude Code, check /mcp; in Claude Desktop, check the path in the config file.
node not foundDesktop apps don’t always see your shell’s PATH. Run which node and put that full path in "command" instead of node.
R3NE runs on another portSet R3NE_API_PORT in the server’s env to the same port the app uses.

For the full list of tools and what each one does, see MCP.