Your agent.
Your editor.

The agent starts the server over stdio. The server talks to a small plugin in your editor over 127.0.0.1 on your computer, so the project does not leave your machine. This path is free and uses no Synagy credits.

1. Get the server

You need Node.js. Download synagy-mcp.mjs, save it as ~/.synagy/synagy-mcp.mjs (Windows: %USERPROFILE%\.synagy\synagy-mcp.mjs) and compare its SHA-256 with the value in the download manifest before you run it.

mkdir -p ~/.synagy && curl -fL https://synagy.org/downloads/synagy-mcp.mjs -o ~/.synagy/synagy-mcp.mjs
shasum -a 256 ~/.synagy/synagy-mcp.mjs

2. Register it with your agent

Replace the path with the absolute path of the file. The editor plugins come next: the quickest way is the setup prompt, which your agent follows step by step. Open it from the Unity or Roblox install section after you sign in. Blender and Unreal are set up the same way from the Synagy section in the studio.

claude mcp add synagy --scope user -- node <absolute path to synagy-mcp.mjs>

[mcp_servers.synagy]
command = "node"
args = ["<absolute path to synagy-mcp.mjs>"]
tool_timeout_sec = 1800

{
  "mcpServers": {
    "synagy": {
      "command": "node",
      "args": [
        "<absolute path to synagy-mcp.mjs>"
      ]
    }
  }
}

{
  "mcpServers": {
    "synagy": {
      "command": "node",
      "args": [
        "<absolute path to synagy-mcp.mjs>"
      ]
    }
  }
}

echo y | hermes mcp add synagy --command node --args <absolute path to synagy-mcp.mjs>

3. One-minute test

With Unity, Roblox Studio or Blender open and the plugin installed, paste this into your agent. It should create an object, find it again, show you a picture and clean up after itself.

Use the synagy MCP server: create a cube named "Synagy Hello" with engine_run, confirm it with engine_scene, show me engine_screenshot, then delete the cube again.

In Roblox Studio, ask for an anchored Part named “SynagyHello” in Workspace instead of a cube. If nothing connects, ask the agent to run engine_status: it names the missing step.

An agent with these tools is powerful, so connect only agents you trust. What you should know:

• It really changes your project. Your agent can create, change and delete files and objects, and run code in the editor with the same rights as your user account. Make a backup or use version control first, as our terms ask, and check changes before you keep or publish them.
• Undo helps, a backup is safer. Unity and Roblox batches land as one undo step, and a batch that fails rolls back. Roblox inserts from the Creator Store get a backdoor scan.
• The editor link stays on your computer. The hub listens on 127.0.0.1 only, rejects browser requests and other host names, and needs a token file that only your user can read. The plugins accept jobs only from a hub that proves it holds the same key.
• You confirm once in the editor. Each plugin shows a notice on first start. Until you click through it, the tools stay locked.
• Tool output can contain text from the outside, such as console lines or script text from a model you inserted. Treat it as data, and do not let an agent run code it merely read.
• Beta, no warranty. As far as the law allows, we give no guarantee that generated changes work. See section 5b of the terms.

Add Synagy as a connector to the AI you already use and ask it for a 3D tree, a sprite sheet, a sound or a whole game. Synagy makes it and shows the result in the chat. You sign in once with your Synagy account.

This costs Synagy credits, shown before it builds, and a part that fails is free. Your AI provider bills the thinking separately. Right now Synagy is a free beta and every account gets 25 free credits a day; see pricing. The connector does not edit your Unity or Roblox project; that is the local server above.

https://api.synagy.org/mcp

https://api.synagy.org/mcp

claude mcp add --transport http synagy https://api.synagy.org/mcp

codex mcp add synagy --url https://api.synagy.org/mcp
codex mcp login synagy