Roblox Studio Rust MCP Server

This server acts as a bridge between an LLM (via an MCP Client like Claude Desktop or Cursor) and Roblox Studio. It uses two main components:

• Axum Web Server: A server that the Roblox Studio plugin long-polls to receive requests.
• rmcp Server: A server that communicates with the LLM via stdio transport.

Workflow: When an LLM requests to run a tool, the request is sent through the long-polling mechanism to the Studio plugin. The plugin executes the command in Studio and posts the response back to the LLM.

To build and install the implementation manually using Rust:

1. Ensure Roblox Studio and Claude Desktop are installed and have been opened at least once.
2. Exit Claude and Roblox Studio.
3. Install Rust.
4. Clone or download this repository.
5. Run the following command from the root directory:

cargo run

This command builds the Rust app, configures Claude communication, and installs the Studio plugin.

To quickly connect an AI client to Roblox Studio using this MCP server:

1. Download and Run the server: Use the Windows binary or macOS zip.
2. Restart Applications: Restart both your AI Client (e.g., Claude Desktop, Cursor) and Roblox Studio.
3. Done: The connection should now be active.

If you prefer not to use the automatic installer, you can manually add the server to your MCP client configuration.

Claude Desktop

Edit your claude_desktop_config.json (found via Settings > Developer > Edit Config) to include the following:

{
  "mcpServers": {
    "Roblox_Studio": {
      "args": [
        "--stdio"
      ],
      "command": "Path-to-downloaded\\rbx-studio-mcp.exe"
    }
  }
}

Note: On macOS, the command path might look like "/Applications/RobloxStudioMCP.app/Contents/MacOS/rbx-studio-mcp" if moved to the Applications directory.

Claude Code

Use the following command to add the server:

claude mcp add --transport stdio Roblox_Studio -- '/Applications/RobloxStudioMCP.app/Contents/MacOS/rbx-studio-mcp' --stdio

The installer automatically configures Claude Desktop and Cursor if they are installed.

1. Ensure Roblox Studio and your MCP Client (Claude/Cursor) are installed and have been opened at least once.
2. Exit all running instances of MCP Clients and Roblox Studio.
3. Download the latest release for your platform from the releases page.
4. Unzip and run the installer.
5. Restart Claude/Cursor and Roblox Studio.

When interacting with Roblox Studio via MCP, you must be aware of the current studio mode. It is recommended to use get_studio_mode to infer the current state before executing commands.

Best Practices for Play Modes

1. Prefer start_stop_play over run_script_in_play_mode: Use start_stop_play for general session management. Only use run_script_in_play_mode when you need to run a one-time unit test on the server datamodel.
2. Handling Session Conflicts: If run_script_in_play_mode fails with a message indicating a previous session is still active, call start_stop_play with the stop mode first to clear the state.
3. Mode Selection: When using start_stop_play, the mode parameter must be one of start_play, stop, or run_server.

To completely uninstall the Roblox Studio MCP plugin, locate your Roblox Studio Plugins directory and delete the following file:

MCPStudioPlugin.rbxm

To add the Roblox Studio MCP server to the Claude Code CLI, use the claude mcp add command. You must provide the path to the server executable and specify the stdio transport.

Run the following command, replacing <EXE_PATH> with the actual path to your server binary:

claude mcp add --transport stdio Roblox_Studio -- '<EXE_PATH>' --stdio

claude mcp add --transport stdio Roblox_Studio -- '/path/to/executable' --stdio

Follow these steps to ensure the connection is working:

1. Check Roblox Studio: Go to the Plugins tab. Verify the MCP plugin appears. Clicking the icon toggles communication. Check the Studio console for: The MCP Studio plugin is ready for prompts.
2. Check Claude Desktop: Click the hammer icon for MCP tools beneath the prompt text field. You should see a list of available tools (e.g., insert_model, run_code).

Troubleshooting: If it fails, try restarting both Studio and Claude Desktop. Ensure Claude is fully exited from the system tray.

The following tools are exposed to the LLM to interact with your Roblox Studio session:

• run_code: Runs a command in Roblox Studio and returns the printed output. Can be used to make changes or retrieve information.
• insert_model: Inserts a model from the Roblox Creator Store into the workspace. Returns the inserted model name.
• get_console_output: Gets the console output from Roblox Studio.
• start_stop_play: Starts or stops play mode or runs the server.
• run_script_in_play_mode: Runs a script in play mode and automatically stops play after the script finishes or times out. Returns structured output including logs, errors, and duration.
• get_studio_mode: Gets the current Studio mode (start_play, run_server, or stop).