How to use the WEPPY MCP Server from WEPPY Roblox AI Toolkit with Antigravity CLI.

Antigravity CLI and Antigravity IDE share the canonical global MCP config at ~/.gemini/config/mcp_config.json.

Prerequisites

Antigravity CLI installed
Node.js (v18.0.0 or higher, with npx available)
WEPPY Roblox Studio Plugin installation complete

Install WEPPY AI Agent Plugin

Use the one-line installer from the WEPPY install page. Antigravity CLI and its agy plugin command are required to install WEPPY AI Agent Plugin. The installer stages the latest public release locally, runs agy plugin install with that local payload, and verifies the result with agy plugin list.

Do not pass a GitHub URL directly to agy plugin install. If the WEPPY AI Agent Plugin installation cannot be verified, the installer preserves the shared direct WEPPY MCP Server fallback.

Manual MCP Fallback

Global Config File

Add/merge the following into the global MCP config file for Antigravity CLI.

OS	Path
macOS / Linux	`~/.gemini/config/mcp_config.json`
Windows	`%USERPROFILE%\.gemini\config\mcp_config.json`

{
  "mcpServers": {
    "weppy-roblox-mcp": {
      "command": "npx",
      "args": ["-y", "@weppy/roblox-mcp@latest"]
    }
  }
}

Workspace Config

If you only want the MCP server in one project, you can put the same JSON in .agents/mcp_config.json at the project root.

The public one-line installer and browser installer use ~/.gemini/config/mcp_config.json as the global fallback. The older ~/.gemini/antigravity-cli/mcp_config.json path is legacy input for migration, not a new registration target.

Connection Test

Launch Roblox Studio → Plugins tab → WEPPY → Connect

Enter the following in Antigravity CLI:

Tell me what is currently selected in Roblox Studio

Use /mcp in the CLI to check MCP server status

Troubleshooting

Server Won’t Start

Run the MCP server directly to see the error:

npx -y @weppy/roblox-mcp@latest

Connection Fails

Confirm the WEPPY Roblox Studio Plugin shows Connected status
Check that port 3002 is not blocked by a firewall
Use /mcp in Antigravity CLI to check server status
Make sure you did not edit Gemini CLI’s ~/.gemini/settings.json or the Antigravity IDE config by mistake

Antigravity CLI Setup