How to connect Fine Structure to Google Antigravity with MCP

Google Antigravity uses mcp_config.json and the serverUrl field. This is the simple guide to connecting Fine Structure.

Antigravity is Google's agentic workspace. Connecting it to Fine Structure gives the Antigravity agent controlled access to your apps, lets it understand the system structure, and lets it run build and validation tools through MCP.

What's different here: In Antigravity you use the serverUrl field for a remote MCP server, not always the url field as in other tools.

Where to configure it: Through the Agent panel, the three-dot menu, MCP Servers, Manage MCP Servers, and then View raw config.

What to paste: A short JSON with serverUrl, the Fine Structure MCP address, and an Authorization header with the token.

Before opening Antigravity

Create an MCP token in Fine Structure. We recommend starting with Build or Read only, and expanding permissions later only if needed.

Steps to connect

Sign in to your Fine Structure account.
Open the MCP page using the Create MCP token button in the docs, or go directly to /mcp.
Choose whether the agent gets access to all the apps you own or to a single app only.
Choose permissions: Read only for testing, Build for editing, Full access only for an agent you trust.
Click Create MCP setup and copy the token or the configuration block. The token is shown only once.
Open Antigravity and the Agent panel.
Open MCP Servers and then Manage MCP Servers.
Click View raw config to open mcp_config.json.
Paste the config below, save, and refresh or restart Antigravity.

{
  "mcpServers": {
    "fine-structure": {
      "serverUrl": "https://finestructure.ai/api/mcp",
      "headers": {
        "Authorization": "Bearer fse2_mcp_<token>"
      }
    }
  }
}

Check after connecting

Open MCP Servers and confirm that the fine-structure server appears as active.
Ask the agent to call get_platform_guide.
Ask for a small, safe task, such as listing apps or running validate_app.

Note: If you copied a configuration from another tool, replace url with serverUrl. This is one of the most common mistakes when connecting Antigravity to MCP.