> ## Documentation Index
> Fetch the complete documentation index at: https://tbd-6fc993ce-hypeship-add-antigravity-mcp-client-doc.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Google Antigravity

> Connect Google Antigravity to the Kernel MCP server

<Warning>
  Antigravity can complete the OAuth flow and still send `initialize` without the bearer token attached, which comes back as `401 Unauthorized` ([antigravity-cli#25](https://github.com/google-antigravity/antigravity-cli/issues/25)).

  If you hit that, [connect with an API key](#connect-with-an-api-key-workaround) instead of OAuth.
</Warning>

## Install with the Kernel CLI

Run the following command:

```bash theme={null}
kernel mcp install --target antigravity
```

## Configure manually

Alternatively, open the agent side panel, click the ellipsis (**…**) menu, and select **MCP Servers**, then **Manage MCP Servers → View raw config**. Add Kernel to the `mcpServers` map in `mcp_config.json` — `~/.gemini/config/mcp_config.json` globally, or `.agents/mcp_config.json` for a single workspace:

```json theme={null}
{
  "mcpServers": {
    "kernel": {
      "serverUrl": "https://mcp.onkernel.com/mcp"
    }
  }
}
```

Antigravity uses `serverUrl` for remote servers; `url` and `httpUrl` are ignored. Reload the window to pick up the change.

## Connect

Press **⌘/Ctrl ,** to open agent settings, go to the **Customizations** tab, and click **Authenticate** next to **kernel**.

Authorize access in the browser window that opens, then copy the authorization code, paste it back into the settings panel, and click **Submit**. Antigravity stores the tokens in `~/.gemini/antigravity/mcp_oauth_tokens.json` and refreshes them for you.

## Connect with an API key (workaround)

Get a project-scoped Kernel API key from the [Kernel Dashboard](https://dashboard.onkernel.com/api-keys) and pass it as a header instead of authenticating. `kernel mcp install --target antigravity` always writes the OAuth config, so add the `headers` block by hand:

```json theme={null}
{
  "mcpServers": {
    "kernel": {
      "serverUrl": "https://mcp.onkernel.com/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_KERNEL_API_KEY"
      }
    }
  }
}
```

Leave the **Authenticate** button alone when using this — Antigravity sends the header on every request, including `initialize`.