# Antigravity

> Give Antigravity's agent live web access with the Search1API plugin, or configure the hosted MCP server in mcp_config.json.

Canonical URL: https://s1.dev/docs/integrations/antigravity

Search1API ships as an [Antigravity plugin](https://antigravity.google/docs/plugins). The plugin connects Antigravity to the hosted Search1API MCP server and adds a Search1API skill, so the agent can search across engines, read pages, find news and check what's trending, then answer with cited sources. It works in the Antigravity App, CLI and IDE.

## What the agent gets

| Tool | What it does | Required |
| --- | --- | --- |
| `search` | Web search | `query` |
| `news` | News search | `query` |
| `ask` | Describe what you need; Search1API picks the engines and time window | `query` |
| `crawl` | Read a URL | `url` |
| `sitemap` | List a site's links | `url` |
| `trending` | GitHub / Hacker News trends | `search_service` |
| `render_results` | Present selected existing sources as cards or a readable list; no search credits | `results` |
| `send_feedback` | Report a wrong result, an unresolved error, or a missing capability to the Search1API team; no credits | `message` |

The plugin also adds the `search1api` skill. It tells the agent when to read a link instead of searching, how to pick engines and compare sources, and how to cite results. Run it directly with `/search1api`.

## Install

### As a plugin

Install the plugin from its GitHub repository:

```bash
agy plugin install https://github.com/superagents-lab/search1api-mcp/tree/main/antigravity-plugin
```

The plugin carries only the server URL. When the Search1API server first connects, Antigravity opens your browser; sign in with your Search1API account, or create one at [s1.dev](https://s1.dev). No API key is involved.

### By hand in `mcp_config.json`

Antigravity reads MCP servers from two files:

| File | Scope |
| --- | --- |
| `~/.gemini/config/mcp_config.json` | Every project |
| `.agents/mcp_config.json` | One workspace |

<Tabs items={['OAuth', 'API key']}>

<Tab value="OAuth">

Configure the endpoint and nothing else. Antigravity registers itself with Search1API's authorization server and prompts you to sign in:

```json
{
  "mcpServers": {
    "search1api": {
      "serverUrl": "https://mcp.search1api.com/mcp"
    }
  }
}
```

</Tab>

<Tab value="API key">

Create a key at [app.s1.dev](https://app.s1.dev) and send it as a bearer token:

```json
{
  "mcpServers": {
    "search1api": {
      "serverUrl": "https://mcp.search1api.com/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_SEARCH1API_KEY"
      }
    }
  }
}
```

Keep keys out of a workspace `.agents/mcp_config.json` that is committed to version control.

</Tab>

</Tabs>

## Verify

1. Run `agy plugin list`, or open **Customizations** > **Installed** in the App, and confirm Search1API is installed and enabled.
2. In a chat, ask: `Find this week's top news on AI coding agents and cite each source.`
3. Approve the tool call if Antigravity asks.

## Troubleshooting

### The plugin is installed but has no tools

Sign-in has not finished. Enable the plugin again from **Customizations** > **Installed** (or `/plugin` in the CLI) and complete sign-in in the browser.

### `401 Unauthorized`

On OAuth, the session expired or was revoked: sign in again from the plugin's MCP tab. On an API key, the key is invalid or revoked. See [Authentication](https://s1.dev/docs/essentials/authentication).

### `402 Payment Required`

The account is out of credits. See [Credits and limits](https://s1.dev/docs/essentials/credits-and-limits).

## Billing

Tool calls from Antigravity are ordinary API calls and spend the same credits at the same rates as calling the endpoints yourself. A search or news request costs one credit; crawling a page costs one credit per page; `ask` costs five credits. See [Credits and limits](https://s1.dev/docs/essentials/credits-and-limits).

## Related documentation

- [MCP server](https://s1.dev/docs/integrations/mcp): the full endpoint reference, OAuth details and other clients
- [Agent skill](https://s1.dev/docs/integrations/skills): teach an agent *when* to search, not just how
- [Antigravity plugin documentation](https://antigravity.google/docs/plugins) · [Antigravity MCP documentation](https://antigravity.google/docs/mcp)

Source: [github.com/superagents-lab/search1api-mcp](https://github.com/superagents-lab/search1api-mcp)