> ## Documentation Index
> Fetch the complete documentation index at: https://exa.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# fx by Vercel Labs

> Add Exa web search to fx, Vercel Labs' native coding agent, with the hosted Exa MCP server.

[fx](https://fx.sh) is a native coding agent and CLI from Vercel Labs, and an MCP client. Add Exa's hosted MCP server to give it live web search and page reading.

<Frame>
  <img src="https://mintcdn.com/exa-52/OvBlIRVK7v5ZDuc4/images/fx/install-fx-exa.gif?s=7fb45e25cc97216b432a92794d5bb33d" alt="Installing fx, adding the Exa MCP server with /mcp add, and running a live Exa web search" style={{width: "100%", height: "auto"}} width="800" height="393" data-path="images/fx/install-fx-exa.gif" />
</Frame>

## Installation

<Steps>
  <Step title="Install fx">
    ```bash theme={null}
    curl -fsSL https://fx.sh/setup.sh | bash
    ```

    Then sign in with `fx login`. See the [fx docs](https://fx.sh/docs) for provider options.
  </Step>

  <Step title="Add Exa">
    Start fx by running `fx`, then add the Exa MCP server from the interactive shell:

    ```text theme={null}
    /mcp add --transport http exa https://mcp.exa.ai/mcp
    ```

    fx saves the server to `~/.fx/mcp.json` and reloads MCP.
  </Step>

  <Step title="Verify the connection">
    ```text theme={null}
    /mcp list
    ```
  </Step>
</Steps>

## Configure by hand

fx reads MCP servers only from `~/.fx/mcp.json`, so you can also add Exa there directly:

```json ~/.fx/mcp.json theme={null}
{
  "mcp": {
    "exa": {
      "type": "http",
      "url": "https://mcp.exa.ai/mcp"
    }
  }
}
```

Run `/mcp reload` to apply the change without restarting fx.

The free plan covers casual use. Add your own [Exa API key](https://dashboard.exa.ai/api-keys) to lift the rate limits:

```json ~/.fx/mcp.json theme={null}
{
  "mcp": {
    "exa": {
      "type": "http",
      "url": "https://mcp.exa.ai/mcp",
      "header_env": {
        "x-api-key": "EXA_API_KEY"
      }
    }
  }
}
```

`header_env` maps a header name to an environment variable, so the key stays out of the config file.

## Tool discovery

fx discovers MCP tools lazily: the server's tools are not in the model's context until a turn needs them, so adding Exa costs nothing on turns that don't search the web.

<Card title="Exa MCP" icon="plug" href="/docs/reference/exa-mcp">
  Review the available tools, configuration options, and other clients.
</Card>