> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.ada.cx/mcp/introduction/getting-started/codex-cli/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.ada.cx/_mcp/server.

# Codex CLI

[Codex CLI](https://developers.openai.com/codex/cli) connects to the MCP server over HTTP. It does not use `mcp-remote`. Both OAuth and API key authentication are supported.

## Requirements

* Codex CLI installed and signed in.
* The `codex mcp add` command with the `--url` option. Run `codex mcp add --help` to confirm. Update Codex CLI if the option is missing.
* An Ada dashboard account. Available tools depend on your role. See [Permissions](/mcp/introduction/authentication#permissions).

## Option 1: OAuth (recommended)

1. Run this command. Replace `acme-corp.ada.support` with your Ada instance domain:

   ```bash
   codex mcp add ada --url https://acme-corp.ada.support/api/mcp/oauth
   ```

2. Codex CLI detects OAuth support and opens a browser window. Log in with your Ada credentials.

3. If the browser window does not open, run:

   ```bash
   codex mcp login ada
   ```

4. Run `codex mcp list`. Confirm that `ada` shows **OAuth** in the Auth column.

5. Start a new Codex CLI session to load the tools.

> **Note**
>
> Pass the URL with the `--url` option. If you omit `--url`, Codex CLI registers the URL as a local command. The command reports success, but the connection fails.

## Option 2: API key

API key authentication uses a token generated from your Ada dashboard. Use it for automated setups or when browser-based login is not available.

Codex CLI reads the key from an environment variable when it starts. The key is not written to the configuration file.

1. Generate an API key from **Config > PLATFORM > API keys** in your Ada dashboard.

2. Set the API key as an environment variable in the shell that launches Codex CLI:

   ```bash
   export ADA_API_KEY=your_api_key_here
   ```

3. Run this command. Replace `acme-corp.ada.support` with your Ada instance domain:

   ```bash
   codex mcp add ada --url https://acme-corp.ada.support/api/mcp --bearer-token-env-var ADA_API_KEY
   ```

4. Run `codex mcp list`. Confirm that `ada` shows **Bearer token** in the Auth column.

5. Start a new Codex CLI session to load the tools.

## Configuration file

Both commands write to `~/.codex/config.toml`. The connection applies to every project. You can also edit the file directly:

```toml
[mcp_servers.ada]
url = "https://acme-corp.ada.support/api/mcp/oauth"
```

For API key authentication, use the `/api/mcp` URL and add `bearer_token_env_var = "ADA_API_KEY"`.

## Next steps

* Try a prompt from the [prompt library](/mcp/prompt-library/overview).
* Review [data privacy](/mcp/introduction/data-privacy) settings.
* Connect additional AI Agents: see [Connecting multiple Agents](/mcp/introduction/getting-started/connecting-multiple-agents).