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

# Codex Agent

> Use Codex as a separate agent in Ona Cloud environments.

<Note>Available on the Core plan. Codex Agent is currently supported on Ona Cloud only. [Contact sales](https://ona.com/contact/sales) to learn more.</Note>

Codex Agent lets you use Codex in an Ona Cloud environment. It is separate from Ona Agent, but it runs with the same project context, environment isolation, integrations, and guardrails.

## How Codex Agent works

Codex Agent can read your repository, use configured tools, run commands, and open pull requests while following your organization's policies.

By default, Codex Agent uses the model access available to your organization. If you connect your ChatGPT account, Codex Agent uses your ChatGPT plan for model requests instead.

## Prerequisites

* Your organization is on the Core plan.
* Your organization uses Ona Cloud.
* Codex Agent is enabled for your organization.

To use your ChatGPT plan for Codex model requests, you also need a ChatGPT account with Codex access. See [Connect Codex to ChatGPT](/ona/integrations/configure-codex).

## Start Codex Agent

1. Start an environment.
2. Open the conversation menu.
3. Choose **Codex**.
4. Describe the task you want Codex Agent to work on.

## Billing

The environment still consumes OCUs while Codex Agent runs. See [Cost & Budgets](/ona/billing/usage).

If you connect your ChatGPT account, OpenAI manages ChatGPT plan usage and limits for Codex model requests. Ona does not charge OCUs for Codex model requests that use your connected ChatGPT account.

## Related setup

* [Connect Codex to ChatGPT](/ona/integrations/configure-codex): use your ChatGPT plan for Codex model requests
* [AGENTS.md](/ona/agents-md): add project context for agents
* [MCP servers](/ona/mcp): extend agent capabilities with external tools