A Practical Guide to Running Codex CLI with a Custom Responses Provider

Running Codex CLI with a Custom Responses Provider, specifically Ace Data Cloud, enables agentic coding in the terminal. The guide explains how to configure Codex CLI to read code, run commands, and use a configured model provider without disrupting normal workflow. Codex CLI, a local programming agent, can perform various tasks such as reading code, modifying files, executing commands, explaining errors, and helping with daily development tasks.

The integration requires Codex CLI's support for custom model providers, which relies on the base URL (https://api.acedata.cloud/v1) and the responses endpoint (https://api.acedata.cloud/v1/responses).

To set up the custom provider, the guide recommends creating a config file in ~/.codex/config.toml and adding specific values for the provider, model, reasoning effort, and the provider-specific configuration. The required protocol field is wire_api = responses, and the model_reasoning_effort can be set to low, medium, or high. The guide also mentions that the installation process is available for macOS, Linux, Windows, and WSL, using either npm or Homebrew.

Authentication is crucial in this setup, and the guide advises using an environment variable (ACEDATACLOUD_API_KEY) to store the API token. It is essential to set the token safely in a shell startup file and reload the shell configuration without printing the token during debugging. The guide also provides a method to clear cached login data if needed.

After installation and configuration, start Codex CLI in a project directory and verify the active model and provider. Run a minimal command-line validation to ensure the provider configuration works correctly.

In case of a 401 error, the guide recommends checking the configuration fields, clearing old cached logins, and restarting the terminal. Codex CLI supports various model IDs, including gpt-5, gpt-5-mini, and others, with gpt-5 being the practical default. You can temporarily override the default model using the codex --model command. The guide also provides a complete configuration checklist and a reference to the official Ace Data Cloud Codex CLI Terminal guide for further details.