Using the Open Codex Command Line Interface Coding Agent

Open Codex is a fork of OpenAI’s codex project that can be used with most LLMs, local using Ollama as well as commercial APIs. Here we look at setting and using Open Codex with Ollama.

Using Open Codex with local Ollama models provides privacy when working with proprietary code bases.

OpenAI Codex CLI and the clone Open Codex are a lightweight, open-source coding agents that run locally in the terminal, integrating AI models with local code and computing tasks. Both tools support multimodal reasoning by allowing users to pass prompts to the model, enhancing its ability to understand and generate code based on various inputs. Both tools are minimal and transparent, providing straightforward interfaces for developers to interact with AI models directly from the command line.

The open-codex clone offers flexibility by allowing users to swap out models from different vendors easily. For instance, users can change the model by adjusting a simple command-line parameter, enabling the use of models like Claude or local models using Ollama. This adaptability makes it suitable for developers who wish to experiment with various AI models without being tied to a specific provider.

Both Codex CLI and open-codex aim to streamline the coding process by integrating AI capabilities directly into the developer’s workflow.

You need to have a recent version of npm installed. You can then install the command line tool for Open Codex globally on your laptop using:

1 npm i -g open-codex

I use the qwen2.5:14b with Ollama so make sure this model is installed locally:

1 ollama pull qwen2.5:14b
2 ollama serve

Create the directory ~/.codex if it does not already exist and edit the file ~/.codex/config.json to contain:

1 {
2     "provider": "ollama",
3     "model": "qwen2.5:14b",
4 }

I use Open Codex with Python, Common Lisp and Haskell projects.

As you run open-codex you may be asked questions about the tasks you requested and for permissions to create new files, commit changes to git, etc.

1 open-codex "Describe the code in this directory"

1 open-codex "Copy the functions summarize and answer-question from ollamaOLD.lisp to ollama.lisp, making any required changes. Create a new test file test.lisp that contains examples of using the functions defined in ollama.lisp"

Using a common line agent like Open Codex provides a quick and intuitive way to interact with and modify code bases on your local computer system.