Codex

Install

Install the Codex CLI:

npm install -g @openai/codex

Usage with Ollama

Codex requires a larger context window. It is recommended to use a context window of at least 64k tokens.

Quick setup

ollama launch codex

To configure without launching:

ollama launch codex --config

Manual setup

To use codex with Ollama, use the --oss flag:

codex --oss

To use a specific model, pass the -m flag:

codex --oss -m gpt-oss:120b

To use a cloud model:

codex --oss -m gpt-oss:120b-cloud

Profile-based setup

For a persistent configuration, add an Ollama provider and profiles to ~/.codex/config.toml:

[model_providers.ollama-launch]
name = "Ollama"
base_url = "http://localhost:11434/v1"

[profiles.ollama-launch]
model = "gpt-oss:120b"
model_provider = "ollama-launch"

[profiles.ollama-cloud]
model = "gpt-oss:120b-cloud"
model_provider = "ollama-launch"

Then run:

codex --profile ollama-launch
codex --profile ollama-cloud