Codex CLI

Install the Codex CLI. For the ChatGPT desktop app, see ChatGPT Desktop.

npm install -g @openai/codex

Usage with Ollama

Use a context window of at least 64k tokens for Codex.

Quick setup

ollama launch codex

When launched through ollama launch codex, Ollama refreshes the model catalog and uses a dedicated Codex profile for that session.

Type /model inside Codex to switch between your installed, tool-capable Ollama models without restarting. The starting model remains selected, and each model keeps its own context window, vision, and thinking settings. Pull additional models with ollama pull <model> before launching to include them in the picker.

To configure without launching:

ollama launch codex --config

To remove the Ollama launch profile and generated model catalog:

ollama launch codex --restore

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 Codex CLI configuration, create ~/.codex/ollama-launch.config.toml:

model = "gpt-oss:120b"
model_provider = "ollama-launch"
model_catalog_json = "/Users/you/.codex/model.json"

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

Then run:

codex --profile ollama-launch

Web search through local Ollama

Codex web-search requests sent through the Ollama profile are executed by Ollama for both local and cloud models. Sign in with ollama signin to use the web-search service.

To disable web search for a Codex session:

codex --profile ollama-launch -c 'web_search="disabled"'