codex
Installation
SKILL.md
Codex Skill Guide
Models
| Model | Notes |
|---|---|
gpt-5.4 |
Default & recommended — frontier reasoning + coding |
gpt-5.3-codex |
Strong coding focus |
gpt-5.3-codex-spark |
Extra fast; ChatGPT Pro only (research preview) |
- Set default:
model = "gpt-5.4"in~/.codex/config.toml - Override per-run:
codex -m gpt-5.4or/modelin-session - Reasoning effort:
--config model_reasoning_effort="high|medium|low"(or set in config)- Low → fast, well-scoped tasks; Medium/High → complex changes or debugging; Extra High → long agentic tasks