Codex Model Selection
Choosing the right model and reasoning effort helps balance quality, speed, and cost.
Available Models (2026)
Model availability depends on your account and product surface. The tutorial uses names such as GPT-5.5, GPT-5.4, GPT-5.4-mini, and Codex Spark as examples; always check the current official model list.
Reasoning Effort
Reasoning effort controls how much thinking budget Codex spends.
Higher effort is useful for architecture, debugging, refactors, and ambiguous product work. Lower effort is better for routine edits.
How To Choose By Task
Switching In Each Surface
The Desktop App, CLI, IDE extension, and Cloud may expose model switching differently, but the concept is the same.
Cost And Rate Limits
Higher-end models and higher reasoning effort can cost more and may hit limits sooner. Use the smallest setup that gets reliable results.
Next Steps
Continue with Subagents.