Command reference ยท Codex CLI
/reasoning
Chooses the reasoning effort for the current chat.
More reasoning means more thorough but slower and costlier answers; less is faster and cheaper. The choice applies to the running chat.
โ WHEN TO USE IT?
Give a tricky task more reasoning
/reasoning
Work faster and cheaper on simple tasks
/reasoning
โ WHEN NOT TO?
Switching the model rather than just the depth
/reasoning changes only the effort level, not the model.
Better: /model
SOURCES
- Codex CLI docs: Slash Commands โ developers.openai.com