How to use multiple models in a Codex workflow

Codex Codex CLI
1

i have a giant task that i dont want gpt 5.5 to work on, i want to use codex cli with gpt 5.4 mini to work on some of it and then hand a report to 5.5 to continue its work and do the actual heavy lifting, is that possible?

2

You can change the model between turns using /model.

There are two ways to approach this:

  1. Start with gpt-5.4-mini, then switch to gpt-5.5 in the next turn. Note that this will send all previous turns in the thread to gpt-5.5 as uncached context.

  2. The preferred method, if your goal is to save the most usage limits:

    • Use gpt-5.4-mini to create a file, such as report.md, containing the results.
      • Prompt: Please analyze <your giant task> and save the report in report.md.
    • Start a new thread with /new, switch to gpt-5.5, and use @report.md to refer to the file. This discards all previous reasoning and initial inputs, using only the summarized report instead, which saves the most tokens.
      • Prompt: @report.md <your gpt-5 task>