I was surprised by that too.

https://developers.openai.com/codex/pricing#what-are-the-usa...

ChatGPT Plus with Codex CLI provides "45-225 local messages per 5 hour period".

The https://chatgpt.com/codex/settings/usage is pretty useless right now - it shows that I used "100%" on December 14th - the day I ran this experiment - which presumably matches that Codex stopped working at 6:30pm but then started again when the 5 hour window reset at 7:14pm.

Running this command:

  npx @ccusage/codex@latest

Reports these numbers for December 14th along with a pricing estimate:

  │ Date         │ Models                                  │       Input │     Output │  Reasoning │   Cache Read │  Total Tokens │  Cost (USD) │
  │ Dec 14, 2025 │ - gpt-5.2                               │   2,988,774 │  1,271,970 │    908,526 │  194,963,328 │   199,224,072 │      $57.16 │

You can spend a lot of tokens on that $20/month plan!

It's possible OpenAI are being generous right now because they see Claude Code as critical competition.