I am using the Codex desktop app without the pi harness and my experience is quite different.

5.5 has been a noticeable improvement over 5.4, solving more complicated issues and faster too.

5.5 does not use a huge amount of my session limits with the $100 plan.

I use multiple conversations in parallel, all on xhigh effort with Fast on (2.5x consumption), and it’s still enough for me not to switch off Fast.

It also runs my tests, but I did not use TDD apart from sometimes telling it to cover an issue in a test before fixing it.