Can GPT-5.6-Terra be considered an actual replacement for GPT-5.5, with essentially the same capabilities but at half the price? Or should it be considered more like a GPT-5.6-Mini–like model?
Suspect the latter (judging by the token prices) but I’ve been having great results with Terra.
And it depends what you are doing.
See this discussion:
Yeah, and OpenAI’s own reasoning ratings in the model comparison section align Terra with Mini and Luna with Nano.