Found this announcement interesting since allegedly OpenAI is retiring their Terra tier. I think for everyday work, two models with various thinking efforts seem enough, plus some frontier level model like Fable or Astra to coordinate.
Terra lost to Sol and Luna at every cost/performance point, it had no reason to exist.
I personally use up to 3 models. Fable/Opus for planning, Opus/Sonnet for implementation depending on complexity.
I would maybe use Haiku 5.5 for highly parallel workflows like checking in on MRs or scanning my entire codebase.
Retiring the Terra tier? Their space-inspired lineup has only been out for 2 months, they're already messing with it?