I run Fable as my main model with Sol as advisor that watches every turn. Fable likes to throw around assumptions that it didn't check that are simply false, and Sol always goes to actually verify them and then alert Fable it's assuming things.
I've tried reversing this pairing with Fable as advisor. It'll just sit there going "sounds good"
But I agree - Fable makes some spectacular assumptions (which are poor assumptions).
GPT models are extremely proactive and gredy. So when Fable mentions something that may affect some obscure component of the system, GPT will start digging the codebase, execute web searches, re-read AGENTS.md and hit fable on the head.
Fable never does that, it just reads the turns and acknowledges it read them. This also explains why GPT models tend to overengineer things and why they're amazing reviewers if you triage their findings.
I was using my own homegrown (mega slop) harness for a while, but it distracted me from working on my actual projects, and I realized oh-my-pi was doing the same things I've been doing, including advisor, native server-side compaction, etc. It's a really good harness.