I've found that Claude nearly always claims to be Opus in the commit message, regardless of the actual model making the commit.

>figure out what the percentage split between Opus/Fable/Sonnet is.

This may be misleading, since I suspect many are using a blend through sub-agents. I tend to bias for Fable to orchestrate and Opus for implementation via sub-agents.

When I'm paying for it, Sonnet. When work is paying, Opus 5, then Fable if Opus gets confused.

Opus 5 is not strong enough as the top-of-stack model, and feels idiotic after a week or two of heavy Fable usage, to the point where I'm paying for Usage Credits to keep using Fable rather than having to slum it with Opus.