A good hammer is good for whatever hammers are for.

Yes, that's what I said above:

the hammer itself is still for something and serves its purpose better when it's good

your claim that all goods are for something is undermined by the way you are handling eudaimonia.

I don't think it is. I did not say I agreed with Aristotle that this sort of infinite regress is bad. Eudaimonia is the good life for me. All other things that are good for me are good in that they are part of the good life. It is the case that I should do what is best for me. As a side effect, being a good human makes me good for all sorts of things that I don't necessarily care about.

This probably reduces to a statement about my preferences / utility function, as long as those things are defined in the 'extrapolated' manner. That is, even if I thought it were the case that I should drink drain cleaner, and I then drank drain cleaner, it was still the case that I preferred not to drink drain cleaner and only did so because I was mistaken about a question of fact. This does not accord well with the usual English meaning of 'preference'.

Full disclosure: Am a moral egoist.