Maybe you read them already, but wikipedia has a bunch of interesting pages about sourcing and truth like: https://en.wikipedia.org/wiki/Wikipedia:Verifiability,_not_t... and https://en.wikipedia.org/wiki/Wikipedia:Reliable_sources

I'll look at reliable-sources, and you are right "verifiability, not truth" is basically what I landed on too. Model doesn't get to decide what's true, it just needs to cite something.

Will read reliable-sources page properly.