The problem is that such ai.txt would be an unidimensional opinion based on what? On the way the site describes itself. So a self-referencing source.
But the AIs reading it, are precisely going to invariably be trained with different world views that will summarize and express opinions biased by these worldviews. It's even deeper as every worldview can't help but belong to one ideology or another.
So who is aligned with truth now?
The author? AI1? AI2? AI3?...AIN?
We're in such a mess.