The AI is not optimized to play tron.

[Ezex]

AI understands that it has to look for the colors first, and that's fine with any deck other than tron. But when the deck is tron in most cases what you want is to first build tron and then look for colors, anyway the AI is not able to build tron with a 100% colorless deck.
And finally you also have to adjust Crop Rotation because the AI uses it to destroy its own tron. And Crop Rotation is the only card available in pauper to search for tron.

[rickp]

I don't think the AI in Xmage is being developed that much, and is more just for goldfishing deck ideas against. It can pull off some good plays and combos though, but it doesn't seem to do proper blocking with creatures or even chump block. I think the devs probably have enough work to do keeping up with all the new cards let alone developing the AI but it would be really cool if they could develop it a bit more when they have time. At least proper blocking for creatures or randomise that a bit more.