#coding manipulation

Much like Dream's spear and power-up, Ink can't really sense it. He can't read into anything that isn't canon to what their creator had in mind. So he would have to otherwise see it firsthand if it wasn't canon.

Aside from code reading and anything else from Ask Error, Ink only knows so much.

As Rev and the canon infos explain, Error was self-taught. He practiced by analyzing and experimenting with the codes of other AUs aside from observing other coders.

Being an outcode hellbent on destroying the multiverse, he has scanned through hundreds of AUs and observed countless people in his time out there. His current state of power in Sagaverse is the consequence of having said inside information, arguably more than Ink due to his greater memory retention. His puppets, the light arrows, and even his moves on the cast are all the results of this.

In summary, he has learned more than other coders.