My agent writes the code now. I built an IDE for the part that's left: reading it

Same here, and multi-file changes are exactly where I lost it too. What helps me is reading them as a route instead of a file list: in Reado's guided review the agent proposes an order that makes each next file make sense (definition before use, the changed function before its callers), and when one file shows that another needs looking at, it proposes adding it to the route instead of wandering off. For what you only see across files, like the same workaround in three places, there's a separate wide pass you trigger on purpose. And after the agent fixes things, a marker on the file tree shows what changed since you last read it, so you pick the thread back up from there. Thanks for the kind words!