That was my experience with Claude when my vibe-coded project was small.

But now that I've been working on it a month and there's a lot of documentation, it's pretty clearly ignoring parts of the documentation and parts of the code. It will come up with some ridiculous statement about how something works, and I'll challenge it, and it'll admit I'm right.

It definitely reads more documentation than any programmer I've ever worked with (myself included) but because it doesn't have a memory other than the documentation, it still makes mistakes like that.

I haven't turned on "memory" or tried it with Codex, so I don't know how that'll change soon, though.