The whole premise of the post, that coders remember what and why they wrote things from 6 months ago, is flawed.
We've always had the problem that understanding while writing code is easier than understanding code you've written. This is why, in the pre-AI era, Joel Spolsky wrote: "It's harder to read code than to write it."
I'd be interested to see results with Opus 4.6 or 4.5
Also, I bet the quality of these docs vary widely across both human and AI generated ones. Good Agents.md files should have progressive disclosure so only the items required by the task are pulled in (e.g. for DB schema related topics, see such and such a file).
Then there's the choice of pulling things into Agents.md vs skills which the article doesn't explore.
I do feel for the authors, since the article already feels old. The models and tooling around them are changing very quickly.
I was trying to get it to create an image of a tiger jumping on a pogo stick, which is way beyond its capabilities, but it cannot create an image of a pogo stick in isolation.