> Agile methodologies killed the specification document long ago. Do we really need to bring it back from the dead?

it didn't really kill it - it just made the spec massively disjoint, split across hundreds to thousands of randomly filled Jira tickets.

I think that might be the key here.

All those small micro decisions, discussions, and dead ends can be recorded and captured by the AI. If you do something that doesn’t make sense given past choices, it can ask you.

Gradually, over time, it can gather more and more data that only lives in your brain at the time you’re building. It’s only partially captured by git commits but mostly lost to time.

Now, when you change code, the system can say, “Jim wrote that 5 years ago for this reason. Is the reason not valid anymore?”. You might get this on a good code review, but probably not. And definitely not if Jim left 2 years ago.

> it didn't really kill it - it just made the spec massively disjoint, split across hundreds to thousands of randomly filled Jira tickets.

Don’t forget 80% of project knowledge in Jim’s head, and nobody knows how it all connects ever since he left 5 years ago.