Here is my approach:

"coding is solved" == "gastown-like systems give a brand-new and useful software"

I don't recall whether GasTown succeeded...

I don’t use gastown specifically but the level of complexity agents can code for is very high now.

Over this weekend in chat with the games discord watching as it iterated a harness built an entire implementation of the board game terraforming mars https://tfmbot.com using agents and harnesses for them.

I think if you can implement a board game end to end by feeding in the rulebooks and having a harness spawn agents to validate it’s reasonably solved.