This works for verifiable performance issues and small bugfixes. In rare cases this can add product features at the cost of some insane interest on tech debt.

You need really good guardrails if you want to automate the software engineering part. And since this meta-layer sits 1 level above code you can't use code to verify and constrain agents effectively. As soon as agents start prompting agents any small wrinkle in the spec the potential to derail the whole thing. You want someting akin to "alignment docs", and even then they rarely follow it to spec.

Left unattended, they just start inventing unspoken requirements, making asinine product decisions and generally dig into a hole they can't get out of. One failure point I've seen regularly is "latching on" to a single word in the alignment doc and blowing it way out of proportion to the point where it no longer makes sense and compromises on core product. They get "tunnel visioned" and lose the big picture. Happens every time.

Will be interesting to see how new model developments progress, but so far the human interlayer is still a requirement.