I think you're right, ephemeral code would be the concept that you have (I'm hand-waving) "the spec", that specifies what the code should be doing and the AI could regenerate the code any time based on it.

I'm also baffled by this concept and fundamentally believe that code _should be_ the ground truth (the spec), hence it should be human readable. That's what "clean code" would be about, choosing tools and abstractions so that code is consumable for humans and easy to reason about, debug and extend.

If we let go of that and rely on LLMs entirely... not sure where that would land, since computers ultimately execute the code - and the company is liable for the results of that code being executed -, not the plain language "specs".

By ephemeral I mean we no longer care about code as an asset. If a feature is broken or requires changes, we can perform a clean organ transplant. The actual code doesn’t matter anymore. Its testable functionality is what matters.