Not completely, just as a very personal example:

In optimizing my game I noticed framerate hitching even after efficient algorithms were in place for expensive stuff, which was caused by shaders not being precompiled consistently or assets not being preloaded in time. The Agent who'd been profiling and optimizing had moved many preloads to a loading screen, which caused a long loading lock, and what it didn't move ahead was loaded and compiled at use, creating slow frames since work was being done on the main game loop.

I instructed the agent to create a speculative pre-warming/compilation priority queue with a per-frame budget, with priority being determined by likelihood signals that the asset or shader will be used soon. Then I had the AI run fully headed games and hunt down causes for frames going over 16ms, and work through them until a batch of games had fewer than 1/1000 frames >16ms and no frames over 60ms after a short initial settling period.

The approach, the metrics, the validation system and the loop were "prompt engineering" above and beyond what I would expect from someone who was merely "vibe coding a game."