I don't blame the agent for mistakes in my vibe coded personal software, it's always my fault. To me it's like this:

80%+: You don't understand the codebase. Correctness is ensured through manual testing and asking the agent to find bugs. You're only concerned with outcomes, the code is sloppy.

50%: You understand the structure of the codebase, you are skimming changes in your session, but correctness is still ensured mostly through manual testing and asking the agent to review. Code quality is questionable but you're keeping it from spinning out of control. Critically, you are hands on enough to ensure security, data integrity, the stuff that really counts at the end of the day.

20%-: You've designed the structure of the codebase, you are writing most of the code, you are probably only copypasting code from a chatbot if you're generating code at all. The code is probably well made and maintainable.

I feel like there’s one more dimension. For me, 95%+ of code that I ship has been written (i.e. typed out) by a LLM, but the architecture and structure, down to method and variable names, is mine, and completely my responsibility.