It depends. I've been working on a series of large, gnarly refactors at work, and the process has involved writing a (fairly long), hand-crafted spec/policy document. The big advantage of Opus has been that the spec is now machine-executable -- I repeatedly fed it into the LLM and see what it did on some test cases. That sped up experimentation and prototyping tremendously, and it also found a lot of ambiguities in the policy document that were helpful to address.
The document is human-crafted and human-reviewed, and it primarily targets humans. The fact that it works for machines is a (pretty neat) secondary effect, but not really the point. And the document sped up the act of doing the refactors by around 5x.
The whole process was really fun! It's not really vibe coding at that point, really (I continue to be relatively unimpressed at vibe coding beyond a few hundred lines of code). It's closer to old-school waterfall-style development, though with much quicker iteration cycles.
The document is human-crafted and human-reviewed, and it primarily targets humans. The fact that it works for machines is a (pretty neat) secondary effect, but not really the point. And the document sped up the act of doing the refactors by around 5x.
The whole process was really fun! It's not really vibe coding at that point, really (I continue to be relatively unimpressed at vibe coding beyond a few hundred lines of code). It's closer to old-school waterfall-style development, though with much quicker iteration cycles.