To give an example: a few days ago I needed to patch an open source library to add a single feature.

This is a pathologically bad case for a human. I'm in an alien codebase, I don't know where anything is. The library is vanilla JS (ES5 even!) so the only way to know the types is to read the function definitions.

If I had to accomplish this task myself, my estimate would be 1-2 days. It takes time to get read code, get orientated, understand what's going on, etc.

I set Claude on the problem. Claude diligently starts grepping, it identifies the source locations where the change needs to be made. After 10 minutes it has a patch for me.

Does it do exactly what I wanted it to do? No. But it does all the hard work. Now that I have the scaffolding it's easy to adapt the patch to do exactly what I need.

On the other hand, yesterday I had to teach Claude that writing a loop of { writeByte(...) } is not the right way to copy a buffer. Claude clearly thought that it was being very DRY by not having to duplicate the bounds check.

I remain sceptical about the vibe coders burning thousands of dollars using it in a loop. It's hardworking but stupid.