These things are amazing for maintenance programming on very large codebases (think, 50-100million lines of code or more, the people who wrote the code no longer work there, it's not open source so "just google it or check stack overflow" isn't even an option at all.)
A huge amount of effort goes into just searching for what relevant APIs are meant to be used without reinventing things that already exist in other parts of the codebase. I can send ten different instantiations of an agent off to go find me patterns already in use in code that should be applied to this spot but aren't yet. It can also search through a bug database quite well and look for the exact kinds of mistakes that the last ten years of people just like me made solving problems just like the one I'm currently working on. And it finds a lot.
Is this better than having the engineer who wrote the code and knows it very well? Hell no. But you don't always have that. And at the largest scale you really can't, because it's too large to fit in any one person's memory. So it certainly does devolve to searching and reading and summarizing for a lot of the time.
A huge amount of effort goes into just searching for what relevant APIs are meant to be used without reinventing things that already exist in other parts of the codebase. I can send ten different instantiations of an agent off to go find me patterns already in use in code that should be applied to this spot but aren't yet. It can also search through a bug database quite well and look for the exact kinds of mistakes that the last ten years of people just like me made solving problems just like the one I'm currently working on. And it finds a lot.
Is this better than having the engineer who wrote the code and knows it very well? Hell no. But you don't always have that. And at the largest scale you really can't, because it's too large to fit in any one person's memory. So it certainly does devolve to searching and reading and summarizing for a lot of the time.