We use it daily in our org. What you’re talking about is not happening. That being said, we have fairly decent mono repo structure, bunch of guides/skills to ensure it doesn’t do it that often. Also the whole plan + implement phases.

If it was July 2025, I would have agreed with you. But not anymore.

Yes, all the time. Yes, those go to production. AI has improved significantly the past 2 years, I highly recommend you give it another try.

I don't see the behaviour you describe, maybe if your impression is that of online articles or you use a local llama model or ChatGPT from 2 years ago. Claude regularly finds and resolves duplicated code in fact. Let me give you a counter-example: For adding dependencies we run an internal whitelist for AI Agents; new dependencies go through this system, we had similar concerns. I have never seen any agent used in our organisation or at a client, in the half year or so that we run the service, hallucinate a dependency.

FWIW I mainly use Opus 4.6 on the $100/mo Max plan, and rarely run into these issues. They certainly occur with lower-tier models, with increased frequency the cheaper the model is - as for someone using it for a significant portion of their professional and personal work, I don’t really understand why this continues to be a widespread issue. Thoroughly vetting Plan Mode output also seems like an easy resolution to this issue, which most devs should be doing anyways IMO (e.g. `npm install random-auth-package`).

We use it for 100s of projects and what you say hasn't happened for a while.

I used to experience those issues a lot. I haven't in a while. Between having good documentation in my projects, well-defined skills for normal things, simple to use testing tools, and giving it clear requirements things go pretty smoothly.

I'd say it still really depends on what you're doing. Are you working in a poorly documented language that few people use solving problems few people have solved? Are you adding yet another normal-ish kind of feature in a super common language and libraries? One will have a lot more pain than the other, especially if you're not supplying your own docs and testing tools.

There's also just a difference of what to include in the context. I had three different projects which were tightly coupled. AI agents had a hard time keeping things straight as APIs changed between them, constantly misnaming them and getting parameters wrong and what not. Combining them and having one agent work all three repos with a shared set of documentation made it no longer make mistakes when it needed to make changes across multiple projects.