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It can do this at the level of a function, and that's -useful-, but like the parent reply to top-level comment, and despite investing the time, using skills & s

It can do this at the level of a function, and that's -useful-, but like the parent reply to top-level comment, and despite investing the time, using skills & subagents, etc., I haven't gotten it to do well with C++ or Rust projects of sufficient complexity. I'm not going to say they won't some day, but, it's not today.

jaggederest 9mo ago
I don't know if you've tried Chatgpt-5.2 but I find codex much better for Rust mostly due to the underlying model. You have to do planning and provide context, but 80%+ of the time it's a oneshot for small-to-medium size features in an existing codebase that's fairly complex. I honestly have to say that it's a better programmer than I am, it's just not anywhere near as good a software developer for all of the higher and lower level concerns that are the other 50% of the job. If you have any opensource examples of your codebase, prompt, and/or output, I would happily learn from it / give advice. I think we're all still figuring it out. Also this SIMD translation wasn't just a single function - it was multiple functions across a whole region of the codebase dealing with video and frame capture, so pretty substantial.
- glhaynes 9mo ago
  "I honestly have to say that it's a better programmer than I am, it's just not anywhere near as good a software developer for all of the higher and lower level concerns that are the other 50% of the job." That's a good way to say it, I totally identify.
rtfeldman 9mo ago
Anecdotally, we use Opus 4.5 constantly on Zed's code base, which is almost a million lines of Rust code and has over 150K active users, and we use it for basically every task you can think of - new features, bug fixes, refactors, prototypes, you name it. The code base is a complex native GUI with no Web tech anywhere in it. I'm not talking about "write this function" but rather like implementing the whole feature by writing only English to the agent, over the course of numerous back-and-forth interactions and exhausting multiple 200K-token context windows. For me personally, definitely at least 99% all of the Rust code I've committed at work since Opus 4.5 came out has been from an agent running that model. I'm reading lots of Rust code (that Opus generated) but I'm essentially no longer writing any of it. If dot-autocomplete (and LLM autocomplete) disappeared from IDE existence, I would not notice.
- Snuggly73 9mo ago
  The article is arguing that it will basically replace devs. Do you think it can replace you basically one-shotting features/bugs in Zed? And also - doesn’t that make Zed (and other editors) pointless?
  - rtfeldman 9mo ago
    > Do you think it can replace you basically one-shotting features/bugs in Zed? Nobody is one-shotting anything nontrivial in Zed's code base, with Opus 4.5 or any other model. What about a future model? Literally nobody knows. Forecasts about AI capabilities have had horrendously low accuracy in both directions - e.g. most people underestimated what LLMs would be capable of today, and almost everyone who thought AI would at least be where it is today...instead overestimated and predicted we'd have AGI or even superintelligence by now. I see zero signs of that forecasting accuracy improving. In aggregate, we are atrocious at it. The only safe bet is that hardware will be faster and cheaper (because the most reliable trend in the history of computing has been that hardware gets faster and cheaper), which will naturally affect the software running on it. > And also - doesn’t that make Zed (and other editors) pointless? It means there's now demand for supporting use cases that didn't exist until recently, which comes with the territory of building a product for technologists! :)
    - Snuggly73 9mo ago
      Thanx. More of a "faster keyboard" so far then? And yeah - if I had a crystal ball, I would be on my private island instead of hanging on HN :)
      - rtfeldman 9mo ago
        Definitely more than a faster keyboard (e.g. I also ask the model to track down the source of a bug, or questions about the state of the code base after others have changed it, bounce architectural ideas off the model, research, etc.) but also definitely not a replacement for thinking or programming expertise.
  - 9mo ago
andai 9mo ago
Is that a context issue? I wonder if LSP would help there. Though Claude Code should grep the codebase for all necessary context and LSP should in theory only save time, I think there would be a real improvement to outcomes as well. The bigger a project gets the more context you generally need to understand any particular part. And by default Claude Code doesn't inject context, you need to use 3rd party integrations for that.

jaggederest 9mo ago

I don't know if you've tried Chatgpt-5.2 but I find codex much better for Rust mostly due to the underlying model. You have to do planning and provide context, but 80%+ of the time it's a oneshot for small-to-medium size features in an existing codebase that's fairly complex. I honestly have to say that it's a better programmer than I am, it's just not anywhere near as good a software developer for all of the higher and lower level concerns that are the other 50% of the job. If you have any opensource examples of your codebase, prompt, and/or output, I would happily learn from it / give advice. I think we're all still figuring it out. Also this SIMD translation wasn't just a single function - it was multiple functions across a whole region of the codebase dealing with video and frame capture, so pretty substantial.

glhaynes 9mo ago
"I honestly have to say that it's a better programmer than I am, it's just not anywhere near as good a software developer for all of the higher and lower level concerns that are the other 50% of the job." That's a good way to say it, I totally identify.

rtfeldman 9mo ago

Anecdotally, we use Opus 4.5 constantly on Zed's code base, which is almost a million lines of Rust code and has over 150K active users, and we use it for basically every task you can think of - new features, bug fixes, refactors, prototypes, you name it. The code base is a complex native GUI with no Web tech anywhere in it. I'm not talking about "write this function" but rather like implementing the whole feature by writing only English to the agent, over the course of numerous back-and-forth interactions and exhausting multiple 200K-token context windows. For me personally, definitely at least 99% all of the Rust code I've committed at work since Opus 4.5 came out has been from an agent running that model. I'm reading lots of Rust code (that Opus generated) but I'm essentially no longer writing any of it. If dot-autocomplete (and LLM autocomplete) disappeared from IDE existence, I would not notice.

Snuggly73 9mo ago
The article is arguing that it will basically replace devs. Do you think it can replace you basically one-shotting features/bugs in Zed? And also - doesn’t that make Zed (and other editors) pointless?
- rtfeldman 9mo ago
  > Do you think it can replace you basically one-shotting features/bugs in Zed? Nobody is one-shotting anything nontrivial in Zed's code base, with Opus 4.5 or any other model. What about a future model? Literally nobody knows. Forecasts about AI capabilities have had horrendously low accuracy in both directions - e.g. most people underestimated what LLMs would be capable of today, and almost everyone who thought AI would at least be where it is today...instead overestimated and predicted we'd have AGI or even superintelligence by now. I see zero signs of that forecasting accuracy improving. In aggregate, we are atrocious at it. The only safe bet is that hardware will be faster and cheaper (because the most reliable trend in the history of computing has been that hardware gets faster and cheaper), which will naturally affect the software running on it. > And also - doesn’t that make Zed (and other editors) pointless? It means there's now demand for supporting use cases that didn't exist until recently, which comes with the territory of building a product for technologists! :)
  - Snuggly73 9mo ago
    Thanx. More of a "faster keyboard" so far then? And yeah - if I had a crystal ball, I would be on my private island instead of hanging on HN :)
    - rtfeldman 9mo ago
      Definitely more than a faster keyboard (e.g. I also ask the model to track down the source of a bug, or questions about the state of the code base after others have changed it, bounce architectural ideas off the model, research, etc.) but also definitely not a replacement for thinking or programming expertise.
- 9mo ago

andai 9mo ago

Is that a context issue? I wonder if LSP would help there. Though Claude Code should grep the codebase for all necessary context and LSP should in theory only save time, I think there would be a real improvement to outcomes as well. The bigger a project gets the more context you generally need to understand any particular part. And by default Claude Code doesn't inject context, you need to use 3rd party integrations for that.