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Microsoft agentically ports Copilot runtime to Rust for $120K
- iamgopal 6d agowhy golang lost to rust ?
- asp_hornet 6d ago> The software engine underpinning GitHub Copilot and a growing number of Microsoft products I’m guessing so it can interop easier with C/C++ codebases? Just a stab in the dark, I have no idea.
- Havoc 6d agoEither would have worked, but rust's fussy compiler & memory features is an advantage for LLMs. The more bug catching you can shift out of runtime and into compile time the better since the LLM can fix it
- hollowturtle 6d agogo is even more straightforward for llms imo. It's a dead simple language with a good garbage collector, where you can still do a lot memory management
- Havoc 5d agoSimplicity is a feature too. > you can still do a lot memory management That’s kinda my point - you don’t really want to trust the LLM to get any sort of memory management right. A system where hard constraints are baked into the language itself and the LLM fights the compiler at compile time removes a lot of hoping the LLM got it right. Ultimately either works though so use whatever you enjoy
- OutOfHere 6d agoI wouldn't say it has lost. Big firms like Microsoft and Amazon are just afraid to use Go since it's by Google, a known evil firm. This doesn't hold back smaller firms that need to move fast.
- tecoholic 6d agoOne of the thorniest conversions was the session.ts file, which was over 30,000 lines of TypeScript that touched all aspects of the runtime. This can’t be real. Single file with 30K lines? Which human being is working on it and how much RAM does it take for a code editor to load that with full symbol tree? I am genuinely curious. Is this common? I think most files I come across stretch to maybe 2-3k lines max.
- smitty1e 6d agoWas the documentation for each function a full-on essay?
- formerly_proven 6d ago> Which human being is working on it If you've ever used that tool you wouldn't ask this question, since it's obviously fully vibecoded.
- wayvey 6d agoI recently saw a ~60k lines / 3mb .cpp file in one vibe coded project (and yes I was a bit horrified) Surprised it works at all but it apparently does. Not really for a human though and even for an LLM it would be more beneficial for it to be split up.
- NewsaHackO 6d agoThis has to be 1) early LLM vibe coding or 2) “hand” vibe codingwhere the user asked the LLM to code sections and stitches them together manually, and the programmer is a novice. The second part I speak from experience; got to ~2k before realizing this is out of the script range and started to break it up. Regardless, it would be almost impossible to get an SOTA LLM agent to ever do this.
- applfanboysbgon 6d agoIt is very possible. Sol Max created a 17k line monolithic file in a prototype not long ago. If I didn't stop it and make it refactor everything it easily would have went to 60k. I think it's the default if you start a new project and don't define the architecture concretely with files and folders beforehand. Models have zero concept of architecture or long-term planning, they just band-aid the fastest immediate solution that gets them the reward.
- Rexxar 6d agoThey don't have to tell us they are vibe coding everything. - there are now ridiculous vibe coded localisation in VS2026 - task manager started to not report cpu usage correctly recently (the number becomes stalled) - file explorer display the "loading" icon infinitely on some directories - and many other things!
- chrischen 6d agoThe line between vibe coding and just coding has now moved. Vibe coding is specifically when the output is not understood by the prompter. Even in the back in the days of the earlier models i used the models to do my basic typing because it was easier than me typing it out…
- Icathian 6d agoYour reply misunderstands the parent comment, I think. MS devs clearly don't understand their output given how garbage it is.
- fingerlocks 6d agoWe’re not allowed to understand it. Gotta hit your PR quota to keep your job. I wish I was joking.
- sharktheone 6d agoEven if they wouldn't be vibecoding. They were able to write slop before AI
- GrayShade 6d ago> file explorer display the "loading" icon infinitely on some directories Nautilus had that feature 10 years ago, good to hear they've reached parity.
- edg5000 6d agoI love Nautilus, but the one I run (42.6) still has that ocasionally. May be fixed in latest stable by now though.
- amelius 6d agoStill hoping for a company to agentically port the python ecosystem to GIL-free python.
- andrewstuart 6d agoI did a lot of benchmarking of Gil free python. Greenlets were much faster. Gil free python gets stuck on all sorts of python locks. It’s slow.
- rienbdj 6d agoIf runtime performance is the goal it’s easier to port the required libraries to another language at this point.
- amelius 6d agoI'd certainly like to see more of this, yes. It would be great if scipy, numpy, pytorch, etc. would be available universally, if only because you'd use the same function names in every language. And if LLMs are as great as they make us believe they are, then this should be easily possible.
- andrewstuart 6d agoCan we not say “agentically” please?
- perching_aix 6d agoIs that why session compaction stopped working for me in VS Code at the end of this week, or is that just the integrated extension itself having a normal one? Though it's the same extension that can't keep its session timestamps straight, randomly hides sessions I was just in (then suddenly remembers them after going in and out of a session), and completely shits itself visually when using OpenAI's models, so maybe it really is just the latter.
- dmix 6d ago> agents converted 430,000 lines of TypeScript into 800,000 lines of production Rust The +400k new lines were probably code comments the agents added to everything
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- meerita 6d ago832K + 469k of tests.
- hollowturtle 6d ago> The original TypeScript implementation completed 7.55 of those lifecycles per second, while Rust running in-process managed 120 per second - representing a 15.9x speedup on that particular workload. Does this impresses/surprises anyone? Two folds: 1) I believe the most optimized JavaScript code could near the performance of this phase 1 port without optimizations. I would have gone with that first, many would think that would not be as cost efficient but: 2) optimizing the rust code will require 10x the effort of the 1 by 1 conversion, just because you now need idiomatic rust code that likely has nothing to do with a plain translation. So defeating the initial gain, there's nothing to do the bottleneck gets just pushed elsewhere
- meerita 6d agoI wrote to the post of Andrea (a dev from the Copilot team) about their 800K LoC: 128 PRs, shipped incrementally. Existing end-to-end tests ran against the new code at every step. Total: ~1,301,378 lines of Rust. Production: 832,378 Unit tests: ~469,000 Combined: ~1.30 million lines On top of the 832K LoC are mostly tests she answered: > Yeap, 832,378 lines of production Rust. the +800K number is production only; unit tests are another +469K on top. https://x.com/acolombiadev/status/2100660224298193081?s=20 https://x.com/acolombiadev/status/2100660224298193081?s=20
- baxuz 6d agoThe fuck does "agentically" mean
- mg74 6d agoProbably that they used dynamic workflows to run long agent sessions to do the conversion, like Anthropic did when they ported Bun from Zig to Rust. Minimize Human in the Loop workflows, maximize Agents in the Loop workflows.
- dgellow 6d agoThat’s they used Claude code
- supermatt 6d agoIt’s the adverb of agentic, which is an adjective to describe something as having agency. I get it was a snark on the word, but it’s actually a legitimate pre-ai term.
- alex_duf 6d agoUsing agents?
- OutOfHere 6d agoDid you just wake up after a multi year slumber? Agentically means using tools. It means the workflow isn't predefined. It also spawned subagents.
- jdw64 6d agoNow I'm starting to really feel that I should use Rust, but I have no idea where to actually apply it.
- Havoc 6d agoCan they port their m365 chat UI too? Don't know what tech stack it is but I'm guessing electron judging by how buggy and slow it is
- aniceperson 6d agothey ported their coding harness, something known for being simply an extensible http and subprocess wrapper, into a monolithic blob. They took their bloated and slow coding harness, and turned into an un-maintanable blob.
- blacklimetea 6d ago[dead]
- pinkmoonx 6d ago[dead]
- turowicz 6d agoThey really built that shit in TS? Mad!
- ChrisArchitect 6d agoSource: https://github.blog/ai-and-ml/generative-ai/migrating-the-github-copilot-runtime-to-rust-using-copilot/ https://github.blog/ai-and-ml/generative-ai/migrating-the-gi...
- mixxit 6d agoI'm slowing moving everything to kubuntu and have for some time has it in my non work life Really nothing works anymore as great a product full fat visual studio and windows 7 was I don't have time to deal with your bugs