Vibe coding complex changes in Rust

Jon Gjengset2 HN recommenders · 2025–2026
55K views · demo · dated · Uploaded 2025-08-01

Jon Gjengset spends about three hours livecoding complex changes in a Rust codebase with agentic AI tools, testing his hypothesis that AI is weak at non-pattern work. He documents where Claude Code helps and where it struggles.

Pointed to as a non-promotional, realistic long session of an experienced engineer working with AI on non-trivial code.

Watch on YouTube

4 comments from Hacker News

@sitkack2025 · in “AI doesn't lighten the burden of mastery”

Jon Gjengset (jonhoo) Who is famously fastidious did a stream on live coding where he did something similar in terms of control. Worth of a watch if that is a style you want to explore. [VIDEO] I don't have the energy to do that for most things I am writing these days which are small PoC where the vibe is fine. I suspect as you do more, you will create dev guides and testing guides that can encapsulate more of that direction so you won't need to micromanage it. If you used Gemini CLI, you picked the coding agent with the worst output. So if you got something that worked to your liking, you should try Claude.

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@coffeeri2025 · in “A staff engineer's journey with Claude Code”

This video [0] is relevant, though it actually supports your point - it shows Claude Code struggling with non-trivial tasks and needing significant hand-holding. I suspect videos meeting your criteria are rare because most AI coding demos either cherry-pick simple problems or skip the messy reality of maintaining real codebases. [0] [VIDEO]

@anuramat2025 · in “Ask HN: Share a video-series of developing non-trivial things with AI?”

take a look at the replies to [LINK] eg [LINK] and [VIDEO] PS, what was your last setup? performance depends a lot on the domain/model/workflow[1]; some combinations don't work at all [1] by workflow I mean: trying to oneshot a feature VS interactive exploration VS boilerplate generation

@ontouchstart2026 · in “Profession by Isaac Asimov”

Ironically, when machine learning is getting “deeper & deeper”, human learning is getting more and more impatient and shallow. I have been searching “Vibe coding” videos on YouTube that are not promoting something. And I found this one and sat down and watched the whole three hours. It does take a lot of real effort. [VIDEO]

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