Andrej Karpathy — former Tesla AI director, OpenAI founding member, and arguably the most-followed individual AI researcher alive — spent a Friday night staring at YouTube's recommendation wall and decided he was done. By Saturday morning, he had a replacement live at hackertube.org, built almost entirely by Anthropic's Claude Opus 5.5 in roughly two hours. The pipeline is straightforward but revealing. Opus downloaded the full HN comment corpus, filtered for YouTube links, then ran a secondary Sonnet pass to strip spam and low-quality recommendations. The result: 6,454 videos across 150 topics, curated by roughly 40,000 individual HN comments spanning 2007–2026. No accounts, no tracking, no algorithmic feed — just a local browser session storing your state. The design choices are pointed critiques of YouTube's current UX. HackerTube uses the 50% frame as the thumbnail instead of the creator-uploaded clickbait image. There are keyboard shortcuts. The "For You" recommendations run locally without user accounts. The site's underlying data is exportable so anyone can fork and rebuild. Every decision is an implicit indictment of what YouTube has become. What matters here is not HackerTube itself — it's a weekend project with 6,454 videos, not a platform. What matters is the production function. A single person with access to a frontier model can now stand up a curated, deployed, hardened web application in two hours. The labor cost of building a niche alternative to a platform monopoly just collapsed by orders of magnitude. The curation layer is worth examining. HN commenters are a specific demographic: technical, English-speaking, skewing male, skewing Bay Area. This isn't "quality" in any universal sense — it's one community's collective taste filtered through another model's judgment. The 150-topic taxonomy and spam filtering were Sonnet's editorial decisions, not human ones. The editorial stack is LLM-curated community taste presented as an antidote to algorithmic slop. Karpathy's implicit argument is that recommendation systems can be replaced by community-filtered curation plus AI labor. He's right for his niche. But the HN filter produces a very particular lens — you'll find conference talks and explainer videos, not cooking tutorials or sports analysis. The generativity here is real but narrow: it demonstrates a workflow that anyone could replicate with a different source community and a different taste profile. The deeper question is whether this pattern — frontier model as full-stack developer, community corpus as taste engine — scales beyond weekend projects by celebrity engineers. If it does, the monopoly power of recommendation algorithms weakens significantly. If it doesn't, it's a compelling demo that reinforces how much leverage accrues to people who already have audience, taste, and model access.