Karpathy slammed YouTube's poor recommendation algorithm, having Claude build HackerTube in just two hours.

Beating AI Flash News: OpenAI co-founder and current Anthropic pre-training team member Andrej Karpathy grew frustrated with YouTube’s one-size-fits-all recommendations and exaggerated thumbnails, so he had Claude build a video recommendation site called HackerTube, a process that took only around two hours. HackerTube features 6,454 YouTube videos spanning 150 topics, all sourced from Hacker News tech community’s 20 years of recommendation records, not YouTube’s own algorithm. The site requires no login, is accessible immediately, and saves individual browsing status locally. Instead of creators’ exaggerated thumbnails, videos use a uniform frame captured from the middle of the clip. To source these videos, Claude processed roughly 43 million historical Hacker News comments. It first narrowed the scope via link matching, regular expressions, and other methods, then used Sonnet to identify video-recommending comments and filter out spam, finally curating the videos from around 40,000 valid comments. The entire project was built with Claude Code: Opus 5.5 handled data processing workflows, website development, and deployment, while Sonnet managed large-scale comment classification. Karpathy noted he did not write code or operate the terminal manually; he only manually applied for a YouTube API key, purchased the domain, launched the server, and configured DNS. The remaining work, including server hardening and performance optimization, was delegated to Claude. Karpathy disclosed the project consumed a total of 504 million input tokens (about 90% cached) and 7.6 million output tokens. Over 90% of the token usage went to Sonnet’s comment classification, while website development and deployment consumed roughly 1 million Opus 5.5 tokens. HackerTube is now live, and its curated recommendation data is available for download. Others can feed this data to their own AI agents to create video sites tailored to personal interests.