What happened
The Decoder reports that Andrej Karpathy built HackerTube over a weekend using Claude's Opus 5.5, which filtered 43 million comments from 20 years of Hacker News into 6,454 recommended videos. The site requires no login, displays a single mid-video frame, and stores state locally in the browser. Karpathy then built TristanTube in three minutes with Claude Code, using 47,000 videos from Tristan Hume's YouTube channel list.