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I Rebuilt Andrej Karpathy’s HackerTube With His Workflow. Here Is Every Step, the Token Bill, and My Own Version.
One year of Hacker News comments, Gemini Flash in Antigravity CLI, 514 videos, about 17M input tokens and $0 in API charges. Plus the three things I had to fix by hand.
I made full repo Public: Hackertube
I rebuilt Andrej Karpathy’s HackerTube on one year of Hacker News comments using Antigravity CLI and Gemini 3.8 Flash. The agent and model work took 41.5 minutes and produced a YouTube-style site with 514 videos in 28 topics. It used about 17 million input tokens (84% cached) and 409,000 output tokens on my Gemini subscription, so I paid $0 in API charges. I had to step in three times, and those fixes are the most useful part of this post.
On 31 October Karpathy posted HackerTube, a YouTube clone filled only with videos that Hacker News commenters recommended. The HN thread passed 2,400 points. His post says what he built. The thread kept asking how, and above all what it cost. So I repeated it and measured everything.
What is HackerTube?
HackerTube is a YouTube-style site that Karpathy built in about two hours with Claude Code…
