Karpathy Uses GPT-5.1 Thinking to Grade December 2015 Hacker News Discussions in Hindsight

Andrej Karpathy built hn-time-capsule, a tool that feeds each December 2015 Hacker News front-page article and its comment thread to GPT-5.1 Thinking for a retrospective analysis.

The project, written with Claude Opus 4.5 in about three hours, processes 930 articles at a cost of about $58 and roughly one hour.

Results include prescience and wrongness grades for commenters, and the project is hosted on his website with the intermediate data available for download.