Simon Willison's Datasette code frequency spikes with Opus 4.8 and GPT-5.5

Simon Willison analyzed the impact of coding agents and Opus 4.5 class models on his open source project, Datasette, by examining its GitHub code frequency chart.

The data reveals sporadic bursts of activity, with the largest spike occurring in 2026 featuring 37,022 additions and -9,528 deletions. A significant deletion spike of -10,658 occurred in mid-2020, while earlier notable activity included 15,998 additions in early 2018.

Willison notes that the major spike in activity at the end of the timeline aligns with the release of Opus 4.8, GPT-5.5, Fable 5, and GPT-5.6 Sol.