Willison Quantifies the Coding-Agent Effect on His Own Repo: Datasette Hit 37K Additions in 2026 via GitHub's Code-Frequency Chart

Simon Willison·medium signal

Curious about how much Opus 4.8 / GPT-5.5-class coding agents changed his throughput, Willison used GitHub's code-frequency chart on Datasette and found 37,022 additions against 9,528 deletions in 2026 — the largest spike in the project's history. He attributes the surge directly to AI-assisted development. It's a rare concrete, self-measured data point on agent productivity rather than a vendor benchmark.