Simon Willison, a software developer, recently analyzed his GitHub code-frequency chart to track the impact of coding agents and advanced language models on his development workflow. He identified a significant spike in code activity for his open-source project, Datasette, which correlates with the introduction of several high-performance AI models. These models include Opus 4.8, GPT-5.5, Fable 5, and the recently released GPT-5.6 Sol.

Willison noted that his work on sqlite-utils 4.0rc2, published on July 5, 2026, was primarily generated by the Claude Fable model at a cost of $149.25. He further detailed the release of the GPT-5.6 model family—comprising Luna, Terra, and Sol—on July 9, 2026. This analysis highlights how AI-assisted programming tools are actively shifting productivity metrics within his personal open-source software development projects.

Simon Willison, a software developer, recently analyzed his GitHub code-frequency chart to track the impact of coding agents and advanced language models on his development workflow. He identified a significant spike in code activity for his open-source project, Datasette, which correlates with the introduction of several high-performance AI models. These models include Opus 4.8, GPT-5.5, Fable 5, and the recently released GPT-5.6 Sol.

Willison noted that his work on sqlite-utils 4.0rc2, published on July 5, 2026, was primarily generated by the Claude Fable model at a cost of $149.25. He further detailed the release of the GPT-5.6 model family—comprising Luna, Terra, and Sol—on July 9, 2026. This analysis highlights how AI-assisted programming tools are actively shifting productivity metrics within his personal open-source software development projects.