Simon Willison

There's No Limit to How Bad Code Can Get

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Simon Willison discusses the pitfalls of attempting to replace a legacy system with a new one when technical debt is overwhelming. He explains that while the old system continues to evolve, developers lack incentive to improve it, and the new team, initially fast, eventually struggles to understand and deliver the required functionality. The result is often two partially functional systems in production, with the new one abandoned and the old one still running, increasing risk and complexity.

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Simon Willison
Sep 11

Feeling sad about AI

Simon Willison reflects on the emotional impact of AI tools that can produce code quickly, noting that many developers experience an initial sense of disheartenment. He argues that recognizing the shift from coding to higher‑level problem solving allows experienced engineers to leverage new tools and add greater value. Willison emphasizes that software engineering has always faced rapid change, so adapting to AI is part of the profession’s ongoing evolution.

Simon Willison
Sep 14

What blog posts influenced your thinking the most?

Simon Willison reflects on three blog posts that shaped his professional outlook: Joel Spolsky’s *The Law of Leaky Abstractions*, Will Larson’s 2018 article *Migrations: the sole scalable fix to tech debt*, and Charity Majors’ *The Engineer/Manager Pendulum*. Each piece offered a distinct lesson—recognizing hidden complexities in abstractions, embracing migrations as a core engineering skill, and validating the fluid movement between engineering and management roles. These insights collectively encouraged Willison to deepen his technical understanding, prioritize migration work, and feel empowered to shift career tracks without fear.

Simon Willison
Aug 9

GitHub Models is now retired

GitHub Models is now retired I missed this news until today, when the GitHub Actions run for my simonw/research repository failed with this error message: GitHub Models is temporarily unavailable as part of a scheduled retirement brownout. That message is already stale, because the retirement has been completed.

Simon Willison
Aug 28

Just a rumour of a bug is enough to find a security exploit these days

The article reports that rumors of bugs in open‑source projects now trigger rapid security exploits, with automated agents probing for vulnerabilities within minutes of a patch being discussed. Anil Madhavapeddy demonstrates how modern coding agents can exploit even minimal hints, and rclone maintainer Nick Craig‑Wood notes a dramatic spike in security disclosures and delayed CVE assignments. The post highlights the need for new processes to protect open‑source communities from swift exploitation.