Simon Willison

Quoting Laurie Voss

Laurie Voss argues that while the cost of writing code has fallen dramatically, the costs of reviewing, fixing, and operating software are rising and will continue to do so. She emphasizes that the true expense lies in understanding user needs, precisely defining requirements, and ensuring a pleasant user experience—costs that are unique to each software product and do not scale with reuse. As software demand grows without an upper limit, these user‑centric costs will dominate the overall development effort.

Simon Willison
Sep 11

Quoting Boris Cherny

The article discusses how production code generated by Claude, Anthropic’s AI, should meet higher standards than human-written code. Anthropic enforces this through numerous guardrails such as lint rules, extensive testing, Claude-driven end‑to‑end tests, daily fuzzers, automated code and security reviews, and automated refactoring. These measures aim to prevent the code from becoming difficult to maintain.

Simon Willison
Aug 23

Quoting Drew Breunig

The article reflects on the shift in perspective after the release of Fable, a new model that promised to solve many coding challenges at a comparable or lower cost. Prior to Fable, developers felt it was pointless to invest heavily in coding tools or context strategies, as newer models would likely render them obsolete. However, Fable’s performance was so impressive that, despite its high cost, it prompted a reevaluation of how work was distributed across different models such as Opus, 5.6, K3, and GLM.

Simon Willison
Sep 12

Quoting Paul Ford

Simon Willison reflects on the evolving role of software developers in the age of AI, noting that while AI can produce high‑quality code, it also enables poor execution that leads to project failures. He argues that the industry is beginning to recognize the continued need for human collaboration and expertise to truly innovate. The piece highlights the tension between automation and the essential human element in software creation.

Simon Willison
Aug 26

Quoting Paul Dix

The article highlights Paul Dix’s astonishment that AI was able to generate one million lines of code and then refine it over several months into a reliable software product now used by millions of developers. Dix argues that this achievement is far more impressive than merely translating code between languages, emphasizing that with a verification system and clear guidance, AI can produce and iteratively improve highly complex, sophisticated software until it functions perfectly.

Simon Willison
4d ago

Quoting Thariq Shihipar

The article announces that Claude Code will now support AGENTS.md files starting with version 2.1.277. If a CLAUDE.md file is absent in a folder, Claude will automatically look for and use AGENTS.md, leveraging Claude Code mods to customize the harness. The built‑in mod is available for use, and users can also create their own custom project instructions.

Simon Willison
Aug 22

More than just code review

The article discusses the essential skill of effectively instructing coding agents and verifying their changes. It highlights that while line‑by‑line code review is one method, it is not the most efficient way to validate software changes. The focus is on confidently guiding agents and confirming correct implementation without exhaustive inspection.

Simon Willison
Sep 6

Quoting Zach Kehs

The article discusses the idea that, unlike physical structures that can only grow until they collapse, software can continue to accumulate complexity indefinitely. It highlights that code can always degrade, with new layers of indirection or performance reductions emerging over time. The piece underscores the ongoing risk of technical debt in software development.

Simon Willison
Aug 19

Quoting Jeremy Morrell

My hypothesis is that there is a new opportunity for Extensible Software on the web . LLMs radically lower the cost of authoring extensions, and modern sandbox primitives lower the deployment cost and provide good security boundaries.

Simon Willison
2d ago

Quoting voxium

Simon Willison describes his experience at a large company where all documentation, code, tests, PRDs, tickets, and reports are generated by Claude Code. His team is forced to ship rapidly, working long hours, yet management insists that code push is not a bottleneck, leading to frustration and a lack of meaningful reading or review. The situation highlights a reliance on AI-generated content that may undermine quality and collaboration.

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.