Glitterball: Design after generation https://www.glitterball.dev/blog/ Writing by Mark Boyes-Smith on evals for product design. en Prototypes got cheap. Judgement didn't. https://www.glitterball.dev/blog/prototypes-got-cheap/ https://www.glitterball.dev/blog/prototypes-got-cheap/ Thu, 01 Oct 2026 09:00:00 GMT Mark Boyes-Smith Generating an interface now costs minutes. Deciding whether it's any good still costs a meeting. That gap is the most important problem in product design right now. AI slop is what the average looks like https://www.glitterball.dev/blog/slop-is-the-average/ https://www.glitterball.dev/blog/slop-is-the-average/ Thu, 01 Oct 2026 09:00:00 GMT Mark Boyes-Smith Generated interfaces converge on the same purple gradients, glass cards and "Get started" buttons. That isn't a bug in the models. It's what you get when nobody states a point of view, and it's measurable. What design should steal from how AI labs test their models https://www.glitterball.dev/blog/steal-from-model-evals/ https://www.glitterball.dev/blog/steal-from-model-evals/ Thu, 01 Oct 2026 09:00:00 GMT Mark Boyes-Smith AI labs spent years learning how to tell whether a new version is actually better. Five of their habits translate directly to product design. One of their failure modes does too. Measure what you can. Judge what you must. https://www.glitterball.dev/blog/measure-then-judge/ https://www.glitterball.dev/blog/measure-then-judge/ Thu, 01 Oct 2026 09:00:00 GMT Mark Boyes-Smith My first design eval flagged so much that nobody read it. The fix was to stop asking a model questions a ruler could answer, and to let the judge say "I'm not sure". Design systems were written for people. Agents need rules. https://www.glitterball.dev/blog/design-systems-for-agents/ https://www.glitterball.dev/blog/design-systems-for-agents/ Thu, 01 Oct 2026 09:00:00 GMT Mark Boyes-Smith The most prolific contributor to your product's UI may soon be an agent that has never read your design system. Here's what changes when the standard has to be machine-readable. The design leader's job is now to write the eval https://www.glitterball.dev/blog/leaders-write-the-eval/ https://www.glitterball.dev/blog/leaders-write-the-eval/ Thu, 01 Oct 2026 09:00:00 GMT Mark Boyes-Smith When agents produce most first drafts, a design leader's taste can't be applied one screen at a time any more. It has to be written down, versioned and run. That changes the job.