The role of engineers in the software factory

Engineering leader Cate Huston traced one misplaced mobile button to tests that checked only desktop width, and argues that engineers now fix the system that let it through.

Cate Huston, an engineering leader who writes the blog Accidentally in Code, found a menu button out of place on a phone screen. Her team builds its product with AI agents and had a design system and automated screenshot tests, yet the bug reached users. She fixed the bug in a day, then spent two weeks changing the checks that had missed it.

• The screenshot service Chromatic captured only desktop width. Phone-width captures of every component found nine more layout bugs and missing mobile navigation in internal tools.
• A new detector checks every component at phone width for overlapping or overflowing elements. It records existing problems as a baseline that may only shrink, and fails the build on new overflow.
• An audit with an AI model found two invitation flows that were 93 per cent identical. Each fix came with an automatic check, such as a lint rule or a test page for every component.
• A rule in the AI agent's instruction file to use the design system had not been enough. Standards once applied unevenly in code review are now enforced by the build.

Huston argues that maintaining such systems is why engineers remain employed. That a team should treat each escaped bug as a missing check, and budget time for tuning unreliable checks, is an inference and is not the author's claim.

Derived by Working Surface from the article; more in the Playbook. Source line: An instruction is a suggestion. A guard fails the build.

4 November 2026: teams building with AI agents are turning each failure or correction into a permanent check, rule or shared record, rather than fixing one result at a time.