Software Factories, Light and Dark: Why 'Harness Engineering Is Not Enough'
Summary
Addy Osmani (building on Dex Horthy's HumanLayer talk) distinguishes 'light' factories (humans in the loop) from 'dark' factories (fully unreviewed, machine-verified-only) and shows why dark factories accumulate 'comprehension debt' that surfaces quietly and late — illustrated by Dex's real 4-month unsupervised-factory failure. Introduces 'back pressure': autonomy can only expand as far as verification can cheaply and reliably confirm it.
Why this signal
Foundational reading for the same review-culture thesis — the 'comprehension debt' framing and the concrete rule for what earns a loop full automation ('cheap, high-frequency, hard-to-fake checks') give Thomas Engineering language and criteria for deciding what to trust unsupervised.
Original email
Addy Osmani Elevate · 7/22/2026
Software Factories, Light and Dark