The loop engineering theme explained how to replace turn-by-turn prompting with a system that discovers work, assigns it, checks the result, and remembers what comes next. AI engineering writer and former Google engineering leader Addy Osmani scales that idea into a software factory and adds the governing constraint: the work can move only as fast as humans can review it.
A software factory is many harnessed loops running at once, fed by a queue of work and drained through a review gate into production, with humans owning the whole thing from above. It is not a bigger agent; it is an org chart made of loops.
Osmani follows that definition through the factory’s wiring diagram:
By and large, every box in this diagram is almost zero cost: generation, tests, scanning. They all run at scale for negligible cost. There is only one expensive box that proves stubbornly resistant to scaling, and that’s the review gate. That shiny amber box is “judgment”, and where the crux of the argument about whether we can make development faster and more frequent resides.
For Osmani, the review gate sets the pace. More generation only helps when verification scales with it; otherwise the factory manufactures a queue of code no one has the attention to understand. Imagine a conveyor belt of products being assembled together, only to pile up at the end, waiting for a poor human quality checker.
Osmani turns that constraint into architecture:
You might be thinking that all sounds unglamorous. You’re right. The safety net is made up of perfectly ordinary architectural practices we’ve always known about and mostly ignored: good types and method signatures so that mistakes are caught by the compiler instead of in production; test seams where we can pin behavior and make change observable; laying out the code so the next reader, human or model, knows where to find the thing they care about; keeping call stacks short and legible; keeping component boundaries well defined so a change doesn’t have a huge blast radius; and dependency injection so we can swap out one piece for another. None of it is new. We’ve always said we care about good architecture. But now that we’re using automated coding agents, that architecture is finally doing a second job as a cheap and hard-to-fake safety net against the mistakes the agent will make.
Put plainly, structure the work so mistakes are easy to spot and changing one thing doesn’t break everything else.
For designers, that means clear rules for each component, documented states, testable prototypes, and explicit review criteria. Build loops that can keep moving without you, but let them move only as far as those checks can prove the work is sound.

Software Factories, Light and Dark
A software factory is many harnessed loops running at once — the system that builds your software instead of you. You can keep humans in the loop, or take them out entirely.





















