Building a software factory out of Unix mail
"Agentic software factory" became the phrase of 2026. StrongDM decided no human would write or review code. OpenAI shipped about a million lines in five months with a handful of engineers. Uber says about 70% of its pull requests now come from agents. The picture is always a production line: planner agents, coder agents, tester agents, reviewer agents, and engineers who design the line instead of writing code. I wanted to try one. Before building anything, though, I asked a more basic question: why would I want a factory at all, rather than a single actor that produces software? This post covers where that question took me, from first principles to two small proofs of concept built with the most old-fashioned tool I could find: Unix mail. I did this exploration together with an AI coding agent (Claude Code), in a loop of research, argument and building. Some of the best turns came from pushing back on its answers, and I'll point those out as they come. Does softwar...