I spent a day building a code factory: a manager agent that reads a project's own build plan, works out what can be built in parallel, hands each subtask to an engineer in an isolated workspace, and merges the result behind a test gate.
It works. Five subtasks built, tested, merged and logged in under a minute, on a backlog that was written weeks before the factory existed.
Three things about it were wrong on the way there. None of them showed up in the design, in review, or in the tests. All three showed up in the log, and two of them only because I went looking for something else.
What the thing is
A manager agent on Google ADK, running gemini-3.7-flash. Six tools: read the graph, read what the human pointed at, delegate, poll, merge, finish. The engineers work in their own git worktree on their own branch, run the tests for the area they touched, and commit. The manager merges to one trial branch, one at a time.
