Line those checks up and make them binding, and you have a gate. This is where our experiment has the most to say, and it isn't what you might hope.
Quality gate
A set of conditions work has to meet before it may go further, where failing any one stops it: types clean, tests pass, no new security findings. It answers yes or no, and nobody gets to argue with it on the day.
A mechanical gate can only refuse what someone thought to check. An agent can pass every one and still have built the wrong thing, because the behaviour that mattered was never asked for, so no check knows it is missing. Someone reading the code and thinking about the job sometimes will. A gate works with a good brief. It can't stand in for one.
Say it to your agent
“Our gate is: bun run typecheck, bun run lint and bun test all exit 0. Before you start, list the behaviours this brief needs that none of those would notice if you got them wrong, such as what happens when events arrive out of order. Write a test for each, or ask me.”