Gate
A check every proposal must pass before it can reach you. Most pass silently.
Gates are the engine's safety checks: is there enough evidence, is this term protected, does it already exist in the account, is the data fresh, is there stock to sell.
Most proposals pass every gate, which is why AutoPPC no longer shows you a row of green ticks on each one. A gate is only worth your attention when it changed the outcome — when it held a change back or dropped it. Those are labelled in plain language on the row.
A gate that fails does not silently disappear. It is recorded in the run, counted in the funnel, and visible in the proposal's detail.