Existing Mechanisms

This file holds one definition the rest of the workflow depends on and must never restate: the questions that prove you understand what the codebase already does, before you propose changing it.

It is not a step. Reading this satisfies no gate. It tells you what the gate you are already standing in has to answer.

Why this exists

The expensive failures of this workflow are almost never bad trade-off analysis. They are analysis that was never done: a mechanism that already existed under a name nobody searched for, a caller nobody enumerated, a subsystem left unreachable by a change that replaced it, a second pathway bolted alongside the first because unifying them was never considered.

These questions find something almost every time they are asked. That is the whole argument for asking them by default instead of waiting for a human to ask them again.