You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.
Use when you have a written implementation plan to execute in a separate session with review checkpoints
Use when turning a rough ML idea into a runnable experiment - define the experiment card (question, hypothesis, baseline, primary metric, budget, cheapest verification rung) before writing training code.
Use when planning how to verify an ML experiment cheaply before expensive runs - design the R0-R7 ladder from local sanity checks to full study, with promotion/stop criteria.
Use when concluding an ML experiment - produce a sober conclusion that separates confirmed results from exploratory observations and states the highest verified rung.
Use when executing implementation plans with independent tasks in the current session
Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes
Use when implementing any feature or bugfix, before writing implementation code