Use when reviewing code for first-principles alignment — structural and logical issues, not style. Triggers on: "review this code from first principles", "first principles code review", or when the user wants deeper-than-surface code analysis.
Use when evaluating software architecture decisions from first principles. Triggers on: "review this architecture", "evaluate architecture", "architecture review", "are these service boundaries right", or when discussing system-level structure.
Use when planning a new project or feature using first-principles thinking. Triggers on: "plan this feature", "design from scratch", "greenfield", "what should we build", or when starting something new and wanting a principled foundation.
Use when reviewing a software design for first-principles alignment. Triggers on: "review this design", "evaluate this design", "design review", "is this design sound", or when a user shares a design doc/spec for feedback.