plan

To turn a PRD or spec into a phased implementation plan, you provide the goal to be broken down into vertical slices. It generates a plan.md capturing context, out of scope items, phase steps, and testing notes for execution.

Vertical slicing in project planning is breaking complex work into phases that deliver end-to-end value. This approach ensures each implementation step covers code, tests, and documentation rather than isolated horizontal layers.

You need to create an implementation plan before coding when a change is large enough to require sequencing. It captures assumptions and re-plan triggers to prevent guesswork during complex feature execution.

To write a plan.md for project execution, input your feature request or spec. The output includes objective, context, out of scope boundaries, phase steps, verification notes, and review guidance directly in the project root.

Features not targeted by the current vertical slices should be marked as out of scope in a feature specification. Documenting these boundaries in plan.md maintains focus on the immediate implementation phases.

Project planning is designed for changes large enough to need sequencing before execution begins. Small feature requests that do not require deliberate vertical slicing across code and tests may not need a plan.md.