Skill: Plan and Scope

Purpose

Guide the creation of a structured, phased implementation plan before any code is written.

When to Use

At the start of any new feature, refactor, or project. Always plan before executing.

Process

1. Clarify the Goal

• What is the end-user outcome?
• What are the constraints (time, tech, compatibility)?
• What already exists that we're building on?
• If a PRD exists (*-prd.md), read it — scope and goals are already defined. Focus on dependencies, risks, and phasing.
• If a UX spec exists (*-ux-spec.md), read it — reference states, flows, and affordances when defining phase tasks.

2. Define the Scope

• List what IS in scope (be specific)
• List what is NOT in scope (be explicit — this prevents creep)
• Identify assumptions that need validation

3. Map Dependencies

• What existing code/APIs/services does this touch?
• Are there cross-repo dependencies (backend ↔ frontend)?
• What needs to exist before this can start?
• Repo strategy: Will this be a monorepo (single fullstack profile) or separate repos per concern (e.g., django-api + nextjs)? Ask the user — this affects how /scaffold creates sub-projects and how phases are organized.

4. Identify Risks

• What could go wrong?
• What are we unsure about technically?
• Where might the plan need to change?

5. Produce the Plan Document

Output a plan.md with this structure:

# Plan: [Feature Name]

## Goal
One paragraph describing the desired outcome.

## Scope
### In Scope
- ...

### Out of Scope
- ...

## Phases
Grouping and ordering only. Each phase's internal structure — objective, input,
tasks, output, suggested skills, branch, verification checklist — follows the
`phase-breakdown` skill; don't duplicate those fields here. Tag every phase with
its `[directory/]` and mark parallel groups and sync points.

## Parallel Group A (Phases 1-2)
### Phase 1: [Backend — Name] [server/]
### Phase 2: [Frontend — Name] [web/]

## Sync Point: [e.g., Integration Summary]

## Phase 3: [Name] [directory/]
...

## Repo Strategy
Monorepo / Separate repos: [choice]
Sub-projects: [e.g., api (django-api), web (nextjs)]

## Dependencies
- ...

## Risks & Open Questions
- ...

## Cross-Repo Notes
- Backend contract changes needed: Y/N
- Frontend integration summary required: Y/N

Key Principles

• Plans are living documents — update them as you learn
• Each phase should be independently reviewable (own branch, own PR)
• A plan that's too detailed upfront is as bad as no plan — aim for clarity on WHAT, flexibility on HOW
• Keep phases small — the phase-breakdown skill owns the sizing rule (target: 1-3 hours of focused execution, reviewable in a single PR). If a phase feels too big, split it.