plan-task

name	plan-task
description	Break complex features into a phased plan with parallel tasks, dependency graph, and verifiable success criteria. Use before multi-file work.
origin	FlowDeck

Plan Task Skill

Turns vague feature requests into concrete, executable plans. Each step maps to a file, has a verification, and fits within a working session.

When to Activate

Activate when:

• A feature touches more than 2 files
• You are unsure what order to implement things
• Multiple people need to work on the feature in parallel
• The feature involves data model changes or API changes

Core Principles

• Foundation first: types → data → services → routes → UI
• Steps must be independently verifiable
• No step longer than 2-3 hours of work
• Success criteria must be observable (not "it works")

Task Sizing Guide

Size	Duration	Action
Too small	< 30 min	Combine with a related task
Right size	1-3 hours	Keep as is
Too large	> 3 hours	Split into two steps in separate waves

Workflow

1. Parse requirements — list every behavior the feature must have
2. Map to files — which files must change for each behavior?
3. Build dependency graph — which changes depend on others?
4. Group into waves — independent changes in same wave
5. Write success criteria — one observable outcome per requirement

Wave Assignment Rules

Same wave (run in parallel):

• Different files, no shared mutable state
• Neither task reads the other's output

Next wave:

• Integration tasks (wiring together Wave 1 outputs)
• Review and documentation
• Any task that reads output produced by Wave 1

Plan Format

# Plan: [Feature Name]

## Objective
[What this delivers and why]

## Wave 1 — Foundation (parallel)

### Task 1.A — [Name]
- **Agent**: @backend-coder
- **File**: `src/models/subscription.ts`
- **Scope**: Create Subscription model with id, userId, status, expiresAt
- **Verify**: `npx tsc --noEmit` passes

### Task 1.B — [Name]
- **Agent**: @researcher
- **Scope**: Document Stripe subscription API
- **Verify**: Research covers: create, cancel, webhook events

## Wave 2 — Implementation (after Wave 1)

### Task 2.A — [Name]
- **Agent**: @backend-coder
- **Depends on**: Task 1.A, Task 1.B
- **File**: `src/services/billing-service.ts`
- **Scope**: Implement subscribe(), cancel(), handleWebhook()
- **Verify**: `npm test src/billing.test.ts` passes

## Success Criteria
- [ ] [Observable outcome 1]
- [ ] [Observable outcome 2]
- [ ] `npm test` exits 0
- [ ] `npx tsc --noEmit` exits 0

Success Criteria Quality

✅ Good: "User can log in with email+password and receives a JWT"
❌ Bad: "Authentication works"

✅ Good: "GET /users/:id returns 404 when user does not exist"
❌ Bad: "Error handling works"

✅ Good: "npm test produces 0 failures"
❌ Bad: "Tests pass"