pm-user-stories — Break an Epic into User Stories

Part of the Personal Corp framework — running a one-person business through AI agents. Decompose a large requirement or Epic into independently-deliverable User Stories. Every Story is validated against INVEST. Output is ready to paste into Jira, Linear, or GitHub Issues.

Inputs

| Field | Required | Notes | |---|---|---| | Requirement description | yes | An Epic or large requirement; can paste a PRD section | | Granularity | no | Sprint-level (1-3 days/story) or iteration-level (1-2 weeks); default Sprint | | Team composition | no | FE+BE split / full-stack / has mobile — affects per-tier splitting | | Estimation system | no | Fibonacci (1/2/3/5/8/13) or T-shirt (S/M/L/XL); default Fibonacci |

Step 1 — Map the full requirement

Extract from the requirement:

• Roles involved: who uses this? (end user, admin, ops, etc.)
• Core flow: main path? branches?
• Business rules: constraints and conditions?
• Data entities: what data objects are involved?

Step 2 — Pick a splitting pattern

Five patterns. Pick by requirement shape; combine for hybrids.

| Pattern | When to use | Example | |---|---|---| | By workflow step | Requirement is a complete process | Checkout → pick item / address / payment / confirm | | By business-rule variant | Same feature with multiple rule sets | Discount → fixed-amount / coupon / points / combined | | By CRUD operation | Requirement centers on one data object | Address book → create / edit / delete / set default | | By role perspective | Multi-role feature | Order management → user view / merchant processing / ops dashboard | | By complexity progression | Feature has simple and full versions | Search → keyword / filters / suggestions / history |

Selection principle: target ≤ 1 Sprint per Story. Hybrid requirements combine patterns.

Granularity calibration:

• Stories < 3 → likely too coarse; check for hidden sub-flows
• Stories > 20 → likely too fine, or this is multiple Epics; split Epics first
• Single Story estimate > 8 points → too big; split further

Step 3 — Write each User Story + AC

### US-{N}: {Story title — verb-led, e.g. "Choose payment method"}

**Role:** As a {role}
**Action:** I want to {specific action}
**Value:** so that {business value}
**Priority:** P0 (must) / P1 (important) / P2 (nice-to-have)
**Story Points:** {estimate}

**Acceptance Criteria:**
- [ ] Given {precondition}, When {action}, Then {expected result}
- [ ] Given {exception precondition}, When {action}, Then {error handling}

**Dependencies:** {other Story IDs, or "none"}
**Tech notes:** {dev callouts, optional}

Story Point reference (Fibonacci):

| Points | Complexity | Effort | Typical scope | |---|---|---|---| | 1 | Trivial | < 0.5 day | Copy change, config tweak, add an event | | 2 | Simple | 0.5-1 day | One CRUD operation, form validation | | 3 | Medium | 1-2 days | A complete feature point with business logic | | 5 | Complex | 2-4 days | Multi-module interaction | | 8 | Big | 4-7 days | New system / new flow core module | | 13 | Re-split | > 1 week | Means the Story is too big — must split |

AC quality rules — every AC must satisfy:

• Specific: Given clause has a concrete precondition ("user logged in AND balance ≥ 100"), not "user logged in"
• Testable: Then clause has a verifiable result ("balance decreases by 100 AND order status = paid"), not "payment succeeds"
• Edge coverage: every Story has ≥ 1 happy-path AC + ≥ 1 exception-path AC

Step 4 — INVEST validation

Run each Story against the six checks:

| Principle | Check | If fails | |---|---|---| | Independent | Delete this Story — can the others still ship? | Cyclic deps → merge or re-split | | Negotiable | Does it describe "what" or "how"? | Strip implementation detail, keep value | | Valuable | Will the user perceive value when this ships? | Pure refactor → attach to a user-perceivable feature | | Estimable | Can the team agree on points within 5 minutes? | Wide spread = unclear requirement; clarify first | | Small | Fits in one Sprint? | Larger → split | | Testable | Can QA write test cases directly from the AC? | Add concrete edge values and expected results |

Definition of Ready (must hold before entering development):

| Check | Standard | If unmet | |---|---|---| | AC complete | ≥ 1 happy + ≥ 1 exception | Fill ACs, then schedule | | No blocking deps | All upstream Stories done or mockable | Tag "Blocked", push to a later Sprint | | Designs ready | UI Stories have design specs | No designs → tag "Needs design" | | Estimation consensus | Spread < 2× | Re-discuss scope until agreed | | Business rules confirmed | All [TBD] resolved | Confirm with PM/business, then dev |

Dependency rules:

• Data dependency: Story B needs data created by Story A → B depends on A
• Interface dependency: Story B calls API provided by A → B depends on A
• No dependency: Stories on different objects or different roles → parallel
• Pseudo-dependency: looks dependent but mockable → tag "Mockable to decouple"

Step 5 — Output a Story Map

markdown
## Epic: {requirement name}

### Story Map (user journey → Story mapping)

| Journey stage | Stories | Priority | Points |
|---|---|---|---|
| {stage 1} | US-001, US-002 | P0 | 5 |
| {stage 2} | US-003, US-004 | P1 | 8 |

### Sprint planning
- **Sprint 1 (MVP):** {Story list}, total {X} points
- **Sprint 2:** {Story list}, total {X} points

### Dependencies
US-001 → US-003 → US-005 (must follow this order)
US-002, US-004 (parallel)

Quality bar

1. Every Story passes all six INVEST checks
2. AC uses Given-When-Then with ≥ 1 happy + ≥ 1 exception
3. Dependencies tagged explicitly, with mockability flagged
4. 13-point Stories must be re-split
5. Story Map includes Sprint planning suggestion

When input is incomplete

• One-sentence requirement → first output a feature outline, confirm scope, then split
• Too large (> 20 Stories) → recommend splitting into Epics; agree on MVP scope first
• Missing business rules → tag [business rule TBD] and propose plausible assumptions for confirmation

Related skills

• /pm-prd — write a PRD first to lock scope, then break into Stories
• /pm-prioritize — when there are many Stories, RICE-rank for Sprint priority