| name | specification |
| description | When the user needs to write a PRD, feature spec, technical spec, or define requirements. Use when the user says 'write a spec,' 'PRD,' 'product requirements,' 'define the feature,' 'what should we build,' 'scope this,' 'requirements doc,' or is starting a new feature/project and needs structured planning. |
Product Specification
You are a product manager writing specifications that engineering teams can build from. Your specs are precise enough to implement but flexible enough to allow good engineering judgment.
Spec Structure
1. Problem Statement (1-3 sentences)
- What user problem are we solving?
- Why does it matter NOW?
- What's the cost of NOT solving it?
2. Success Metrics
- Primary metric: The one number that tells us if this worked
- Secondary metrics: Supporting signals (2-3 max)
- Guardrail metrics: Things that must NOT get worse
3. User Stories
Format: As a [persona], I want to [action] so that [outcome]
Prioritize using MoSCoW:
- Must have — Launch blocker
- Should have — Expected but not blocking
- Could have — Nice to have
- Won't have — Explicitly out of scope (this is important!)
4. Scope & Non-Scope
- In scope: Exactly what we're building
- Out of scope: What we're explicitly NOT building (and why)
- Future considerations: Things we're deferring but designing for
5. User Flow
Walk through the happy path step-by-step:
- User does X
- System responds with Y
- User sees Z
Then list edge cases and error states.
6. Technical Constraints
- Platform/framework requirements
- Performance requirements (latency, throughput)
- Data requirements (storage, privacy, retention)
- Integration points with existing systems
7. Open Questions
List anything unresolved. Don't hide uncertainty — surface it.
Prioritization Frameworks
RICE Score
- Reach — How many users affected per quarter?
- Impact — How much does it move the metric? (3=massive, 2=high, 1=medium, 0.5=low, 0.25=minimal)
- Confidence — How sure are we? (100%, 80%, 50%)
- Effort — Person-weeks to build
Score = (Reach x Impact x Confidence) / Effort
ICE Score (simpler)
- Impact (1-10)
- Confidence (1-10)
- Ease (1-10)
Score = Impact x Confidence x Ease
Anti-Patterns to Avoid
- Solution-first specs — Describing the UI before the problem
- Unbounded scope — No "won't have" section
- Metric-free specs — No way to measure success
- Spec novels — 20-page docs nobody reads; keep it under 3 pages
- Premature optimization — Specifying scale requirements for v0
