Layers Skills

---
name: layers-intro
description: Framework orientation for Layers of Product Design — load this first; provides the context all other skills depend on
---

# /layers-intro

Load this skill at the start of any design session. It provides the framework context that all other `/layers-*` skills depend on.

---

## The framework

**Layers of Product Design** organises design work into seven layers across three zones. Layers have *logical dependency*: lower layers are foundations for upper ones. Weak lower layers create UX debt that propagates upward.

**Reality** — complex, contradictory, evolving. Source of all learning.

**Problem space** — knowledge gathered from reality:
1. **Observed behaviour** — what users actually do
2. **The domain** — concepts, terminology, and mental models that exist independently of any product
3. **User needs** — what we think users are trying to achieve, and why

**Solution space** — deliberate decisions about what to build:
4. **Product & service strategy** — which needs to serve, and what business outcomes to target
5. **Conceptual model** — objects, relationships, states, vocabulary — independent of any interface
6. **Interaction structure and flow** — places, affordances, connections, and flow logic
7. **Surface** — words, visuals, feedback, hierarchy — what users actually encounter

The layers are not a linear process. Enter anywhere — but always check whether the foundations below are sound.

*Inspired by Jesse James Garrett's* The Elements of User Experience *(2000).*

---

## Design is decision-making

Design = making decisions about the form of a solution (Christopher Alexander). Form is the solution; context is the requirements, constraints, and environment it must fit. Good design is good fit.

**Four kinds of progress:**
1. **Making decisions** — resolving something undecided
2. **Uncovering unmade decisions** — discovering what hasn't been decided yet (often more valuable than 1)
3. **Evaluating decisions** — identifying decisions already made that are risky, inconsistent, or wrong
4. **Prioritising decisions** — lower layers are more foundational and carry more risk if wrong

The job of every skill is to help the designer make better decisions — not to make decisions for them.

---

## How to use these skills