---
name: skill-user-modelling
type: skill
description: >-
  Produce the user-modelling artefacts for a venture — segment, persona, JTBD
  layers, forces, opportunity solution tree, behavioural modes, scenarios — one
  artefact per job, grounded in research and tagged known/assumed/unknown. Use
  this whenever Sonar needs to understand who a venture serves and why they
  progress, or to decompose an overloaded "ICP one-pager" into its proper parts.
  Reads convention-user-modelling. Shares the ICP/segment artefact with Reach's
  skill-audience-icp — model once, let Reach consume it. Surfaced by a1.Muse.
---

# user-modelling

Sonar's "who and why" skill. Produces the modelling artefacts that anchor an engagement to real people and the progress they want, using the toolkit's shared definitions rather than an ad-hoc one-pager.

## Trigger

A venture's audience and motivation are unclear, compressed into one overloaded artefact, or assumed rather than modelled. The first run's first fix was decomposing the a1.Muse ICP one-pager.

## Behaviour

1. **Pick the job, then the artefact.** Name what you need to understand and select the single artefact for it from `convention-user-modelling` — one artefact per job, never one artefact doing several.
2. **Decompose anything overloaded.** Where a single "ICP one-pager" is carrying segment, persona, JTBD, and forces at once, split it into a needs-based **Segment**, a **Persona**, the **JTBD layers** (higher / core / lower), and the **Forces**. This is the standing first fix.
3. **Settle the Why before the How.** Establish JTBD and Forces before journey, modes, scenarios, or OST — the motivation layer frames everything above it.
4. **Ground in research, tag confidence.** Build each artefact from evidence where it exists; tag every claim known / assumed / unknown. An assumed persona trait is labelled, not asserted.
5. **Keep the distinctions clean.** Hold archetype (pattern) ≠ persona (person) ≠ behavioural mode (state); hold Forces (the switch drivers) ≠ Modes (the resulting state). The pitfalls in `convention-user-modelling` are the checklist.
6. **Hand off.** The model feeds the conversion diagnostic (forces, modes), the service blueprint (modes, scenarios), and the opportunity solution tree (outcome → opportunities).

## Reads

`convention-user-modelling` (the artefact definitions, hierarchy, JTBD altitudes, pitfalls), `standard-prioritisation` (the confidence overlay).

## Relationship to skill-audience-icp

Reach's `skill-audience-icp` produces a marketing-targeting ICP for go-to-market; this skill produces the full diagnostic model for strategy and service design. They share the segment/persona artefact. The division: model the audience once here against `convention-user-modelling`, and let `skill-audience-icp` consume that model for targeting rather than re-deriving it. Where only targeting is needed, Reach's skill stands alone; where strategy or service design is the job, this skill leads.

## Guardrails

One artefact per job — never overload. Why before How. Ground in research; mark assumptions and unknowns. Keep the archetype/persona/mode and forces/modes distinctions. Don't duplicate Reach's ICP — reconcile through the shared artefact. Propose-only.