core-domain-chart-author

name

core-domain-chart-author

description

Create (render) a Core Domain Chart as an SVG in the Nick Tune / DDD Crew style, synthesizing a Capability Map (current positions) and a Devil's Advocate critique (recommended moves) into one picture: each capability plotted on business differentiation × model complexity, with an arrow from its Capability-Map position (grey dashed circle) to its critic-derived target (bold black circle). Use whenever someone wants to build, draw, generate, render, or produce a Core Domain Chart, plot (sub)domains or capabilities as core/supporting/generic, or visualize where capabilities should move and why — e.g. "make a core domain chart from this capability map and critique," "chart these subdomains," "show the target positions with arrows," even if they don't name the technique. Pairs with the core-domain-chart-critic (which supplies the critique). Produces a single .svg matching the bundled gold-standard example. Grounded in Millett & Tune, Patterns, Principles, and Practices of DDD.

Core Domain Chart Author

This skill renders a Core Domain Chart as an SVG that matches the bundled gold-standard (assets/example-core-domain-chart.svg). It is the synthesis step in the loop: a Capability Map says where each capability sits today, a Devil's Advocate critique says where it should move and why, and this skill draws both — current position, target position, and the arrow between them.

The chart plots each capability on two axes — Business differentiation (horizontal, Low→High) against Model complexity (vertical, Low→High) — over Generic / Supporting / Core regions. Movement is the point: a grey dashed circle marks the Capability-Map (origin) position, a bold black hollow circle marks the critic-derived target, and a thin arrow runs origin→target.

Don't hand-author the SVG. Use the generator; it encodes the palette, geometry, markers, legend, and icons so every chart comes out consistent.

Workflow

1. Gather the two inputs

• Capability Map — the capabilities (names) and where each sits today: its core/supporting/generic standing and, where available, its complexity. This fixes the grey origin positions.
• Devil's Advocate critique — typically the output of the core-domain-chart-critic (or capability-map-critic). Its findings are the recommended moves: each "this is mis-placed" becomes a black target and an arrow.

If you have a map but no critique, you can still plot the portfolio — every capability becomes a single static black circle at its position (no arrows). If you have a critique but no map, ask for the map (or the positions); the origins are what give the arrows meaning. Extract everything you can from what the user already gave you and ask only what you genuinely can't infer.

2. Read the references

• references/critique-to-moves.md — read this first. How to turn the map + critique into origin/target positions and arrow directions, with a table mapping each Devil's Advocate finding (core inflation, Hidden Core, Suspect Supporting, outsourced core, …) to a move.
• references/visual-style.md — the house look: palette, regions, the marker convention, labels, legend, and how/when to deviate. Read before editing the generator or hand-tuning an SVG.

3. Derive positions

For each capability decide: its origin (grey, from the Capability Map), whether the critique moves it, and its target (black). Positions are normalized 0..1 on each axis (0 = Low, 1 = High), origin bottom-left. Static capabilities (endorsed / no critique) get a target only — no from. Choose each label_pos (right/left/above/below) to avoid collisions; the generator does not auto-resolve overlaps.

4. Write the spec

Author a JSON spec (see assets/example-spec.json for a complete worked example):

{
  "axes": { "x": "Business differentiation", "y": "Model complexity" },
  "regions": { "generic_max_x": 0.34, "core_min_x": 0.66, "core_min_y": 0.35 },
  "capabilities": [
    { "label": "Fraud Detection", "x": 0.80, "y": 0.62,
      "from": { "x": 0.55, "y": 0.55 }, "label_pos": "right" },
    { "label": "Email Sending", "x": 0.18, "y": 0.60, "label_pos": "right" }
  ],
  "options": { "swap_marker_colors": false }
}

• x, y — the target / final position → black circle.
• from (optional) — the Capability-Map origin → grey dashed circle, with an arrow drawn from → (x, y). Omit for a static capability.
• regions — boundaries of the Generic band / Core box; the defaults reproduce the gold-standard, adjust only if the data calls for it.
• options.swap_marker_colors — leave false (grey = origin, black = target, as in the example). Only flip if the user explicitly wants the target in grey; see the note in references/visual-style.md.

5. Generate

python scripts/generate_chart.py SPEC.json -o core-domain-chart.svg

(Needs only Python 3 — no third-party packages.) Open the SVG (render it to PNG if you want to eyeball it) and check for label collisions, markers outside the plot, or arrows crossing region borders awkwardly; adjust the spec and re-run.

6. Present

Save the .svg to the outputs directory and present it. Add the short rationale described in references/critique-to-moves.md: one line per arrow (capability, from → to, and the critique finding that drove it), then a closing line for the static ones. The picture shows the moves; your text says why.

House style at a glance

A compressed reminder — references/visual-style.md has the full detail.

• Axes: X = Business differentiation (Low→High); Y = Model complexity (Low→High).
• Regions: Generic #fff8aa (left band, dashed), Supporting #d1f09f (base layer), Core #90baf9 (upper-right box, dashed); page #f2f2f2; icons globe / magnifier / person-check in #232f3d.
• Markers: grey dashed #b0b0b0 = Capability-Map origin; bold black hollow = critic-derived target; thin arrow origin→target; single black circle = static.
• Don't hand-write the SVG, add your own legend, or compute pixels in the spec — the generator handles all three.

Bundled resources

• scripts/generate_chart.py — the SVG generator. Reads a JSON spec, emits the chart. Palette/canvas/radius are constants at the top.
• assets/example-spec.json — a complete worked spec (the gold-standard input).
• assets/example-core-domain-chart.svg — the gold-standard output; mirror it.
• references/critique-to-moves.md — map + critique → positions and arrows.
• references/visual-style.md — the full visual specification.

References

Scott Millett with Nick Tune, Patterns, Principles, and Practices of Domain-Driven Design. Indianapolis: Wrox / Wiley, 2015.

Nick Tune, "Core Domain Patterns." https://medium.com/nick-tune-tech-strategy-blog/core-domain-patterns-941f89446af5

DDD Crew, Core Domain Charts (CC BY 4.0). https://github.com/ddd-crew/core-domain-charts