--- name: diagram-design description: Create branded architecture, IT current-state, flowchart, sequence, state machine, ER/data model, timeline, swimlane, quadrant, radar/spider, polar chart (polar/radial lollipop), loop/flywheel, nested, tree, org chart, layer stack, Venn, pyramid/funnel, treemap, bar, line, Gantt and scatter charts, high-level, process, medallion, data flow, DP integration, DP security matrix, Sankey, fishbone, Wardley map, kanban, user journey, deployment, dependency graph, UML class, story map, or database schema diagrams as standalone HTML/SVG/PNG. Redraw .drawio/.drawio.png/.drawio.svg or Mermaid .mmd sources at a chosen size/detail; onboard brand tokens from a website; add semantic patterns, callouts, accessible motion, or sketchy/hand-drawn styling. license: MIT metadata: version: "2.6" ---

# Diagram Design

Create visual diagrams as self-contained HTML files with inline SVG and CSS, following an opinionated editorial design system.

Thirty-nine visual types. Semantic patterns describe behavior independently; type references describe layout. Details load from `references/` only when selected.

---

## 0. First-time setup — style guide gate

**Before generating your first diagram in a new project, verify the style guide has been customized.**

Don't silently ship default-skinned diagrams into a branded project.

First check the project root for a `.diagram-design` marker and resolve it per [`references/profiles.md`](references/profiles.md). A valid marker whose profile exists selects that file directly and skips this gate; `profile: default` also skips it. A malformed or missing-profile marker follows the visible failure handling in that reference. Never copy a marker-selected profile over the installed working copy.

Open [`references/style-guide.md`](references/style-guide.md) and check the default tokens. If they're still the shipped defaults (paper `#f5f5f5`, ink `#2d3142`, accent `#eb6c36` atomic-tangerine), **pause and ask the user**:

> *"This is your first diagram in this project. The style guide is still at the default (neutral white-smoke + atomic-tangerine). Do you want to customize it to match your brand first? Options: (a) pull from your website URL, (b) extract from an installed skill, (c) extract from a local folder / design-system directory, (d) paste tokens manually, (e) proceed with the default for now, (f) load a saved client profile."*

Then branch per the matching section of [`references/onboarding.md`](references/onboarding.md); for **(f)** follow [`references/profiles.md`](references/profiles.md).

**Once the style guide has been customized** (or the user explicitly opted for default), skip this gate on subsequent runs. A leading profile header names the copied-in active profile. Without a header, any semantic-role value or typography family differing from shipped defaults means **custom-unsaved**: skip the gate and offer to save it as a profile. All-default tokens with no marker/header trigger the gate. At the end of every onboarding method, offer to save the result as a named client profile per `references/profiles.md`.

---

## 1. Philosophy

**The highest-quality move is usually deletion.**

Applied to schematics:

- Every node represents a distinct idea. Two nodes that always travel together are one node. - Every connection carries information. If the relationship is obvious from layout, remove the line. - Coral is **editorial, not a flag.** 1–2 focal nodes per diagram. Using it on 5 nodes erases the signal. - The schematic isn't done when everything is added. It's done when nothing can be removed.

**Target density: 4/10.** Enough to be technically complete. Not so dense it needs a guide. Above 9 nodes, it's probably two diagrams.

---

## 2. When to Use

Use for any of the 39 visual types (§3) when a reader will learn more from a visual than from prose, a table, or a bulleted list.

**Don't use for:**

- Quick unicode diagrams → use **wiretext**. - Lists of things → table or bullets. - Simple before/after → table. - One-shape "diagrams" → just write the sentence.

Before drawing, ask: *Would the reader learn more from this than from a well-written paragraph?* If no, don't draw.

---

## 3. Selection: semantic pattern, then visual type

When behavior, state, enforcement, or risk carries the meaning, first load [`references/semantic-patterns.md`](references/semantic-patterns.md) and choose one primary pattern. Then choose the nearest visual type for layout. If no pattern matches, choose the type directly.

| Behavioral trigger | Semantic pattern → nearest type | |---|---| | Fan-in, queue depth, finite capacity, bottleneck | **Fan-in queue / bottleneck** → Data flow | | Repeated Question / Input / Governance / Output slots across stages | **Stage framework with semantic slots** → Process | | Conversation or loose input becomes a structured durable artifact | **Unstructured input → structured artifact** → Data flow | | Two rule traces need pass/fail/skipped/not-reached and first divergence | **Paired policy-evaluation traces** → Flowchart | | Trust boundaries plus permitted/forbidden ingress or deploy paths | **Secure paved road** → Architecture | | Controls grouped by where they are enforced | **Governance / control catalog** → Layer stack | | Defenses compensate for prior gaps and residual risk propagates | **Compensating security layers** → Layer stack |

The pattern owns semantic primitives and its tighter budget; the type owns layout grammar. Use [`references/animation.md`](references/animation.md) only when motion is requested or materially clarifies ordered change; static remains the default.

### Visual-type guide (39)

| If you're showing… | Use | Reference | |---|---|---| | Components + connections in a system | **Architecture** | [type-architecture.md](references/type-architecture.md) | | Legacy IT landscape grouped by phase/department; documents the *before* state in modernization proposals | **IT current-state** | [type-it-state.md](references/type-it-state.md) | | Decision logic with branches | **Flowchart** | [type-flowchart.md](references/type-flowchart.md) | | Time-ordered messages between actors | **Sequence** | [type-sequence.md](references/type-sequence.md) | | States + transitions + guards | **State machine** | [type-state.md](references/type-state.md) | | Entities + fields + relationships | **ER / data model** | [type-er.md](references/type-er.md) | | Events positioned in time | **Timeline** | [type-timeline.md](references/type-timeline.md) | | Cross-functional process with handoffs | **Swimlane** | [type-swimlane.md](references/type-swimlane.md) | | Two-axis positioning / prioritization | **Quadrant** | [type-quadrant.md](references/type-quadrant.md) | | Multiple entities scored across 3–5 quantitative criteria | **Radar / Spider** | [type-radar.md](references/type-radar.md) | | One quantitative series across cyclic categories; angle=category, radius=magnitude | **Polar chart** | [type-polar.md](references/type-polar.md) | | Reinforcing cycle / flywheel where the last step feeds the first and a shared hub accumulates state | **Loop** | [type-loop.md](references/type-loop.md) | | Hierarchy through containment / scope | **Nested** | [type-nested.md](references/type-nested.md) | | Parent → children relationships | **Tree** | [type-tree.md](references/type-tree.md) | | Human/agent/team ownership, reporting, routing, escalation | **Org chart** | [type-org-chart.md](references/type-org-chart.md) | | Stacked abstraction levels | **Layer stack** | [type-layers.md](references/type-layers.md) | | Overlap between sets | **Venn** | [type-venn.md](references/type-venn.md) | | Ranked hierarchy or conversion drop-off | **Pyramid / funnel** | [type-pyramid.md](references/type-pyramid.md) | | Quantitative comparison across categories | **Bar chart** | [type-bar.md](references/type-bar.md) | | Part-of-whole where the relative sizes are the story | **Treemap** | [type-treemap.md](references/type-treemap.md) | | Continuous trends over time, or change between exactly two states (slopegraph) | **Line chart** | [type-line.md](references/type-line.md) | | Tasks and phases on a timeline | **Gantt** | [type-gantt.md](references/type-gantt.md) | | Distribution and correlation between two variables | **Scatter plot** | [type-scatter.md](references/type-scatter.md) | | End-to-end data stack on a container cluster | **High-Level** | [type-high-level.md](references/type-high-level.md) | | Multi-actor sequential process with data handoffs | **Process** | [type-process.md](references/type-process.md) | | Multi-tier data storage with quality levels and access policies | **Medallion** | [type-medallion.md](references/type-medallion.md) | | Role-scoped data flow: who does what at each pipeline step | **Data flow** | [type-data-flow.md](references/type-data-flow.md) | | Integration topology of a data platform — sources → core → consumers | **DP integration** | [type-dp-integration.md](references/type-dp-integration.md) | | Per-role / per-component access permissions matrix | **DP security matrix** | [type-dp-security-matrix.md](references/type-dp-security-matrix.md) | | A quantity splitting and merging across stages, band width = amount | **Sankey** | [type-sankey.md](references/type-sankey.md) | | Causes of one observed effect, grouped by category (root-cause analysis) | **Fishbone** | [type-fishbone.md](references/type-fishbone.md) | | Value chain against evolution — what to build, buy, and what is moving | **Wardley map** | [type-wardley.md](references/type-wardley.md) | | Work-in-progress by state, with WIP limits and blocked items | **Kanban** | [type-kanban.md](references/type-kanban.md) | | What a person does across stages of an experience, and how it feels | **User journey** | [type-journey.md](references/type-journey.md) | | Where software runs — zones, hosts, artifacts, replicas, ports | **Deployment** | [type-deployment.md](references/type-deployment.md) | | What depends on what, with fan-in and cycles a tree cannot express | **Dependency graph** | [type-dependency.md](references/type-dependency.md) | | Classes with operations, inheritance, composition (other UML routes elsewhere) | **UML class** | [type-uml-class.md](references/type-uml-class.md) | | Narrative backbone sliced into releases, with the cut line | **Story map** | [type-story-map.md](references/type-story-map.md) | | Physical tables: SQL types, constraints, indexes, column-level FKs | **Database schema** | [type-db-schema.md](references/type-db-schema.md) |

Rules of thumb:

- If a 3-column table communicates the same thing, pick the table. - If two types seem useful, pick the dominant axis; a semantic pattern may add behavior-specific primitives, not a second layout grammar. - If you're past the complexity budget (§7), split into an overview + detail.

**Always load the chosen type reference linked in the guide before drawing.** When routed above, also load `semantic-patterns.md`; when animation is chosen, load `animation.md`.

### Confirm before drawing

Before rendering, state the plan in one short message: the chosen visual type (and semantic pattern, if routed), the size preset, and anything the complexity budget (§7) will force out. If the user is reachable, let them redirect before you draw; if not, proceed and note the assumptions beside the deliverable. Skip the pause only when the request already pins type, size, and content exactly.

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## 4. Universal Anti-patterns

These mark "AI slop" schematics of any type:

| Anti-pattern | Why it fails | |---|---| | Dark mode + cyan/purple glow | Looks "technical" without design decisions | | JetBrains Mono as blanket "dev" font | Mono is for *technical* content — ports, commands, URLs. Names go in Geist sans. | | Identical boxes for every node | Erases hierarchy | | Legend floating inside the diagram area | Collides with nodes | | Arrow labels with no masking rect | Bleeds through the line | | Vertical `