excalidraw-diagram

name	excalidraw-diagram
description	Create Excalidraw diagram JSON files that make visual arguments. Use when the user wants to visualize workflows, architectures, or concepts.

Excalidraw Diagram Creator

Generate .excalidraw JSON files that argue visually, not just display information.

Setup: If the user asks you to set up this skill (renderer, dependencies, etc.), see README.md for instructions.

Customization

All colors and brand-specific styles live in one file: references/color-palette.md. Read it before generating any diagram and use it as the single source of truth for all color choices — shape fills, strokes, text colors, evidence artifact backgrounds, everything.

To make this skill produce diagrams in your own brand style, edit color-palette.md. Everything else in this file is universal design methodology and Excalidraw best practices.

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Core Philosophy

Diagrams should ARGUE, not DISPLAY.

A diagram isn't formatted text. It's a visual argument that shows relationships, causality, and flow that words alone can't express. The shape should BE the meaning.

The Isomorphism Test: If you removed all text, would the structure alone communicate the concept? If not, redesign.

The Education Test: Could someone learn something concrete from this diagram, or does it just label boxes? A good diagram teaches—it shows actual formats, real event names, concrete examples.

Omit meaningless bookends. Do NOT add terminal "start" and "end" nodes — the rounded ( start ) / ( end ) circles, or context-only labels like render, canvas, Sprite atlas, input, output, user, done. The reader already knows the surrounding context; these nodes carry no information, waste space, and pad the diagram's footprint. Begin the diagram at the first node that actually does something and end it at the last meaningful step. A pipeline starts at its first real stage and ends at its last real stage — not at a decorative terminal. (Genuine intermediate artifacts that the pipeline transforms — a buffer, a render target, a distance field — are real nodes and stay; the rule is specifically about content-free entry/exit terminals.)

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Depth Assessment (Do This First)

Before designing, determine what level of detail this diagram needs:

Simple/Conceptual Diagrams

Use abstract shapes when:

• Explaining a mental model or philosophy
• The audience doesn't need technical specifics
• The concept IS the abstraction (e.g., "separation of concerns")

Comprehensive/Technical Diagrams

Use concrete examples when:

• Diagramming a real system, protocol, or architecture
• The diagram will be used to teach or explain (e.g., YouTube video)
• The audience needs to understand what things actually look like
• You're showing how multiple technologies integrate

For technical diagrams, you MUST include evidence artifacts (see below).

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Research Mandate (For Technical Diagrams)

Before drawing anything technical, research the actual specifications.

If you're diagramming a protocol, API, or framework:

1. Look up the actual JSON/data formats
2. Find the real event names, method names, or API endpoints
3. Understand how the pieces actually connect
4. Use real terminology, not generic placeholders

Bad: "Protocol" → "Frontend" Good: "AG-UI streams events (RUN_STARTED, STATE_DELTA, A2UI_UPDATE)" → "CopilotKit renders via createA2UIMessageRenderer()"

Research makes diagrams accurate AND educational.

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Evidence Artifacts

Evidence artifacts are concrete examples that prove your diagram is accurate and help viewers learn. Include them in technical diagrams.

Types of evidence artifacts (choose what's relevant to your diagram):

Artifact Type	When to Use	How to Render
Code snippets	APIs, integrations, implementation details	Dark rectangle + syntax-colored text (see color palette for evidence artifact colors)
Data/JSON examples	Data formats, schemas, payloads	Dark rectangle + colored text (see color palette)
Event/step sequences	Protocols, workflows, lifecycles	Timeline pattern (line + dots + labels)
UI mockups	Showing actual output/results	Nested rectangles mimicking real UI
Real input content	Showing what goes IN to a system	Rectangle with sample content visible
API/method names	Real function calls, endpoints	Use actual names from docs, not placeholders

Example: For a diagram about a streaming protocol, you might show:

• The actual event names from the spec (not just "Event 1", "Event 2")
• A code snippet showing how to connect
• What the streamed data actually looks like

Example: For a diagram about a data transformation pipeline:

• Show sample input data (actual format, not "Input")
• Show sample output data (actual format, not "Output")
• Show intermediate states if relevant

The key principle: show what things actually look like, not just what they're called.

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Multi-Zoom Architecture

Comprehensive diagrams operate at multiple zoom levels simultaneously. Think of it like a map that shows both the country borders AND the street names.

Level 1: Summary Flow

A simplified overview showing the full pipeline or process at a glance. Often placed at the top or bottom of the diagram.

Example: Input → Processing → Output or Client → Server → Database

Level 2: Section Boundaries

Labeled regions that group related components. These create visual "rooms" that help viewers understand what belongs together.

Example: Grouping by responsibility (Backend / Frontend), by phase (Setup / Execution / Cleanup), or by team (User / System / External)

Level 3: Detail Inside Sections

Evidence artifacts, code snippets, and concrete examples within each section. This is where the educational value lives.

Example: Inside a "Backend" section, you might show the actual API response format, not just a box labeled "API Response"

For comprehensive diagrams, aim to include all three levels. The summary gives context, the sections organize, and the details teach.

Bad vs Good

Bad (Displaying)	Good (Arguing)
5 equal boxes with labels	Each concept has a shape that mirrors its behavior
Card grid layout	Visual structure matches conceptual structure
Icons decorating text	Shapes that ARE the meaning
Same container for everything	Distinct visual vocabulary per concept
Everything in a box	Free-floating text with selective containers

Simple vs Comprehensive (Know Which You Need)

Simple Diagram	Comprehensive Diagram
Generic labels: "Input" → "Process" → "Output"	Specific: shows what the input/output actually looks like
Named boxes: "API", "Database", "Client"	Named boxes + examples of actual requests/responses
"Events" or "Messages" label	Timeline with real event/message names from the spec
"UI" or "Dashboard" rectangle	Mockup showing actual UI elements and content
~30 seconds to explain	~2-3 minutes of teaching content
Viewer learns the structure	Viewer learns the structure AND the details

Simple diagrams are fine for abstract concepts, quick overviews, or when the audience already knows the details. Comprehensive diagrams are needed for technical architectures, tutorials, educational content, or when you want the diagram itself to teach.

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Container vs. Free-Floating Text

Not every piece of text needs a shape around it. Default to free-floating text. Add containers only when they serve a purpose.

Use a Container When...	Use Free-Floating Text When...
It's the focal point of a section	It's a label or description
It needs visual grouping with other elements	It's supporting detail or metadata
Arrows need to connect to it	It describes something nearby
The shape itself carries meaning (decision diamond, etc.)	Typography alone creates sufficient hierarchy
It represents a distinct "thing" in the system	It's a section title, subtitle, or annotation

Typography as hierarchy: Use font size, weight, and color to create visual hierarchy without boxes. A 28px title doesn't need a rectangle around it.

The container test: For each boxed element, ask "Would this work as free-floating text?" If yes, remove the container.

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Design Process (Do This BEFORE Generating JSON)

Step 0: Assess Depth Required

Before anything else, determine if this needs to be:

• Simple/Conceptual: Abstract shapes, labels, relationships (mental models, philosophies)
• Comprehensive/Technical: Concrete examples, code snippets, real data (systems, architectures, tutorials)

If comprehensive: Do research first. Look up actual specs, formats, event names, APIs.

Step 1: Understand Deeply

Read the content. For each concept, ask:

• What does this concept DO? (not what IS it)
• What relationships exist between concepts?
• What's the core transformation or flow?
• What would someone need to SEE to understand this? (not just read about)

Step 2: Map Concepts to Patterns

For each concept, find the visual pattern that mirrors its behavior:

If the concept...	Use this pattern
Spawns multiple outputs	Fan-out (radial arrows from center)
Combines inputs into one	Convergence (funnel, arrows merging)
Has hierarchy/nesting	Tree (lines + free-floating text)
Is a sequence of steps	Timeline (line + dots + free-floating labels)
Loops or improves continuously	Spiral/Cycle (arrow returning to start)
Is an abstract state or context	Cloud (overlapping ellipses)
Transforms input to output	Assembly line (before → process → after)
Compares two things	Side-by-side (parallel with contrast)
Separates into phases	Gap/Break (visual separation between sections)

Step 3: Ensure Variety

For multi-concept diagrams: each major concept must use a different visual pattern. No uniform cards or grids.

Step 4: Sketch the Flow

Before JSON, mentally trace how the eye moves through the diagram. There should be a clear visual story.

Step 5: Generate JSON

Only now create the Excalidraw elements. See below for how to handle large diagrams.

Step 6: Render & Validate (MANDATORY)

After generating the JSON, you MUST run the render-view-fix loop until the diagram looks right. This is not optional — see the Render & Validate section below for the full process.

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Large / Comprehensive Diagram Strategy

For comprehensive or technical diagrams, you MUST build the JSON one section at a time. Do NOT attempt to generate the entire file in a single pass. This is a hard constraint — Claude Code has a ~32,000 token output limit per response, and a comprehensive diagram easily exceeds that in one shot. Even if it didn't, generating everything at once leads to worse quality. Section-by-section is better in every way.

The Section-by-Section Workflow

Phase 1: Build each section

1. Create the base file with the JSON wrapper (type, version, appState, files) and the first section of elements.
2. Add one section per edit. Each section gets its own dedicated pass — take your time with it. Think carefully about the layout, spacing, and how this section connects to what's already there.
3. Use descriptive string IDs (e.g., "trigger_rect", "arrow_fan_left") so cross-section references are readable.
4. Namespace seeds by section (e.g., section 1 uses 100xxx, section 2 uses 200xxx) to avoid collisions.
5. Update cross-section bindings as you go. When a new section's element needs to bind to an element from a previous section (e.g., an arrow connecting sections), edit the earlier element's boundElements array at the same time.

Phase 2: Review the whole

After all sections are in place, read through the complete JSON and check:

• Are cross-section arrows bound correctly on both ends?
• Is the overall spacing balanced, or are some sections cramped while others have too much whitespace?
• Do IDs and bindings all reference elements that actually exist?

Fix any alignment or binding issues before rendering.

Phase 3: Render & validate

Now run the render-view-fix loop from the Render & Validate section. This is where you'll catch visual issues that aren't obvious from JSON — overlaps, clipping, imbalanced composition.

Section Boundaries

Plan your sections around natural visual groupings from the diagram plan. A typical large diagram might split into:

• Section 1: Entry point / trigger
• Section 2: First decision or routing
• Section 3: Main content (hero section — may be the largest single section)
• Section 4-N: Remaining phases, outputs, etc.

Each section should be independently understandable: its elements, internal arrows, and any cross-references to adjacent sections.

What NOT to Do

• Don't generate the entire diagram in one response. You will hit the output token limit and produce truncated, broken JSON. Even if the diagram is small enough to fit, splitting into sections produces better results.
• Don't use a coding agent to generate the JSON. The agent won't have sufficient context about the skill's rules, and the coordination overhead negates any benefit.
• Don't write a Python generator script. The templating and coordinate math seem helpful but introduce a layer of indirection that makes debugging harder. Hand-crafted JSON with descriptive IDs is more maintainable.

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Visual Pattern Library

Fan-Out (One-to-Many)

Central element with arrows radiating to multiple targets. Use for: sources, PRDs, root causes, central hubs.

        ○
       ↗
  □ → ○
       ↘
        ○

Convergence (Many-to-One)

Multiple inputs merging through arrows to single output. Use for: aggregation, funnels, synthesis.

  ○ ↘
  ○ → □
  ○ ↗

Tree (Hierarchy)

Parent-child branching with connecting lines and free-floating text (no boxes needed). Use for: file systems, org charts, taxonomies.

  label
  ├── label
  │   ├── label
  │   └── label
  └── label

Use line elements for the trunk and branches, free-floating text for labels.

Spiral/Cycle (Continuous Loop)

Elements in sequence with arrow returning to start. Use for: feedback loops, iterative processes, evolution.

  □ → □
  ↑     ↓
  □ ← □

Cloud (Abstract State)

Overlapping ellipses with varied sizes. Use for: context, memory, conversations, mental states.

Assembly Line (Transformation)

Input → Process Box → Output with clear before/after. Use for: transformations, processing, conversion.

  ○○○ → [PROCESS] → □□□
  chaos              order

Side-by-Side (Comparison)

Two parallel structures with visual contrast. Use for: before/after, options, trade-offs.

Gap/Break (Separation)

Visual whitespace or barrier between sections. Use for: phase changes, context resets, boundaries.

Lines as Structure

Use lines (type: line, not arrows) as primary structural elements instead of boxes:

• Timelines: Vertical or horizontal line with small dots (10-20px ellipses) at intervals, free-floating labels beside each dot
• Tree structures: Vertical trunk line + horizontal branch lines, with free-floating text labels (no boxes needed)
• Dividers: Thin dashed lines to separate sections
• Flow spines: A central line that elements relate to, rather than connecting boxes

Timeline:           Tree:
  ●─── Label 1        │
  │                   ├── item
  ●─── Label 2        │   ├── sub
  │                   │   └── sub
  ●─── Label 3        └── item

Lines + free-floating text often creates a cleaner result than boxes + contained text.

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Shape Meaning

Choose shape based on what it represents—or use no shape at all:

Concept Type	Shape	Why
Labels, descriptions, details	none (free-floating text)	Typography creates hierarchy
Section titles, annotations	none (free-floating text)	Font size/weight is enough
Markers on a timeline	small ellipse (10-20px)	Visual anchor, not container
Start, trigger, input	ellipse	Soft, origin-like
End, output, result	ellipse	Completion, destination
Decision, condition	diamond	Classic decision symbol
Process, action, step	rectangle	Contained action
Abstract state, context	overlapping ellipse	Fuzzy, cloud-like
Hierarchy node	lines + text (no boxes)	Structure through lines

Rule: Default to no container. Add shapes only when they carry meaning. Aim for <30% of text elements to be inside containers.

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Color as Meaning

Colors encode information, not decoration. Every color choice should come from references/color-palette.md — the semantic shape colors, text hierarchy colors, and evidence artifact colors are all defined there.

Key principles:

• Each semantic purpose (start, end, decision, AI, error, etc.) has a specific fill/stroke pair
• Free-floating text uses color for hierarchy (titles, subtitles, details — each at a different level)
• Evidence artifacts (code snippets, JSON examples) use their own dark background + colored text scheme
• Always pair a darker stroke with a lighter fill for contrast

Do not invent new colors. If a concept doesn't fit an existing semantic category, use Primary/Neutral or Secondary.

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Modern Aesthetics

For clean, professional diagrams:

Roughness

• roughness: 0 — Clean, crisp edges. Use for modern/technical diagrams.
• roughness: 1 — Hand-drawn, organic feel. Use for brainstorming/informal diagrams.

Default to 0 for most professional use cases.

Stroke Width

• strokeWidth: 1 — Thin, elegant. Good for lines, dividers, subtle connections.
• strokeWidth: 2 — Standard. Good for shapes and primary arrows.
• strokeWidth: 3 — Bold. Use sparingly for emphasis (main flow line, key connections).

Opacity

Always use opacity: 100 for all elements. Use color, size, and stroke width to create hierarchy instead of transparency.

Small Markers Instead of Shapes

Instead of full shapes, use small dots (10-20px ellipses) as:

• Timeline markers
• Bullet points
• Connection nodes
• Visual anchors for free-floating text

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Layout Principles

Hierarchy Through Scale

• Hero: 300×150 - visual anchor, most important
• Primary: 180×90
• Secondary: 120×60
• Small: 60×40

Whitespace = Importance

The most important element has the most empty space around it (200px+).

Flow Direction

Guide the eye: typically left→right or top→bottom for sequences, radial for hub-and-spoke.

Connections Required

Position alone doesn't show relationships. If A relates to B, there must be an arrow.

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Text Rules

CRITICAL: The JSON text property contains ONLY readable words.

{
  "id": "myElement1",
  "text": "Start",
  "originalText": "Start"
}

Settings: fontSize: 16, fontFamily: 3, textAlign: "center", verticalAlign: "middle"

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JSON Structure

{
  "type": "excalidraw",
  "version": 2,
  "source": "https://excalidraw.com",
  "elements": [...],
  "appState": {
    "viewBackgroundColor": "#ffffff",
    "gridSize": 20
  },
  "files": {}
}

Element Templates

See references/element-templates.md for copy-paste JSON templates for each element type (text, line, dot, rectangle, arrow). Pull colors from references/color-palette.md based on each element's semantic purpose.

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Author for correctness: bind text, don't float it

The single biggest cause of broken diagrams — labels overrunning their box, text clipping at the diagram edge, labels sitting on top of shapes — is free-floating text. When a piece of text belongs inside a shape (a node, a cell, a titled box), make it bound text on that shape. Do not position a separate label on top of the shape.

Why this is the difference between first-try success and an endless overflow-fix loop:

• Bound text auto-wraps to the container's width, and Excalidraw grows the container's height to fit. You never guess a pixel width and you never hand-insert line breaks.
• Free text forces you to do both by hand. Font metrics are not intuitive — you will mis-guess the rendered width (this is why labels keep overflowing and why text lands a few pixels past its box), and a too-small declared width makes the text spill past the diagram's own viewBox and clip on the page.
• The render-time overflow linter can only verify text that is bound to a container, plus each text's own declared box. A free label laid over a shape is invisible to the linter. The more you bind, the more the mechanical safety net actually covers — so binding is what makes the checks trustworthy.

How to bind text to a shape:

1. Give the text element containerId: "<shape-id>".
2. Add the text id to the shape's boundElements: "boundElements": [{ "id": "<text-id>", "type": "text" }].
3. Set textAlign (left/center) and verticalAlign (top/middle) on the text.

Excalidraw then wraps the text to container.width − 10 and reflows the container height. Size the container to the content you want; let wrapping do the rest — never reverse-engineer the text width.

// container — sized to taste; height will grow to fit the wrapped text
{ "id": "cellSys", "type": "rectangle", "x": 100, "y": 100, "width": 220, "height": 70,
  "boundElements": [{ "id": "cellSys-label", "type": "text" }] }
// bound label — wraps inside cellSys automatically, no manual newlines
{ "id": "cellSys-label", "type": "text", "containerId": "cellSys",
  "text": "instanceSystem vec4 — floats 8..11 — flipX, flipY, sysFlags, enableBits",
  "fontSize": 14, "textAlign": "center", "verticalAlign": "middle" }

When free-floating text is acceptable: true open-space annotations — the diagram title, a section header, a caption in genuinely empty space. Even then, keep them short and single-purpose, and over-declare their width by ~15–20% so a metric mis-guess never clips them. A finished diagram is mostly bound text with a handful of free labels — not the inverse. If you find yourself authoring dozens of positioned labels, stop and bind them to the shapes they belong to.

Heuristic: if a label's center sits inside a box, it should almost certainly be bound to that box.

Fonts: diagrams render in the docs font

The render pipeline forces ALL text to JetBrains Mono (references/diagram-font.woff2) for layout, and rewrites the exported SVG to reference JetBrains Mono — because the docs page renders inlined-SVG text in JetBrains Mono regardless of Excalidraw's own font. If the diagram were laid out in Excalidraw's default (narrower) font, the wider docs font would overflow every baked label position on the page. You don't configure this per diagram — it's automatic — but know that all text is monospace JetBrains Mono, so size boxes and estimate widths accordingly (mono ≈ 0.6em per character). To retarget another project's font, replace references/diagram-font.woff2 and the family name in render_excalidraw.py's rewrite_fonts + render_template.html's swapInDocsFont.

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Render & Validate (MANDATORY)

You cannot judge a diagram from JSON alone. After generating or editing the Excalidraw JSON, you MUST render it to PNG, view the image, and fix what you see — in a loop until it's right. This is a core part of the workflow, not a final check.

Validate as you go, not just at the end. After you finish each major section or cluster, render and lint it. Catching a sizing/overflow problem in one section is cheap; discovering ten of them after the whole diagram is laid out is not.

How to Render

cd .claude/skills/excalidraw-diagram/references && uv run python render_excalidraw.py <path-to-file.excalidraw>

This outputs a PNG next to the .excalidraw file. Then use the Read tool on the PNG to actually view it.

Flags:

• --svg --output <path>.svg — emit embeddable SVG markup (self-contained: baked background + embedded fonts) instead of a PNG raster. Use this for the final deliverable when the diagram is embedded in a web page.
• --strict — exit non-zero (3) if the automatic overflow lint (below) finds any spill. Use it as a hard gate in a fix loop: keep rendering until the command exits 0.

Automatic text-overflow lint

Every render runs a geometric overflow check and prints to stderr any bound text (text with a containerId) whose measured size spills outside its container box:

⚠ TEXT OVERFLOW: 1 text element(s) spill outside their container:
  - 'instanceSystem  vec4 floats 8..11 · flipX, …'  (+62px horizontal)
  Fix: widen/raise the container box, lower fontSize, or split the label across lines.

This catches the most common defects and is genuinely easy to miss by eye, so do not rely on visual inspection alone for it. The check has several parts:

• Crowding — bound text must keep ~8px of breathing room inside its container. Text that sits flush against the box edge reads as cramped and is flagged even though it technically "fits." Never run text right up to the line.
• Own-box overflow — any text (bound or free-floating) whose rendered glyphs exceed its own declared width/height. A free label with a too-small declared width renders past its box and can clip at the export bound, so these are checked too.
• Free label over a sibling box — a free (unbound) label that rests on a filled box (≥50% horizontal overlap) but pokes past that box's top or bottom edge. Catches text spilling out of a code block / inner box even while it still sits inside a larger container — the collision the container-margin check alone misses (the label's center can fall just outside the small box it overlaps). Vertical only: horizontal spill is already covered by own-box overflow, and a wide label legitimately crossing a narrow cell is not a defect.

Treat any ⚠ TEXT OVERFLOW line as a must-fix. Fix order matters: first try splitting the label across more lines, then shortening/truncating it (an ellipsis is fine). Widening the box is a last resort — it bloats the diagram's overall footprint, and a diagram that keeps growing wider to fit text is a design smell. Keep an eye on total width: prefer wrapping tall over sprawling wide. Re-render until the warning is gone (or --strict exits 0).

The Loop

After generating the initial JSON, run this cycle:

1. Render & View — Run the render script, then Read the PNG.

2. Audit against your original vision — Before looking for bugs, compare the rendered result to what you designed in Steps 1-4. Ask:

• Does the visual structure match the conceptual structure you planned?
• Does each section use the pattern you intended (fan-out, convergence, timeline, etc.)?
• Does the eye flow through the diagram in the order you designed?
• Is the visual hierarchy correct — hero elements dominant, supporting elements smaller?
• For technical diagrams: are the evidence artifacts (code snippets, data examples) readable and properly placed?

3. Check for visual defects:

• Text clipped by or overflowing its container
• Text overlapping a shape it is not bound to — a free label sitting on a circle, arrow, or another box. The linter now flags free text that breaks a filled box's top/bottom edge, but it still can't see overlaps on circles, arrows, or purely horizontal collisions — zoom into every dense cluster.
• Text clipped at the diagram's outer edge — if a label's declared width was too small it renders past the viewBox and gets cut off on the page even though the standalone PNG looks fine. Bind it, or widen its declared box.
• Text or shapes overlapping other elements
• Arrows crossing through elements instead of routing around them
• Arrows landing on the wrong element, pointing into empty space, or terminating in the middle of a box instead of on its entry edge
• Labels floating ambiguously (not clearly anchored to what they describe) — usually a sign the label should be bound to the shape it describes
• Uneven spacing between elements that should be evenly spaced
• Sections with too much whitespace next to sections that are too cramped
• Text too small to read at the rendered size
• Overall composition feels lopsided or unbalanced

4. Fix — Edit the JSON to address everything you found. Common fixes:

• Widen containers when text is clipped
• Adjust x/y coordinates to fix spacing and alignment
• Add intermediate waypoints to arrow points arrays to route around elements
• Reposition labels closer to the element they describe
• Resize elements to rebalance visual weight across sections

5. Re-render & re-view — Run the render script again and Read the new PNG.

6. Repeat — Keep cycling until the diagram passes both the vision check (Step 2) and the defect check (Step 3). Typically takes 2-4 iterations. Don't stop after one pass just because there are no critical bugs — if the composition could be better, improve it.

Self-validation gate — run this before you call it done

Do not report a diagram as finished until every item passes. This is a hard gate, not a suggestion:

1. Lint is green. uv run python render_excalidraw.py <file> --strict exits 0. If it prints any ⚠ TEXT OVERFLOW, you are not done — fix and re-run.
2. You looked at the full render. Read the full-resolution PNG (not just trust the exit code).
3. You looked at the dense areas up close. Read zoomed crops of every region where shapes or labels cluster — circle marches, columns of cells, anywhere a label sits near a stroke. The linter is blind to text-on-shape collisions; this is how you catch them.
4. No text touches a shape it isn't bound to, nothing clips at the diagram's outer edge, and every free label sits in clear space.
5. Arrows connect to entry edges, not box middles or empty space.

Only when all five pass do you export the SVG and report done. If you cannot honestly check item 3 or 4, say so rather than claiming success.

When to Stop

The loop is done when the self-validation gate above passes AND:

• The rendered diagram matches the conceptual design from your planning steps
• Spacing is consistent and the composition is balanced
• You'd be comfortable showing it to someone without caveats

First-Time Setup

If the render script hasn't been set up yet:

cd .claude/skills/excalidraw-diagram/references
uv sync
uv run playwright install chromium

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Quality Checklist

Depth & Evidence (Check First for Technical Diagrams)

1. Research done: Did you look up actual specs, formats, event names?
2. Evidence artifacts: Are there code snippets, JSON examples, or real data?
3. Multi-zoom: Does it have summary flow + section boundaries + detail?
4. Concrete over abstract: Real content shown, not just labeled boxes?
5. Educational value: Could someone learn something concrete from this?

Conceptual

6. Isomorphism: Does each visual structure mirror its concept's behavior?
7. Argument: Does the diagram SHOW something text alone couldn't?
8. Variety: Does each major concept use a different visual pattern?
9. No uniform containers: Avoided card grids and equal boxes?

Container Discipline

10. Minimal containers: Could any boxed element work as free-floating text instead?
11. Lines as structure: Are tree/timeline patterns using lines + text rather than boxes?
12. Typography hierarchy: Are font size and color creating visual hierarchy (reducing need for boxes)?

Structural

13. Connections: Every relationship has an arrow or line
14. Flow: Clear visual path for the eye to follow
15. Hierarchy: Important elements are larger/more isolated

Technical

16. Text clean: text contains only readable words
17. Font: fontFamily: 3
18. Roughness: roughness: 0 for clean/modern (unless hand-drawn style requested)
19. Opacity: opacity: 100 for all elements (no transparency)
20. Container ratio: <30% of text elements should be inside containers

Visual Validation (Render Required)

21. Rendered to PNG: Diagram has been rendered and visually inspected
22. No text overflow: All text fits within its container
23. No overlapping elements: Shapes and text don't overlap unintentionally
24. Even spacing: Similar elements have consistent spacing
25. Arrows land correctly: Arrows connect to intended elements without crossing others
26. Readable at export size: Text is legible in the rendered PNG
27. Balanced composition: No large empty voids or overcrowded regions