PluginBench
Skill
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Audit score 90

html-diagram

plannotator/effective-html

Build self-contained HTML diagrams that clarify relationships, sequence, topology, state, hierarchy, or structure.

What is html-diagram?

A direct-invocation specialist for creating visual diagrams embedded in HTML. Use it when you need to clarify relationships, sequences, hierarchies, or quantitative structures through diagrams—activated explicitly or when routing diagram requests. Delivers a single self-contained HTML file with no external dependencies.

  • Select diagram form (topology, sequence, process, state, hierarchy, timeline, matrix, quantitative) based on the question being answered
  • Choose rendering method (HTML/CSS, SVG, Canvas, WebGL) appropriate to information density and scale
  • Build self-contained HTML with inline CSS and JavaScript—no build step or external services required
  • Optimize for legibility: stable node positions, minimal edge crossings, clear direction and connectors
  • Add interaction (filtering, path tracing, pan/zoom, animation) only when it answers the stated question
  • Verify across widths, check accessibility, ensure keyboard operation and reduced-motion compatibility

How to install html-diagram

npx skills add https://github.com/plannotator/effective-html --skill html-diagram
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How to use html-diagram

  1. 1.Identify the core question the diagram must answer
  2. 2.Select the appropriate diagram form (topology, sequence, process, state, hierarchy, timeline, matrix, or quantitative)
  3. 3.Choose the rendering method (HTML/CSS, SVG, Canvas, or WebGL) based on scale and interactivity needs
  4. 4.Build the diagram with inline CSS and JavaScript in a single HTML file
  5. 5.Verify legibility at multiple widths and test all interactive states
  6. 6.Return the file path, diagram form chosen, and key simplifications or assumptions made

Use cases

Good for
  • Visualize system architecture or component topology with connections and dependencies
  • Show message flow or event sequences over time with ordered interactions
  • Illustrate process workflows with steps, branches, and decision points
  • Display state machines with transitions and conditional logic
  • Represent organizational or containment hierarchies
Who it's for
  • Engineers designing or documenting system architecture
  • Product managers explaining workflows or user journeys
  • Technical writers clarifying complex relationships or sequences
  • Data analysts presenting structural or quantitative relationships
  • Anyone needing a diagram that's easier to understand than prose alone

html-diagram FAQ

When should I use html-diagram instead of a general diagram tool?

Use html-diagram when you need a self-contained, embeddable diagram with no external dependencies, custom interaction, or tight integration with your project's visual language.

What diagram forms are supported?

Topology (components and connections), sequence (ordered messages), process (steps and branches), state (transitions), hierarchy (containment), timeline (change over time), matrix (repeated relationships), and quantitative views.

Do I need a build step or external service?

No. html-diagram delivers a single self-contained HTML file with all CSS and JavaScript inline.

Can I add interaction like pan, zoom, or filtering?

Yes, but only when it helps answer the stated question. Keep overlays dismissible, controls keyboard-accessible, and respect prefers-reduced-motion.

How do I ensure the diagram is accessible?

Use accessible text alternatives, keep important meaning available without animation or color alone, verify keyboard operation, and test across different widths and zoom levels.

Full instructions (SKILL.md)

Source of truth, from plannotator/effective-html.


name: html-diagram description: Direct-invocation specialist for self-contained HTML diagrams whose layout, notation, and interaction clarify relationships, sequence, topology, state, hierarchy, or quantitative structure. Use when the user explicitly invokes html-diagram or the broad html skill routes a diagram request here. Do not activate independently from a general request.

HTML Diagram

Build the smallest visual model that makes the relationship easier to understand than prose alone. Match the notation and visual language to the user's project and subject. Do not force every topic into the same SVG boxes and arrows.

Choose the right model

Identify the question the reader should answer, then select the form:

  • topology for components and connections;
  • sequence for ordered messages over time;
  • process for steps, branches, and handoffs;
  • state for transitions and conditions;
  • hierarchy for containment or ownership;
  • timeline for change over time;
  • matrix for repeated relationships;
  • quantitative view when magnitude matters.

Decide what must remain visible together and what can be revealed on demand. Use a simpler form when it carries the same meaning.

Choose the rendering method

Use HTML and CSS, SVG, Canvas, or WebGL according to the information and scale. Do not use SVG merely because the output is a diagram.

  • Keep labels, grouping, direction, and connectors legible before adding interaction.
  • Use stable node positions when readers must compare states or steps.
  • Keep edge crossings and ambiguous arrowheads to a minimum.
  • Put intentionally broad canvases in a contained pan or scroll region.
  • Use legends only when notation is not self-explanatory.

Add sequencing, filtering, path tracing, pan and zoom, or animation only when it helps answer the stated question. Keep overlays dismissible, controls keyboard-accessible, and motion compatible with prefers-reduced-motion.

When design-artifact is available, read it for the diagram's surrounding composition and visual register. Keep the chosen diagram grammar, label legibility, and relationships authoritative over decorative treatment.

Build and verify

Deliver one self-contained HTML file with essential CSS and JavaScript inline. Require no build step or external service. Use accessible text alternatives and keep important meaning available without animation or color alone.

Inspect the result at wide and narrow widths. Check label collisions, clipped nodes, edge routing, reading order, keyboard operation, overflow, and every interactive state.

Return the absolute path, the diagram form chosen, and the main simplifications or assumptions.