/markdown-mermaid-writing

name: markdown-mermaid-writing
description: >
  Comprehensive markdown and Mermaid diagram writing skill that establishes text-based
  diagrams as the DEFAULT documentation standard. Use this skill when creating ANY
  scientific document, report, analysis, or visualization — it ensures all outputs are
  in version-controlled, token-efficient markdown with embedded Mermaid diagrams as the
  source of truth, with clear pathways to downstream Python or AI-generated images.
  Includes full style guides (markdown + mermaid), 24 diagram type references, and
  9 document templates ready to use.
allowed-tools: Read Write Edit Bash
license: Apache-2.0
metadata:
  skill-author: Clayton Young / Superior Byte Works, LLC (@borealBytes)
  skill-source: https://github.com/SuperiorByteWorks-LLC/agent-project
  skill-version: "1.0.0"
  skill-contributors:
    - name: Clayton Young
      org: Superior Byte Works, LLC / @borealBytes
      role: Author and originator
    - name: K-Dense Team
      org: K-Dense Inc.
      role: Integration target and community feedback

Markdown and Mermaid Writing

Overview

This skill teaches you — and enforces a standard for — creating scientific documentation using **markdown with embedded Mermaid diagrams as the default and canonical format**.

The core bet: a relationship expressed as a Mermaid diagram inside a `.md` file is more valuable than any image. It is text, so it diffs cleanly in git. It requires no build step. It renders natively on GitHub, GitLab, Notion, VS Code, and any markdown viewer. It uses fewer tokens than a prose description of the same relationship. And it can always be converted to a polished image later — but the text version remains the source of truth.

> "The more you get your reports and files in .md in just regular text, which mermaid is > as well as being a simple 'script language'. This just helps with any downstream rendering > and especially AI generated images (using mermaid instead of just long form text to > describe relationships < tokens). Additionally mermaid can render along with markdown for > easy use almost anywhere by humans or AI." > > — Clayton Young (@borealBytes), K-Dense Discord, 2026-02-19

When to Use This Skill

Use this skill when:

• Creating **any scientific document** — reports, analyses, manuscripts, methods sections
• Writing **any documentation** — READMEs, how-tos, decision records, project docs
• Producing **any diagram** — workflows, data pipelines, architectures, timelines, relationships
• Generating **any output that will be version-controlled** — if it's going into git, it should be markdown
• Working with **any other skill** — this skill defines the documentation layer that wraps every other output
• Someone asks you to "add a diagram" or "visualize the relationship" — Mermaid first, always

Do NOT start with Python matplotlib, seaborn, or AI image generation for structural or relational diagrams. Those are Phase 2 and Phase 3 — only used when Mermaid cannot express what's needed (e.g., scatter plots with real data, photorealistic images).

🎨 The Source Format Philosophy

Why text-based diagrams win

| What matters | Mermaid in Markdown | Python / AI Image | | ----------------------------- | :-----------------: | :---------------: | | Git diff readable | ✅ | ❌ binary blob | | Editable without regenerating | ✅ | ❌ | | Token efficient vs. prose | ✅ smaller | ❌ larger | | Renders without a build step | ✅ | ❌ needs hosting | | Parseable by AI without vision | ✅ | ❌ | | Works in GitHub / GitLab / Notion | ✅ | ⚠️ if hosted | | Accessible (screen readers) | ✅ accTitle/accDescr | ⚠️ needs alt text | | Convertible to image later | ✅ anytime | — already image |

The three-phase workflow

flowchart LR
    accTitle: Three-Phase Documentation Workflow
    accDescr: Phase 1 Mermaid in markdown is always required and is the source of truth. Phases 2 and 3 are optional downstream conversions for polished output.

    p1["📄 Phase 1<br/>Mermaid in Markdown<br/>(ALWAYS — source of truth)"]
    p2["🐍 Phase 2<br/>Python Generated<br/>(optional — data charts)"]
    p3["🎨 Phase 3<br/>AI Generated Visuals<br/>(optional — polish)"]
    out["📊 Final Deliverable"]

    p1 --> out
    p1 -.->|"when needed"| p2
    p1 -.->|"when needed"| p3
    p2 --> out
    p3 --> out

    classDef required fill:#dbeafe,stroke:#2563eb,stroke-width:2px,color:#1e3a5f
    classDef optional fill:#fef9c3,stroke:#ca8a04,stroke-width:2px,color:#713f12
    classDef output fill:#dcfce7,stroke:#16a34a,stroke-width:2px,color:#14532d

    class p1 required
    class p2,p3 optional
    class out output

**Phase 1 is mandatory.** Even if you proceed to Phase 2 or 3, the Mermaid source stays committed.

What Mermaid can express

Mermaid covers 24 diagram types. Almost every scientific relationship fits one:

| Use case | Diagram type | File | | -------------------------------------------- | ---------------- | ---------------------------------------------------- | | Experimental workflow / decision logic | Flowchart | `references/diagrams/flowchart.md` | | Service interactions / API calls / messaging | Sequence | `references/diagrams/sequence.md` | | Data model / schema | ER diagram | `references/diagrams/er.md` | | State machine / lifecycle | State | `references/diagrams/state.md` | | Project timeline / roadmap | Gantt | `references/diagrams/gantt.md` | | Proportions / composition | Pie | `references/diagrams/pie.md` | | System architecture (zoom levels) | C4 | `references/diagrams/c4.md` | | Concept hierarchy / brainstorm | Mindmap | `references/diagrams/mindmap.md` | | Chronological events / history | Timeline | `references/diagrams/timeline.md` | | Class hierarchy / type relationships | Class | `references/diagrams/class.md` | | User journey / satisfaction map | User Journey | `references/diagrams/user_journey.md` | | Two-axis comparison / prioritization | Quadrant | `references/diagrams/quadrant.md` | | Requi