Mermaid Diagrams

What it does

When your agent uses it

• Tasks that involve Diagrams

Example prompts

• “/mermaid-diagrams”

Requirements

• Python 3
• Node.js
• A Bash shell
• Docker

Workflow steps

6 steps, taken from the first numbered list in SKILL.md.

1. 1Create the diagram as a standalone .mmd file
2. 2Pre-render to SVG: npx @mermaid-js/mermaid-cli -i diagram.mmd -o diagram.svg --width 800
3. 3Embed the raw SVG content directly in the markdown (not as )
4. 4Strip hardcoded max-width pixel values from the SVG tags
5. 5Use flowchart TD (portrait) not flowchart LR (landscape) — see references/portrait-layout.md
6. 6Add page-break divs before/after each full-page diagram

What it can do on your machine

Read from SKILL.md and the folder at commit 867a555. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships 1 file in scripts/ (Shell), which the agent can run.

  Shell commands in SKILL.md call:

  • npx
  • docker

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Hosts in commands or code, which the agent is likely to contact:

  • cdn.jsdelivr.net

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Mermaid Diagrams loads about 2.2k tokens when it runs, and up to ~7.9k if it reads all its reference files. Until then it costs about 88 tokens; SKILL.md has 866 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~88

When it runs · the whole SKILL.md, loaded when a task matches

~2.2k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~7.9k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from magnus919/hermes-profiles at commit 867a555, republished under its MIT licence (© magnus919). 866 words, ~2,165 tokens.

name

mermaid-diagrams

description

Platform-agnostic Mermaid.js diagramming — flowcharts, sequence diagrams, C4 (via Structurizr or flowchart workarounds), class/state/ER diagrams, Gantt, and block diagrams. Generates valid Mermaid syntax, renders via mmdc CLI or CDN, and validates before output. Portable — works in CLI, markdown, HTML, PDF, and any agentic context.

npx @mermaid-js/mermaid-cli -i diagram.mmd -o diagram.svg
npx @mermaid-js/mermaid-cli -i diagram.mmd -o diagram.png
npx @mermaid-js/mermaid-cli -i diagram.mmd -o diagram.pdf

docker run --rm -v $(pwd):/data ghcr.io/mermaid-js/mermaid-cli mermaid-cli -i /data/diagram.mmd -o /data/diagram.svg

<script src="https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.min.js"></script>
<script>mermaid.initialize({startOnLoad:true});</script>
<div class="mermaid">
flowchart LR
  A-->B
</div>

// Node.js validation
import { parse } from 'mermaid';
try {
  parse('flowchart LR\n  A-->B');
  console.log('Valid');
} catch (e) {
  console.error('Invalid:', e.message);
}

© magnus919, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 8 other files (scripts, references) in skills/mermaid-diagrams of magnus919/hermes-profiles.

• SKILL.md
• references/c4-mermaid.md
• references/c4-to-flowchart.md
• references/flowchart.md
• references/mmdc-spacing-config.md
• references/pdf-rendering-pipeline.md
• references/portrait-layout.md
• references/sequence.md
• scripts/validate-mermaid.sh

Open the folder on GitHubat commit 867a555