What is creating-mermaid-diagrams?

A diagram-making skill for Mermaid, a text format that GitHub can render as flowcharts and other diagrams inside Markdown.

Use it to create flowcharts, sequence diagrams, and other Mermaid diagram types, preview them locally, and check how they render on GitHub.

It helps you create diagrams that display correctly in pull requests, issues, comments, and Markdown files, while keeping structure and accessibility in mind.

creating-mermaid-diagrams — Skill for Claude Code by mdsakalu

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add mdsakalu/agent-plugins --skill creating-mermaid-diagrams

Clone the repo

git clone --depth 1 https://github.com/mdsakalu/agent-plugins

Made for: Claude Code.

Or install creating-mermaid-diagrams, the plugin that ships this one along with the rest of its 1 skill.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/mdsakalu/agent-plugins/creating-mermaid-diagrams/github.svg)](https://agentmods.dev/skills/mdsakalu/agent-plugins/creating-mermaid-diagrams)

Your own site

<a href="https://agentmods.dev/skills/mdsakalu/agent-plugins/creating-mermaid-diagrams"><img src="https://agentmods.dev/badge/skills/mdsakalu/agent-plugins/creating-mermaid-diagrams/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/mdsakalu/agent-plugins/creating-mermaid-diagrams"><img src="https://agentmods.dev/badge/skills/mdsakalu/agent-plugins/creating-mermaid-diagrams.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 100 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,659 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00100	$0.02659
Opus 5	$0.00050	$0.01329
Sonnet 5	$0.00020	$0.00532
Haiku 4.5	$0.00010	$0.00266

Measured 11d ago against content hash 75946f22c0dc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

creating-mermaid-diagrams scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/preview.sh, scripts/theme-preview.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

creating-mermaid-diagrams/skills/creating-mermaid-diagrams/SKILL.md · 287 lines

How it starts

The opening of the file, as written. The whole thing — 287 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Creating Mermaid Diagrams

Quick Start

Wrap mermaid in a fenced code block for GitHub:

```mermaid
flowchart TD
    A["Start"] --> B{"Decision"}
    B -->|Yes| C["Action"]
    B -->|No| D["Other Action"]
    C --> E["End"]
    D --> E

    classDef primary fill:#4493f8,stroke:#1f6feb,color:#fff
    classDef success fill:#3fb950,stroke:#238636,color:#fff
    classDef warning fill:#d29922,stroke:#9e6a03,color:#fff
    classDef danger fill:#f85149,stroke:#da3633,color:#fff

    class A primary
    class C success
    class D warning
    class E danger
```

Always include accTitle and accDescr for accessibility.

Design Philosophy

Start with structure. Add styling only where it earns its place. See references/style-guide.md for the full guide. The priority order:

Structure -- Shapes carry meaning (diamonds=decisions, cylinders=storage, pills=terminals)
Edge weight -- ==> for happy path, --> for standard, -.-> for optional/fallback
Color -- Reinforces meaning, never carries it alone. Most nodes should be neutral.
Emphasis -- stroke-width, dashed borders, emoji, bold labels -- only to solve specific problems

Workflow

Choose diagram type -- Match the user's intent to a diagram type (see table below or references/diagram-types.md for full syntax)
Write the diagram -- Use snake_case node IDs, quote reserved words, pick shapes that match meaning
Apply styling -- Start with 0-1 colors. Add more only as the diagram demands. Pick a theme from references/themes.md as a palette menu.
Preview -- Local SVG via preview.sh local or GitHub rendering via preview.sh gist
Embed -- Place the fenced code block in the target markdown file

Choosing a Diagram Type

Use Case	Diagram Type	Keyword
Process flow, decision tree	`flowchart`	flowchart TD/LR
API call sequence, auth flow	`sequenceDiagram`	sequenceDiagram
Object model, inheritance	`classDiagram`	classDiagram
Lifecycle, transitions	`stateDiagram-v2`	stateDiagram-v2
Database schema, relationships	`erDiagram`	erDiagram
Project timeline	`gantt`	gantt
Task board	`kanban`	kanban
Historical/event timeline	`timeline`	timeline
Distribution, proportions	`pie`	pie
2x2 matrix, positioning	`quadrantChart`	quadrantChart
Line/bar chart	`xychart-beta`	xychart-beta
Flow volume, allocation	`sankey-beta`	sankey-beta
Brainstorming, hierarchy	`mindmap`	mindmap
System context, containers	`C4Context`	C4Context
Infrastructure layout	`architecture-beta`	architecture-beta
Block layout	`block-beta`	block-beta
Git history visualization	`gitGraph`	gitGraph
Network packets	`packet-beta`	packet-beta
Requirements traceability	`requirementDiagram`	requirementDiagram

Read the full file on GitHub · 287 lines

Files

What ships with it

7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

11d ago First seen · 287 lines · 100 tokens per session scan A 75946f22c0dc

Subscribe to this mod's changes

creating-mermaid-diagrams is a skill published in the GitHub repository mdsakalu/agent-plugins (4 stars, last pushed 3mo ago), licensed MIT. It adds 100 tokens to every session and 2,659 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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