mermaid-diagrams

mermaid-diagrams is a skill for Claude Code, Codex from sammcj/agentic-coding. It costs 30 tokens per session (359 once invoked), scanned A, original, Apache-2.0.

Guidelines for creating or updating Mermaid diagrams, which are text descriptions that render as flowcharts and other diagrams.

In plain words
What is it for?
Use it when writing or editing Mermaid flowcharts, state diagrams, class diagrams, or similar visual documentation.
Why use it?
It helps diagrams render correctly and keeps their labels, colours, and structure consistent.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when writing or editing Mermaid flowcharts, state diagrams, class diagrams, or similar visual documentation.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/sammcj/agentic-coding/mermaid-diagrams
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 sammcj/agentic-coding --skill mermaid-diagrams
Clone the repo
git clone --depth 1 https://github.com/sammcj/agentic-coding

Made for: Claude Code, Codex.

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.

agentmods badge for mermaid-diagrams

README.md
[![agentmods](https://agentmods.dev/badge/skills/sammcj/agentic-coding/mermaid-diagrams/github.svg)](https://agentmods.dev/skills/sammcj/agentic-coding/mermaid-diagrams)
Your own site
<a href="https://agentmods.dev/skills/sammcj/agentic-coding/mermaid-diagrams"><img src="https://agentmods.dev/badge/skills/sammcj/agentic-coding/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.

agentmods 80×15 button for mermaid-diagrams

Your own site · 80×15
<a href="https://agentmods.dev/skills/sammcj/agentic-coding/mermaid-diagrams"><img src="https://agentmods.dev/badge/skills/sammcj/agentic-coding/mermaid-diagrams.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 30 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 359 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00030 $0.00359
Opus 5 $0.00015 $0.00179
Sonnet 5 $0.00006 $0.00072
Haiku 4.5 $0.00003 $0.00036

Measured 9d ago against content hash b1f7ac8ed5de, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

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 9d ago.

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.

Skills/mermaid-diagrams/SKILL.md · 25 lines

What it actually says

Mermaid Diagramming Guidelines

  • Wrap any label containing parentheses or other special characters in double quotes, e.g. id1["Send request (POST)"]; unquoted parentheses break parsing
  • Use <br> instead of \n for line breaks
  • Mermaid does not support unordered lists within item labels
  • For flowchart, state and class diagrams, apply this colour theme unless specified otherwise:
classDef inputOutput fill:#F5F5F5,stroke:#9E9E9E,color:#616161
classDef llm fill:#E8EAF6,stroke:#7986CB,color:#3F51B5
classDef components fill:#F3E5F5,stroke:#BA68C8,color:#8E24AA
classDef process fill:#E0F2F1,stroke:#4DB6AC,color:#00897B
classDef stop fill:#FFEBEE,stroke:#E57373,color:#D32F2F
classDef data fill:#E3F2FD,stroke:#64B5F6,color:#1976D2
classDef decision fill:#FFF3E0,stroke:#FFB74D,color:#F57C00
classDef storage fill:#F1F8E9,stroke:#9CCC65,color:#689F38
classDef api fill:#FFF9C4,stroke:#FDD835,color:#F9A825
classDef error fill:#FFCDD2,stroke:#EF5350,color:#C62828
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.

  1. 9d ago First seen · 25 lines · 30 tokens per session scan A b1f7ac8ed5de

Subscribe to this mod's changes

mermaid-diagrams is a skill published in the GitHub repository sammcj/agentic-coding (160 stars, last pushed today), licensed Apache-2.0. It adds 30 tokens to every session and 359 once invoked, about $0.0002 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 2026-08-30.