mermaid-diagram-driven-development: Skill for Claude Code

.agents/skills/mermaid-diagrams/SKILL.md

mermaid-diagrams is a skill for Claude Code, Codex from JulioCRFilho/mermaid-diagram-driven-development. It costs 143 tokens per session (1,683 once invoked), scanned A, original, no licence file.

A guide to creating software diagrams with Mermaid, a text-based format for describing diagrams. It covers diagrams for system structure, interactions, processes, and other software designs.

In plain words
What is it for?
Use it to create class diagrams for models, sequence diagrams for interactions such as API calls, and flowcharts for processes.
Why use it?
It helps you document software clearly without drawing diagrams by hand or leaving the intended design implicit in code.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing. Also seen: installed under .agents/ (shared by several agents).

This is JulioCRFilho/mermaid-diagram-driven-development's own configuration. It tells Claude Code and Codex how to work on mermaid-diagram-driven-development itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything mermaid-diagram-driven-development configures →

Reuse

Borrowing it

Nothing to install: this file belongs to JulioCRFilho/mermaid-diagram-driven-development. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/JulioCRFilho/mermaid-diagram-driven-development/main/.agents/skills/mermaid-diagrams/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/JulioCRFilho/mermaid-diagram-driven-development

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/juliocrfilho/mermaid-diagram-driven-development/mermaid-diagrams/github.svg)](https://agentmods.dev/skills/juliocrfilho/mermaid-diagram-driven-development/mermaid-diagrams)
Your own site
<a href="https://agentmods.dev/skills/juliocrfilho/mermaid-diagram-driven-development/mermaid-diagrams"><img src="https://agentmods.dev/badge/skills/juliocrfilho/mermaid-diagram-driven-development/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/juliocrfilho/mermaid-diagram-driven-development/mermaid-diagrams"><img src="https://agentmods.dev/badge/skills/juliocrfilho/mermaid-diagram-driven-development/mermaid-diagrams.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 143 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,683 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 unknown 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 $0.00143 $0.01683
Opus 5 $0.00072 $0.00842
Sonnet 5 $0.00029 $0.00337
Haiku 4.5 $0.00014 $0.00168

Measured 12d ago against content hash 09a93c300eb5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, 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 12d 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.

.agents/skills/mermaid-diagrams/SKILL.md · 217 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Files

What ships with it

8 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.

  1. 12d ago First seen · 217 lines · 143 tokens per session scan A 09a93c300eb5

Subscribe to this mod's changes

mermaid-diagrams is a skill published in the GitHub repository JulioCRFilho/mermaid-diagram-driven-development (21 stars, last pushed 1mo ago), with no licence file. It adds 143 tokens to every session and 1,683 once invoked, about $0.0007 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.