agentmods.dev

mermaid

mermaid is a skill for Claude Code from bendrucker/claude. It costs 23 tokens per session (261 once invoked), scanned A, original, MIT.

A skill for creating and checking Mermaid diagrams, which are text-based diagrams used in Markdown.

In plain words
What is it for?
Making flowcharts, sequence diagrams, state diagrams, and database relationship diagrams, then validating them with the supplied script.
Why use it?
It provides guidance for choosing diagram types and checking their syntax, reducing errors in diagrams stored as text.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Part of the mermaid plugin — 1 skill shipped together

not rated 18repo changed 10d ago A scan SkillSpector: pass 23 tokens original MIT

Good fit Making flowcharts, sequence diagrams, state diagrams, and database relationship diagrams, then validating them with the supplied script.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/bendrucker/claude/diagram
View source ↗ bendrucker/claude
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 bendrucker/claude --skill diagram
Clone the repo
git clone --depth 1 https://github.com/bendrucker/claude

Made for: Claude Code.

Or install mermaid, 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.

agentmods badge for mermaid

README.md
[![agentmods](https://agentmods.dev/badge/skills/bendrucker/claude/diagram/github.svg)](https://agentmods.dev/skills/bendrucker/claude/diagram)
Your own site
<a href="https://agentmods.dev/skills/bendrucker/claude/diagram"><img src="https://agentmods.dev/badge/skills/bendrucker/claude/diagram/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

Your own site · 80×15
<a href="https://agentmods.dev/skills/bendrucker/claude/diagram"><img src="https://agentmods.dev/badge/skills/bendrucker/claude/diagram.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 261 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 $0.00023 $0.00261
Opus 5.5 $0.00009 $0.00104
Sonnet 5.5 $0.00005 $0.00052
Haiku 4.5 $0.00002 $0.00026

Measured 10d ago against content hash b46931294798, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mermaid 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 10d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/validate.test.ts, scripts/validate.ts), 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.

plugins/mermaid/skills/diagram/SKILL.md · 27 lines

What it actually says

Mermaid Diagrams

Write Mermaid diagrams in markdown that parse cleanly. The work is done when the validator exits 0 on every file you touched:

bun ${CLAUDE_SKILL_DIR}/scripts/validate.ts <file.md>...

It prints each failing block's line and parser message. Add --json for structured output.

Diagram Types

Type Directive Use For Reference
Flowchart flowchart TB Process flows, decision trees, architecture flowchart.md
Sequence sequenceDiagram API interactions, message passing, protocols sequence.md
State stateDiagram-v2 State machines, lifecycles state.md
ER erDiagram Database schemas, entity relationships er.md

Write node and message labels in a few words, with full descriptions in the surrounding prose.

Files

What ships with it

9 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. 10d ago Changed · -14 lines b46931294798
  2. 2mo ago First seen · 41 lines · 23 tokens per session scan A e3aa7db0de78

Subscribe to this mod's changes

mermaid is a skill published in the GitHub repository bendrucker/claude (18 stars, last pushed today), licensed MIT. It adds 23 tokens to every session and 261 once invoked, about $0.0001 per session on Opus 5.5. 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.

Claude CodeDesign and UXWriting and docsclaude-code-plugin
Related

mermaid compared with skills from other repositories

mermaid next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
mermaidbendrucker/claudeSkill18todayMITA23Claude Code
top-designwondelai/skillsSkill2.7k7d agoMITA113Claude Code, Codex
sxonowork-studio/notfair-pluginSkill4.1k3d agoMITA211Claude Code
influence-psychologywondelai/skillsSkill2.7k7d agoMITA156Claude Code
refactoring-uiwondelai/skillsSkill2.7k7d agoMITA132Claude Code, Codex
ux-heuristicswondelai/skillsSkill2.7k7d agoMITA122Claude Code, Codex
shiny-bslibposit-dev/skillsSkill5617d agoMITA107Claude Code