mermaid-syntax

mermaid-syntax is a skill for Claude Code, Codex from tractorjuice/arckit-gemini. It costs 99 tokens per session (1,543 once invoked), scanned A, original, MIT.

A reference for Mermaid, a text-based language that turns descriptions into diagrams. It covers flowcharts, sequence diagrams, class diagrams, timelines, and other diagram types.

In plain words
What is it for?
Use it to create or fix diagrams, choose node shapes, apply styles and themes, and write diagrams for processes, software structure, data relationships, schedules, and project plans.
Why use it?
It helps when you need to write Mermaid diagrams correctly or diagnose rendering errors without guessing at the syntax.

Skill for Claude CodeCodex

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

Good fit Use it to create or fix diagrams, choose node shapes, apply styles and themes, and write diagrams for processes, software structure, data relationships, schedules, and project plans.

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Install with agentmods
npx agentmods add skills/tractorjuice/arckit-gemini/mermaid-syntax
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 tractorjuice/arckit-gemini --skill mermaid-syntax
Clone the repo
git clone --depth 1 https://github.com/tractorjuice/arckit-gemini

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-syntax

README.md
[![agentmods](https://agentmods.dev/badge/skills/tractorjuice/arckit-gemini/mermaid-syntax/github.svg)](https://agentmods.dev/skills/tractorjuice/arckit-gemini/mermaid-syntax)
Your own site
<a href="https://agentmods.dev/skills/tractorjuice/arckit-gemini/mermaid-syntax"><img src="https://agentmods.dev/badge/skills/tractorjuice/arckit-gemini/mermaid-syntax/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-syntax

Your own site · 80×15
<a href="https://agentmods.dev/skills/tractorjuice/arckit-gemini/mermaid-syntax"><img src="https://agentmods.dev/badge/skills/tractorjuice/arckit-gemini/mermaid-syntax.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 99 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,543 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00099 $0.01543
Opus 5 $0.00049 $0.00772
Sonnet 5 $0.00020 $0.00309
Haiku 4.5 $0.00010 $0.00154

Measured 5d ago against content hash b6c4acbe68b6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

mermaid-syntax 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 5d 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-syntax/SKILL.md · 86 lines

How it starts

The opening of the file, as written. The whole thing — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Mermaid Syntax Reference

A comprehensive reference for all 23 Mermaid diagram types plus configuration and theming. This skill provides official Mermaid syntax documentation sourced from the mermaid-skill project (auto-synced from upstream Mermaid docs).

This skill ships reference material, not runnable scripts. Read the relevant reference file with Read, apply the syntax, and write the diagram into the user's artefact. Do not Bash-execute anything from references/ — they are Mermaid syntax docs, not commands.

To look up syntax for a specific diagram type, identify the type from the table below and read the corresponding reference file.

Supported Diagram Types

Select the appropriate diagram type and read the corresponding reference file:

Type Reference ArcKit Commands Using It
Flowchart flowchart.md /arckit:diagram, /arckit:dfd, /arckit:roadmap, /arckit:plan, /arckit:backlog, /arckit:strategy, /arckit:story, /arckit:jsp-936
Sequence Diagram sequenceDiagram.md /arckit:diagram
Class Diagram classDiagram.md
State Diagram stateDiagram.md
ER Diagram entityRelationshipDiagram.md /arckit:data-model
Gantt Chart gantt.md /arckit:roadmap, /arckit:plan, /arckit:strategy, /arckit:story, /arckit:presentation
Pie Chart pie.md /arckit:story, /arckit:presentation
Mindmap mindmap.md /arckit:story
Timeline timeline.md /arckit:story
Git Graph gitgraph.md
Quadrant Chart quadrantChart.md /arckit:presentation
Requirement Diagram requirementDiagram.md
C4 Diagram c4.md /arckit:diagram, /arckit:presentation
Sankey Diagram sankey.md
XY Chart xyChart.md
Block Diagram block.md
Packet Diagram packet.md
Kanban kanban.md
Architecture Diagram architecture.md
Radar Chart radar.md
Treemap treemap.md
User Journey userJourney.md
ZenUML zenuml.md

Read the full file on GitHub · 86 lines

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. 5d ago Changed · +4 lines · +38 tokens per session b6c4acbe68b6
  2. 10d ago First seen · 82 lines · 61 tokens per session scan A 3637374125fe

Subscribe to this mod's changes

mermaid-syntax is a skill published in the GitHub repository tractorjuice/arckit-gemini (3 stars, last pushed 6d ago), licensed MIT. It adds 99 tokens to every session and 1,543 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.