Agent skill

Mermaid

by WH-2099 in WH-2099/mermaid-skill

Generate Mermaid diagrams from user requirements. An agent skill from WH-2099/mermaid-skill.

MITAuto-check passedDevelopment

Install Mermaid

skills CLI

$ npx skills add WH-2099/mermaid-skill --skill mermaid -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install WH-2099/mermaid-skill mermaid --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/WH-2099/mermaid-skill.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/mermaid .claude/skills/mermaid && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "mermaid" agent skill from https://github.com/WH-2099/mermaid-skill/tree/main/.claude/skills/mermaid into .claude/skills/mermaid/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mermaid", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/WH-2099/mermaid-skill/tree/main/.claude/skills/mermaid

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add WH-2099/mermaid-skill --skill mermaid -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install WH-2099/mermaid-skill mermaid --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/WH-2099/mermaid-skill.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.claude/skills/mermaid .agents/skills/mermaid && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "mermaid" agent skill from https://github.com/WH-2099/mermaid-skill/tree/main/.claude/skills/mermaid into .agents/skills/mermaid/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mermaid", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add WH-2099/mermaid-skill --skill mermaid -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install WH-2099/mermaid-skill mermaid --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/WH-2099/mermaid-skill.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.claude/skills/mermaid .cursor/skills/mermaid && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "mermaid" agent skill from https://github.com/WH-2099/mermaid-skill/tree/main/.claude/skills/mermaid into .cursor/skills/mermaid/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mermaid", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/WH-2099/mermaid-skill.git --path .claude/skills/mermaid

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add WH-2099/mermaid-skill --skill mermaid -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install WH-2099/mermaid-skill mermaid --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/WH-2099/mermaid-skill.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.claude/skills/mermaid .gemini/skills/mermaid && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "mermaid" agent skill from https://github.com/WH-2099/mermaid-skill/tree/main/.claude/skills/mermaid into .gemini/skills/mermaid/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mermaid", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install WH-2099/mermaid-skill mermaid

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add WH-2099/mermaid-skill --skill mermaid -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/WH-2099/mermaid-skill.git skills-src && mkdir -p .github/skills && cp -r skills-src/.claude/skills/mermaid .github/skills/mermaid && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "mermaid" agent skill from https://github.com/WH-2099/mermaid-skill/tree/main/.claude/skills/mermaid into .github/skills/mermaid/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mermaid", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add WH-2099/mermaid-skill --skill mermaid -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install WH-2099/mermaid-skill mermaid --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/WH-2099/mermaid-skill.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.claude/skills/mermaid .opencode/skills/mermaid && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "mermaid" agent skill from https://github.com/WH-2099/mermaid-skill/tree/main/.claude/skills/mermaid into .opencode/skills/mermaid/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mermaid", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: mermaid
GitHub stars: 288
Used in: 4 other repos
Token cost: ~958 tokens
SKILL.md length: 279 words
Files: 39 (incl. references)
Skills in repo: 1
Repo updated: Aug 11, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Generate Mermaid diagrams from user requirements. An agent skill from WH-2099/mermaid-skill.

Works in 4 steps: Understand Requirements: Analyze user… → Read Documentation: Read the… → Generate Code: Generate Mermaid code… → …
Tasks that involve Diagrams
SKILL.md covers Workflow, Diagram Type Reference, Configuration & Themes and Output Specification, plus 1 more section
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Mermaid is an agent skill from WH-2099/mermaid-skill. Generate Mermaid diagrams from user requirements. Supports flowcharts, sequence diagrams, class diagrams, ER diagrams, Gantt charts, and 18 more diagram types.

Its SKILL.md is about 960 tokens, which your agent loads only when the skill is triggered. The skill folder holds 39 other files, including reference files (for example `references/architecture.md`, `references/block.md` and `references/c4.md`).

It sits in Development, covering Diagrams. It works with Mermaid. The repository describes itself as: A Claude Code skill for generating Mermaid diagrams with all diagram types supported. The licence is MIT.

When your agent uses it

Tasks that involve Diagrams

Example prompts

“/mermaid”

Requirements

Pre-approved tools (allowed-tools): Read, Write, Edit

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

Understand Requirements: Analyze user description to determine the most suitable diagram type
Read Documentation: Read the corresponding syntax reference for the diagram type
Generate Code: Generate Mermaid code following the specification
Apply Styling: Apply appropriate themes and style configurations

What it can do on your machine

Read from SKILL.md and the folder at commit 982d903. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves these tools, so the agent can use them without asking each time:
- Read
- Write
- Edit
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are mermaid).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Mermaid loads about 958 tokens when it runs, and up to ~139k if it reads all its reference files. Until then it costs about 42 tokens; SKILL.md has 279 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~42
When it runs · the whole SKILL.md, loaded when a task matches: ~958
With references · SKILL.md plus every file in references/, read only if the agent opens them: ~139k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from WH-2099/mermaid-skill at commit 982d903, republished under its MIT licence (© WH-2099). 279 words, ~958 tokens.

Download SKILL.mdSave it as .claude/skills/mermaid/SKILL.md (or your agent's skills folder). This skill also uses 38 other files; get the full folder from GitHub.

name: mermaid
description: Generate Mermaid diagrams from user requirements. Supports flowcharts, sequence diagrams, class diagrams, ER diagrams, Gantt charts, and 18 more diagram types.
allowed-tools: Read, Write, Edit
metadata.argument-hint: [diagram description or requirements]

Mermaid Diagram Generator

Generate high-quality Mermaid diagram code based on user requirements.

Workflow

Understand Requirements: Analyze user description to determine the most suitable diagram type
Read Documentation: Read the corresponding syntax reference for the diagram type
Generate Code: Generate Mermaid code following the specification
Apply Styling: Apply appropriate themes and style configurations

Diagram Type Reference

Select the appropriate diagram type and read the corresponding documentation:

Type	Documentation	Use Cases
Flowchart	flowchart.md	Processes, decisions, steps
Sequence Diagram	sequenceDiagram.md	Interactions, messaging, API calls
Class Diagram	classDiagram.md	Class structure, inheritance, associations
State Diagram	stateDiagram.md	State machines, state transitions
ER Diagram	entityRelationshipDiagram.md	Database design, entity relationships
Gantt Chart	gantt.md	Project planning, timelines
Pie Chart	pie.md	Proportions, distributions
Mindmap	mindmap.md	Hierarchical structures, knowledge graphs
Timeline	timeline.md	Historical events, milestones
Git Graph	gitgraph.md	Branches, merges, versions
Quadrant Chart	quadrantChart.md	Four-quadrant analysis
Requirement Diagram	requirementDiagram.md	Requirements traceability
C4 Diagram	c4.md	System architecture (C4 model)
Sankey Diagram	sankey.md	Flow, conversions
XY Chart	xyChart.md	Line charts, bar charts
Block Diagram	block.md	System components, modules
Packet Diagram	packet.md	Network protocols, data structures
Kanban	kanban.md	Task management, workflows
Architecture Diagram	architecture.md	System architecture
Radar Chart	radar.md	Multi-dimensional comparison
Treemap	treemap.md	Hierarchical data visualization
User Journey	userJourney.md	User experience flows
ZenUML	zenuml.md	Sequence diagrams (code style)

Configuration & Themes

Theming - Custom colors and styles
Directives - Diagram-level configuration
Layouts - Layout direction and spacing
Configuration - Global settings
Math - LaTeX math support

Output Specification

Generated Mermaid code should:

Be wrapped in ```mermaid code blocks
Have correct syntax that renders directly
Have clear structure with proper line breaks and indentation
Use semantic node naming
Include styling when needed to improve visual appearance

Example Output

mermaid

flowchart TD
    A[Start] --> B{Condition}
    B -->|Yes| C[Execute]
    B -->|No| D[End]
    C --> D

User requirements: $ARGUMENTS

Files

SKILL.md and 38 other files (references) in .claude/skills/mermaid of WH-2099/mermaid-skill.

SKILL.md
references/architecture.md
references/block.md
references/c4.md
references/classDiagram.md
references/config-configuration.md
references/config-directives.md
references/config-layouts.md
references/config-math.md
references/config-theming.md
references/config-tidy-tree.md
references/cynefin.md
references/entityRelationshipDiagram.md
references/eventmodeling.md
references/examples.md
references/flowchart.md
references/gantt.md
references/gitgraph.md
references/ishikawa.md
references/kanban.md
… and 19 more

Open the folder on GitHubat commit 982d903

Used in 4 other repositories

We found 4 copies of this SKILL.md (exact, near-identical or edited) in other folders, from 4 other GitHub owners. This page covers the copy in WH-2099/mermaid-skill, which our catalogue first saw on October 7, 2026.

Compare with similar skills

Mermaid next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Mermaid compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Mermaid this skillWH-2099/mermaid-skill	288	4 repos	~958	Automated safety check: Pass	MIT	2 mo ago
Archify Diagramstt-a1i/archify	82k	—	~2.9k	Automated safety check: Pass	MIT	today
Diagram Designcathrynlavery/diagram-design	49k	1 repos	~7.6k	Automated safety check: Pass	MIT	today
Draw.io Diagram StudioAgents365-ai/drawio-skill	10k	—	~2.4k	Automated safety check: Notes	MIT	today
Pretty Mermaid Rendererimxv/Pretty-mermaid-skills	1.5k	—	~2k	Automated safety check: Pass	MIT	1 mo ago
Archify Diagram BuilderUnclecheng-li/AI_Animation	1.5k	2 repos	~4.1k	Automated safety check: Pass	MIT	6 days ago

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Works with

Mermaid

Questions about Mermaid

What does Mermaid do?

Generate Mermaid diagrams from user requirements. An agent skill from WH-2099/mermaid-skill. Mermaid is an agent skill from WH-2099/mermaid-skill. Generate Mermaid diagrams from user requirements.

When should I use Mermaid?

Mermaid fits situations like: tasks that involve Diagrams.

How do I install Mermaid in Claude Code?

Run `npx skills add WH-2099/mermaid-skill --skill mermaid -a claude-code`. Or copy the skill folder (.claude/skills/mermaid in WH-2099/mermaid-skill) into .claude/skills/mermaid in your project. Claude Code loads it when a task matches its description.

How do I install Mermaid in Codex?

Run `npx skills add WH-2099/mermaid-skill --skill mermaid -a codex`. Or copy the skill folder (.claude/skills/mermaid in WH-2099/mermaid-skill) into .agents/skills/mermaid in your project. Codex loads it when a task matches its description.

Can I use Mermaid in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add WH-2099/mermaid-skill --skill mermaid -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/mermaid, .gemini/skills/mermaid, .github/skills/mermaid and .opencode/skills/mermaid in your project.

What does Mermaid need to run?

SKILL.md names no scripts, command-line tools or credentials: Mermaid is instructions for the agent only. Its frontmatter pre-approves these tools: Read, Write, Edit.

Does Mermaid access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Mermaid safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Mermaid use?

Mermaid is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Mermaid use?

About 958 tokens (SKILL.md is roughly 3.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 138k tokens, read only when the agent opens those files.

What are the alternatives to Mermaid?

Skills that share tags, products or a category with Mermaid: Archify Diagrams (tt-a1i/archify, 82k stars), Diagram Design (cathrynlavery/diagram-design, 49k stars), Draw.io Diagram Studio (Agents365-ai/drawio-skill, 10k stars) and Pretty Mermaid Renderer (imxv/Pretty-mermaid-skills, 1.5k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Mermaid?

WH-2099 (a GitHub user) maintains it in WH-2099/mermaid-skill, which has 288 GitHub stars. The repository was last updated on August 11, 2026.

Source: WH-2099/mermaid-skill on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Mermaid

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Mermaid Diagram Generator

Workflow

Diagram Type Reference

Configuration & Themes

Output Specification

Example Output

Files

Used in 4 other repositories

Compare with similar skills

Similar skills

Archify Diagrams

Diagram Design

Draw.io Diagram Studio

Pretty Mermaid Renderer

Archify Diagram Builder

Archify

Related

Questions about Mermaid