mermaid-skill MCP — Casos de uso, Instalar & Demo ao vivo

Por que usar

Principais recursos

Covers 10+ Mermaid diagram types
Local render via mmdc (PNG / SVG / PDF)
Automatic layout hints to avoid crossing edges
Iterates on diagrams based on feedback
Works inside your repo, diagrams committed alongside code

Demo ao vivo

Como fica na prática

mermaid-skill.replay ▶ pronto

0/0

Instalar

Escolha seu cliente

~/Library/Application Support/Claude/claude_desktop_config.json · Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "mermaid-skill": {
      "command": "git",
      "args": [
        "clone",
        "https://github.com/Agents365-ai/mermaid-skill",
        "~/.claude/skills/mermaid-skill"
      ],
      "_inferred": true
    }
  }
}

Abra Claude Desktop → Settings → Developer → Edit Config. Reinicie após salvar.

~/.cursor/mcp.json · .cursor/mcp.json

{
  "mcpServers": {
    "mermaid-skill": {
      "command": "git",
      "args": [
        "clone",
        "https://github.com/Agents365-ai/mermaid-skill",
        "~/.claude/skills/mermaid-skill"
      ],
      "_inferred": true
    }
  }
}

Cursor usa o mesmo esquema mcpServers que o Claude Desktop. Config de projeto vence a global.

VS Code → Cline → MCP Servers → Edit

{
  "mcpServers": {
    "mermaid-skill": {
      "command": "git",
      "args": [
        "clone",
        "https://github.com/Agents365-ai/mermaid-skill",
        "~/.claude/skills/mermaid-skill"
      ],
      "_inferred": true
    }
  }
}

Clique no ícone MCP Servers na barra lateral do Cline, depois "Edit Configuration".

~/.codeium/windsurf/mcp_config.json

{
  "mcpServers": {
    "mermaid-skill": {
      "command": "git",
      "args": [
        "clone",
        "https://github.com/Agents365-ai/mermaid-skill",
        "~/.claude/skills/mermaid-skill"
      ],
      "_inferred": true
    }
  }
}

Mesmo formato do Claude Desktop. Reinicie o Windsurf para aplicar.

~/.continue/config.json

{
  "mcpServers": [
    {
      "name": "mermaid-skill",
      "command": "git",
      "args": [
        "clone",
        "https://github.com/Agents365-ai/mermaid-skill",
        "~/.claude/skills/mermaid-skill"
      ]
    }
  ]
}

O Continue usa um array de objetos de servidor em vez de um map.

~/.config/zed/settings.json

{
  "context_servers": {
    "mermaid-skill": {
      "command": {
        "path": "git",
        "args": [
          "clone",
          "https://github.com/Agents365-ai/mermaid-skill",
          "~/.claude/skills/mermaid-skill"
        ]
      }
    }
  }
}

Adicione em context_servers. Zed recarrega automaticamente ao salvar.

claude mcp add mermaid-skill -- git clone https://github.com/Agents365-ai/mermaid-skill ~/.claude/skills/mermaid-skill

Uma linha só. Verifique com claude mcp list. Remova com claude mcp remove.

Casos de uso

Usos do mundo real: mermaid-skill

Draw an architecture diagram for your current project

👤 Devs writing docs, ADRs, or onboarding guides ⏱ ~20 min beginner

Quando usar: You keep explaining your architecture in Slack and want a picture.

Pré-requisitos

mmdc installed — npm i -g @mermaid-js/mermaid-cli
Skill installed — git clone https://github.com/Agents365-ai/mermaid-skill ~/.claude/skills/mermaid-skill

Fluxo

Describe the system

Use mermaid-skill. Draw a flowchart of our service: client → API gateway → (auth / orders / payments) → Postgres / Redis / Stripe.✓ Copiado

→ .mmd source with meaningful node names, rendered to PNG in docs/
Add details

Add labels on each edge showing the protocol (HTTPS, gRPC, TCP) and auth type.✓ Copiado

→ Updated source and re-render
Commit it

Commit docs/architecture.mmd and its PNG.✓ Copiado

→ git add and commit run

Resultado: A living diagram in the repo, not a stale slide in Confluence.

Armadilhas

Diagram becomes a maze of edges — Let Claude use subgraphs and direction hints; don't cram everything on one layer

Combine com: filesystem · git

Produce a sequence diagram while debugging

👤 Engineers tracing a cross-service bug ⏱ ~15 min beginner

Quando usar: You're trying to understand an async interaction and English isn't cutting it.

Fluxo

Describe the flow

Use mermaid-skill. Sequence diagram: browser → SSR → auth service → session store → page render, with failure mode when session is stale.✓ Copiado

→ Sequence diagram with the failure annotated
Annotate the bug

Highlight the line where the bug manifests.✓ Copiado

→ Annotated box/note on the offending message

Resultado: A picture you can paste in the bug ticket.

Generate an ERD from your actual database schema

👤 Data engineers, backend devs ⏱ ~20 min intermediate

Quando usar: You want a visual of your schema for a design review.

Fluxo

Introspect

Use mermaid-skill. Read the schema.sql (or query the live DB via postgres MCP) and produce a Mermaid ERD.✓ Copiado

→ .mmd ERD with relationships and cardinalities
Trim noise

Drop audit tables and focus on the core domain entities.✓ Copiado

→ Trimmed ERD

Resultado: An accurate ERD without manual drawing.

Armadilhas

Cardinalities wrong when inferred — Provide the actual foreign-key definitions; don't let the model guess

Combine com: postgres

Combinações

Combine com outros MCPs para 10× de alavancagem

mermaid-skill + filesystem

Keep diagrams alongside the code they describe

For every service in services/, add a docs/architecture.mmd and render it.✓ Copiado

mermaid-skill + postgres

Auto-generate ERDs from live databases

Connect to the staging DB and render its schema as a Mermaid ERD.✓ Copiado

mermaid-skill + git

Diagram stays versioned with code changes

Commit updated diagrams in the same PR as the code changes they describe.✓ Copiado

Ferramentas

O que este MCP expõe

Ferramenta	Entradas	Quando chamar	Custo
write_mermaid	description, diagram type	Any diagram request	0
render_mmdc	.mmd path, output format	After source is final	local mmdc
iterate_diagram	current diagram + feedback	Reviewer feedback	0

Custo e limites

O que custa rodar

Cota de API: None
Tokens por chamada: Small — Mermaid source is compact
Monetário: Free (mmdc is open source)
Dica: For big diagrams, generate subgraphs separately to avoid retrying large rewrites.

Segurança

Permissões, segredos, alcance

Armazenamento de credenciais: None

Saída de dados: None from skill itself

Solução de problemas

Erros comuns e correções

mmdc not found

Install globally: npm i -g @mermaid-js/mermaid-cli

Verificar: which mmdc

Render fails with syntax error

Mermaid has version-specific syntax; run mmdc --version and match the skill's assumed version

Verificar: mmdc --version

Diagram is a mess of crossing edges

Add direction hints (TD/LR), group with subgraphs, or split into multiple diagrams

Alternativas

mermaid-skill vs. outros

Alternativa	Quando usar	Troca
PlantUML / draw.io	You need more control or non-Mermaid syntax	More setup, different rendering toolchain
paperbanana-skill	Academic publication-quality diagrams	Heavier; different aesthetic goals

Mais

Recursos

📖 Leia o README oficial no GitHub

🐙 Ver issues abertas

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