mermaid-skill MCP — Cas d'usage, Installer & Démo en direct

Pourquoi l'utiliser

Fonctionnalités clés

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

Démo en direct

Aperçu en pratique

mermaid-skill.replay ▶ prêt

0/0

Installer

Choisissez votre client

~/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
    }
  }
}

Ouvrez Claude Desktop → Settings → Developer → Edit Config. Redémarrez après avoir enregistré.

~/.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 utilise le même schéma mcpServers que Claude Desktop. La config projet l'emporte sur la globale.

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
    }
  }
}

Cliquez sur l'icône MCP Servers dans la barre latérale Cline, puis "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
    }
  }
}

Même format que Claude Desktop. Redémarrez Windsurf pour appliquer.

~/.continue/config.json

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

Continue utilise un tableau d'objets serveur plutôt qu'une 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"
        ]
      }
    }
  }
}

Ajoutez dans context_servers. Zed recharge à chaud à la sauvegarde.

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

Une seule ligne. Vérifiez avec claude mcp list. Supprimez avec claude mcp remove.

Cas d'usage

Usages concrets : mermaid-skill

Draw an architecture diagram for your current project

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

Quand l'utiliser : You keep explaining your architecture in Slack and want a picture.

Prérequis

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

Déroulement

Describe the system

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

→ .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.✓ Copié

→ Updated source and re-render
Commit it

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

→ git add and commit run

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

Pièges

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

Combiner avec : filesystem · git

Produce a sequence diagram while debugging

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

Quand l'utiliser : You're trying to understand an async interaction and English isn't cutting it.

Déroulement

Describe the flow

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

→ Sequence diagram with the failure annotated
Annotate the bug

Highlight the line where the bug manifests.✓ Copié

→ Annotated box/note on the offending message

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

Generate an ERD from your actual database schema

👤 Data engineers, backend devs ⏱ ~20 min intermediate

Quand l'utiliser : You want a visual of your schema for a design review.

Déroulement

Introspect

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

→ .mmd ERD with relationships and cardinalities
Trim noise

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

→ Trimmed ERD

Résultat : An accurate ERD without manual drawing.

Pièges

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

Combiner avec : postgres

Combinaisons

Associez-le à d'autres MCPs pour un effet X10

mermaid-skill + filesystem

Keep diagrams alongside the code they describe

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

mermaid-skill + postgres

Auto-generate ERDs from live databases

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

mermaid-skill + git

Diagram stays versioned with code changes

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

Outils

Ce que ce MCP expose

Outil	Entrées	Quand appeler	Coût
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

Coût et limites

Coût d'exécution

Quota d'API: None
Tokens par appel: Small — Mermaid source is compact
Monétaire: Free (mmdc is open source)
Astuce: For big diagrams, generate subgraphs separately to avoid retrying large rewrites.

Sécurité

Permissions, secrets, portée

Stockage des identifiants : None

Sortie de données : None from skill itself

Dépannage

Erreurs courantes et correctifs

mmdc not found

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

Vérifier : which mmdc

Render fails with syntax error

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

Vérifier : mmdc --version

Diagram is a mess of crossing edges

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

Alternatives

mermaid-skill vs autres

Alternative	Quand l'utiliser	Compromis
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

Plus

Ressources

📖 Lire le README officiel sur GitHub

🐙 Voir les issues ouvertes

🔍 Parcourir les 400+ serveurs MCP et Skills