Mermaid

v1.6.3โ€ขDeveloper Toolsโ€ขstable

๐Ÿ“‡ ๐Ÿ  ๐ŸŽ ๐ŸชŸ ๐Ÿง - A Mermaid diagram rendering MCP server for Claude Code with live reload functionality, supporting multiple export formats (SVG, PNG, PDF) and themes.

claude-codemcp-servermcpmermaidclaude
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What is Mermaid?

Mermaid is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to ๐Ÿ“‡ ๐Ÿ  ๐ŸŽ ๐ŸชŸ ๐Ÿง - a mermaid diagram rendering mcp server for claude code with live reload functionality, supporting multiple export formats (svg, png, pdf) and themes.

๐Ÿ“‡ ๐Ÿ  ๐ŸŽ ๐ŸชŸ ๐Ÿง - A Mermaid diagram rendering MCP server for Claude Code with live reload functionality, supporting multiple export formats (SVG, PNG, PDF) and themes.

This server falls under the Developer Tools category on MCPgee, the world's largest MCP server directory with 33,000+ servers.

Features

  • ๐Ÿ“‡ ๐Ÿ  ๐ŸŽ ๐ŸชŸ ๐Ÿง - A Mermaid diagram rendering MCP server for Claud

Use Cases

๐Ÿ“‡ ๐Ÿ  ๐ŸŽ ๐ŸชŸ ๐Ÿง - A Mermaid diagram rendering MCP server for Claude Code with live rel
veelenga

Maintainer

LicenseMIT License
Languagetypescript
Versionv1.6.3
UpdatedMay 21, 2026
Statushealthy
Maintenanceactive

Works with

ClaudeOpenAIwindowsmacoslinux

Installation

NPM

npx -y claude-mermaid

Manual Installation

npx -y claude-mermaid

Configuration

Configuration Details

Config File

claude_desktop_config.json

Performance

Response Metrics

Response Time< 200ms
ThroughputMedium

Resource Usage

Memory UsageLow
CPU UsageLow

How to Set Up and Use Mermaid

claude-mermaid is an MCP server that renders Mermaid diagram syntax into visual diagrams with live reload functionality directly inside Claude Code. When you describe a flowchart, sequence diagram, class diagram, or architecture diagram in natural language, Claude generates the Mermaid DSL and this server opens a browser preview that auto-refreshes as the diagram evolves. It supports SVG, PNG, and PDF export formats with configurable themes and background colors, making it useful for documentation, system design, and architecture visualization workflows without leaving the coding environment.

Prerequisites

  • Node.js 18+ with npm installed
  • Claude Code (the server is optimized for Claude Code's MCP plugin system)
  • A modern browser for live preview rendering
  • Mermaid CLI (mmdc) installed if using PNG or PDF export formats
1

Install the server via Claude Code plugin marketplace

The recommended installation method uses the Claude Code plugin system, which automatically handles setup and configuration.

/plugin marketplace add veelenga/claude-mermaid
/plugin install claude-mermaid@claude-mermaid
2

Alternatively, install globally via npm

If you prefer a manual install, install the package globally with npm, then register it as an MCP server in Claude Code.

npm install -g claude-mermaid
claude mcp add --scope user mermaid claude-mermaid
3

Add to MCP client configuration (non-Claude Code clients)

For Claude Desktop or other MCP clients, add the server using the npx launch command.

{
  "mcpServers": {
    "mermaid": {
      "command": "npx",
      "args": ["-y", "claude-mermaid"]
    }
  }
}
4

Configure logging verbosity (optional)

Set the CLAUDE_MERMAID_LOG_LEVEL environment variable to control how much output the server produces. Valid values are DEBUG, INFO (default), WARN, ERROR, and OFF.

{
  "mcpServers": {
    "mermaid": {
      "command": "npx",
      "args": ["-y", "claude-mermaid"],
      "env": {
        "CLAUDE_MERMAID_LOG_LEVEL": "WARN"
      }
    }
  }
}
5

Request your first diagram

Ask Claude to create any Mermaid diagram. The server will open a browser window with a live preview. As you refine the diagram through follow-up prompts, the browser auto-reloads.

Mermaid Examples

Client configuration

Example claude_desktop_config.json entry for the claude-mermaid MCP server.

{
  "mcpServers": {
    "mermaid": {
      "command": "npx",
      "args": ["-y", "claude-mermaid"],
      "env": {
        "CLAUDE_MERMAID_LOG_LEVEL": "INFO"
      }
    }
  }
}

Prompts to try

Sample requests that exercise live preview, theming, and export capabilities.

- "Create a Mermaid sequence diagram showing the OAuth2 authorization code flow."
- "Draw a flowchart for a CI/CD pipeline from code commit to production deployment."
- "Generate a class diagram for a User, Order, and Product e-commerce model with relationships."
- "Create a dark theme architecture diagram with transparent background showing our microservices."
- "Save the current diagram as a PNG file to /tmp/architecture.png"

Troubleshooting Mermaid

Browser preview window does not open after requesting a diagram

Ensure a default browser is configured on your system. On Linux, set the BROWSER environment variable (e.g., export BROWSER=firefox). On macOS and Windows, the default browser should open automatically. Check server logs by setting CLAUDE_MERMAID_LOG_LEVEL=DEBUG.

PNG or PDF export fails with 'mmdc not found'

PNG and PDF export require Mermaid CLI. Install it with 'npm install -g @mermaid-js/mermaid-cli'. After installation, verify with 'mmdc --version'. SVG export works without this dependency.

Plugin install command not recognized in Claude Code

Ensure you are using a recent version of Claude Code that supports the /plugin command. Alternatively, use the npm global install method: 'npm install -g claude-mermaid' followed by 'claude mcp add --scope user mermaid claude-mermaid'.

Frequently Asked Questions about Mermaid

What is Mermaid?

Mermaid is a Model Context Protocol (MCP) server that ๐Ÿ“‡ ๐Ÿ  ๐ŸŽ ๐ŸชŸ ๐Ÿง - a mermaid diagram rendering mcp server for claude code with live reload functionality, supporting multiple export formats (svg, png, pdf) and themes. It connects AI assistants to external tools and data sources through a standardized interface.

How do I install Mermaid?

Install via npm with the command: npx -y claude-mermaid. Then add the server configuration to your AI client's JSON config file (e.g., claude_desktop_config.json or .cursor/mcp.json).

Which AI clients work with Mermaid?

Mermaid works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.

Is Mermaid free to use?

Yes, Mermaid is open source and available under the MIT License license. You can use it freely in both personal and commercial projects.

Browse More Developer Tools MCP Servers

Explore all developer tools servers available in the MCPgee directory. Each server includes setup guides for Claude, Cursor, and VS Code.

Quick Config Preview

{ "mcpServers": { "claude-mermaid": { "command": "npx", "args": ["-y", "claude-mermaid"] } } }

Add this to your claude_desktop_config.json or .cursor/mcp.json

Read the full setup guide โ†’

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