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How to connect Mermaid Chart MCP to Claude

Connect Claude Web, Desktop and Cowork to Mermaid Chart MCP. Validate checkout flow mermaid syntax, render deployment sequence diagram as svg, and more using natural language, with authentication handled for you.

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No Auth

Mermaid Chart MCP is a no-auth MCP server for validating Mermaid syntax and rendering diagrams as SVG. Use it to preview, zoom, and iterate on diagrams quickly without wiring up custom rendering code.

1 Tools

Introduction

Claude is Anthropic's AI assistant, available on the web, in the desktop app, and on mobile. Cowork is its agent for knowledge work, and it runs on all of those surfaces too. Connected to your apps, Claude can work with your files and services to accomplish complex tasks on your behalf.

This guide walks you through the easiest and most secure way to connect your Mermaid Chart account to Claude via Composio Connect, enabling it to validate checkout flow Mermaid syntax, render deployment sequence diagram as SVG, preview user journey diagram interactively, and more such actions on your behalf without compromising your account security.

Setup is the same on Claude Web, Desktop, and Cowork, and you only need to do it once. The connector is tied to your account, so it's available in all three.

Also integrate Mermaid Chart MCP with

ChatGPTGrok Bot

Connecting Mermaid Chart to Claude Web, Desktop, and Cowork

Two ways to add the Composio connector. Pick whichever you prefer.

1. Add with one click

Click the button. Claude opens with the Composio connector filled in. Click Add, then go to step 2.

Add to Claude

Add manually

In Claude Desktop, click Customize in the left sidebar, then select Connectors and click the + icon at the top.

Claude Desktop connectors screen with Add custom connector selected

Click Add custom connector and paste in the Composio MCP server URL:

bash
https://connect.composio.dev/mcp
Add custom connector dialog with Composio MCP server URL

2. Authorize in your browser

Click Connect. You'll be redirected to a browser window where you can authorize Composio to continue.

Composio authorization screen for Claude Web, Desktop, and Cowork

3. Connect your Mermaid Chart account

Back in Claude, ask it to connect to Mermaid Chart or give it any Mermaid Chart-related task.

For example, ask Claude to:

  • "Validate checkout flow Mermaid syntax"
  • "Render deployment sequence diagram as SVG"
  • "Preview user journey diagram interactively"

It will prompt you to authenticate and authorize access.

That's it. Composio's tools are now available in Claude, and your Mermaid Chart account is ready to use.

What is the Mermaid Chart Claude Connector, and what's possible with it?

The Mermaid Chart MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Mermaid Chart account. It provides structured and secure access so your agent can perform Mermaid Chart operations on your behalf.

Troubleshooting

1. Why does Claude not use the Composio connector for Mermaid Chart?

The connector can show as connected, but Claude must use it in each Mermaid Chart conversation.

  • Click + at the lower left of the chat, or type /.
  • Hover Connectors.
  • Turn on Composio.
  • Ask Claude to connect to Mermaid Chart again.

2. Why does Claude show an MCP server error before Mermaid Chart connects?

Claude can show Couldn't reach the MCP server or Authorization with the MCP server failed when you add the connector for Mermaid Chart.

  • Check that the connector URL is https://connect.composio.dev/mcp.
  • Connectors run from Anthropic's cloud, so your device network is usually not the problem.
  • Add the connector again from Customize > Connectors, then ask Claude to connect Mermaid Chart.
  • If it fails again, send the error and the ofid_ reference id to support@composio.dev.

3. Why does the Mermaid Chart authorization link not work?

The Composio connector is one server. Your Mermaid Chart account connects separately when Claude asks for it.

  • If the browser does not open, or the link expires, ask Claude to retry the Mermaid Chart connection.
  • Composio creates a fresh Mermaid Chart authorization link.
  • Open that link in your browser and finish the Mermaid Chart sign-in.

4. Why do Mermaid Chart actions fail after they worked before?

The Mermaid Chart connection can expire or lose permission.

  • Ask Claude to inspect the Mermaid Chart connection.
  • If the connection is unhealthy, disconnect it when Claude prompts you.
  • Reconnect the Mermaid Chart account and retry the action.
  • If Claude shows a permission prompt, approve it before Claude changes data in Mermaid Chart.
  • If the action still fails with a permission error, check that the connected account has that permission in Mermaid Chart itself.

5. How do I switch to a different Mermaid Chart account?

Claude can manage the Mermaid Chart connection for you.

  • Ask Claude to disconnect or delete the current Mermaid Chart account.
  • Ask Claude to connect Mermaid Chart again.
  • Open the new Composio authorization link for Mermaid Chart.
  • Sign in with the other Mermaid Chart account in the browser.
  • After the account connects, ask Claude to retry the Mermaid Chart task.

6. Why is my Mermaid Chart connection missing in Claude Desktop or on a Team plan?

The connector belongs to your Claude account, so your Mermaid Chart connection works in Claude Web, Desktop, and Cowork.

  • In Claude Desktop, open Customize > Connectors.
  • Next to Composio, click ⋮ and click Clear cache.
  • If Mermaid Chart tools still do not appear, click ⋮, disconnect, remove the connector, and add it again.
  • On Team or Enterprise, an Owner or Primary Owner must enable the connector before you can connect Mermaid Chart.
TOOLS

Supported Tools

Every Mermaid Chart MCP action and event your agent gets out of the box.

Validate and render mermaid diagram

Use this tool to output a Mermaid diagram: - The tool will validate the diagram syntax and render it to a UI widget.

FRAMEWORKS

How to build Mermaid Chart MCP Agent with another framework

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ChatGPT

Use Mermaid Chart MCP with ChatGPT

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Grok Bot

Use Mermaid Chart MCP with Grok Bot

FAQ

Frequently asked questions

With a standalone Mermaid Chart MCP server, the agents and LLMs can only access a fixed set of Mermaid Chart tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Mermaid Chart and many other apps based on the task at hand, all through a single MCP endpoint.

Yes, you can. Claude Cowork fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Mermaid Chart tools.

Yes, absolutely. You can configure which Mermaid Chart scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Mermaid Chart data and credentials are handled as safely as possible.

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