Mermaid Chart MCP server for AI agents and assistants

Securely connect your AI agents and chatbots (Claude, ChatGPT, Cursor, etc) with Mermaid Chart MCP or direct API to validate Mermaid syntax, render diagrams as SVG, preview diagrams interactively, and iterate on chart fixes through natural language.

Mermaid Chart MCP logoMermaid Chart MCP
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

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Type what you want done — sign in and watch it run live in the Tool Router playground.

TOOL ROUTER PLAYGROUND
Mermaid Chart MCP
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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.

SETUP GUIDE

Connect Mermaid Chart MCP Tool with your Agent

1

Install Composio

typescript
npm install @composio/core ai @ai-sdk/openai @ai-sdk/mcp
Install the Composio SDK for Python or TypeScript
2

Initialize Client and Create Tool Router Session

typescript
import { Composio } from '@composio/core';

const composio = new Composio({ apiKey: 'your-api-key' });
const session = await composio.create('your-user-id');
console.log(`Tool Router session created: ${session.mcp.url}`);
Import and initialize the Composio client, then create a Tool Router session for Mermaid Chart MCP
3

Connect to AI Agent

typescript
import { openai } from '@ai-sdk/openai';
import { experimental_createMCPClient as createMCPClient } from '@ai-sdk/mcp';
import { generateText } from 'ai';

const client = await createMCPClient({
  transport: {
    type: 'http',
    url: session.mcp.url,
    headers: {
      'x-api-key': 'your-composio-api-key',
    },
  },
});

const tools = await client.tools();
const { text } = await generateText({
  model: openai('gpt-4o'),
  tools,
  messages: [{
    role: 'user',
    content: 'Render this Mermaid sequence diagram as SVG and tell me if the syntax is valid: sequenceDiagram\nparticipant User\nparticipant API\nUser->>API: Submit order\nAPI-->>User: Return confirmation'
  }],
  maxSteps: 5,
});

console.log(`Agent: ${text}`);
Use the MCP server with your AI agent (Anthropic Claude or Mastra)
SETUP GUIDE

Connect Mermaid Chart MCP API Tool with your Agent

1

Install Composio

typescript
npm install @composio/openai
Install the Composio SDK
2

Initialize Composio and Create Tool Router Session

typescript
import OpenAI from 'openai';
import { Composio } from '@composio/core';
import { OpenAIResponsesProvider } from '@composio/openai';

const composio = new Composio({
  provider: new OpenAIResponsesProvider(),
});
const openai = new OpenAI({});
const session = await composio.create('your-user-id');
Import and initialize Composio client, then create a Tool Router session
3

Execute Mermaid Chart MCP Tools via Tool Router with Your Agent

typescript
const tools = session.tools;
const response = await openai.responses.create({
  model: 'gpt-4.1',
  tools: tools,
  input: [{
    role: 'user',
    content: 'Validate this Mermaid flowchart syntax and render it as SVG: graph TD; A[User] --> B[Checkout]; B --> C[Payment]; C --> D[Confirmation]'
  }],
});
const result = await composio.provider.handleToolCalls(
  'your-user-id',
  response.output
);
console.log(result);
Get tools from Tool Router session and execute Mermaid Chart MCP actions with your Agent

Why Use Composio?

AI Native Mermaid Chart MCP Integration

  • Supports both Mermaid Chart MCP and direct API based integrations
  • Structured, LLM-friendly schemas so agents can validate Mermaid diagrams without guessing
  • Ready-made tools for syntax checks, SVG rendering, and interactive diagram previews

Managed Auth

  • Mermaid Chart MCP uses no-auth access, so your agents can start validating and rendering diagrams right away
  • No hard-coded API keys or OAuth setup needed for this toolkit
  • Composio still gives you a central place to manage agent access and execution

Agent Optimized Design

  • Tools are shaped for language models, making Mermaid syntax fixes more reliable
  • Agents can move from broken diagram text to a rendered SVG in one flow
  • Comprehensive execution logs show every validation, render, and preview request

Enterprise Grade Security

  • Fine-grained RBAC so you control which agents and users can access Mermaid Chart MCP
  • Scoped access for diagram validation and rendering workflows
  • Full audit trail of agent actions to support review and compliance
FRAMEWORKS

Use Mermaid Chart MCP with any AI Agent Framework

Choose a Framework you want to connect Mermaid Chart MCP with

FAQ

Frequently asked questions

No. Mermaid Chart MCP uses no-auth access, so you don't need to configure OAuth credentials, API keys, or bearer tokens. Composio handles the tool routing layer so your agents can validate Mermaid syntax, render SVG diagrams, and preview charts without custom integration code.

Yes! Composio's Tool Router enables agents to use multiple toolkits. Learn more.

Yes. Composio is SOC 2 Type II compliant and is built to keep your Mermaid Chart connection and credentials secure. OAuth tokens and API keys are encrypted, and sensitive customer data is protected at rest and in transit.

Composio also undergoes independent security testing and continuously monitors its systems for security threats. You can review the latest reports and policies in the Composio Trust Center.

Composio maintains and updates all toolkit integrations automatically, so your agents always work with the latest API versions.

When you connect a Mermaid Chart account through Composio, every action runs under that account, so anything the agent creates, sends, or changes shows up in Mermaid Chart as done by you. Keep an approval step in your prompt for actions with side effects, such as sending or deleting, and have the agent draft first.

Whatever the credentials you connect allow inside Mermaid Chart. If Mermaid Chart lets you scope a key to specific permissions, create a scoped one so the agent can only do what you intend. You can revoke the key inside Mermaid Chart at any time.

Yes. Composio supports multiple connected accounts for the same app, and that works in Claude, ChatGPT, or any other assistant you connect through Composio. Give each Mermaid Chart connection a name such as work or personal, and the assistant uses the one you mention in the request. Each account keeps its own credentials and nothing is merged.

Composio's free plan includes 100,000 tool calls per month with no credit card, which covers most personal Mermaid Chart use. Paid plans add higher limits and team features. Your Mermaid Chart plan and its API limits still apply as usual.

Built-in connectors usually give one AI access to a limited set of apps. Many people use Composio because it lets their AI connect to more apps than it normally supports, or connect to multiple accounts for the same app (e.g. connect Claude to multiple Mermaid Chart accounts).

With Composio, you connect Mermaid Chart once and then use it across different AI assistants without setting it up separately in each one. Connect your apps to Composio once, then connect Composio to whichever AI you use, whether that's Claude, ChatGPT, Hermes, or your own custom assistant.

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