Chhart MCP

An MCP (Model Context Protocol) server that enables AI assistants like ChatGPT, Claude, and others to programmatically create flowcharts and Sankey diagrams onchhart.app.

- Features
- Prerequisites
- Installation
- Usage

- Quick Start (Public Server)
- Local Mode (stdio)
- Remote Mode (StreamableHTTP)

# Clone the repository git clone https://github.com/alwank/chhart_MCP.git cd chhart_MCP # Install dependencies npm install # Build the project npm run build

{ "mcpServers": { "chhart": { "url": "https://mcp.chhart.app/mcp" } } }

{ "mcpServers": { "chhart": { "command": "npx", "args": ["-y", "chhart-mcp"] } } }

ForCursoror other clients, seeCONFIG_EXAMPLES.mdfor more examples.

{ "mcpServers": { "chhart": { "url": "https://your-deployment-url.com/mcp" } } }

See theRailway Deployment Guidefor detailed instructions.

npm run start:sse # Not recommended for production

{ "content": "Start\n Process Step\n Decision? [shape=diamond]\n Yes\n Action\n End\n No\n Skip\n End", "title": "Simple Workflow" }

Creates a Sankey diagram showing flows between nodes.

- content(string, required) - Sankey diagram content in Chhart DSL format
- title(string, optional) - Title for the diagram

{ "content": "Revenue [value=100]\n Costs [value=40]\n Salaries [value=25]\n Operations [value=15]\n Profit [value=60]", "title": "Budget Flow" }

Returns documentation and examples for Chhart syntax.

- type(enum, optional) -'flowchart','sankey', or'all'(default:'all')

Once configured, you can ask your AI assistant:

"Create a flowchart showing a user login process with email verification"

"Create a Sankey diagram showing how $100 of revenue splits into costs, taxes, and profit"

"Show me the syntax for creating flowcharts in Chhart"

# Install dependencies npm install # Build npm run build # Watch mode (auto-rebuild on changes) npm run watch # Run locally (stdio mode) npm start # Run StreamableHTTP server (recommended for remote access) npm run start:streamable # Run SSE server (legacy, deprecated) npm run start:sse

chhart_MCP/ ├── src/ │ ├── index.ts # Main entry point (stdio mode) │ ├── server-streamable.ts # StreamableHTTP server (recommended) │ ├── server-sse.ts # SSE server (legacy) │ ├── tools/ # MCP tool implementations │ ├── utils/ # Utility functions │ └── transports/ # Transport implementations │ ├── streamable.ts # StreamableHTTP transport │ └── sse.ts # SSE transport (legacy) ├── dist/ # Compiled JavaScript (generated) └── docs/ # Documentation files

The MCP server generates shareable URLs by encoding chart data into the URL hash, leveraging chhart.app's existing URL-based sharing feature. This means:

- ✅ No backend API required
- ✅ Charts are fully client-side
- ✅ URLs work immediately without storage
- ✅ Charts can be edited on chhart.app
- ✅ Privacy-friendly (data stays in the URL)

"Command not found" or "Module not found"

- Ensure you've runnpm installandnpm run build
- Verify the path in your MCP client configuration is absolute
- Check that Node.js 20+ is installed:node --version

"connection closed: EOF" or similar errors:

- If using remote mode, ensure you're using StreamableHTTP transport (npm run start:streamable)
- The legacy SSE transport is deprecated and may have stability issues
- Verify the server is running: check the health endpoint athttp://localhost:3000/health
- Check firewall settings if deploying remotely
- Ensure CORS is properly configured for your domain

- StreamableHTTP clients useapplication/jsonrequests to/mcp
- Legacy SSE clients requiretext/event-streamfor the/mcpstream and JSON for/messages
- Ensure the URL points to the/mcpendpoint

- Verify the generated URL is complete and not truncated
- Check browser console for errors
- Try opening the URL directly in a browser
- Very large diagrams may exceed URL length limits (typically 2000 characters)

- Ensure you're using Node.js 20+
- Deletenode_modulesanddist, then runnpm installandnpm run build
- Check for TypeScript version compatibility

For more help, seeCONTRIBUTING.mdor open an issue.

We welcome contributions! Please seeCONTRIBUTING.mdfor guidelines on:

For security concerns, please see ourSecurity Policy. Do not open public issues for security vulnerabilities.

- Chhart.app- Create and share diagrams
- Model Context Protocol- Learn about MCP
- Documentation- Additional guides and examples
- Changelog- Version history and updates
- Issues- Report bugs or request features

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