Chartpane MCP Server

ChartPane

MCP App that renders interactive Chart.js charts inline in Claude's UI. Works with Claude Desktop, ChatGPT, VS Code, Cursor, and any client that supports MCP Apps.

Live instance: mcp.chartpane.com

Features

• 9 chart types: bar, line, area, pie, doughnut, polarArea, bubble, scatter, radar
• Stacked and horizontal bar chart variants
• Multi-chart dashboard grids (up to 4 columns)
• Custom colors or automatic 12-color palette
• Client-side rendering — chart data never stored server-side
• Works with any MCP-compatible client (Claude Desktop, ChatGPT, VS Code, Cursor)

Tools

• render_chart — Render a single chart (bar, line, area, pie, doughnut, polarArea, bubble, scatter, radar, stacked)
• render_dashboard — Render a multi-chart grid layout

Quick Start

Add ChartPane to Claude Desktop via Settings > Connectors > Add custom connector:

https://mcp.chartpane.com/mcp

Or use mcp-remote (requires Node.js):

{
  "mcpServers": {
    "chartpane": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://mcp.chartpane.com/mcp"]
    }
  }
}

Usage Examples

1. Bar chart

Prompt: "Create a bar chart of quarterly revenue: Q1 $50k, Q2 $80k, Q3 $120k, Q4 $95k"

Claude calls render_chart with:

{
  "type": "bar",
  "title": "Quarterly Revenue",
  "data": {
    "labels": ["Q1", "Q2", "Q3", "Q4"],
    "datasets": [{ "label": "Revenue ($k)", "data": [50, 80, 120, 95] }]
  }
}

An interactive bar chart renders inline in the conversation.

2. Pie chart

Prompt: "Show browser market share as a pie chart: Chrome 65%, Safari 19%, Firefox 8%, Edge 5%, Other 3%"

Claude calls render_chart with:

{
  "type": "pie",
  "title": "Browser Market Share",
  "data": {
    "labels": ["Chrome", "Safari", "Firefox", "Edge", "Other"],
    "datasets": [{ "label": "Share", "data": [65, 19, 8, 5, 3] }]
  }
}

Each slice gets a distinct color from the built-in palette.

3. Multi-chart dashboard

Prompt: "Build a dashboard with monthly active users as a line chart and signups by channel as a bar chart"

Claude calls render_dashboard with:

{
  "title": "Growth Dashboard",
  "charts": [
    {
      "type": "line",
      "title": "Monthly Active Users",
      "data": {
        "labels": ["Jan", "Feb", "Mar", "Apr", "May", "Jun"],
        "datasets": [{ "label": "MAU", "data": [12000, 15000, 18000, 22000, 28000, 35000] }]
      }
    },
    {
      "type": "bar",
      "title": "Signups by Channel",
      "data": {
        "labels": ["Organic", "Referral", "Paid", "Social"],
        "datasets": [{ "label": "Signups", "data": [4500, 3200, 2800, 1500] }]
      }
    }
  ],
  "columns": 2
}

Both charts render side-by-side in a grid layout.

Self-Hosting

ChartPane runs on Cloudflare Workers.

npm install
cp .dev.vars.example .dev.vars    # Configure secrets (optional)
npm run dev                        # Local dev server (port 8787 + sandbox on 3456)
npm run deploy                     # Deploy to Cloudflare Workers

You'll need to create your own KV namespace and D1 database — see comments in wrangler.jsonc.

Development

npm run dev        # wrangler dev + sandbox dev server (localhost:3456)
npm run build      # Type-check (tsc --noEmit) + bundle UI
npm test           # Run all tests (vitest)
npm run test:watch # Watch mode

Architecture

Claude tool calls flow through a thin MCP server that validates input and returns structuredContent. The browser-side UI transforms input into Chart.js configs and renders to canvas. All shared logic (types, validation, colors, config) lives in shared/.

Claude tool call → server.ts (validate) → structuredContent
    → mcp-app.ts (browser) → buildChartConfig() → Chart.js canvas

Privacy

ChartPane logs only request metadata (chart type, title, timestamp). Chart data values are never stored. Charts render entirely client-side in your browser. Full policy: chartpane.com/privacy

Support

• GitHub Issues: github.com/ahmadnassri/chartpane/issues
• Email: support@chartpane.com

License

MIT