dataviz-mcp

Data Visualization MCP

A Model Context Protocol server that turns tabular data into interactive D3 visualizations. It exposes a single create_data_visualization tool that returns an MCP App: an HTML page the host renders inline in the conversation, inside a sandboxed iframe.

Supported visualizations

Type	Required encodings	Optional	Interactivity
bar	x (category), y (number)	series	tooltips, legend toggle
stacked-bar	x (category), y (number), series		tooltips, legend toggle
histogram	x (number, binned)		tooltips (bin range + count)
line	x (number or ISO date), y (number)	series	tooltips, legend toggle, x zoom/pan
area	x (number or ISO date), y (number)	series	tooltips, legend toggle, x zoom/pan
stacked-area	x (number or ISO date), y (number), series		tooltips, legend toggle
scatter	x (number or ISO date), y (number)	series	tooltips, legend toggle, x/y zoom/pan
bubble	x (number or ISO date), y (number), size (number)	series	tooltips, legend toggle, x/y zoom/pan
pie	category, value (number)		tooltips with percentage, legend toggle
donut	category, value (number)		tooltips with percentage, legend toggle
heatmap	x (category), y (category), value (number)		tooltips, gradient legend

All types support an optional title, xLabel, yLabel, and colorScheme, and re-render responsively when the container resizes.

Tool input

create_data_visualization takes the data in columnar form (field names declared once, then positional value rows) plus a map of field names to visual channels. Declaring the columns once keeps the payload compact for large tables:

{
  "type": "bar",
  "columns": ["month", "sales", "region"],
  "rows": [
    ["Jan", 100, "EU"],
    ["Jan", 80, "US"],
    ["Feb", 120, "EU"],
    ["Feb", 90, "US"]
  ],
  "encodings": { "x": "month", "y": "sales", "series": "region" },
  "title": "Quarterly Sales"
}

Each row holds one value per column, in column order. colorScheme accepts tableau10, category10, or dark2 for categorical types (bar, stacked-bar, histogram, line, area, stacked-area, scatter, bubble, pie, donut), and viridis or plasma for heatmaps. The server validates the spec before rendering and returns a corrective message if, for example, a row length does not match the columns or an encoding references a name absent from the columns.

Setup and development

See CONTRIBUTING.md for requirements, build, running over stdio or HTTP, configuring Claude Desktop, and the development workflow.

License

MIT