vega

vega diagram (uml-mcp)

diagram_type: vega
Backend: vega
Output formats: png, svg, pdf

Vega visualization grammar

Load the workflow skill uml-mcp-diagrams for URL-first replies, progressive discovery, and which MCP tool to call. This file is notation only; it does not add an MCP tool.

Styling

• Set background, config.axis, config.view, and mark fill/stroke.
• No MCP theme param.

Starter template

{"$schema":"https://vega.github.io/schema/vega/v5.json","width":200,"height":200,"data":[{"name":"d","values":[{"v":1},{"v":2}]}],"marks":[{"type":"rect","from":{"data":"d"},"encode":{"enter":{"x":{"value":0},"y":{"scale":"y","field":"v"},"width":{"value":20},"height":{"scale":"y","band":1}}}}],"scales":[{"name":"y","type":"band","range":"height","domain":{"data":"d","field":"v"}}],"axes":[{"orient":"left","scale":"y","title":"v"}]}

Example

{"$schema":"https://vega.github.io/schema/vega/v5.json","width":200,"height":200,"data":[{"name":"table","values":[{"x":1,"y":2},{"x":2,"y":4}]}],"scales":[{"name":"x","type":"linear","range":"width","nice":true,"domain":{"data":"table","field":"x"}},{"name":"y","type":"linear","range":"height","nice":true,"domain":{"data":"table","field":"y"}}],"axes":[{"orient":"bottom","scale":"x","title":"x"},{"orient":"left","scale":"y","title":"y"}],"marks":[{"type":"symbol","from":{"data":"table"},"encode":{"enter":{"x":{"scale":"x","field":"x"},"y":{"scale":"y","field":"y"},"size":{"value":50}}}}]}

Render with uml-mcp

1. Set diagram_type to vega exactly.
2. Call validate_uml when the source is untrusted (prefer strict: true for Mermaid sequence).
3. Call generate_uml, generate_uml_image (chat PNG), or generate_uml_batch.
4. Pass theme when this skill's Themes section lists supported values.
5. Surface the returned url / playground (see the workflow skill).

Confirm formats with uml://formats or list_diagram_types when unsure.