generate_sankey_chart
Visualize flow relationships between nodes in complex networks to display distribution and flow paths of source and target data using Sankey diagrams.
Instructions
Generate a Sankey diagram to visualize the flow relationships between nodes in complex networks, suitable for displaying the distribution and flow paths of source and target data.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| output | No | Chart output type. Defaults to 'image'. | image |
| width | No | Chart width. Optional, defaults to 500. | |
| height | No | Chart height. Optional, defaults to 500. | |
| dataTable | Yes | Data for the Sankey diagram, e.g., [{ category: 'category 01', value: 10 }]. | |
| sourceField | Yes | The source field in the Sankey diagram; must exist in the data. | |
| targetField | Yes | The target field in the Sankey diagram; must exist in the data. | |
| valueField | Yes | Measure field. Must be numeric and exist in the data. | |
| chartTheme | No | Chart theme. Optional, defaults to 'light'. | |
| title | No | Chart title text. | |
| subTitle | No | Chart subtitle text. | |
| titleOrient | No | Title position in the chart. | |
| background | No | Chart background color (hex). Optional, defaults to white. | |
| colors | No | Color palette for chart elements. |
Implementation Reference
- src/server.ts:43-125 (handler)The central MCP CallToolRequestHandler that handles execution for all chart tools, including 'generate_sankey_chart'. It maps tool name to chartType ('sankey'), validates input with the specific Zod schema, calls generateChartByType('sankey', args), and returns the chart output (spec, image URL, or HTML).server.setRequestHandler(CallToolRequestSchema, async request => { const toolName = request.params.name; const chartType = Object.keys(Charts).find( key => (Charts as any)[key].tool.name === toolName ); if (!chartType) { throw new McpError( ErrorCode.MethodNotFound, `Unknown tool: ${request.params.name}.` ); } try { // Validate input using Zod before generating chart const args = request.params.arguments || {}; // Select the appropriate schema based on the chart type const schema = Charts[chartType as keyof typeof Charts].schema; if (schema) { const result = schema.safeParse(args); if (!result.success) { throw new McpError( ErrorCode.InvalidParams, `Invalid parameters: ${result.error.message}` ); } } const res = await generateChartByType(chartType, args); if (res && (res as any).spec) { return { content: [ { type: 'text', text: JSON.stringify((res as any).spec, null, 2), }, ], }; } if (res && (res as any).image) { return { content: [ { type: 'text', text: (res as any).image, }, ], }; } if (res && (res as any).html) { return { content: [ { type: 'text', text: (res as any).html, }, ], }; } return { content: [ { type: 'text', text: 'Failed to generate chart', }, ], }; } catch (error: any) { if (error instanceof McpError) { throw error; } throw new McpError( ErrorCode.InternalError, `Failed to generate chart: ${error?.message || 'Unknown error.'}` ); } });
- src/utils/generateChart.ts:42-202 (helper)Core helper function generateChartByType that implements the chart generation logic for all types including Sankey. Processes input options (sourceField -> cell.source, etc.), generates VChart spec using @visactor/generate-vchart, and renders to image/HTML/spec via a remote server.export async function generateChartByType(chartType: string, options: any) { const { title, subTitle, titleOrient, xAxisType, xAxisOrient, xAxisTitle, xAxisHasGrid, xAxisHasLabel, xAxisHasTick, yAxisType, yAxisOrient, yAxisTitle, yAxisHasGrid, yAxisHasLabel, yAxisHasTick, leftYAxisTitle, leftYAxisHasGrid, leftYAxisHasLabel, leftYAxisHasTick, rightYAxisTitle, rightYAxisHasGrid, rightYAxisHasLabel, rightYAxisHasTick, angleAxisTitle, angleAxisHasGrid, angleAxisHasLabel, angleAxisHasTick, angleAxisType, radiusAxisHasGrid, radiusAxisHasLabel, radiusAxisHasTick, radiusAxisType, radiusAxisTitle, output, width, height, ...res } = options; const opts = { ...res }; const titleObj = filterValidAttributes({ text: title, subText: subTitle, orient: titleOrient, }); const xAxisObj = filterValidAttributes({ type: xAxisType, orient: xAxisOrient, title: xAxisTitle, hasGrid: xAxisHasGrid, hasLabel: xAxisHasLabel, hasTick: xAxisHasTick, }); const yAxisObj = filterValidAttributes({ type: yAxisType, orient: yAxisOrient, title: yAxisTitle, hasGrid: yAxisHasGrid, hasLabel: yAxisHasLabel, hasTick: yAxisHasTick, }); const leftYAxisObj = filterValidAttributes({ title: leftYAxisTitle, hasGrid: leftYAxisHasGrid, hasLabel: leftYAxisHasLabel, hasTick: leftYAxisHasTick, }); const rightYAxisObj = filterValidAttributes({ title: rightYAxisTitle, hasGrid: rightYAxisHasGrid, hasLabel: rightYAxisHasLabel, hasTick: rightYAxisHasTick, }); const angleAxisObj = filterValidAttributes({ title: angleAxisTitle, hasGrid: angleAxisHasGrid, hasLabel: angleAxisHasLabel, hasTick: angleAxisHasTick, type: angleAxisType, }); const radiusAxisObj = filterValidAttributes({ hasGrid: radiusAxisHasGrid, hasLabel: radiusAxisHasLabel, hasTick: radiusAxisHasTick, type: radiusAxisType, title: radiusAxisTitle, }); const cell: Record<string, string> = {}; [ "xField", "yField", "colorField", "categoryField", "valueField", "wordField", "sizeField", "timeField", "sourceField", "targetField", "setsField", "radiusField", ].forEach((fieldName) => { if (isValid(options[fieldName])) { cell[fieldName.replace("Field", "")] = options[fieldName]; delete opts[fieldName]; } }); opts.cell = cell; if (!isEmpty(titleObj)) { opts.title = titleObj; } const axes = [ xAxisObj, yAxisObj, leftYAxisObj, rightYAxisObj, angleAxisObj, radiusAxisObj, ]; if (axes.some((axis) => !isEmpty(axis))) { opts.axes = axes.filter((axis) => !isEmpty(axis)); } const { spec } = generateChart(options.chartType ?? chartType, opts); if (!spec) { return null; } if (output === "spec") { if (isValid(width)) { spec.width = width; } if (isValid(height)) { spec.height = height; } return { spec: spec, }; } return gentrateChartImageOrHtml(output, spec, { width: `${width ?? 500}px`, height: `${height ?? 500}px`, }); }
- src/charts/sankey.ts:16-48 (schema)Zod schema defining the input parameters and validation for the generate_sankey_chart tool.const schema = z.object({ output: ChartOutputSchema, width: WidthSchema, height: HeightSchema, dataTable: z .array(z.any()) .describe( "Data for the Sankey diagram, e.g., [{ category: 'category 01', value: 10 }]." ) .nonempty({ message: "Sankey diagram data cannot be empty." }), sourceField: z .string() .nonempty({ message: "Source field cannot be empty." }) .describe( "The source field in the Sankey diagram; must exist in the data." ), targetField: z .string() .nonempty({ message: "Target field cannot be empty." }) .describe( "The target field in the Sankey diagram; must exist in the data." ), valueField: YFieldSchema, chartTheme: ThemeSchema, title: TitleTextSchema, subTitle: TitleSubTextSchema, titleOrient: TitleOrientSchema, background: BackgroundSchema, colors: ColorsSchema, });
- src/server.ts:34-38 (registration)MCP ListToolsRequestHandler that registers and lists all chart tools, including generate_sankey_chart, by exporting tool metadata from Charts module.server.setRequestHandler(ListToolsRequestSchema, async () => { return { tools: Object.values(Charts).map(chart => (chart as any).tool), }; });
- src/charts/sankey.ts:50-60 (registration)Tool metadata definition and export for dynamic registration in the MCP server.const tool = { name: "generate_sankey_chart", description: "Generate a Sankey diagram to visualize the flow relationships between nodes in complex networks, suitable for displaying the distribution and flow paths of source and target data.", inputSchema: convertZodToJsonSchema(schema), }; export const sankey = { schema, tool, };