MCP Server Chart

Instructions

Implementation Reference

• src/charts/treemap.ts:13-77 (schema)

  Defines the Zod input schema (TreeNodeSchema and main schema) and tool descriptor including name 'generate_treemap_chart' and inputSchema for the tool.
  // Define recursive schema for hierarchical data. // The recursive schema is not supported by gemini, and other clients, so we use a non-recursive schema which can represent a tree structure with a fixed depth. // Ref: https://github.com/antvis/mcp-server-chart/issues/155 // Ref: https://github.com/antvis/mcp-server-chart/issues/132 const TreeNodeSchema = z.object({ name: z.string(), value: z.number(), children: z .array( z.object({ name: z.string(), value: z.number(), children: z .array( z.object({ name: z.string(), value: z.number(), }), ) .optional(), }), ) .optional(), }); // Treemap chart input schema const schema = { data: z .array(TreeNodeSchema) .describe( "Data for treemap chart which is a hierarchical structure, such as, [{ name: 'Design', value: 70, children: [{ name: 'Tech', value: 20 }] }], and the maximum depth is 3.", ) .nonempty({ message: "Treemap chart data cannot be empty." }), style: z .object({ backgroundColor: BackgroundColorSchema, palette: PaletteSchema, texture: TextureSchema, }) .optional() .describe( "Style configuration for the chart with a JSON object, optional.", ), theme: ThemeSchema, width: WidthSchema, height: HeightSchema, title: TitleSchema, }; // Treemap chart tool descriptor const tool = { name: "generate_treemap_chart", description: "Generate a treemap chart to display hierarchical data and can intuitively show comparisons between items at the same level, such as, show disk space usage with treemap.", inputSchema: zodToJsonSchema(schema), annotations: { title: "Generate Treemap Chart", readOnlyHint: true, }, }; export const treemap = { schema, tool, };
• src/server.ts:64-77 (registration)

  Registers all chart tools (imported via * as Charts, including treemap tool) for ListToolsRequest, and sets the generic callTool as the handler for CallToolRequest for tools like generate_treemap_chart.
  function setupToolHandlers(server: Server): void { logger.info("setting up tool handlers..."); server.setRequestHandler(ListToolsRequestSchema, async () => ({ tools: getEnabledTools().map((chart) => chart.tool), })); // biome-ignore lint/suspicious/noExplicitAny: <explanation> server.setRequestHandler(CallToolRequestSchema, async (request: any) => { logger.info("calling tool", request.params.name, request.params.arguments); return await callTool(request.params.name, request.params.arguments); }); logger.info("tool handlers set up"); }
• src/utils/callTool.ts:8-111 (handler)

  Generic handler function callTool for all generate_*_chart tools. For generate_treemap_chart, maps tool name to chartType 'treemap' via CHART_TYPE_MAP, validates arguments using Charts.treemap.schema, and generates chart URL via generateChartUrl('treemap', args).
  // Chart type mapping const CHART_TYPE_MAP = { generate_area_chart: "area", generate_bar_chart: "bar", generate_boxplot_chart: "boxplot", generate_column_chart: "column", generate_district_map: "district-map", generate_dual_axes_chart: "dual-axes", generate_fishbone_diagram: "fishbone-diagram", generate_flow_diagram: "flow-diagram", generate_funnel_chart: "funnel", generate_histogram_chart: "histogram", generate_line_chart: "line", generate_liquid_chart: "liquid", generate_mind_map: "mind-map", generate_network_graph: "network-graph", generate_organization_chart: "organization-chart", generate_path_map: "path-map", generate_pie_chart: "pie", generate_pin_map: "pin-map", generate_radar_chart: "radar", generate_sankey_chart: "sankey", generate_scatter_chart: "scatter", generate_treemap_chart: "treemap", generate_venn_chart: "venn", generate_violin_chart: "violin", generate_waterfall_chart: "waterfall", generate_word_cloud_chart: "word-cloud", } as const; /** * Call a tool to generate a chart based on the provided name and arguments. * @param tool The name of the tool to call, e.g., "generate_area_chart". * @param args The arguments for the tool, which should match the expected schema for the chart type. * @returns */ export async function callTool(tool: string, args: object = {}) { logger.info(`Calling tool: ${tool}`); const chartType = CHART_TYPE_MAP[tool as keyof typeof CHART_TYPE_MAP]; if (!chartType) { logger.error(`Unknown tool: ${tool}`); throw new McpError(ErrorCode.MethodNotFound, `Unknown tool: ${tool}.`); } try { // Validate input using Zod before sending to API. // Select the appropriate schema based on the chart type. const schema = Charts[chartType].schema; if (schema) { // Use safeParse instead of parse and try-catch. const result = z.object(schema).safeParse(args); if (!result.success) { logger.error(`Invalid parameters: ${result.error.message}`); throw new McpError( ErrorCode.InvalidParams, `Invalid parameters: ${result.error.message}`, ); } } const isMapChartTool = [ "generate_district_map", "generate_path_map", "generate_pin_map", ].includes(tool); if (isMapChartTool) { // For map charts, we use the generateMap function, and return the mcp result. const { metadata, ...result } = await generateMap(tool, args); return result; } const url = await generateChartUrl(chartType, args); logger.info(`Generated chart URL: ${url}`); return { content: [ { type: "text", text: url, }, ], _meta: { description: "This is the chart's spec and configuration, which can be renderred to corresponding chart by AntV GPT-Vis chart components.", spec: { type: chartType, ...args }, }, }; // biome-ignore lint/suspicious/noExplicitAny: <explanation> } catch (error: any) { logger.error( `Failed to generate chart: ${error.message || "Unknown error"}.`, ); if (error instanceof McpError) throw error; if (error instanceof ValidateError) throw new McpError(ErrorCode.InvalidParams, error.message); throw new McpError( ErrorCode.InternalError, `Failed to generate chart: ${error?.message || "Unknown error."}`, ); } }
• src/utils/generate.ts:12-39 (helper)

  Helper function generateChartUrl called by callTool to proxy the request (type='treemap', options) to the visualization server and return the chart URL.
  export async function generateChartUrl( type: string, // biome-ignore lint/suspicious/noExplicitAny: <explanation> options: Record<string, any>, ): Promise<string> { const url = getVisRequestServer(); const response = await axios.post( url, { type, ...options, source: "mcp-server-chart", }, { headers: { "Content-Type": "application/json", }, }, ); const { success, errorMessage, resultObj } = response.data; if (!success) { throw new Error(errorMessage); } return resultObj; }