MCP Server Chart

Instructions

Implementation Reference

• src/charts/violin.ts:1-63 (schema)

  Defines the Zod input schema, tool metadata (name, description), and inputSchema for the 'generate_violin_chart' tool.
  import { z } from "zod"; import { zodToJsonSchema } from "../utils"; import { AxisXTitleSchema, AxisYTitleSchema, BackgroundColorSchema, HeightSchema, PaletteSchema, TextureSchema, ThemeSchema, TitleSchema, WidthSchema, } from "./base"; const data = z.object({ category: z .string() .describe("Category of the data point, such as '分类一'."), value: z.number().describe("Value of the data point, such as 10."), group: z .string() .optional() .describe( "Optional group for the data point, used for grouping in the violin chart.", ), }); const schema = { data: z .array(data) .describe( "Data for violin chart, such as, [{ category: 'Category A', value: 10 }], when the data is grouped, the 'group' field is required, such as, [{ category: 'Category B', value: 20, group: 'Group A' }].", ) .nonempty({ message: "Violin 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, axisXTitle: AxisXTitleSchema, axisYTitle: AxisYTitleSchema, }; const tool = { name: "generate_violin_chart", description: "Generate a violin chart to show data for statistical summaries among different categories, such as, comparing the distribution of data points across categories.", inputSchema: zodToJsonSchema(schema), }; export const violin = { schema, tool, };
• src/server.ts:64-77 (registration)

  Registers the tool list handler (including 'generate_violin_chart' via Charts.violin.tool) and the call tool handler that invokes callTool for execution.
  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:9-110 (handler)

  The callTool function serves as the handler for all chart generation tools, including 'generate_violin_chart'. It maps the tool name to 'violin', validates input, and calls generateChartUrl to produce the chart URL.
  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_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 that sends the chart configuration (type='violin', options) to the visualization server API to generate 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; }