Vega-Lite MCP Server

#!/usr/bin/env node import { Server } from "@modelcontextprotocol/sdk/server/index.js"; import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js"; import { CallToolRequestSchema, ListToolsRequestSchema, } from "@modelcontextprotocol/sdk/types.js"; // Import tool handlers import { searchDocs } from "./tools/search.js"; import { getExample } from "./tools/examples.js"; import { validateSpec } from "./tools/validate.js"; // Create server instance const server = new Server( { name: "vegalite-mcp-server", version: "0.1.0", }, { capabilities: { tools: {}, }, } ); // Register tools server.setRequestHandler(ListToolsRequestSchema, async () => { return { tools: [ { name: "search_docs", description: "Search through Vega-Lite documentation for information about charts, encodings, marks, and more", inputSchema: { type: "object", properties: { query: { type: "string", description: "Search query (e.g., 'bar chart', 'color encoding', 'scale domain')", }, }, required: ["query"], additionalProperties: false, }, }, { name: "get_example", description: "Retrieve Vega-Lite example specifications by category or type", inputSchema: { type: "object", properties: { category: { type: "string", description: "Example category (e.g., 'bar', 'line', 'scatter', 'area', 'histogram', 'heatmap', 'interactive')", }, search: { type: "string", description: "Optional search term to filter examples within the category", }, }, required: ["category"], additionalProperties: false, }, }, { name: "validate_spec", description: "Validate a Vega-Lite specification and check for errors", inputSchema: { type: "object", properties: { spec: { type: "object", description: "Vega-Lite JSON specification to validate", }, }, required: ["spec"], additionalProperties: false, }, }, { name: "get_schema_info", description: "Get information about Vega-Lite schema properties and structure", inputSchema: { type: "object", properties: { property: { type: "string", description: "Schema property to get information about (e.g., 'mark', 'encoding', 'data', 'transform')", }, }, additionalProperties: false, }, }, ], }; }); // Handle tool calls server.setRequestHandler(CallToolRequestSchema, async (request) => { const { name, arguments: args } = request.params; try { switch (name) { case "search_docs": { if (!args?.query) { throw new Error("Query parameter is required"); } const results = await searchDocs(args.query as string); return { content: [ { type: "text", text: JSON.stringify(results, null, 2), }, ], }; } case "get_example": { if (!args?.category) { throw new Error("Category parameter is required"); } const examples = await getExample( args.category as string, args.search as string | undefined ); return { content: [ { type: "text", text: JSON.stringify(examples, null, 2), }, ], }; } case "validate_spec": { if (!args?.spec) { throw new Error("Spec parameter is required"); } const validation = await validateSpec(args.spec as Record<string, unknown>); return { content: [ { type: "text", text: JSON.stringify(validation, null, 2), }, ], }; } case "get_schema_info": { return { content: [ { type: "text", text: JSON.stringify({ message: "Schema info tool - to be implemented", property: args?.property || "all", }, null, 2), }, ], }; } default: throw new Error(`Unknown tool: ${name}`); } } catch (error) { const errorMessage = error instanceof Error ? error.message : String(error); return { content: [ { type: "text", text: JSON.stringify({ error: errorMessage, tool: name, }, null, 2), }, ], isError: true, }; } }); // Start server async function main() { const transport = new StdioServerTransport(); await server.connect(transport); console.error("Vega-Lite MCP Server running on stdio"); } main().catch((error) => { console.error("Fatal error in main():", error); process.exit(1); });