Vega-Lite MCP Server

import { promises as fs } from "fs"; import path from "path"; import { fileURLToPath } from "url"; const __filename = fileURLToPath(import.meta.url); const __dirname = path.dirname(__filename); interface DocSection { title: string; url: string; content: string; category: string; source?: string; // 'vega-lite' or 'deneb' } interface SearchResult { results: DocSection[]; query: string; totalResults: number; sources: string[]; // Which sources were searched } /** * Search through Vega-Lite and Deneb documentation */ export async function searchDocs(query: string): Promise<SearchResult> { const vegaLitePath = path.join(__dirname, "..", "data", "documentation.json"); const denebPath = path.join(__dirname, "..", "data", "deneb-documentation.json"); let allDocs: DocSection[] = []; const sources: string[] = []; try { // Try to load Vega-Lite documentation const vegaLiteData = await fs.readFile(vegaLitePath, "utf-8"); const vegaLiteDocs: DocSection[] = JSON.parse(vegaLiteData); vegaLiteDocs.forEach(doc => doc.source = 'vega-lite'); allDocs = allDocs.concat(vegaLiteDocs); sources.push('vega-lite'); } catch (error) { // Vega-Lite docs not available, will use fallback } try { // Try to load Deneb documentation const denebData = await fs.readFile(denebPath, "utf-8"); const denebDocs: DocSection[] = JSON.parse(denebData); denebDocs.forEach(doc => doc.source = 'deneb'); allDocs = allDocs.concat(denebDocs); sources.push('deneb'); } catch (error) { // Deneb docs not available, will use fallback } // If no docs loaded, use fallback if (allDocs.length === 0) { return getFallbackDocs(query); } // Simple text search (case-insensitive) const lowerQuery = query.toLowerCase(); const results = allDocs.filter((doc) => { return ( doc.title.toLowerCase().includes(lowerQuery) || doc.content.toLowerCase().includes(lowerQuery) || doc.category.toLowerCase().includes(lowerQuery) ); }); // Sort by relevance (simple: title matches first, then content matches) results.sort((a, b) => { const aTitle = a.title.toLowerCase().includes(lowerQuery); const bTitle = b.title.toLowerCase().includes(lowerQuery); if (aTitle && !bTitle) return -1; if (!aTitle && bTitle) return 1; return 0; }); return { results: results.slice(0, 10), // Return top 10 results query, totalResults: results.length, sources, }; } /** * Fallback documentation when data files don't exist */ function getFallbackDocs(query: string): SearchResult { return { results: [ { title: "Getting Started with Vega-Lite", url: "https://vega.github.io/vega-lite/docs/", content: "Vega-Lite is a high-level grammar of interactive graphics. It provides a concise, declarative JSON syntax to create an expressive range of visualizations for data analysis and presentation.", category: "introduction", source: "vega-lite", }, { title: "Mark Types", url: "https://vega.github.io/vega-lite/docs/mark.html", content: "Marks are the basic visual building blocks of a visualization. Common mark types include: bar, line, point, area, circle, square, tick, rect, rule, and text.", category: "marks", source: "vega-lite", }, { title: "Encoding Channels", url: "https://vega.github.io/vega-lite/docs/encoding.html", content: "Encodings map data fields to visual properties (channels) such as x, y, color, size, shape, and opacity. Each encoding channel can be customized with scales, axes, and legends.", category: "encoding", source: "vega-lite", }, { title: "Getting Started with Deneb for Power BI", url: "https://deneb.guide/docs/getting-started", content: "Deneb is a certified custom visual for Microsoft Power BI that allows you to create your own data visualizations using the declarative Vega or Vega-Lite languages. It's perfect for Power BI users who want to go beyond standard visuals.", category: "introduction", source: "deneb", }, { title: "Deneb and Power BI Integration", url: "https://deneb.guide/docs/", content: "Deneb provides seamless integration with Power BI, including cross-filtering, tooltips, and data interaction. You can use Power BI fields directly in your Vega-Lite specifications.", category: "power-bi", source: "deneb", }, ], query, totalResults: 5, sources: ['vega-lite', 'deneb'], }; }