Paper Search MCP

Instructions

Implementation Reference

• src/mcp/handleToolCall.ts:408-425 (handler)

  Executes the search_crossref tool by calling the Crossref searcher's search method with parsed arguments and returns formatted JSON results.
  case 'search_crossref': { const { query, maxResults, year, author, sortBy, sortOrder } = args; const results = await searchers.crossref.search(query, { maxResults, year, author, sortBy, sortOrder }); return jsonTextResponse( `Found ${results.length} Crossref papers.\n\n${JSON.stringify( results.map((paper: Paper) => PaperFactory.toDict(paper)), null, 2 )}` ); }
• src/mcp/schemas.ts:192-201 (schema)

  Zod schema definition for validating search_crossref tool input arguments.
  export const SearchCrossrefSchema = z .object({ query: z.string().min(1), maxResults: z.number().int().min(1).max(100).optional().default(10), year: z.string().optional(), author: z.string().optional(), sortBy: SortBySchema.optional().default('relevance'), sortOrder: SortOrderSchema.optional().default('desc') }) .strip();
• src/mcp/tools.ts:465-493 (registration)

  MCP tool registration entry defining name, description, and JSON input schema for search_crossref.
  name: 'search_crossref', description: 'Search academic papers from Crossref database. Free API with extensive scholarly metadata coverage across publishers.', inputSchema: { type: 'object', properties: { query: { type: 'string', description: 'Search query string' }, maxResults: { type: 'number', minimum: 1, maximum: 100, description: 'Maximum number of results to return' }, year: { type: 'string', description: 'Year filter (e.g., "2023", "2020-2023")' }, author: { type: 'string', description: 'Author name filter' }, sortBy: { type: 'string', enum: ['relevance', 'date', 'citations'], description: 'Sort results by relevance, date, or citations' }, sortOrder: { type: 'string', enum: ['asc', 'desc'], description: 'Sort order: ascending or descending' } }, required: ['query'] } }
• src/platforms/CrossrefSearcher.ts:56-108 (helper)

  Implements the core search logic for Crossref API, including query construction, filtering, sorting, API call, and response parsing.
  async search(query: string, options: SearchOptions = {}): Promise<Paper[]> { const maxResults = Math.min(options.maxResults || 10, 1000); const params: Record<string, any> = { query: query, rows: maxResults, mailto: this.mailto }; // Build filters const filters: string[] = []; // Year filter if (options.year) { const yearMatch = options.year.match(/^(\d{4})(?:-(\d{4})?)?$/); if (yearMatch) { const startYear = yearMatch[1]; const endYear = yearMatch[2] || startYear; if (startYear) { filters.push(`from-pub-date:${startYear}`); } if (endYear && endYear !== startYear) { filters.push(`until-pub-date:${endYear}`); } } } // Add filters if (filters.length > 0) { params.filter = filters.join(','); } // Sorting const sortMapping: Record<string, string> = { 'relevance': 'relevance', 'date': 'published', 'citations': 'is-referenced-by-count' }; params.sort = sortMapping[options.sortBy || 'relevance'] || 'relevance'; params.order = options.sortOrder === 'asc' ? 'asc' : 'desc'; try { const response = await this.client.get('', { params }); if (response.status === 200 && response.data?.message?.items) { return this.parseSearchResponse(response.data); } return []; } catch (error: any) { this.handleHttpError(error, 'search'); } }
• src/mcp/searchers.ts:13-76 (helper)

  Imports and instantiates the CrossrefSearcher, making it available as searchers.crossref for use in tool handlers.
  import { CrossrefSearcher } from '../platforms/CrossrefSearcher.js'; import { logDebug } from '../utils/Logger.js'; export interface Searchers { arxiv: ArxivSearcher; webofscience: WebOfScienceSearcher; pubmed: PubMedSearcher; wos: WebOfScienceSearcher; biorxiv: BioRxivSearcher; medrxiv: MedRxivSearcher; semantic: SemanticScholarSearcher; iacr: IACRSearcher; googlescholar: GoogleScholarSearcher; scholar: GoogleScholarSearcher; scihub: SciHubSearcher; sciencedirect: ScienceDirectSearcher; springer: SpringerSearcher; wiley: WileySearcher; scopus: ScopusSearcher; crossref: CrossrefSearcher; } let searchers: Searchers | null = null; export function initializeSearchers(): Searchers { if (searchers) return searchers; logDebug('Initializing searchers...'); const arxivSearcher = new ArxivSearcher(); const wosSearcher = new WebOfScienceSearcher(process.env.WOS_API_KEY, process.env.WOS_API_VERSION); const pubmedSearcher = new PubMedSearcher(process.env.PUBMED_API_KEY); const biorxivSearcher = new BioRxivSearcher('biorxiv'); const medrxivSearcher = new MedRxivSearcher(); const semanticSearcher = new SemanticScholarSearcher(process.env.SEMANTIC_SCHOLAR_API_KEY); const iacrSearcher = new IACRSearcher(); const googleScholarSearcher = new GoogleScholarSearcher(); const sciHubSearcher = new SciHubSearcher(); const scienceDirectSearcher = new ScienceDirectSearcher(process.env.ELSEVIER_API_KEY); const springerSearcher = new SpringerSearcher( process.env.SPRINGER_API_KEY, process.env.SPRINGER_OPENACCESS_API_KEY ); const wileySearcher = new WileySearcher(process.env.WILEY_TDM_TOKEN); const scopusSearcher = new ScopusSearcher(process.env.ELSEVIER_API_KEY); const crossrefSearcher = new CrossrefSearcher(process.env.CROSSREF_MAILTO); searchers = { arxiv: arxivSearcher, webofscience: wosSearcher, pubmed: pubmedSearcher, wos: wosSearcher, biorxiv: biorxivSearcher, medrxiv: medrxivSearcher, semantic: semanticSearcher, iacr: iacrSearcher, googlescholar: googleScholarSearcher, scholar: googleScholarSearcher, scihub: sciHubSearcher, sciencedirect: scienceDirectSearcher, springer: springerSearcher, wiley: wileySearcher, scopus: scopusSearcher, crossref: crossrefSearcher