medical-mcp

Instructions

Implementation Reference

• src/utils.ts:291-338 (handler)

  Main handler function that performs the actual API call to RxNorm database to search for drugs by name and returns standardized drug nomenclature data.

  export async function searchRxNormDrugs(query: string): Promise<RxNormDrug[]> {
    try {
      const res = await superagent
        .get(`${RXNAV_API_BASE}/drugs.json`)
        .query({ name: query })
        .set("User-Agent", USER_AGENT);
  
      const drugGroup = res.body.drugGroup;
      if (!drugGroup || !drugGroup.conceptGroup) {
        return [];
      }
  
      // Find concept groups that have conceptProperties
      const results: RxNormDrug[] = [];
      for (const conceptGroup of drugGroup.conceptGroup) {
        if (
          conceptGroup.conceptProperties &&
          Array.isArray(conceptGroup.conceptProperties)
        ) {
          for (const concept of conceptGroup.conceptProperties) {
            // Transform the API response to match our RxNormDrug type
            results.push({
              rxcui: concept.rxcui || "",
              name: concept.name || "",
              synonym: concept.synonym
                ? Array.isArray(concept.synonym)
                  ? concept.synonym
                  : [concept.synonym]
                : [],
              tty: concept.tty || "",
              language: concept.language || "",
              suppress: concept.suppress || "",
              umlscui: concept.umlscui
                ? Array.isArray(concept.umlscui)
                  ? concept.umlscui
                  : [concept.umlscui]
                : [],
            });
          }
        }
      }
  
      return results;
    } catch (error) {
      console.error("Error searching RxNorm drugs:", error);
      return [];
    }
  }

• src/index.ts:157-171 (registration)

  MCP tool registration including input schema (query string) and handler that delegates to searchRxNormDrugs and formatRxNormDrugs functions.

  server.tool(
    "search-drug-nomenclature",
    "Search for drug information using RxNorm (standardized drug nomenclature)",
    {
      query: z.string().describe("Drug name to search for in RxNorm database"),
    },
    async ({ query }) => {
      try {
        const drugs = await searchRxNormDrugs(query);
        return formatRxNormDrugs(drugs, query);
      } catch (error: any) {
        return createErrorResponse("searching RxNorm", error);
      }
    },
  );

• src/utils.ts:674-696 (helper)

  Helper function that formats the RxNorm search results into a readable MCP response.

  export function formatRxNormDrugs(drugs: any[], query: string) {
    if (drugs.length === 0) {
      return createMCPResponse(
        `No drugs found in RxNorm database for "${query}". Try a different search term.`,
      );
    }
  
    let result = `**RxNorm Drug Search: "${query}"**\n\n`;
    result += `Found ${drugs.length} drug(s)\n\n`;
  
    drugs.forEach((drug, index) => {
      result += `${index + 1}. **${drug.name}**\n`;
      result += `   RxCUI: ${drug.rxcui}\n`;
      result += `   Term Type: ${drug.tty}\n`;
      result += `   Language: ${drug.language}\n`;
      if (drug.synonym && drug.synonym.length > 0) {
        result += `   Synonyms: ${drug.synonym.slice(0, 3).join(", ")}${drug.synonym.length > 3 ? "..." : ""}\n`;
      }
      result += "\n";
    });
  
    return createMCPResponse(result);
  }

• src/types.ts:37-45 (schema)

  TypeScript type definition for RxNormDrug, defining the structure of the output data from the search.

  export type RxNormDrug = {
    rxcui: string;
    name: string;
    synonym: string[];
    tty: string;
    language: string;
    suppress: string;
    umlscui: string[];
  };

• src/constants.ts:3-3 (helper)

  API base URL constant used by the search handler for RxNorm queries.

  export const RXNAV_API_BASE = "https://rxnav.nlm.nih.gov/REST";