NPM MCP Server

Implementation Reference

• src/index.ts:37-92 (handler)

  Handler function for the 'searchNpmPackage' MCP tool. Fetches package info from npm registry, processes it, logs details, and returns structured JSON content.

  async ({ packageName }) => {
    try {
      console.log(`\nBuscando informações para o pacote: ${packageName}`);
      const response = await fetch(`https://registry.npmjs.org/${packageName}`);
      const data = (await response.json()) as NpmPackage;
      
      if (response.ok) {
        const result = {
          name: data.name,
          version: data["dist-tags"].latest,
          description: data.description,
          author: typeof data.author === 'string' ? data.author : data.author?.name,
          homepage: data.homepage,
          repository: data.repository?.url,
          dependencies: data.versions[data["dist-tags"].latest].dependencies
        };
  
        console.log('\nInformações do pacote:');
        console.log('-------------------');
        Object.entries(result).forEach(([key, value]) => {
          if (key === 'dependencies') {
            console.log('\nDependências:');
            console.log(JSON.stringify(value, null, 2));
          } else {
            console.log(`${key}: ${value}`);
          }
        });
  
        return {
          content: [{
            type: "text",
            text: JSON.stringify(result, null, 2)
          }]
        };
      } else {
        const errorMsg = `Erro: Pacote '${packageName}' não encontrado`;
        console.log(`\n${errorMsg}`);
        return {
          content: [{
            type: "text",
            text: errorMsg
          }]
        };
      }
    } catch (error: unknown) {
      const errorMessage = error instanceof Error ? error.message : 'Erro desconhecido';
      const errorMsg = `Erro ao buscar informações do pacote: ${errorMessage}`;
      console.log(`\n${errorMsg}`);
      return {
        content: [{
          type: "text",
          text: errorMsg
        }]
      };
    }
  }

• src/index.ts:34-93 (registration)

  Registers the 'searchNpmPackage' tool on the MCP server with name, input schema, and handler function.

  server.tool(
    "searchNpmPackage",
    { packageName: z.string() },
    async ({ packageName }) => {
      try {
        console.log(`\nBuscando informações para o pacote: ${packageName}`);
        const response = await fetch(`https://registry.npmjs.org/${packageName}`);
        const data = (await response.json()) as NpmPackage;
        
        if (response.ok) {
          const result = {
            name: data.name,
            version: data["dist-tags"].latest,
            description: data.description,
            author: typeof data.author === 'string' ? data.author : data.author?.name,
            homepage: data.homepage,
            repository: data.repository?.url,
            dependencies: data.versions[data["dist-tags"].latest].dependencies
          };
  
          console.log('\nInformações do pacote:');
          console.log('-------------------');
          Object.entries(result).forEach(([key, value]) => {
            if (key === 'dependencies') {
              console.log('\nDependências:');
              console.log(JSON.stringify(value, null, 2));
            } else {
              console.log(`${key}: ${value}`);
            }
          });
  
          return {
            content: [{
              type: "text",
              text: JSON.stringify(result, null, 2)
            }]
          };
        } else {
          const errorMsg = `Erro: Pacote '${packageName}' não encontrado`;
          console.log(`\n${errorMsg}`);
          return {
            content: [{
              type: "text",
              text: errorMsg
            }]
          };
        }
      } catch (error: unknown) {
        const errorMessage = error instanceof Error ? error.message : 'Erro desconhecido';
        const errorMsg = `Erro ao buscar informações do pacote: ${errorMessage}`;
        console.log(`\n${errorMsg}`);
        return {
          content: [{
            type: "text",
            text: errorMsg
          }]
        };
      }
    }
  );

• src/index.ts:36-36 (schema)

  Input schema for the tool using Zod: requires a 'packageName' string.

  { packageName: z.string() },

• src/index.ts:7-15 (helper)

  TypeScript interface defining the structure of NPM package data used in the handler.

  interface NpmPackage {
    name: string;
    description: string;
    "dist-tags": { latest: string };
    versions: { [key: string]: { dependencies: Record<string, string> } };
    author: { name: string } | string;
    homepage: string;
    repository: { url: string };
  }