MongoDB MCP Server

Instructions

Implementation Reference

• src/tools/mongodb/metadata/listCollections.ts:15-36 (handler)

  The handler function that implements the core logic of the 'list-collections' tool: connects to the MongoDB provider, lists collections for the given database, and formats the response appropriately, handling empty cases.

  protected async execute({ database }: ToolArgs<typeof this.argsShape>): Promise<CallToolResult> {
      const provider = await this.ensureConnected();
      const collections = await provider.listCollections(database);
  
      if (collections.length === 0) {
          return {
              content: [
                  {
                      type: "text",
                      text: `Found 0 collections for database "${database}". To create a collection, use the "create-collection" tool.`,
                  },
              ],
          };
      }
  
      return {
          content: formatUntrustedData(
              `Found ${collections.length} collections for database "${database}".`,
              collections.map((collection) => `"${collection.name}"`).join("\n")
          ),
      };
  }

• src/tools/mongodb/metadata/listCollections.ts:9-11 (schema)

  Defines the input schema for the tool, requiring a 'database' parameter from DbOperationArgs.

  protected argsShape = {
      database: DbOperationArgs.database,
  };

• src/tools/mongodb/metadata/listCollections.ts:7-7 (registration)

  Sets the tool's name to 'list-collections', identifying it in the MCP tool registry.

  public name = "list-collections";

• src/tools/mongodb/tools.ts:2-2 (registration)

  Re-exports the ListCollectionsTool class from its implementation file for inclusion in the MongoDB tools module.

  export { ListCollectionsTool } from "./metadata/listCollections.js";

• src/tools/index.ts:3-11 (registration)

  Imports the MongoDB tools module (including ListCollectionsTool) and includes it in the AllTools array, which is used by the server to register all available tools.

  import * as MongoDbTools from "./mongodb/tools.js";
  import type { ToolClass } from "./tool.js";
  
  // Export the collection of tools for easier reference
  export const AllTools: ToolClass[] = Object.values({
      ...MongoDbTools,
      ...AtlasTools,
      ...AtlasLocalTools,
  });