mongo-count-documents
Count documents in a MongoDB collection using a query filter to get precise document totals for data analysis and monitoring.
Instructions
Count documents in a MongoDB collection
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| database | Yes | Database name | |
| collection | Yes | Collection name | |
| filter | No | Query filter as JSON object (optional) |
Implementation Reference
- src/index.ts:272-290 (handler)The main handler function for the 'mongo-count-documents' tool. It ensures a connection to the specified MongoDB database, retrieves the collection, counts the documents matching the optional filter using countDocuments(), and returns a text response with the count.
async ({ database: dbName, collection: collectionName, filter = {} }) => { try { const db = await ensureConnection(dbName); const collection: Collection = db.collection(collectionName); const count = await collection.countDocuments(filter); return { content: [ { type: "text", text: `Found ${count} document(s) matching the filter`, }, ], }; } catch (error) { throw new Error(`Failed to count documents: ${error instanceof Error ? error.message : 'Unknown error'}`); } } - src/index.ts:267-271 (schema)Zod input schema defining parameters: database (string), collection (string), and optional filter (JSON object).
{ database: z.string().describe("Database name"), collection: z.string().describe("Collection name"), filter: z.record(z.any()).optional().describe("Query filter as JSON object (optional)"), }, - src/index.ts:264-291 (registration)Registration of the 'mongo-count-documents' tool using server.tool(), including name, description, schema, and handler function.
server.tool( "mongo-count-documents", "Count documents in a MongoDB collection", { database: z.string().describe("Database name"), collection: z.string().describe("Collection name"), filter: z.record(z.any()).optional().describe("Query filter as JSON object (optional)"), }, async ({ database: dbName, collection: collectionName, filter = {} }) => { try { const db = await ensureConnection(dbName); const collection: Collection = db.collection(collectionName); const count = await collection.countDocuments(filter); return { content: [ { type: "text", text: `Found ${count} document(s) matching the filter`, }, ], }; } catch (error) { throw new Error(`Failed to count documents: ${error instanceof Error ? error.message : 'Unknown error'}`); } } ); - src/index.ts:88-99 (helper)Helper function to ensure MongoDB client connection and database instance are available, used by the tool handler.
async function ensureConnection(dbName: string): Promise<Db> { if (!mongoClient) { const uri = getMongoUri(); mongoClient = new MongoClient(uri); await mongoClient.connect(); } if (!databases.has(dbName)) { databases.set(dbName, mongoClient.db(dbName)); } return databases.get(dbName)!;