MongoDB MCP Server

Execute a read-only aggregation pipeline on a collection.

Supported Stages:

• $match: Filter documents
• $group: Group documents by a key
• $sort: Sort documents
• $project: Shape the output
• $lookup: Perform left outer joins
• $unwind: Deconstruct array fields

Unsafe/Blocked Stages:

• $out: Write results to collection
• $merge: Merge results into collection
• $addFields: Add new fields
• $set: Set field values
• $unset: Remove fields
• $replaceRoot: Replace document structure
• $replaceWith: Replace document

Example - User Statistics by Role: use_mcp_tool with server_name: "mongodb", tool_name: "aggregate", arguments: { "collection": "users", "pipeline": [ { "$match": { "active": true } }, { "$group": { "_id": "$role", "count": { "$sum": 1 }, "avgAge": { "$avg": "$age" } }}, { "$sort": { "count": -1 } } ], "limit": 100 }

Example - Posts with Author Details: use_mcp_tool with server_name: "mongodb", tool_name: "aggregate", arguments: { "collection": "posts", "pipeline": [ { "$match": { "published": true } }, { "$lookup": { "from": "users", "localField": "authorId", "foreignField": "_id", "as": "author" }}, { "$unwind": "$author" }, { "$project": { "title": 1, "authorName": "$author.name", "publishDate": 1 }} ] }