mongodb3-mcp-server

A lightweight MCP (Model Context Protocol) server for MongoDB, compatible with MongoDB 3.6.18+.

Uses mongodb driver v4.x which officially supports MongoDB 3.6+.

Quick Start

# Install dependencies
npm install

# Build
npm run build

# Run (stdio transport)
MDB_MCP_CONNECTION_STRING="mongodb://localhost:27017" node dist/index.js

MCP Client Configuration

{
  "mcpServers": {
    "MongoDB": {
      "command": "node",
      "args": ["/path/to/mongodb3-mcp-server/dist/index.js"],
      "env": {
        "MDB_MCP_CONNECTION_STRING": "mongodb://localhost:27017"
      }
    }
  }
}

Enable Write Mode

By default, the server runs in read-only mode for safety. To enable write/delete operations:

{
  "mcpServers": {
    "MongoDB": {
      "command": "node",
      "args": ["/path/to/mongodb3-mcp-server/dist/index.js"],
      "env": {
        "MDB_MCP_CONNECTION_STRING": "mongodb://localhost:27017",
        "MDB_MCP_WRITABLE": "true"
      }
    }
  }
}

Pass --writable CLI flag as an alternative.

Kiro MCP Configuration

Add the following to your Kiro MCP config (~/.kiro/settings/mcp.json):

{
  "mcpServers": {
    "dev-mongodb3": {
      "command": "npx",
      "args": ["mongodb3-mcp-server"],
      "env": {
        "MDB_MCP_WRITABLE": "false",
        "MDB_MCP_CONNECTION_STRING": "mongodb://root:root@localhost:17017/admin?authSource=admin"
      },
      "disabled": true
    }
  }
}

Configuration

Environment Variable / CLI Flag	Default	Description
MDB_MCP_CONNECTION_STRING / --connectionString	-	MongoDB connection string
MDB_MCP_WRITABLE / --writable	false (read-only)	Set MDB_MCP_WRITABLE=true or pass --writable to enable write operations
MDB_MCP_MAX_DOCUMENTS_PER_QUERY / --maxDocumentsPerQuery	100	Max documents per query

Supported Tools (23 tools)

Connection (2)

Tool	Description
connect	Connect to a MongoDB instance
switch-connection	Switch to a different connection

Read (5)

Tool	Description
find	Query documents in a collection
aggregate	Run aggregation pipeline on a collection
aggregate-db	Run aggregation pipeline at database level
count	Count documents with optional filter
explain	Get execution plan for find/aggregate/count

Metadata (7)

Tool	Description
list-databases	List all database names (uses nameOnly for efficiency)
list-collections	List collections in a database
collection-indexes	List indexes on a collection
collection-schema	Infer schema by sampling documents
collection-storage-size	Get collection storage size
db-stats	Get database statistics
mongodb-logs	Get recent mongod log entries

Write (requires --writable or MDB_MCP_WRITABLE=true) (3)

Tool	Description
insert-many	Insert documents into a collection
update-many	Update documents matching a filter
delete-many	Delete documents matching a filter

Manage (requires --writable or MDB_MCP_WRITABLE=true) (6)

Tool	Description
create-collection	Create a new collection
drop-collection	Drop a collection
drop-database	Drop a database
rename-collection	Rename a collection
create-index	Create an index
drop-index	Drop an index

Resources

Resource	URI	Description
config	config://config	Server configuration (redacted)

MongoDB 3.6 Compatibility

This server uses mongodb driver v4.17.x which officially supports MongoDB 3.6+. All tools use commands and operations available in MongoDB 3.6:

• find, aggregate, count — core query operations
• $sample aggregation stage for schema inference
• collStats, dbStats, getLog admin commands
• createIndexes, dropIndexes index management
• listDatabases, listCollections metadata commands
• insert, update, delete write operations

No features requiring MongoDB 4.0+ (like transactions or $merge) are used.