issue while connecting with mcp

[ravi-singh-123]

"mongodb-lens": {
"command": "npx",
"args": [
"-y",
"mongodb-lens@latest",
"mongodb://localhost:27017"
]
} , this is the configuration i am using , but error is coming in cursor, when i see log by going to view->outout->mcp server, this is the log found, 2025-04-08 20:12:54.072 [info] lens: Starting new stdio process with command: npx -y mongodb-lens@latest mongodb://localhost:27017
2025-04-08 20:13:08.416 [info] lens: Client closed for command
2025-04-08 20:13:08.416 [error] lens: Error in MCP: Client closed
2025-04-08 20:13:08.905 [info] lens: Client closed for command
2025-04-08 20:13:08.906 [error] lens: Error in MCP: Client closed
2025-04-08 20:13:09.363 [info] lens: Client closed for command
2025-04-08 20:13:09.364 [error] lens: Error in MCP: Client closed
2025-04-08 20:13:09.366 [info] thub: Handling ListOfferings action
2025-04-08 20:13:09.367 [info] thub: Listing offerings

and also i used docker, unable to connect.

[furey]

Hi @ravi-singh-123

Thanks for trying MongoDB Lens

The error messages suggest MongoDB Lens can't connect to your MongoDB instance

Here's MongoDB Lens in Cursor unable to connect to a MongoDB URI (i.e. in this case localhost:27017 NOT running)

Here's MongoDB Lens in Cursor successfully connected to a MongoDB URI (i.e. in this case localhost:27017 IS running)

(please note how the Cursor MCP.log error messages in the first screenshot are the same as yours)

Troubleshooting

Let's verify your MongoDB is running and accessible

If you're running MongoDB locally:

# Check process
ps aux | grep mongo
systemctl status mongodb  # If using systemd

# Connect via MongoDB shell
mongosh mongodb://localhost:27017

If you're running MongoDB in Docker:

# Check if container is running
docker ps | grep mongo

# Check container logs
docker logs <container_id>

# Connect using Docker's MongoDB instance
docker exec -it <container_id> mongosh

# Verify container is exposing port 27017
docker port <container_id>

# Inspect network the MongoDB container is on
docker network inspect <network_name>

Network accessibility test (i.e. test if port 27017 is reachable):

nc -zv localhost 27017  # Linux/macOS
telnet localhost 27017  # Windows

Additional information needed:

• OS and version
• How MongoDB was installed (native, Docker, etc.)
• MongoDB version
• Is any MongoDB authentication configured
• Firewall settings, if any
• Are you running Cursor in the same network context as MongoDB?

Can you try these basic tests and share the results and additional info if you're still stuck

Cheers

[ravi-singh-123]

still it's not working and yes mongodb is running fine and i have also run above command to test .

1. Windows 11 Pro and 23H2
2. docker
3. 7.0.12(i went inside docker container inside inspect to see mongodb version as it's not installed on my os).
4. no
5. no
6. i am running mongodb on docker and using cursor in my local system(my answer what i understood).

[furey]

Hi @ravi-singh-123

Thanks for the extra context

I don't have a Windows machine handy to test against unfortunately

Stepping away from Cursor, are you able to run MongoDB Lens via command line?

e.g. if using NPX do you see an output similar to this (make sure you set the CONFIG_LOG_LEVEL env var however your Windows terminal requires i.e. example)

> CONFIG_LOG_LEVEL='verbose' npx -y mongodb-lens@latest mongodb://localhost:27017

MongoDB Lens v9.1.0 starting…
Connecting to MongoDB at: mongodb://localhost:27017
Connected to MongoDB server version: 7.0.18
Connected to MongoDB successfully, using database: admin
Starting watchdog…
DB Operation: Set slow query threshold to 100ms
Initializing MCP server…
Registering MCP resources…
Total MCP resources: 12
Registering MCP prompts…
Total MCP prompts: 14
Registering MCP tools…
Total MCP tools: 42
Creating stdio transport…
Connecting MCP server transport…
MongoDB Lens server running.

Cheers

[furey]

Closing due to inactivity