MongoDB extension fails to activate: onDidReceiveFeedback missing on ChatParticipant API

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

After updating Cursor, the MongoDB for VS Code extension (mongodb.mongodb-vscode) fails during activation. Extension Host logs:

TypeError: this._participant.onDidReceiveFeedback is not a function
    at ParticipantController.createParticipant
    at MDBExtensionController.activate

Because activation fails, all mdb.* commands are never registered (e.g. command 'mdb.addConnection' not found). The MongoDB sidebar tab does not appear. Reinstalling the extension does not help.

MongoDB extension v1.16.0 registers a VS Code Chat Participant during activate() and calls participant.onDidReceiveFeedback(...). Cursor’s vscode.chat.createChatParticipant appears to return an object missing this method (partial VS Code Chat API). The crash happens before connection explorer, playgrounds, or MCP initialize.

This is not the older MongoDB v1.14.1 yargs-parser bug.

Steps to Reproduce

  1. Install Cursor 3.7.36 (stable) on Windows 10 x64
  2. Install MongoDB for VS Code v1.16.0 from Marketplace (mongodb.mongodb-vscode)
  3. Run Developer: Reload Window
  4. Open Output → Extension Host — observe activation error
  5. Run any mdb.* command → command not found
  6. Developer: Show Running Extensions → MongoDB shows Activation failed

Same extension works in Microsoft VS Code with the same VS Code engine APIs.

Expected Behavior

  • vscode.chat.createChatParticipant should return a compatible ChatParticipant object including onDidReceiveFeedback, OR Cursor should stub missing methods so extensions can still activate non-chat features (connection explorer, playgrounds, MCP server, etc.)
  • MongoDB sidebar and commands should work as in VS Code

Operating System

Windows 10/11

Version Information

Version: 3.7.36
Commit: 776d1f9d76df50a4e0aeca61819a88e7c1b861e0
VSCode Version: 1.105.1
Extension: mongodb.mongodb-vscode 1.16.0-universal

Additional Information

Extension Host stack trace (paths anonymized):

2026-06-16 11:01:55.353 [error] Activating extension mongodb.mongodb-vscode failed due to an error:
2026-06-16 11:01:55.353 [error] TypeError: this._participant.onDidReceiveFeedback is not a function
    at ParticipantController.createParticipant (%USERPROFILE%\.cursor\extensions\mongodb.mongodb-vscode-1.16.0-universal\dist\extension.js:41:1829139)
    at MDBExtensionController.activate (%USERPROFILE%\.cursor\extensions\mongodb.mongodb-vscode-1.16.0-universal\dist\extension.js:41:124515)
    at t.activate (%USERPROFILE%\.cursor\extensions\mongodb.mongodb-vscode-1.16.0-universal\dist\extension.js:5:1633032)
    at xze._callActivateOptional (file:///.../cursor/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:146:25520)
    at xze._callActivate (file:///.../cursor/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:146:25188)

Does this stop you from using Cursor

No - Cursor works, but with this issue

8

Same for me, Downgrading to 1.6.0 fixed it.

10

Hi!
Thanks for the clear write-up and stack trace. This is a confirmed bug on our side, and it’s not Windows-specific. MongoDB v1.16.0 registers a VS Code chat participant during activation and then calls onDidReceiveFeedback on it. Cursor doesn’t currently support the VS Code Chat Participant API, so that call throws and aborts the whole activation, which is why none of the mdb.* commands or the sidebar load.

The fix on our end is to make sure an unsupported chat API can’t block the rest of an extension from activating (the connection explorer, playgrounds, and MCP server don’t depend on chat). I’ve reported this to our team and will update this thread once the fix ships.

If you need MongoDB access before then, you can try installing an earlier version of the extension that doesn’t register a chat participant.

12

Hi @tcdnw!

We should see a fix for this come not in Cursor 3.8, but the release following.