Severe Performance Degradation, Network Errors, and Listener Leaks in Cursor During Complex Automated Testing

Bug Reports
1

I am experiencing significant performance issues with the Cursor extension in VS Code, particularly when running complex automated testing scripts. The extension becomes extremely slow, unresponsive, and throws numerous errors in the VS Code Developer Tools console. This makes it very difficult to use Cursor reliably for my automated workflows.

The primary symptoms include:

  • Long delays (often 5-7 minutes or more) before the AI generates a response.

  • Periods where CPU usage is low, suggesting the agent is waiting or stuck, rather than processing.

  • Frequent network-related errors.

  • Accumulating listener leaks over time.

  • Errors related to file access (especially images) and internal components.

Key Issues Observed (with examples from VS Code Developer Tools Console):

  1. Network Errors:

  • ConnectError: [unavailable] HTTP 502

  • ConnectError: [unknown] Premature close

  • [composer] Error getting conversation summary: ConnectError: [invalid_argument] Error

  1. Listener Leaks:
  • [1dc] potential listener LEAK detected, having 175 listeners already. MOST frequent listener (1): (and similar messages with different identifiers like [14e], ``)
  1. File Access / Image Errors:

  • nd: Unable to read file ‘c:**\AppData\Roaming\Cursor\User\workspaceStorage\images\image-4e9aa433-f766-4d46-bd94-735eaae94c3f.png’ (Error: Unable to resolve nonexistent file …)

  • Error: Image selected in conversation was not found on disk

  1. Other Internal Errors:

  • [composer] ToolFormer: error in toolWrappedStream undefined

  • Error checking if repo is ready for background composer: Error: No full commit provider registered

  • ERROR WHEN RENDERING SOLID COMPONENT TypeError: Cannot read properties of undefined (reading ‘length’)

Steps to Reproduce (General Idea):

While my specific automated testing script is complex and proprietary, the issues seem to be triggered by:

  1. Initiating a series of many sequential chat interactions with the Cursor AI.

  2. These interactions involve referencing local project files as context (even if the files themselves are small and plain text).

  3. The process runs for an extended period, making numerous calls to the Cursor agent.

  4. Monitoring the VS Code Developer Tools console will show the errors listed above accumulating.

  5. The listener leaks, in particular, seem to build up over time with continued interaction.

  6. The HTTP 502 and Premature close errors occur during attempts to get responses from the AI.

Expected Behavior:

  • Cursor should maintain responsiveness and provide timely AI responses, even during extended or complex automated interactions.

  • Network connections to the AI backend should be stable and resilient.

  • The extension should manage resources efficiently without listener leaks or excessive memory consumption.

  • Errors related to file access or internal components should be handled gracefully or not occur.

Actual Behavior:

  • Significant delays in AI responses.

  • Frequent unresponsiveness of the Cursor interface.

  • A high volume of errors in the VS Code Developer Tools console (as detailed above).

  • Evidence of resource leaks (listeners).

  • Previously, the extension has become completely unresponsive, requiring a VS Code and sometimes a system restart.

Environment:

  • Operating System: Windows [e.g., Windows 10 Pro Version 22H2, Windows 11]

  • VS Code Version: [Please find this in Help > About]

  • Cursor Extension Version: Version: 0.49.6 (user setup)
    VSCode Version: 1.96.2
    Commit: 0781e811de386a0c5bcb07ceb259df8ff8246a50
    Date: 2025-04-25T04:49:20.797Z
    Electron: 34.3.4
    Chromium: 132.0.6834.210
    Node.js: 20.18.3
    V8: 13.2.152.41-electron.0
    OS: Windows_NT x64 10.0.19045

  • **Other Relevant Extensions: Tested with all other extensions disabled

  • Network Connection: Ethernet (Wired)