[MCP] Multi-root workspace causes duplicate MCP server initialization (4x CreateClient actions)

[nathan_song]

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

When using a multi-root workspace configuration with 4 workspaces, the MCP client initialization triggers 3 simultaneous CreateClient actions within ~76ms, causing:
3 separate MCP server processes to spawn
2 processes fail with “address already in use” errors
Unnecessary resource consumption and error logs

Steps to Reproduce

Open Cursor with 4+ workspaces in a multi-root configuration
Enable an MCP server in settings (e.g., serena-mcp)
MCP Server: Serena MCP (uvx --from git+https://github.com/oraios/serena)
Multi-root Workspaces: 4 workspaces
Start Cursor or reload the window

Expected Behavior

Single CreateClient action
One MCP server process initialized per server configuration

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

version: 2.0.77 (Universal)
commit: 1.99.3
date: ba90f2f88e4911312761abab9492c42442117cf0
Electron: 2025-11-13T23:10:43.113Z
ElectronBuildId: 37.7.0
Chromium: undefined
Node.js: 138.0.7204.251
V8: 22.20.0
OS: 13.8.258.32-electron.0

Does this stop you from using Cursor

No

[deanrie]

Hey, thanks for the report. This is a known issue and it’s already being tracked.

Your multi-root workspace setup is triggering the same MCP client race condition described here: MCP Server Race Condition Causes Infinite Process Spawning on Windows (Cursor 2.0.34)

The team is already working on this. The root cause is that Cursor spawns multiple CreateClient actions at the same time before the first one finishes. In your case this shows up as duplicate processes, and in more severe cases it can lead to infinite process spawning.

The team is aware of the problem and actively working on a fix. I’ll add the details of your multi-root workspace to help with the investigation.