Project-level mcp.json Configuration Not Working in Windows11

Bug Reports
1

Issue Description

When using Cursor’s MCP (Model Context Protocol) feature, configuring MCP servers through the project-level .cursor/mcp.json file does not work. According to the official documentation, it should be possible to configure project-specific MCP servers by creating a .cursor/mcp.json file in the project directory, but in practice this method has no effect. In contrast, manually adding the same MCP server through the Cursor settings interface works correctly.

Steps to Reproduce

  1. Create a .cursor/mcp.json file in the project directory according to the official documentation
  2. Configure MCP servers in the file, for example:
{
  "mcpServers": {
    "calculate_sum": {
      "command": "node",
      "args": ["F:/modelcontextprotocol_repositories/013_sum/build/index.js"]
    }
  }
}
  1. Restart Cursor or open a new project
  2. Try to use the configured MCP tools in Agent, but find that the tools are unavailable or not properly loaded
  3. Manually add the same MCP server configuration through the Cursor settings interface
  4. Try to use the MCP tools again, and this time the tools work, and a terminal window pops up in Windows

Test Results

  • The calculate_sum tool added manually through the settings interface works correctly (e.g., 5+7=12)
  • Tools configured through mcp.json cannot be recognized or used by Cursor
  • In Windows environment, a terminal window pops up when MCP tools are successfully loaded, but this does not happen when using mcp.json configuration

Screenshots

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image934×379 17.9 KB

Environment Information

  • Operating System: Windows 11 Enterprise
  • Cursor Version: 0.46.11

Impact Level

This issue hinders the ability to automate MCP tool setup through project configuration files, requiring manual configuration of MCP servers in each Cursor instance, affecting development efficiency and team collaboration. It is particularly inconvenient for developers who need to use the same MCP tools across multiple projects.

Additional Notes

According to the official documentation, the MCP configuration file feature was newly added in version 0.46, but it currently does not work properly in Windows environments.

2

Oh, I found the reason. I need to click Disabled to Enabled :sweat_smile: