Unity Editor is not running at the specified project root

[daidaoshiwei]

Title: Unity Editor detected by list_unity_project_roots but get_unity_editor_state / get_unity_logs fail with "Unity Editor is not running at the specified project root"

Environment:

• OS: Windows 10 (win32 10.0.17763)
• Unity project path: E:\NewClient\ReleaseCold
• MCP For Unity: v9.4.7 (HTTPLocal, URL http://127.0.0.1:8080, Session Active)
• Cursor + coplay-mcp: coplay-mcp-server (Python 3.11, installed as shown in Cursor MCP panel)

Minimal Repro Steps:

1. Open the Unity project located at E:\NewClient\ReleaseCold in the Unity Editor.
2. In Unity, open the “MCP For Unity” window and start the local server:
   • Transport: HTTPLocal
   • HTTP URL: http://127.0.0.1:8080
   • Ensure the status shows: “Session Active (ReleaseCold)”.
3. In Cursor, enable the coplay-mcp server.
4. From Cursor, call the set_unity_project_root tool with:
   • unity_project_root = "E:\\NewClient\\ReleaseCold"
     This call succeeds and returns:
     Unity project root set to: E:\NewClient\ReleaseCold
5. From Cursor, call the list_unity_project_roots tool with empty arguments:
   • This call succeeds and returns something like:
     {
     "count": 1,
     "projectRoots": [
     {
     "projectRoot": "E:\NewClient\ReleaseCold",
     "projectName": "ReleaseCold"
     }
     ]
     }
     So the MCP server clearly detects one running Unity instance at the expected project root.
6. Now call the get_unity_editor_state tool with empty arguments.
7. Also try calling the get_unity_logs tool with:
   • {"limit": 20, "show_logs": true, "show_warnings": true, "show_errors": true, "show_stack_traces": false}

Observed Behavior:

• Both get_unity_editor_state and get_unity_logs fail with the same error:
  Unity Editor is not running at the specified project root
• Other tools that only set or query configuration (such as set_unity_project_root and list_unity_project_roots) work as expected.

Expected Behavior:

• Since list_unity_project_roots successfully detects a running Unity instance with:
  • projectRoot = E:\NewClient\ReleaseCold
  • projectName = ReleaseCold
    and this matches the configured unity_project_root, calls to get_unity_editor_state and get_unity_logs should succeed and return the current editor state / console logs, instead of reporting that the Unity Editor is not running.

Additional Notes:

• This suggests that the internal check used by get_unity_editor_state / get_unity_logs to validate that "the Unity Editor is running at the specified project root" may be stricter or inconsistent with the logic used by list_unity_project_roots.
• It might be comparing paths in a way that fails on Windows (e.g., different path normalization, case sensitivity, or drive letter handling), even though the project root strings look identical in the tool outputs.

[dsarno]

This is an issue with Coplay mcp server, a different project. Please leave a note on that project or in the discord (we share a discord with them)