Cursor "failed to create client" when Unity MCP project path contains spaces?

Question

With unity-mcp (CoplayDev/unity-mcp) and Cursor on Linux, Cursor shows "failed to create client" when the Unity project folder name contains spaces, e.g. "My project (1)". The Unity MCP bridge side appears to work fine. How do I fix the MCP config or project setup so spaces in the path stop breaking the client?

Originally asked on GitHub: https://github.com/CoplayDev/unity-mcp/issues/21

AgentArmor team · Accepted Answer

The cause is that spaces in a path are parsed as separate command arguments, so the auto-generated config breaks when the project lives in a folder like "My project (1)". The thread confirms a working fix: remove spaces from the project folder name. A contributor also said an installer update (PR #82) should fix the auto-config, but that fix is not yet confirmed by a user in this thread.

Confirmed workaround: rename the Unity project so its path has no spaces, update the path in Cursor, stop/restart the bridge, click auto-generate config, then restart Cursor and verify the generated paths look correct.

Immediate workaround suggested by a contributor (not confirmed in the thread): open Window > Unity MCP > Manual Setup > Open File and wrap the Python directory path in escaped double quotes inside the args array:

```json
{
  "mcpServers": {
    "unityMCP": {
      "command": "uv",
      "args": [
        "--directory",
        "\"/home/.../.../Python\"",
        "run",
        "server.py"
      ]
    }
  }
}
```

The contributor also advises avoiding spaces in folder names in general.

AgentArmor team · Answer

**What a GitHub user tried on GitHub** (Didn't work)

Used the auto-generated unity-mcp config with a Unity project path containing spaces ("My project (1)"); Cursor reported "failed to create client" while the Unity side looked fine.

Source: https://github.com/CoplayDev/unity-mcp/issues/21

AgentArmor team · Answer

**What @justinpbarnett tried on GitHub** (Outcome unclear)

A contributor suggested escaping the directory path inside the args array by wrapping it in escaped double quotes (\"/home/.../.../Python\") in the MCP config JSON as an immediate fix.

Source: https://github.com/CoplayDev/unity-mcp/issues/21#issuecomment-2743086524

AgentArmor team · Answer

**What @ChuloIva tried on GitHub** (Worked)

A user renamed the project to remove spaces, updated the path in Cursor, stopped and restarted the bridge, regenerated the config, and restarted Cursor; this resolved the issue.

Source: https://github.com/CoplayDev/unity-mcp/issues/21#issuecomment-2743176485

Cursor "failed to create client" when Unity MCP project path contains spaces?

4 answers

Add your answer or comment

Cursor "failed to create client" when Unity MCP project path contains spaces?

4 answers

Add your answer or comment

Related questions