"Git executable not found" when starting Serena with Claude Desktop 1.1.8629 (befdfc) 2026-03-24T22:13:01.000Z

[kazup0n]

Note

This is a self-resolved issue, not a question. I'm posting it here for the benefit of other users who may encounter the same problem.

Note

The version shown is the one used during testing; the issue may also occur in nearby versions.

An error may occur when starting Serena with the following configuration:

{
   "command": "uvx",
      "args": [
        "--from",
        "git+https://github.com/oraios/serena",
        "serena",
        "start-mcp-server"
      ]}

Error

2026-03-25T04:04:59.713Z [serena-git] [info] Message from client: {"method":"initialize",...}
   Updating https://github.com/oraios/serena (HEAD)
  × Failed to download and build `serena-agent @
  │ git+https://github.com/oraios/serena@8c62b0d991f280af62531fb2c62bd1bb3310f0d4`
  ├─▶ Git operation failed
  ╰─▶ Git executable not found. Ensure that Git is installed and available.

Workaround

Set the PATHEXT environment variable:

{
      "command": "uvx",
      "args": [
        "--from",
        "git+https://github.com/oraios/serena",
        "serena",
        "start-mcp-server"
      ],
      "env": {
        "PATHEXT": ".COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC;.PY;.PYW"
      }
    },

Root Cause

• When uv accesses a repository, it uses the locally installed git command.
  • Git command lookup uses which-rs. This crate checks the PATHEXT environment variable on Windows to determine whether a file is executable.
• When Claude launches an MCP server, it appears that the PATHEXT environment variable is not included in the spawned process's environment, causing the git lookup to fail.

[kazup0n]

Workaround

Set the PATHEXT environment variable:

{
      "command": "uvx",
      "args": [
        "--from",
        "git+https://github.com/oraios/serena",
        "serena",
        "start-mcp-server"
      ],
      "env": {
        "PATHEXT": ".COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC;.PY;.PYW"
      }
    },