[BUG] macOS allowUnixSockets does not match /tmp symlink path

Summary

On macOS, allowing an existing Unix socket through its /tmp path does not permit a sandboxed direct connection. The connection returns EPERM. Using the socket's physical /private/tmp path works.

Environment

• Claude Code 2.1.236
• macOS Darwin 23.6.0 (x86_64)

Reproduction

/tmp is a symlink to /private/tmp:

/tmp/mysql56.sock -> /private/tmp/mysql56.sock

Configure:

{
  "sandbox": {
    "enabled": true,
    "network": {
      "allowUnixSockets": [
        "/tmp/mysql56.sock"
      ]
    }
  }
}

From sandboxed Bash, connect to the existing socket:

mysql --protocol=SOCKET --socket=/tmp/mysql56.sock --user=__sandbox_probe__ --execute='SELECT 1'

Actual result:

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql56.sock' (1)

The equivalent PDO connection returns:

SQLSTATE[HY000] [2002] Operation not permitted

Workaround

Allow both path spellings and make the client use the physical path:

"allowUnixSockets": [
  "/tmp/mysql56.sock",
  "/private/tmp/mysql56.sock"
]

mysql:unix_socket=/private/tmp/mysql56.sock

After restarting Claude Code, the same sandboxed database query succeeds.

Expected behavior

allowUnixSockets should handle the standard macOS /tmp to /private/tmp symlink consistently, or the documentation should require canonical socket paths.

Related: #40672 reports a similar /tmp path issue while binding a Unix socket. This report covers connecting to an existing socket.