How the agent-start command is quoted for the login shell OpenSSH uses on the Windows agent (its DefaultShell registry value). Jenkins starts the agent with a cd "<dir>" && java ... command; && is valid in Command Prompt and PowerShell 7 but not in Windows PowerShell 5.x.

• Auto-detect (recommended): probes the agent's shell once at launch and wraps the command only if the shell rejects &&. Leave this selected; the options below are manual overrides.
• Command Prompt (cmd.exe): the OpenSSH default when no DefaultShell is set. Runs the command as-is (no wrapping).
• PowerShell: wraps the command as cmd /c '<command>' so it is handed to cmd.exe as a literal string. Needed for Windows PowerShell 5.x (which rejects &&) and also works for PowerShell 7.

Only applies to Windows agents.