You'll notice
Custom output styles can't be selected or changed over Remote Control or in relayed sessions
What
Claude Code now blocks selecting a custom (non-built-in) output style when connected through Remote Control or via a relayed message, showing the message: "Custom output styles can't be selected over Remote Control or from a relayed message. Select one in the session itself, or pick a built-in style here." It also now blocks changing output styles at all from sessions that don't load local settings.
Why
Custom output styles depend on settings stored locally, so a remote or relayed session that doesn't have access to those local files can't safely apply one; built-in styles remain available in those cases.