Under the hood
fork_conversation requests now get a clear 'unsupported' response instead of a generic bridge error
What
The REPL control bridge (used by applications embedding Claude Code) previously returned a generic 'REPL bridge does not handle control_request subtype' error for any request type it didn't recognize, including fork_conversation. Now fork_conversation is explicitly handled and always returns {forked: false, error: "unsupported", reason: "requires_remote_control_server"}.
Why
This gives embedding applications a clear, specific reason when they attempt to fork a conversation: the feature requires a remote control server, rather than a vague 'not handled' error that doesn't explain why.