What
The advisor is a second model Claude Code can consult, and a standby advisor model is used when the main choice is unavailable. Claude Code now checks the first matching standby model against the models your organisation has access to. This check applies only when you connect directly to Anthropic.
If your organisation is not known to serve that model, no standby is used. Claude Code writes a line to its debug log (a detailed record for troubleshooting) instead of falling back to that model.
Why
This stops Claude Code from falling back to an advisor model your organisation cannot use.