List the refinement dimensions (specializations, practice areas, service types, service modes, etc.) available for a specific subcategory. Call this BEFORE search_businesses when the user's request is broad (e.g. 'therapist in Greece', 'lawyer in London') so you can politely ask the user whether to narrow by any of these dimensions — and always offer them the option to see all results without filtering. Returns the attributes defined for the vertical with their possible option values, plus the universal serviceMode options. If refinementAvailable is false, skip refinement and go directly to search_businesses.
Connector