'\n The model used by the research agent. Can be "mini",
"pro",
or "auto".\n "mini" is optimized for targeted,
efficient research and works best for narrow or well-scoped questions. \n "pro" provides comprehensive,
multi-angle research and is suited for complex topics that span multiple subtopics or domains.\n "auto" lets Tavily automatically determine the appropriate model based on the task complexity.\n Default is "auto".\n '
