Claude Sonnet is the strongest fit for triaging support tickets, assigning labels, and drafting responses. Its instruction-following and tone-matching capabilities make it reliable for classifying tickets into consistent label sets and generating on-brand reply drafts at scale via the API or in the chat interface. Claude Haiku is a faster and cheaper alternative when ticket volume is high and response quality requirements are moderate. ChatGPT is worth considering if you prefer OpenAI's ecosystem or need GPT-4o's function-calling to integrate with a helpdesk platform. Gemini Flash works well as a free-tier option for lighter workloads where cost is the primary constraint.