By skyforbes 
OpenAI launches GPT-5.1 with adaptive reasoning and personality controls. Here’s what changed on November 12, 2025 and how to use it today.
TL;DR: What You Need to Know
ChatGPT’s GPT-5.1 launched November 12, 2025 with adaptive reasoning (Instant model now “thinks” on complex queries), GPT-5.1 Auto routing system, and 8 personality modes. Three personalities are new: Professional, Candid, and Quirky. Paid users get immediate access; free users follow within weeks. All changes apply instantly to existing conversations. Performance: 2x faster on simple tasks, 2x more thorough on complex problems.
What Is GPT-5.1? The Three-Model System
OpenAI’s latest release includes three interconnected models:
GPT-5.1 Auto (The Router)
Automatically selects between Instant and Thinking based on query complexity. You don’t control which runs — the system decides intelligently. This fixes GPT-5’s unpredictable routing that frustrated users.
GPT-5.1 Instant