ChatGPT adds Auto-switch, Fast answers settings

OpenAI is prioritizing "routing as a feature," allowing the system to dynamically allocate compute based on the complexity of the user's intent. Auto-switch eliminates manual toggling by automatically selecting the required reasoning level, while the new Fast answers mode provides sub-second latency for factual queries. The shift to GPT-5.5 Instant as the default model suggests a significant efficiency leap, and new controls for "Thinking Effort" allow users to granularly budget compute for deep reasoning.