Definition: GPT-5

(Generative Pre-trained Transformer-5) A major upgrade to ChatGPT from OpenAI. Introduced in 2025, GPT-5 was designed to improve in all areas of AI, including creative writing, content and code creation, health analysis, as well as overall execution speed (see AI training vs. inference). GPT-5 also has built-in Web search and generates fewer errors. See GPT.

Less Sycophantic
GPT-5 was designed to not heap as much praise on the user; for example, a bit less of "great question, you're really getting this."

Some Bumps in the Road
The initial reaction to GPT-5 has been mixed, especially in coding skill. However, people have also complained that it is flawed in other areas, including storytelling and counseling. Stay tuned.

A Unified System
GPT-5 is a unified system that automatically selects the best model based on the prompt submitted. Previously, users had to select the model they thought fitted the occasion. Following are the GPT-5 models:

   Model                Attributes

   GPT-5.1              more "empathetic"

   GPT-5                all purpose

   GPT-5-mini           smaller, cost efficient

   GPT-5-nano           ultra lightweight and fast

   GPT-5-thinking       deep multi-step reasoning

   GPT-5-thinking-mini  lightweight reasoning

   GPT-5-thinking-nano  fastest minimal version

   GPT-5-thinking-pro   speed and depth
                        (ChatGPT Pro subscription)

   GPT-5-chat           optimized for conversation

GPT-5.5 (Refinements)
In 2026, GPT 5.5 added more refined capabilities. It is able to allocate more processing to difficult tasks and handle huge prompts better, and it is able to use external systems more effectively. Although not officially confirmed, GPT 5 models are likely trained on trillions of tokens.