Although the company has not disclosed many details, a number of early users have already started sharing their first impressions of the new model.

According to most feedback, GPT-5.6 represents a significant step forward compared with GPT-5.5, especially in programming, computer use and AI-agent orchestration. Many issues that appeared in GPT-5.5 have been fixed, the model performs more reliably in long-running tasks and is better able to coordinate multiple tasks at the same time.

 

Developer Theo Browne, known from t3.gg, said GPT-5.6 could become his default choice for most programming work thanks to its agent-orchestration capabilities and strong understanding of software-development workflows. He also described it as one of the strongest models currently available for computer control.

 

Meanwhile, professor Ethan Mollick noted that GPT-5.6 has power comparable to Fable but with a completely different style. According to him, GPT-5.6 is well suited for work that requires continuous interaction between humans and AI, while Fable performs better on long tasks with clearly defined goals that can be completed autonomously over an extended period.

 

Researcher Matt Shumer, however, said GPT-5.6 still does not surpass Fable on complex problems. According to him, tasks that Fable can complete in a single pass often require several rounds of interaction with GPT-5.6. Even so, he still considers GPT-5.6 a major leap forward compared with GPT-5.5.

Other testers also praised GPT-5.6 for its speed, creativity and improved programming quality, although they noted that the model still has several areas that need improvement.

Fable Is Still Seen as a Strong Rival

Although GPT-5.6 has received considerable praise, most reviews suggest that Fable remains the model with the strongest autonomous capabilities today. Fable’s advantage lies in its ability to plan and complete long tasks with very little human intervention, while GPT-5.6 is more oriented toward step-by-step collaboration with users.

Based on the early reviews, the current picture can be summarized as follows:

Fable: strongest in autonomy and long-task execution.

GPT-5.6 Sol: more balanced, suitable for programming, collaboration and AI-agent orchestration.

GPT-5.5: now significantly behind GPT-5.6.

Many experts also believe that the competition between OpenAI and Anthropic is entering a new phase. Previously, models mainly competed on their ability to answer questions, but now the biggest differentiator is autonomy — how well AI can plan, break down work and complete tasks without requiring users to guide it step by step.