AI News Flash: OpenAI released a ‘GPT-5.6 Builder’s Guide’ aimed at startups, showing how to use the new generation of models to build faster, more cost-effective AI agent systems. The guide focuses on two key areas: ‘intelligent model selection’ strategy, which helps dev teams dynamically route different model tiers based on task complexity to avoid the cost waste of applying the top-tier model to every request; and the newly launched Responses API, which offers a more complete interface for building AI agents. The guide primarily targets startups, emphasizing how to balance development speed with operating costs under limited resources. Since the original summary only provides a high-level directional description without specific pricing figures, API spec details, or performance comparison data, see the original link for full details.