The GPT‑5.6 model family is now available in Kiro, a software development agent that brings engineering rigor and quality to AI-native coding at scale. For Kiro users, the update brings Open AI’s latest flagship model series, including Sol, Terra, and Luna, into the development workflows where teams plan, build, review, and test software.

Together, these models can help developers produce higher-quality code with fewer iterations and better value per token. GPT‑5.6 delivers more useful work from every token, with stronger performance per dollar and on-demand capability for complex tasks. In Kiro, developers can apply these capabilities to long-running development work grounded in their requirements, codebase, and team standards.

Open AI and AWS have also worked together to optimize the Kiro environment and Open AI models. Testing found that on Terminal-Bench 2.1, GPT‑5.6 Terra completed successful tasks in Kiro at roughly 82% cost reduction. Kiro’s spec-driven approach grounds the model in clear requirements, technical designs, and task context from the start, so it arrives at working solutions faster, with fewer missteps along the way.