The GPT-5.6 model family is now available in Kiro, AWS's software development agent designed to bring engineering rigor and quality to AI-native coding at scale. This update introduces OpenAI's latest flagship model series-Sol, Terra, and Luna-into the development workflows where teams plan, build, review, and test software. Together, these models aim to help developers produce higher-quality code with fewer iterations and better value per token.
GPT-5.6 is designed to deliver more useful work from every token, offering stronger performance per dollar and on-demand capability for complex tasks. Within Kiro, developers can apply these capabilities to long-running development work grounded in their requirements, codebase, and team standards.
Kiro converts high-level intent into clear requirements, technical designs, and executable tasks. This structured context helps GPT-5.6 understand what a team is building, how the system should work, and what the final implementation needs to accomplish.
With GPT-5.6 in Kiro, developers can:
- Turn product ideas and requirements into structured implementation plans.
- Complete complex, multi-step coding tasks with greater consistency.
- Bring structure to AI coding with spec-driven development.
- Work with context from across their codebase and established team standards.
- Review and refine the model's work at key checkpoints before changes are implemented.
- Check correctness of implementation using property-based testing.
OpenAI and AWS have collaborated to optimize the Kiro environment and OpenAI's 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, enabling it to arrive at working solutions faster with fewer missteps. For developers, that translates to more finished work, less wasted effort, and better value from every coding session.
"We are always looking to make the latest foundation models available to developers and expand their options to accelerate AI-native development using Kiro. We are excited to add the GPT-5.6 family of models to power complex and long-running development tasks in Kiro." -Swami Sivasubramanian, Vice President, Agentic AI, AWS
"By bringing the GPT-5.6 family to Kiro, developers gain more room to match intelligence, speed, and cost to each stage of the software development lifecycle. Together with AWS, we're helping teams get more from every dollar they invest in AI while moving faster when time matters." -Colleen Kapase, Vice President of Strategic Global Partnerships and Ecosystems, OpenAI
OpenAI and AWS plan to continue working together to improve the performance of OpenAI's models in Kiro and help developers extract more value from AI across the software development lifecycle.
The GPT-5.6 family is available in Kiro. Developers can get started at https://kiro.dev/.