What happened
OpenAI announced GPT 5.6 as the "preferred model" for Microsoft 365 Copilot, integrating its latest model into productivity applications including Word, Excel, PowerPoint, and Cowork. This follows recent Bloomberg reports that Microsoft was deploying its in-house MAI models to reduce costs. OpenAI stated the partnership continues to bring advanced AI benefits to individuals and organisations, reaffirming its software will power Microsoft's apps.
Why it matters
This announcement indicates the continued role of OpenAI's frontier models for core Microsoft 365 Copilot functionality, despite Microsoft's internal AI development efforts. The continued designation of an external model for core functionality means Microsoft's cost-reduction strategy, which involves deploying in-house models, is not yet fully realised for Copilot. Platform engineers integrating Copilot features should anticipate a hybrid model landscape, balancing external API dependencies with potential internal model deployments.
