Microsoft made OpenAI’s deep reasoning O1 model available free to all Copilot users in July 2026, removing paywalls around reasoning-class AI models. The move represents a strategic shift: reasoning models are now table stakes, not premium features.

Copilot Chat now includes GPT 5.5 Thinking, a model designed for multistep reasoning and structured analysis. Users can follow the chain-of-thought, seeing how the model arrived at its answer. That transparency matters for professional users who need to verify logic, not just get answers.

SharePoint Gets Native O1 Integration

Copilot in SharePoint now runs on the latest reasoning OpenAI model for everyone without a fallback to lighter models. The integration means enterprise users working with large documents can get deeper analysis without waiting or changing tools.

For reasoning tasks, Copilot shows its working. That’s different from older models that gave answers without explanation. Users can validate the reasoning chain and catch errors the AI might have missed.

Microsoft 365 Declarative Agents Use GPT-5.1

Microsoft 365 Copilot declarative agents now default to GPT-5.1 with automatic model selection. The company is moving toward letting different tasks pick their own models based on complexity, rather than forcing one model for everything.

Competitive Pressure From DeepSeek

The timing of making O1 free comes as DeepSeek’s reasoning models generate buzz in the market. Microsoft is signaling that it won’t lose users to cheaper alternatives by keeping advanced reasoning models exclusive or expensive.

Making reasoning models free to all Copilot users is Microsoft betting that reasoning is the future of AI productivity, not a premium feature.

References

Microsoft Community Hub. (2026). What’s new in Copilot in SharePoint: July 2026. Published July 2026.
Cloud Wars. (2026). OpenAI’s deep reasoning o1 models available for free to all Copilot users. Published July 2026.