Microsoft has just announced the availability of Claude Sonnet 4.5, Anthropic’s most advanced AI model, in Microsoft Copilot Studio. This significant development, rolling out on September 28, 2025, marks a pivotal moment in Microsoft’s commitment to providing multi-model flexibility within its AI ecosystem.
The Multi-Model Revolution
The integration of Claude Sonnet 4.5 represents more than just another model option; it signals Microsoft’s strategic shift toward providing organisations with unprecedented choice in AI model selection. This move directly challenges the traditional single-vendor AI approach, positioning Copilot Studio as a truly flexible platform where businesses can select the optimal model for their specific use cases.
Claude Sonnet 4.5 will replace Claude Sonnet 4 in Copilot Studio and can be selected for orchestration tasks immediately. Organisations that have already opted into using Anthropic models require no additional action. New adopters can easily enable access through the Microsoft Admin Centre.
Why This Matters for Enterprise AI
Anthropic positions Claude Sonnet 4.5 as the world’s best coding model and the strongest model for building complex agents. The model demonstrates exceptional capabilities in:
- Advanced reasoning and mathematics with substantial improvements over previous versions
- Computer use capabilities, achieving 61.4% on OSWorld benchmarks, a significant leap from the previous 42.2%
- Long-horizon task execution, maintaining focus for over 30 hours on complex, multi-step processes
For Copilot Studio users, this translates to more sophisticated agent behaviours, better code generation, and enhanced problem-solving capabilities that can tackle enterprise-scale challenges with greater precision.
Strategic Timing and Market Impact
The timing of this announcement is particularly strategic. Coming just days after Anthropic’s launch of Claude Sonnet 4.5, Microsoft’s rapid integration demonstrates its commitment to staying at the forefront of AI innovation. This multi-model approach allows organisations to:
- Match the right AI model to specific business scenarios
- Reduce vendor lock-in by maintaining flexibility across AI providers
- Future-proof their AI investments as new models emerge
Looking Forward: October Updates and Beyond
While Claude Sonnet 4.5 is immediately available for orchestration, availability from the prompt builder will arrive later in October. This phased rollout ensures stability while expanding the model’s accessibility across Copilot Studio’s comprehensive feature set.
The integration also builds on Microsoft’s broader AI strategy announced at Build 2025, which includes multi-agent orchestration, enhanced security features, and expanded connectivity through the Model Context Protocol. These combined capabilities position Copilot Studio as a comprehensive platform for enterprise AI deployment.
The Competitive Landscape Shift
This development represents a significant shift in the enterprise AI landscape. By embracing multiple AI providers within a single platform, Microsoft is responding to the demands of enterprises for flexibility and best-of-breed solutions. Organisations no longer need to choose between platforms based solely on their default AI models; they can now leverage the strengths of different models within a unified development environment.
For businesses building AI agents and workflows, the arrival of Claude Sonnet 4.5 in Copilot Studio offers immediate access to state-of-the-art capabilities without the complexity of managing multiple AI platforms. This integration exemplifies how the enterprise AI market is evolving toward collaborative ecosystems rather than competitive silos.
The availability of Claude Sonnet 4.5 in Copilot Studio marks a transformative moment for enterprise AI development, offering organisations the flexibility to choose the most appropriate AI model for their specific needs while maintaining the security, governance, and integration capabilities that Microsoft’s platform provides.
