We’re living in an exciting new era of productivity AI. With Microsoft’s continued investment, the Microsoft 365 ecosystem is becoming smarter and more connected than ever - from Copilot in the apps we know and love, like Word, Excel, Outlook, and Teams, to new experiences such as Copilot Create, Pages, and Notebooks, which help users turn ideas into action, explore concepts, and organise work more intelligently.

Alongside these tools, Copilot also introduces Microsoft-built and custom agents that can automate processes, surface insights, and connect your organisation’s data in powerful new ways.

At the heart of it all are the AI models that power these capabilities. Here’s what you need to know - which models are available, what they excel at, and how Microsoft’s new multi-model approach gives you more flexibility and choice than ever before.

💼 What is Microsoft 365 Copilot?

Microsoft 365 Copilot is more than an assistant inside your apps - it’s an intelligent layer that connects your work, data, and creativity across the Microsoft 365 ecosystem.

It helps you create, analyse, summarise, and automate tasks across your favourite apps, while also serving as a hub for ready-made Copilot agents and custom ones built through Copilot Studio. Meanwhile, new tools like Copilot Create, Pages, and Notebooks empower users to build content, plan projects, and experiment with prompts in entirely new ways.

Behind it all, Copilot brings together your organisational data through the Microsoft Graph and powerful large-language models - and now, Microsoft gives you the freedom to choose which AI model powers your experience.

🤖 The Models Available - and What They Do

Here are some of the key AI model options now available in Microsoft 365 Copilot and Copilot Studio, and how to think about choosing between them.

Open AI's GPT-4 (And earlier OpenAI models) ⚙️

The “classic” foundation. The earlier version of Copilot was powered by models built initially on GPT-4.

What it's good for:

• Trusted general-purpose tasks: drafting, summarising, conversational Q&A.

• Strong at many language tasks, with good balance of speed and accuracy.

When you might choose it:

• If you want reliability and broad support.

• For everyday productivity workflows where you don’t need ultra-specialised reasoning.

Open AI's GPT-5 🚀

Microsoft officially started rolling out GPT-5 in Copilot starting August 2025.

What's new / what it adds:

• Smart mode that dynamically routes your prompt to the best model for the task.

• Better at longer, more complex interactions, deeper reasoning, and cross-context understanding.

When you might choose it:

• When you want higher-end reasoning and richer context awareness.

Anthropic's Claude Models (Sonnet, Opus) 🌐

Microsoft no longer limits itself to OpenAI. Alongside GPT, you can now choose models from Anthropic - Claude Sonnet 4 and Claude Opus 4.1.

What they introduce:

• Specialist reasoning and strong performance in structured tasks.

• Flexibility for agent creation in Copilot Studio.

When to choose them:

• When building custom agents or experimenting with alternative reasoning styles.

• When you want vendor diversity or different response behaviour.

🎯 How to Decide: Which Model for Which Job?

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Key takeaway: there’s no one “best” model - the right choice depends on your task, data, goals, and preference.

🤝 Why Model Choice Matters - and Why Microsoft is Opening Up

• Flexibility & control: Choose the model that fits your workflow.

• Performance optimisation: Some models excel at language, others at logic.

• Innovation: Microsoft’s open approach invites more partners, driving faster improvement.

• Customisation: Copilot Studio lets you build and tailor agents with your preferred model.

• Experimentation: Compare models safely within the Microsoft ecosystem.

💡 What This Means for Your Business

• You’re no longer tied to one AI model - you have options.

• Identify a few use-cases to start testing (reports, emails, meetings).

• Experiment with both GPT-5 and Claude models to see which aligns best.

• Scale what works, govern what you build, and train users effectively.

• Review regularly - AI models evolve fast, and flexibility keeps you ahead.

✨ Adopt AI, Embrace Copilot

Copilot is more than a license - it’s a strategy. At Mondo Cloud, we specialise in helping businesses like yours adopt Microsoft 365 Copilot and Copilot Chat securely and effectively. From assessing your environments readiness for AI and implementing data security controls, to running training & enablement programs, we’ve got you covered every step of the way.

📨 Get in touch to discuss how we can help you unlock the full potential of Copilot and achieve a seamless AI-powered transformation.

• info@mondocloud.co.uk

• 0800 640 4258