On day one of it’s release, Microsoft has now rolled out support for Claude Opus 4.8 across Microsoft 365 Copilot for most commercial customers.
This latest version of Opus is available across Researcher, Copilot Chat, Cowork, Edit with in Office Apps and Copilot Studio, GitHub Copilot and Foundry.
Claude Opus 4.8 improvements
According to Anthropic, Opus 4.8 is positioned as a more capable, more reliable, and more agent‑ready model where they highlight improvements in:
- long‑context reasoning
- structured analysis
- tool‑use and agentic behaviour
- consistency across multi‑step tasks
Claude Code has a new “dynamic workflows” feature that allows it to tackle very large-scale problems. And fast mode for Opus 4.8—where the model can work at 2.5× the speed—is now three times cheaper than it was for previous models.
ANTHROPIC
For M365 Copilot users, this should result in:
- stronger research and synthesis in the Researcher agent
- more dependable reasoning in documents and spreadsheets
- better performance in multi‑step workflows
- a second high‑quality model option for creators and admins.
Where Claude Opus 4.8 “Shows Up”
You will find that in some Copilot experiences, there will be a choice of using Opus 4.8 or staying with the older versions and of course GPT Models. Office Apps like Excel, Word, PowerPoint are examples). In CoWork, Opus 4.7 is no more and this has been replaced with 4.8. Copilot Chat (at time of writing was not showing an option to use 4.8 but I suspect this will change over the next day or so. Copilot Studio retains the older versions.
Users may seen “changes in behaviour” which can affect scheduled prompts and output generation (hopefully for the better), but be aware that in Office apps and Chat, eventually older models “do” get retired.
Note: If you have agents built in Copilot Studio, the new Opus models will NOT automatically be updated in your agents, giving you time to test the next models ensuring your agents do not break or change behaviour!
Availability and Admin Controls
Microsoft is enabling Anthropic models on by default for most commercial tenants outside the EU/EFTA and UK
In these regions, Claude is off by default, with admins able to opt in.
Currently, Government and sovereign clouds remain excluded but updates to this are expected soon.
Admins can manage Claude model access through a couple of places
- Microsoft 365 admin center
- Power Platform Admin Center
This keeps control firmly in the hands of IT, while still making the capability broadly accessible.
Why This Matters for Business
Claude 4.8’s arrival reinforces Microsoft’s speed to market (available on day of release) and direction of travel.
- Choice: organisations can select the model that best fits the task
- Resilience: Microsoft’s multi‑model approach reduces dependency on a single provider
- Capability: Claude brings strengths in reasoning and agentic tasks
- Compliance: all models are wrapped in Microsoft’s enterprise data protection and privacy guarantees
Copilot is firmly a model‑agnostic productivity platform, not a single‑vendor solution. Whilst M365 Copilot supports both Open AI and Claude, whilst Copilot Studio and Azure AI support dozens of different vendors and models.
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