TL;DR: Microsoft has restructured Copilot into three core pillars (Home, Code, and Autopilot), introduced an in-chat model switcher featuring frontier models, brought Copilot in SharePoint and OneDrive to General Availability, and launched FinOps controls with usage-based “Copilot Credits.”
If you felt the summer updates were incremental, September changes the tempo completely. Following our look at the August 2026 Copilot updates, Microsoft is no longer just tweaking prompts inside sidebar panes.
Instead, the entire surface area of Microsoft 365 Copilot has received a structural redesign. The way users interact with files, how administrators budget for frontier intelligence, and how autonomous agents work in the background have all shifted into clearer focus.
If you are a SharePoint site owner, a business professional, or an IT administrator managing tenant licenses, here is what changed in September 2026 — and what you should do next.
Official Website: Microsoft 365 Copilot September 2026 Feature Roundup
What is new in Microsoft 365 Copilot this month?
September delivered substantial changes across six key areas:
- The New Copilot Experience — A unified portal organized into Home, Code, and Autopilot modes.
- Frontier Model Switcher — In-chat access to select GPT-6.1 Sol and Claude Sonnet 5.5 for complex reasoning.
- General Availability for SharePoint & OneDrive — Direct file grounding, folder queries, and natural-language site pages are now standard.
- FinOps & Copilot Credits — A split billing model separating core seat licenses from usage-based frontier compute.
- Unified Plugin & Agent Registry — Consolidated admin governance replacing the legacy agents portal.
- Enhanced Document Generation — Python-powered data transformations in Excel and storyboard creation in PowerPoint.
1. The “New” Copilot Interface: Home, Code, and Autopilot
What is the new Copilot interface?
Microsoft has moved past the era of disjointed side panels. The standalone Copilot workspace now organizes work into three distinct operational modes: Home, Code, and Autopilot.
In plain terms: you no longer have to guess whether you are chatting with a generic bot or running an automated task. You pick the mode that matches your goal.
How do Home, Code, and Autopilot work?
- Home — This serves as your daily command center. It integrates quick chat queries with “Cowork” features. You can draft an email, ask questions across your OneDrive files, or ask for a briefing on your morning schedule in a single conversation.
- Code — Built on the core technology behind GitHub Copilot, Code is tailored for citizen developers and business analysts. It lets you generate, debug, and review Power Fx formulas, DAX calculations, and Python snippets directly inside the Copilot window without opening Visual Studio Code.
- Autopilot — This is a persistent, proactive agent that works on your behalf when you are away from your desk. It watches flagged threads, prepares draft summaries before scheduled calendar reviews, and compiles daily status logs based on changes in your SharePoint libraries.
Why it matters:
- Less context switching — Business users can transition from querying internal data to building a lightweight automated formula without leaving the browser tab.
- Proactive assistance — Autopilot shifts Copilot from a passive tool that waits for prompts into a background assistant that delivers work ahead of deadlines.
2. In-Chat Model Selection: GPT-6.1 Sol and Claude Sonnet 5.5
What is the new model switcher in Copilot Chat?
Copilot Chat now features a model picker dropdown at the top of the conversation window. Eligible users can choose which underlying large language model powers their current session.
Building on earlier support for Claude models in Microsoft 365 Copilot, Microsoft has added GPT-6.1 Sol alongside Anthropic’s Claude Sonnet 5.5.
When should you switch models?
- Default Balanced Mode — Best for everyday email drafts, meeting recaps, and fast web summaries. It delivers near-instant responses with low compute consumption.
- GPT-6.1 Sol — Tailored for heavy structured data analysis, multi-layered mathematical modeling, and step-by-step logic chains.
- Claude Sonnet 5.5 — Ideal for nuanced long-form editorial writing, contract comparisons, and synthesizing dense policy documents where tone and context matter.
Why it matters:
- Tailored reasoning — You are no longer restricted to a one-size-fits-all model for both a short email reply and a 40-page contract comparison.
- Enterprise data boundaries remain intact — Regardless of which model you select, prompts and responses stay within your Microsoft 365 commercial boundary. Your corporate data is never used to train external foundation models.
3. Copilot in SharePoint & OneDrive Hits General Availability
What reached General Availability on September 30?
Copilot capabilities across SharePoint Online and OneDrive for Business transitioned from preview to General Availability (GA) on September 30, 2026.
Earlier in September, we examined the SharePoint preview features. With full GA rollout now underway across commercial tenants, these tools no longer require targeted release opt-ins.
What can users do in SharePoint and OneDrive now?
- Multi-Document Summaries in OneDrive — Select up to five PDF, Word, or PowerPoint files simultaneously and prompt: “Compare the delivery schedules and budget constraints across these three vendor proposals.” Copilot generates a side-by-side comparison table without downloading or opening a single file.
- Instant SharePoint Site Authoring — Site owners can turn raw notes or Word briefs into complete SharePoint modern pages with suggested layouts, text blocks, and web parts in seconds.
- Natural Language File Filtering — Instead of building complex metadata column filters, you can type: “Show me all signed statements of work from Q3 with values over $50,000.”
Why it matters:
- Time saved on large repositories — You do not need to scroll through 100-page slide decks to find one paragraph. Copilot finds the exact quote and provides a direct citation link.
- Permissions enforcement — Copilot strictly honors existing SharePoint permissions. If a user does not have read access to a folder, Copilot will never summarize its contents for them.
4. FinOps & “Copilot Credits”: Understanding the New Billing Model
How is Microsoft changing Copilot pricing?
Microsoft has introduced a hybrid billing architecture to accommodate heavy computational models without forcing price hikes on standard subscriptions.
Pricing is now split into two clean tiers:
- Everyday AI — Covered by the standard per-user Microsoft 365 Copilot subscription license (USL). This includes daily chat, email drafting, meeting recaps, and standard office application features.
- Advanced AI & Frontier Compute — Handled via usage-based billing through a new metric called Copilot Credits. Calling heavy reasoning models (like GPT-6.1 Sol) or running continuous Autopilot background jobs draws against this credit balance.
[IMAGE: Screenshot of Microsoft 365 Admin Center showing Copilot Credits consumption dashboard, spending limit sliders, and group quotas] Alt text: Admin center dashboard displaying Copilot Credits usage and FinOps budget controls
What controls do administrators get?
Administrators can configure detailed FinOps rules within the Microsoft 365 Admin Center:
- Monthly Credit Budgets — Set hard caps on monthly credit consumption per department or security group.
- Model Access Tiers — Restrict frontier model selection to specific business units (e.g., finance and legal) while keeping general users on standard balanced models.
- Automated Threshold Alerts — Receive automated email notifications when credit consumption hits 75% and 90% of the assigned monthly ceiling.
Why it matters:
- Budget predictability — Finance leaders can lock in fixed monthly thresholds, eliminating the risk of unexpected cloud billing spikes.
- Fair resource distribution — Ensures compute resources are allocated where advanced reasoning delivers the highest business return.
5. Unified Plugin & Agent Registry
What happened to the old “Agents” tab in the admin center?
On September 30, Microsoft retired the standalone “Agents” overview tab and replaced it with a consolidated Plugin & Agent Registry in the Microsoft 365 Admin Center.
If your organization has built custom agents or deployed connectors — similar to the architectures discussed in our guide on enterprise-scale Copilot connectors — this new registry is where all lifecycle management now occurs.
What does the unified registry provide?
- Centralized Security Scanning — Every published agent, declarative copilot, and API plugin is evaluated against automated Microsoft security baselines before user deployment.
- Granular Deployment Scopes — Target agents to individual users, security groups, or the entire tenant with a single policy toggle.
- Important Governance Deadline: Tenant administrators have until October 25, 2026 to review their agent upload settings. After this date, unverified third-party agent sideloading will be disabled by default across all commercial tenants.
6. App Updates: Excel and PowerPoint Upgrades
Excel: Python-Powered Copilot Analysis
Copilot in Excel now supports advanced Python calculations out of the box for commercial tenants. You do not need to install Python locally or manage environments.
You can ask: “Create a correlation matrix between marketing spend and regional churn, and plot an outlier scatter chart.” Copilot writes the Python code, executes it in a secure Azure sandbox, and renders the chart directly into your Excel grid.
PowerPoint: Narrative Storyboard Builder
Creating presentations from scratch often leads to generic bullet points. The updated storyboard engine lets you point Copilot to an existing Word proposal or a recorded Teams meeting transcript.
Copilot builds a coherent multi-slide narrative arc, suggesting slide titles, key talking points, and layout structures that follow your organization’s custom brand template.
Microsoft 365 Copilot September 2026 — Summary
| Update | What it does | Why it matters |
|---|---|---|
| Home, Code & Autopilot | Organizes Copilot into three dedicated operational modes | Simplifies user workflows and introduces background task execution |
| Model Switcher | Adds in-chat selection for GPT-6.1 Sol and Claude Sonnet 5.5 | Delivers deep reasoning for complex tasks while protecting enterprise data |
| SharePoint & OneDrive GA | Brings multi-file summaries and page authoring to general availability | Speeds up document retrieval with strict adherence to tenant permissions |
| FinOps & Copilot Credits | Introduces usage-based billing controls for heavy AI workloads | Protects IT budgets while giving power users access to frontier intelligence |
| Unified Agent Registry | Consolidates agent security, compliance, and deployment controls | Provides audit visibility ahead of the October 25 governance deadline |
| Excel Python Integration | Runs server-side Python data analysis via natural language | Allows non-technical analysts to run statistical models without writing code |
What this means for administrators
If you manage a Microsoft 365 tenant, here are three actions to prioritize this week:
- Review Copilot Credit Allocations Open the Microsoft 365 Admin Center → Billing → Copilot Credits. Set baseline spending limits before power users start running heavy model workloads.
- Prepare for the October 25 Agent Upload Deadline Check Settings → Integrated Apps → Copilot Plugins & Agents. Decide whether standard users should be allowed to install external agents or if your IT team will enforce strict centralized approvals.
- Audit SharePoint Permissions Because Copilot in SharePoint is now generally available, any overshared files (such as confidential folders set to “Everyone except external users”) will become instantly discoverable via natural language prompts. Run a SharePoint access governance review on sensitive document libraries.
What site owners and business users should do next
You do not need to master every new setting on day one. Start with these practical steps:
- Try multi-document queries in OneDrive — Pick two project reports or invoices next time you need a comparison. Prompt Copilot to highlight differences rather than reading both line by line.
- Test the model switcher on a hard problem — If you are drafting a detailed policy or untangling nested financial data, switch from the default model to Claude Sonnet 5.5 or GPT-6.1 Sol to see the difference in reasoning depth.
- Explore Autopilot for meeting preparation — Allow Autopilot to scan your upcoming week and compile an executive briefing on ongoing discussion threads.
The bigger picture: Moving from Chat to Cowork
These updates show a clear strategic direction from Microsoft:
- Before: Open a sidebar → type a question → copy the text → paste it into your document.
- Now: Delegate an objective → Copilot coordinates across files, models, and apps → review the finished output.
Copilot is evolving from a reactive writing assistant into a collaborative workspace. Those who establish sound governance and adopt structured prompt habits today will see the greatest productivity dividends tomorrow.
FAQs: Microsoft 365 Copilot September 2026
Do I have to pay extra for the new Home and Autopilot modes?
No. Home and basic Autopilot features are included as part of your standard Microsoft 365 Copilot per-user subscription license. Only advanced frontier model runs draw from usage-based Copilot Credits.
Can external models access my internal company data?
No. Whether you select GPT-6.1 Sol or Claude Sonnet 5.5, the models run within Microsoft’s commercial data protection boundary. Your prompts and business data are never retained or used to train public AI models.
Is Copilot in SharePoint turned on automatically?
Yes. Since reaching General Availability on September 30, Copilot is enabled for all licensed Microsoft 365 Copilot users across your SharePoint sites. Users only see content they already have permission to access.
What happens if our organization runs out of Copilot Credits?
Users will simply fall back to the default balanced model for everyday chat and document generation. Core Copilot features will not stop working; only frontier model calls and high-compute jobs will pause until credits are replenished or reset.
Where do I manage user permissions for custom agents?
You can manage all internal and third-party agents in the new Unified Plugin & Agent Registry, located under Settings → Integrated Apps in the Microsoft 365 Admin Center.
Does Python in Excel require Python to be installed on local computers?
No. Python code generated by Copilot runs securely in cloud containers hosted on Microsoft Azure, with results and charts returned seamlessly to your spreadsheet.
