MCP server access: Claude, ChatGPT and Copilot in Microsoft 365
Compare Claude, ChatGPT and Copilot connections to Microsoft 365. See how access, write actions and approval differ, with a 100-person cost table.
By Ivan Pylypchuk (opens in a new tab), CEO of Softblues. Checked 12 October 2026.
For a Microsoft-first firm, start with the access already governed in Microsoft 365. Add Claude or ChatGPT where a specific job benefits, then approve reading and changing records separately. An MCP server makes tools available to an assistant; it does not decide who should use them or which business decisions they may commit.
Softblues (softblues.io) is a London AI adoption partner helping UK and Irish firms become AI-native across Copilot, Claude, ChatGPT and custom agents. This comparison is for leaders choosing how staff reach company information, with a named person still responsible for the work.
Key facts
What is an MCP server in plain English?
It is a service that exposes defined tools to an AI assistant through the Model Context Protocol. A tool might retrieve an invoice or prepare an update to a client record. The assistant requests an operation; the connected service and its permissions determine what can happen.
That distinction matters when an IT director hears "we support MCP". The useful follow-up is to ask which operations are exposed, whose account they run under, and which changes require approval. A connector catalogue cannot answer those questions for your deployment.
For a 100-person accountancy or advisory firm, consider preparing a client review pack. Staff find the engagement letter, read relevant correspondence, check an outstanding task and draft a note. Sending that note or changing the client record adds a different responsibility. Buying access to the documents does not settle it.
Our MCP introduction for UK businesses explains the connection itself. This comparison focuses on the tenant decision: which platform can reach the work, and what stops it going further than intended.
How do the three routes compare?
Compare the actual connection and workflow, rather than awarding one platform a universal read/write tick. Copilot's in-suite assistant and a Copilot Studio agent are different surfaces. ChatGPT's live access and synced index are also different configurations.
| Decision | Microsoft 365 Copilot and Studio | Claude Team and Enterprise | ChatGPT Business and Enterprise |
|---|---|---|---|
| Company information | Microsoft 365 grounding follows existing access. Studio adds configured tools. M3 M2 | Microsoft 365 connector reaches SharePoint, OneDrive, Outlook and Teams. C1 | SharePoint includes supported work OneDrive content; Outlook has separate apps. O3 O4 |
| Who enables it | Tenant governance plus Studio connection and environment setup. M1 M2 | Claude owner and Entra Global Administrator for the Microsoft 365 connection. C1 | Workspace administrator and Microsoft consent authority; custom MCP deployment is admin-controlled. O3 O2 |
| Action controls | Power Platform data policies govern connector use in Studio. M1 | Read and write scopes, organisation controls and individual Teams send confirmations. C1 C2 | Available actions and confirmation permissions are distinct; controls vary by app. O1 |
| Data route | Review Microsoft 365 commitments and every additional Studio connection. M3 M2 | Anthropic-hosted proxy; retrieved tool results can remain in stored chats. C2 | Live SharePoint access and administrator-managed indexing are separate routes. O3 |
| Price basis | Named Microsoft subscription, then any additional usage and connector costs. M4 | Team seat subscription; Enterprise seat plus API-rated usage. C4 | Business seat subscription; confirm Enterprise commercial terms separately. O5 |
| Availability | Published Studio MCP connection path uses Streamable transport; check the chosen feature's release status. M2 | Microsoft 365 available on both plans; managed authorisation is generally available for supported connectors. C1 C3 | Custom MCP writes are beta on Business and Enterprise web. O2 |
| Honest limit | A blocked connector prevents the corresponding MCP tools from working. M1 | SharePoint search cannot be restricted to specific sites through this connector's search setting. C1 | SharePoint sync needs an eligible Enterprise workspace and supported region; a personal connection is not a synced index. O3 |
Get the deck: AI-native on Microsoft: Copilot and Claude works through the paired-platform decision. Use it to decide which staff need a second assistant before widening access.
When should a Microsoft-first firm start with Copilot?
Start there when the job is already in Microsoft 365 and the licensed capability meets the requirement. Existing permissions still need attention: an assistant that respects access can surface a file that was shared too widely. Permission inheritance cannot repair that source mistake. M3
For a Studio agent, Microsoft documents MCP connections through an onboarding wizard or a custom Power Platform connector. That gives the IT team an existing policy mechanism to inspect. It does not remove the need to configure authentication and test the tool. M2
The useful fact is narrower than "our DLP blocks MCP". A data policy can block the connector the MCP server depends on. Blocking an unrelated social connector says nothing by itself about a new connection. Check the actual connector and policy scope. M1 M5
In the client-pack example, let the assistant assemble a draft with source references. The responsible adviser checks the content and decides whether it can be sent. Test that boundary with a deliberately disallowed action, not only a successful demonstration.
When is Claude worth adding?
Consider Claude when a defined group's document analysis or working method justifies another assistant. Its Microsoft 365 connection uses delegated permissions. Team and Enterprise owners enable it, while Microsoft consent is handled in Entra. Keep that approval work in the implementation plan. C1
One operational detail changes the client-pack design: the documented write tools reject email attachments. A workflow that must send a pack as an attachment needs another approved sending step. A SharePoint link may be appropriate, but check the recipient's access before adopting that alternative. C2
Managed authorisation is useful for supported connections, with Okta listed as the launch identity provider. Do not promise that this replaces the Microsoft 365 setup: Microsoft's connector is not in the supported list on that managed-authorisation page. C3
Our recommendation is to prove one document workflow before extending it. Keep a reviewer responsible for the final interpretation. Measure the effort to produce an accepted pack, including corrections and approval, so a polished draft does not conceal extra checking work.
When is ChatGPT worth adding?
Consider ChatGPT where the team needs its mix of analysis and connected tools, then inspect the specific app. SharePoint's live route can expose supported file and content actions when the required permissions and workspace actions are enabled. Indexing is a separate decision. O3
OpenAI's administration guidance separates who can use an app, what actions it exposes, and when confirmation is requested. "Allow read actions" describes confirmation behaviour; it does not by itself remove every write capability. Set the action controls as well. O1
For a bespoke connection, full MCP support remains beta. Business administrators can now refresh a published custom app's tool list without recreating it. Enterprise adds further access and action controls. This corrects older guidance that treated a Business app as impossible to update in place. O2
For our client pack, test retrieval against a known set of documents and save the sources beside the draft. If a required record is missing, stop and show the gap. A fluent summary should never be the evidence that the search was complete.
What would this cost a 100-person UK firm?
Separate subscriptions, consumption and implementation. The following is arithmetic on public list prices checked on 12 October 2026, not a like-for-like quote or a claim that every employee needs every product. Start your own value assumptions with the whole-firm AI ROI calculator.
| Subscription scenario | 100 seats | What to add or check |
|---|---|---|
| Microsoft 365 Business Premium with Copilot, £24.60 per user/month, paid yearly | £2,460 monthly equivalent; £29,520 yearly, excluding VAT | This is the named bundle, not an incremental Copilot add-on price. Reconcile existing contracts. M4 |
| Claude Team standard, $20 per seat/month billed annually | $2,000 monthly equivalent; $24,000 yearly | Compare required usage and controls. Monthly billing is $25 per standard seat. C4 |
| Claude Enterprise advertised seat component, $20/month billed annually | $2,000 monthly equivalent before usage | API-rated usage is additional; confirm contract and required administration features. C4 |
| ChatGPT Business standard, $20 per seat/month billed annually | $2,000 monthly equivalent; $24,000 yearly | Monthly billing is $25 per standard seat. Enterprise needs a separate quotation. O5 |
Dollar figures remain dollars to avoid presenting an undated exchange rate as a UK quote. Taxes and local billing can differ. Do not add these rows together and call the result an adoption budget.
A connection also needs ownership: permission review, testing and maintenance when a tool changes. Ask for those costs separately from licence charges and usage. Implementation scope and price follow paid discovery; a connector label is not enough to estimate the work.
How should access and residency be reviewed?
Write the data route down. Include the original Microsoft file, content retrieved by the assistant, conversation storage, any search index and the destination of changes. "The file stays in SharePoint" describes the source location, not every copy or processing step. Claude's security documentation explicitly distinguishes on-demand retrieval from results retained in stored chats. C2
For Microsoft, review the applicable Microsoft 365 commitments and each external connection separately. For ChatGPT, check whether the intended region supports the chosen sync route. A UK Microsoft tenant does not establish the location of every connected service. Treat residency as a documentation task, not a legal barrier; have the responsible team assess the actual arrangement. M3 O3
Before rollout, record the user group, resource permissions, enabled operations and approval point. Keep a sample of a permitted operation, a refused operation and the final filed record. Our anonymised Claude Code audit is an audit example, not evidence of production results for this proposed workflow.
Which route should you choose first?
No new software spend: inspect the work this week. Ask your IT lead: "Show me which account reads the client folder and which operation could change it." A good answer names the account and permission, with a test result. Staff time is still a cost.
Existing entitlement first: test the native route. Say: "Use our current Microsoft licences to prepare this pack, with source links and no automatic send." A good answer shows the accepted output and what the licence covers. Stop here if it does the job.
Additional seats: compare a small named group. Say: "Run the same sanitised pack through Claude or ChatGPT and count review effort." A good answer includes omissions and corrections, alongside the draft. Broader access must earn its place.
Priced after discovery: commission a connector. Say: "Expose only these operations, with an owner and an approval test." A good answer includes the failure path and how access is revoked. If the existing connection works, there is no reason to fund another one.
Softblues runs its own company on AI and helps firms choose the smallest implementation that does the job. We start with the work and its owner, then scope the platform and any engineering.
Get the deck: AI-native on Microsoft, Copilot and Claude. Book a discovery call to discuss whether paid Mapping and Strategy is the right next step.
Frequently asked questions
What is MCP in plain English?
MCP is a protocol for exposing tools to an assistant. It can make a business system reachable, but authentication and permissions still determine which operations are allowed. Agree the work before choosing the connection.
Can Claude's Microsoft 365 connector change files?
Yes, documented write tools support file changes when enabled with the required permissions. Do not infer that read access authorises changes. Test the intended action and approval behaviour in your organisation. C1
Are ChatGPT connectors the same as a synced index?
No. A live app connection and administrator-managed sync are distinct routes. SharePoint sync is limited to eligible Enterprise or Edu workspaces and supported regions. O3
Do Copilot connectors bypass Power Platform policies?
MCP tools in Copilot Studio depend on Power Platform connector connectivity and can be blocked by its data policies. Identify the relevant connector and environment before drawing a conclusion. A successful connection does not prove every proposed action is authorised. M1
Sources checked on 12 October 2026
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