This guide for administrators explains how to set up the M365 Tools MCP server in Theta Assist.

See also:

The M365 Tools MCP server provides broader Microsoft 365 access than the standard built-in connectors. It gives assistants access to email, calendars, Teams, chats, files, SharePoint, OneDrive, people, recent files, Planner and Excel workbook data.

In this guide

Overview

The M365 Tools MCP server allows Theta Assist to work with Microsoft Graph data using delegated user access. In most cases, this means the assistant acts only within the permissions of the signed-in user.

Compared with the standard Microsoft 365 connectors, this MCP server supports a wider range of actions, including:

  • reading emails and attachments
  • reading calendars and shared calendars
  • retrieving Teams meeting transcripts
  • searching across OneDrive, SharePoint and Teams files
  • reading Teams channel posts and chat messages
  • looking up people and directory details
  • listing recent and shared files
  • reading Excel worksheets and cell ranges
  • sending an email to the signed-in user
  • drafting a new email or reply to an existing email - ready to review and send in Outlook
  • work with Planner tasks (see separate setup guide)

Note: built-in Theta Assist MCP server

The M365 Tools MCP tool is a built-in Theta Assist MCP Server.

You do not need to manually enter a custom MCP endpoint URL for this integration.

To add the M365 Tools MCP tool:

  1. Go to Admin → Tools → MCP Servers.
  2. Click the green + Theta Assist MCP Server button.
  3. Select the M365 Tools option.
  4. Attach the appropriate Microsoft auth configuration.
  5. Set the approval policy and save.

What the M365 Tools MCP server can do

Email and mailboxes

The server can:

  • list email messages
  • fetch full message content
  • download email attachments
  • search for shared or delegated mailboxes
  • create draft emails
  • create draft replies to existing messages
  • send an e-mail to self

Calendar and meetings

The server can:

  • search calendar events
  • read calendar attachments
  • retrieve Teams meeting transcripts from meeting join links

Files and documents

The server can:

  • search across Microsoft 365 files
  • browse OneDrive and SharePoint folders
  • download supported files
  • read Excel workbook content by worksheet and cell range
  • coming soon: read SharePoint Lists

Teams and chats

The server can:

  • list joined Teams and channels
  • read channel conversations and replies
  • list personal and group chats
  • search Teams messages

People and profile data

The server can:

  • return the signed-in user profile
  • look up colleagues
  • find relevant people and contacts
  • list recent, used, and shared files

Available tools

The M365 Tools MCP server includes 34 tools.

Email

  • ta_m365_list_emails
  • ta_m365_get_email
  • ta_m365_get_email_attachment
  • ta_m365_find_mailbox
  • ta_m365_create_draft_email
  • ta_m365_create_draft_reply
  • ta_m365_send_email_to_self

Calendar and meetings

  • ta_m365_get_calendar_events
  • ta_m365_get_calendar_attachment
  • ta_m365_get_meeting_transcript

File search, OneDrive and SharePoint

  • ta_m365_search_files
  • ta_m365_onedrive_search
  • ta_m365_onedrive_list
  • ta_m365_onedrive_download
  • ta_m365_sharepoint_find_site
  • ta_m365_sharepoint_get_drives
  • ta_m365_sharepoint_search
  • ta_m365_sharepoint_list
  • ta_m365_sharepoint_download

Teams

  • ta_m365_teams_list_joined
  • ta_m365_teams_list_channels
  • ta_m365_teams_channel_files_root
  • ta_m365_teams_group_drive
  • ta_m365_teams_get_channel_messages
  • ta_m365_teams_get_channel_replies
  • ta_m365_teams_list_chats
  • ta_m365_teams_get_chat_messages
  • ta_m365_teams_search_messages

People, profile and productivity

  • ta_m365_get_user
  • ta_m365_find_people
  • ta_m365_recent_files
  • ta_m365_send_email_to_self

Excel

  • ta_m365_excel_get_worksheets
  • ta_m365_excel_read_range

Admin setup overview

To set up the M365 MCP server:

  1. Create or update a Microsoft Entra ID App Registration.
  2. Add the required Microsoft Graph permissions.
  3. Grant admin consent where required.
  4. Reuse or create a Microsoft OAuth Auth Configuration in Theta Assist.
  5. Go to Admin → Tools → MCP Servers.
  6. Click the green + Theta Assist MCP Server button.
  7. Select M365 Tools.
  8. Choose the auth configuration.
  9. Set approval policy and access controls.
  10. Test with a limited admin or pilot group first.

App registration permissions

Important: If you already have an app registration for the existing Microsoft 365 connectors, you can usually extend that same app registration by adding the extra permissions - see next section to see what the differences are.

Required permissions

Permission Type Purpose
Calendars.Read Delegated Read user calendars
Calendars.Read.Shared Delegated Read user and shared calendars
Channel.ReadBasic.All Delegated Read the names and descriptions of channels
ChannelMessage.Read.All Delegated Read user channel messages
ChannelSettings.Read.All Delegated Read the names, descriptions, and settings of channels
Chat.Read Delegated Read user chat messages
Contacts.Read Delegated Read user contacts
Directory.Read.All Delegated Read directory data
Files.Read Delegated Read user files
Files.Read.All Delegated Read all files that user can access
Group.Read.All Delegated Read all groups
Mail.Read Delegated Read user mail
Mail.ReadWrite Delegated Read and write access to user mail
Mail.Send Delegated Send mail as a user
MailboxSettings.Read Delegated Read user mailbox settings
offline_access Delegated Maintain access to data you have given it access to
OnlineMeetingRecording.Read.All Delegated Read all recordings of online meetings
OnlineMeetings.Read Delegated Read user's online meetings
OnlineMeetingTranscript.Read.All Delegated Read all transcripts of online meetings
openid Delegated Sign users in
People.Read.All Delegated Read all users' relevant people lists
Presence.Read.All Delegated Read presence information of all users in your organisation
profile Delegated View users' basic profile
Sites.Read.All Delegated Read items in all site collections
Tasks.Read Delegated Read user's tasks and task lists
Team.ReadBasic.All Delegated Read the names and descriptions of teams
User.Read Delegated Sign in and read user profile
User.ReadBasic.All Delegated Read all users' basic profiles

Important: extra permissions needed if you already use Microsoft 365 connectors

If your organisation already uses the standard Microsoft 365 connectors described in the existing help article, the following are the main additional permissions typically needed for the M365 Tools MCP server:

  • Calendars.Read.Shared
  • ChannelSettings.Read.All
  • Directory.Read.All
  • Files.Read.All
  • Group.Read.All
  • Mail.ReadWrite
  • Mail.Send
  • MailboxSettings.Read
  • OnlineMeetingRecording.Read.All
  • OnlineMeetings.Read
  • OnlineMeetingTranscript.Read.All
  • People.Read.All
  • Presence.Read.All
  • Tasks.Read
  • User.ReadBasic.All

Why these permissions are needed

These additional permissions enable broader MCP functionality such as:

  • shared calendar access
  • Teams transcript access
  • wider file discovery across Microsoft 365
  • people and directory lookups
  • sending mail to self
  • richer Teams and organisational context
  • for Planner permissions and further details, see Planner MCP tool | Admin guide

Suggested rollout approach

For initial rollout, we recommend:

  • Extend your existing Microsoft app registration rather than creating a duplicate one.
  • Grant the additional permissions listed above.
  • Create a separate Theta Assist Auth Configuration for the M365 MCP server if you want to keep it separate from the built-in connectors.
  • Optionally set the MCP server approval policy to Always require approval during the test.
  • Restrict access using Access Profiles - this restricts who can add the MCP to their assistants.
  • Add a new assistant with the tool and then validate the following scenarios:
    • email listing and attachment access
    • calendar search and transcript retrieval
    • OneDrive and SharePoint file search
    • Teams channel and chat retrieval
    • Excel worksheet and range reading
    • send-email-to-self flow
    • draft email creation
    • draft reply creation
  • Enable an 'Office Assistant" for general use with the tool enabled for all staff

Notes

  • All access is based on delegated permissions, so the assistant can only act on data the signed-in user already has access to.
  • The permission set for this MCP server is broader than the standard connector setup and should be reviewed by your Microsoft 365 administrator and security team.
  • If you already use Microsoft connectors in Theta Assist, this is typically an extension of your existing setup, not a full rebuild.