MSGraph MCP

MSGraph MCP

A Model Context Protocol (MCP) server for Microsoft Graph. It exposes Microsoft Outlook mail and calendar, plus read-only Microsoft Teams message history, to AI agents via the Microsoft Graph SDK. It acts as the signed-in user, using delegated permissions and MSAL device code flow, so it can only reach what that user can reach.

Install

You need Python ≥ 3.11 and an Entra (Azure AD) app registration. The app registration takes about ten minutes and may need an administrator, so do that first: see the Entra setup section below.

uv tool install msgraph-mcp-server   # or: pip install msgraph-mcp-server

The package is msgraph-mcp-server. It installs three commands: msgraph-mcp and its alias msgraph-mcp-server, which both start the stdio server, plus msgraph-mcp-login for the one-time sign-in.

Setup

1. Set your Entra app credentials.

export MSGRAPH_MCP_CLIENT_ID=<your app's client ID>

export MSGRAPH_MCP_TENANT_ID= # or: common / organizations / consumers

2. Sign in once. This prints a URL and a code; visit the URL and enter the code. No client secret is involved or stored.

msgraph-mcp-login

running via uvx instead of installing: uvx --from msgraph-mcp-server msgraph-mcp-login

A token cache is written to ~/.msgraph-mcp/token_cache.bin.

3. Wire the server into your MCP host.

Claude Code:

claude mcp add msgraph \

--env MSGRAPH_MCP_CLIENT_ID=$MSGRAPH_MCP_CLIENT_ID \ --env MSGRAPH_MCP_TENANT_ID=$MSGRAPH_MCP_TENANT_ID \ -- msgraph-mcp

Any other host, over stdio:

{

"mcpServers": { "msgraph": { "command": "msgraph-mcp", "args": [], "env": { "MSGRAPH_MCP_CLIENT_ID": " ", "MSGRAPH_MCP_TENANT_ID": " " } } } }

To run without installing, use "command": "uvx" with "args": ["msgraph-mcp-server"]. Note that uvx does not put msgraph-mcp-login on your PATH, so sign in with the uvx --from form shown in step 2.

MSGRAPH_MCP_TOKEN_CACHE_PATH optionally overrides the cache location. All three variables can also come from a .env file in the working directory; the process environment wins over it.

Entra setup

The app registration requires:

• Account type: single tenant (multi-tenant works too; set MSGRAPH_MCP_TENANT_ID to common, organizations, or consumers)
• Redirect URI (public client): https://login.microsoftonline.com/common/oauth2/nativeclient
• Allow public client flows: Yes, under Authentication → Advanced settings. Device code flow fails without it.
• Delegated permissions (Microsoft Graph):
• Mail: Mail.ReadWrite, Mail.ReadWrite.Shared, Mail.Send
• Rules: MailboxSettings.ReadWrite (Graph requires this for the messageRules endpoints)
• Calendar: Calendars.ReadWrite, Calendars.ReadWrite.Shared
• Identity: User.Read
• Teams: Chat.Read, Team.ReadBasic.All, Channel.ReadBasic.All, ChannelMessage.Read.All

ChannelMessage.Read.All always needs tenant admin consent, and the *.Shared permissions may need it depending on your tenant.

The scope list is all-or-nothing. Sign-in requests every scope at once, so without admin consent for ChannelMessage.Read.All the login fails outright and mail and calendar are unavailable too. For the same reason, adding scopes later means re-running msgraph-mcp-login; until you do, *every* tool fails with NotAuthenticatedError, not just the ones needing the new scope.

Tools

Behavior shared across tools:

• Trimmed responses. Results are reshaped for agents, and message and event bodies are replaced by a short snippet. Pass include_body=true to get_message, list_chat_messages, list_channel_messages, or list_message_replies for the full body, which for Teams is also what surfaces Adaptive Card content. Pass include_raw=true to any tool returning a Graph object to get the full payload alongside the trimmed one; the batch_* tools return per-message status only and do not accept it.
• Other mailboxes. Every mail and calendar tool takes an optional mailbox (email or user ID) to target a shared or delegated mailbox. Omit it for your own. Teams tools are read-only, cover only your own chats, and take no mailbox.
• Pagination. List and search tools take limit (1-100, default 25) and page_token, except list_channel_messages and list_message_replies, which Graph caps at 50. list_folders, list_rules, list_attachments, and list_calendars return the whole collection and take neither. On list_joined_teams and list_channels, limit is applied after fetching because Graph rejects $top there, so it saves tokens rather than round-trips.
• Batch actions. The batch_* tools apply one action to up to 1000 messages via Graph's $batch endpoint, returning a per-message result plus a {total, succeeded, failed} summary.
• Downloads. download_attachment and download_hosted_content return images as native MCP image blocks the agent can view. Pass save_path (a file, or an existing directory) to write bytes to disk and get back a path instead.
• Finding mail. list_messages defaults to the inbox; pass folder_id for another folder, unread_only=true, or a raw OData filter for predicates KQL cannot express. search_messages passes your query to Graph's $search as KQL.

Outgoing attachments are capped at 3 MB total per message; chunked upload is not supported. SharePoint-backed Teams file attachments cannot be downloaded, only inline hosted content.

Security

The token cache holds your refresh token, which can mint access tokens for your mail, calendar, and Teams data. Treat the file as a credential. It lives at ~/.msgraph-mcp/token_cache.bin with mode 0600 inside a 0700 directory.

To revoke access, or to switch accounts, delete the cache and sign in again:

rm -f ~/.msgraph-mcp/token_cache.bin ~/.outlook-mcp/token_cache.bin

The second path matters if you ever ran this server under its former name outlook-mcp: that cache is still used as a fallback when the current one is absent, so deleting only the first file leaves a working refresh token on disk. To revoke fully, also remove the app at https://account.microsoft.com or in your organization's identity portal.

Troubleshooting

• `NotAuthenticatedError: Not authenticated` — run msgraph-mcp-login. If it recurs immediately, a requested scope has not been consented yet; see the note under Entra setup.
• `ConfigError: Missing required env var` — set it in your shell, in a .env in the working directory, or in your MCP host's env config.
• `Graph API 403: ErrorAccessDenied` — the Entra app is missing a delegated permission, or it needs admin consent. Check the list above, then re-consent and sign in again.
• `Graph API 400: BadRequest — Syntax error` from search_messages — the query goes to Graph's $search as KQL. Quote literal phrases ("weekly report") or use fielded forms (from:alice). For predicates KQL cannot express, use list_messages with filter=.
• The host starts the server but lists no tools — confirm it launches msgraph-mcp (or uvx) over stdio and can find that binary on its PATH.

Development

See CONTRIBUTING.md.