Outlook

Use this guide to authorize Outlook, resolve Microsoft tenant consent, and target the correct mailbox or account through MCP and direct execution.

Connect and authorize Outlook

Authenticate the cloud Microsoft account in a browser. Outlook tools authenticate through the Microsoft account/OAuth flow in a browser. Even if you only use Outlook desktop, log into the underlying Microsoft/Outlook account in the browser to complete OAuth. Desktop and cloud use the same account, so once the account is authenticated, the tools can operate against that mailbox.

Check exact tool scopes, then reconnect after changes. For Outlook 403s, look up required scopes with /api/v3/tools/get_scopes_required using the exact Outlook tool slug, not the toolkit name. For example OUTLOOK_GET_MAILBOX_SETTINGS requires MailboxSettings.ReadWrite. After adding scopes to the auth config, create a new auth link session and have the user reconnect so the new scopes are granted.

Complete auth links within about 10 minutes. If a connected account expires because the initiation flow was not completed, the likely reason is that the authorization link timed out. Users have roughly a 10-minute window to complete the auth flow; otherwise Composio invalidates the link and marks the connected account EXPIRED.

Grant Microsoft tenant admin consent

Microsoft/Outlook admin-consent issues are Microsoft 365 tenant-level approval problems, not a Composio-side connection configuration issue. Adding delegated permissions to an Azure app registration is not the same as granting tenant admin consent. Once a tenant admin grants consent for the requested permissions, affected users should start a fresh normal Outlook connection flow with their own accounts; the admin does not need to connect every user individually.

Two concrete ways an admin can approve:

1. App Registration / OAuth app level: in Microsoft Entra / Azure Portal, go to App registrations, open the OAuth app, go to API permissions, click Grant admin consent for [Tenant Name], then confirm/save.

2. Enterprise Applications / org level: in Microsoft Entra / Azure Portal, go to Enterprise applications, find the Composio/Outlook app or the customer's own service principal, open Permissions / admin-consent controls, then grant admin consent for the organization.

For the Composio-managed Outlook app, Microsoft's in-flow sign in as an admin / Connectez-vous avec ce compte link is also a real tenant-admin consent path. If the admin signs in through that same OAuth attempt, that attempt may connect the admin's mailbox, not the original user's mailbox; treat that connected account as the admin's and have the original user start a fresh Connect flow afterward. Incomplete/pending Outlook connection attempts expire after about 10 minutes, so an expired non-admin attempt cannot be resumed. Nothing needs to happen on Composio's side between the admin grant and the user's retry: no cache clear, webhook, or manual status change.

Composio does not publish a client_id for its managed Outlook app for use in direct Microsoft adminconsent URLs. Do not guess this value. For a customer-owned/BYOA Azure app, use your own app's client_id and tenant ID in Microsoft's admin-consent URL.

A customer-owned verified-publisher Azure app can improve branding/control and may reduce consent friction in tenants that allow user consent for verified publishers and the requested delegated permissions. It does not guarantee that no admin approval is needed: each Microsoft tenant's user-consent policy and the exact scopes requested still decide whether admin consent is required.

Use Outlook through MCP and direct execution

Expect Tool Router meta-tools on Connect MCP. connect.composio.dev/mcp uses Tool Router architecture, so it intentionally exposes meta-tools such as COMPOSIO_SEARCH_TOOLS and COMPOSIO_MULTI_EXECUTE_TOOL. The agent discovers and executes Outlook tools at runtime through those meta-tools. If you need specific Outlook tools without meta-tool round trips, use SDK direct execution or create a focused MCP config with selected Outlook tools.

Remove obsolete slugs from MCP configs. If an Outlook MCP config fails due to obsolete or invalid tool slugs, update the MCP config to remove them and include only current supported tools in allowed_tools. This can be done through the dashboard or the MCP patch endpoint.

Pass attachment file paths through the SDK. When using SDK automatic file handling for email attachments, pass the local file path directly in the attachment/attachments argument. Do not pass only a filename or raw content fields unless the tool schema explicitly asks for them.

Target shared mailboxes and multiple accounts

Pass the shared mailbox address as user_id or the mailbox target. Delegated access must already be granted in the Microsoft tenant. This applies to delegated and S2S/application auth patterns where the tenant permissions allow shared mailbox access.

Select an aliased account on every multi-account call. For multi-account Outlook sessions, every connected account needs a unique non-null alias, the session should set multi_account.enable=true and require_explicit_selection=true, and the LLM must set the account field on each item in COMPOSIO_MULTI_EXECUTE_TOOL.tools[]. Without explicit selection, Tool Router cannot disambiguate and may default to one account.