Connecting Claude to Microsoft 365: A Law Firm Test Plan

Anthropic documents its Microsoft 365 connector as an organization-authorized integration through which individual users connect their Microsoft identities. The connector can search SharePoint, OneDrive, Outlook, and Teams, and optional write tools can send email, manage calendars, and create or update files. That reach makes tenant condition, not the convenience of the demonstration, the correct starting point.

Delegated access generally means a person should retrieve only information that identity can already reach. It does not mean the existing access is appropriate. Old sharing links, broad groups, inherited permissions, guest access, shared mailboxes, and weak matter separation can become easier to discover. Before rollout, the firm should treat connector testing as a Microsoft 365 permissions and information-governance project.

Use controlled test identities that represent attorneys, paralegals, administrators, guests, departed users, and members of an ethical wall. Create expected-allow and expected-deny cases across active matters, closed matters, personal OneDrive content, Teams, shared mailboxes, and restricted SharePoint sites. Record both the result returned by Claude and the underlying Microsoft permission that explains it.

Anthropic states that tenant-wide SharePoint search requires the delegated `Sites.Read.All` permission and that site-scoped `Sites.Selected` is not supported for that search path. The firm should therefore understand what the consent permits, what the individual identity can retrieve, and whether current site design provides a defensible boundary before granting administrative consent.

Conditional Access can apply during authentication, but connector requests later originate from Anthropic infrastructure. Device, network-location, session, and sign-in assumptions may therefore behave differently from a lawyer working directly inside a managed Microsoft application. Validate the intended policies in a test group, review Entra sign-in evidence, and document any control that does not transfer cleanly.

Do the same for sensitivity labels, encryption, DLP, audit correlation, eDiscovery expectations, downloads, generated files, and connector-specific logs. A label visible in Microsoft 365 does not by itself prove that a third-party processing path blocks, preserves, or audits the information in the way the firm expects. The answer depends on the feature, license, configuration, and current product behavior.

Begin with a small group, known repositories, read-only search, fictional or approved information, and a named Microsoft 365 administrator working with a responsible attorney. Define prohibited repositories and queries, incident reporting, evidence retention, and a rapid disablement path. Test long after the initial consent screen: permission changes, token expiration, account disablement, group removal, and connector removal all matter.

Enable sending, calendar changes, or file writes only after the read path is understood and the firm has explicit confirmation, destination validation, review, logging, rollback, and exception handling. The goal is not to prove the connector is universally safe. It is to determine whether a specific configuration supports a specific workflow with acceptable evidence and ownership.