An international organization has sensitive shared drives and wants answers only from documents a particular employee could lawfully open. Here is a scenario-based comparison using documentation checked on 2026-10-25, not an independently tested vendor ranking. The region, plan, exact model version and price are unspecified unless a first-party document establishes them; unmatched performance claims stay unknown.
Audience: IT security and compliance teams. Evidence checked: 2026-10-25. Editorial status: ready. Comparison scope: named scenario; region, plan and model/version parity require separate confirmation.
Permission inheritance is not a security audit
Microsoft explains that Copilot accesses material in the user’s authorized context; Google explains that Gemini access can be constrained by Workspace settings and content ownership. Both are descriptions of intended architecture, not guarantees that every enterprise has correctly configured sharing. Pre-existing overshared folders, guest accounts and inherited roles may be exposed to a smarter search interface without becoming newly authorized. Audit permission hygiene before assigning assistant seats.
Construct adversarial test identities
Use a finance employee, contractor and executive with intentionally different permissions. Create synthetic files that contain similar titles but distinct confidential paragraphs. Ask each identity to summarize the same topic and record which source links appear. Test revoked permissions and stale cached documents after a change. Include Gmail, drive and meeting records only where the purchased edition supports them and the account owner has approved the pilot. Never use real personal or regulated data in a default test tenant.
The procurement matrix
Obtain written statements for residency, logging, legal discovery, DLP interactions, administrative disabling, retention and identity provisioning for the selected subscriptions. Neither source page establishes every regional contract term. Separate an assistant’s own chat sharing controls from the underlying document repository’s ACLs. A provider may have impressive policy controls while the buyer’s tenant implementation remains unsafe.
Acceptance is role-specific
Require zero unauthorized source disclosures in the synthetic fixture, clear source links for material answers and a reliable escalation to human administrators. Track support response to permission-change incidents. Compare migrations between SharePoint/OneDrive and Google Drive based on existing institutional investments, not a claim that one assistant wins on an abstract quality score.
What an actual buyer pilot should measure
Freeze the relevant source files, release identifiers, evaluation prompts, operator permissions and reviewer identities. Use the same rights-cleared materials for every candidate; separate tasks that cannot be configured equivalently instead of forcing them into a single ranking. Review the resulting artifacts against objective acceptance criteria specific to this decision: source traceability, error handling, rework, permission boundaries and whether a competent human approves the final deliverable. Record rejected attempts as well as successful examples. This is a proposed method, not a claim that these vendors have been tested by this publication.
Costs and unresolved evidence
Do not equate an interactive assistant seat, media credit, billable character, hosted token or self-hosted GPU hour. To estimate actual spending, count accepted results, failed attempts, revision cycles, human review, security operations and export/storage costs. AI 10 must supply dated provider-specific pricing records with tier, unit, currency and region; in their absence, monetary figures and claims of price parity remain unknown. Account-level availability and contract addenda require verification. No universal winner score or fictitious hands-on rating is assigned.
Decision for this scenario
Choose the ecosystem that can enforce and demonstrate least privilege in the buyer’s actual tenant; pause rollout until oversharing is corrected.
The article has documented feature and policy evidence but no independent hands-on performance test. Reconfirm plan, region and terms before publication; editorial ready is not WordPress publication approval.
Sources and Further Reading
Original provider and policy sources are listed here. Source-to-claim identifiers are maintained separately in the editorial CSV rather than inserting numbered references into the main text. Where documents are mutable, the access date describes the verification point only.
- Microsoft — How does Microsoft 365 Copilot work? (checked 2026-10-25)
- Google Workspace — What controls Gemini’s access to Workspace data (checked 2026-10-25)