Tenant.Read.All permission grants read-only access to tenant-wide metadata in Power BI, including:

• Activity Logs
• Workspace information
• User permissions

Metric Insights maps this telemetry into its Microsoft Power BI Cloud plugin's Lineage, as well the Usage and User Permissions objects, which feed the insights essential for BI Optimizer's governance and cleanup.

• Lineage in Metric Insights is collected through the Get Activity Events API, which requires Tenant.Read.All. Lineage provides the metadata that reflects element and user dependencies: who is connected to what. This metadata is the basis of BI Optimizer. Enabling full Lineage collection is mandatory for BI Optimizer to function, since without this permission, the retrieved metadata will be incomplete and may not cover the required timeframe.
• The Usage Dataset is also powered by Power BI's Get Activity Events API, which requires Tenant.Read.All. These logs form the foundation of adoption and performance analysis, and in Metric Insights appear as Usage data.
• The User Permissions Dataset is powered by Power BI's Get Workspace Info API, which also requires Tenant.Read.All.

This permission is safe and limited to metadata only; it cannot create, modify, or delete any Power BI resources. By granting Tenant.Read.All, you ensure BI Optimizer can deliver the insights required for report cleanup, governance, and optimization, while relying solely on Microsoft's documented and supported Power BI Admin APIs.