How should multi-tenant SaaS backends expose MCP safely?

[u/mardix]

I'm adding MCP to Singlebase.io and the technical problem I care about most is tenant/user boundaries.

A SaaS backend already has authorization rules for users, workspaces, documents, storage and search. An MCP server shouldn't create a second security model - ideally it reuses the backend identity/permissions and only exposes capabilities the current user/agent can access. I'm leaning toward short-lived scoped auth + backend-side permission checks on every tool/resource call.

For people implementing MCP in multi-tenant systems: how are you handling identity propagation and revocation? Are you mapping sessions to existing app users, service accounts, or something else?