Multi-Tenancy and Data Isolation

Multi-tenancy is serving many customers from shared infrastructure while guaranteeing no tenant can ever see another's data. The isolation strategies run a spectrum from row-level filtering to fully separate databases, trading cost against blast radius. The non-negotiable rule for AI systems: tenant scope is enforced below the model, in code that filters queries and scopes credentials, never by instructing the model in a prompt. A single prompt-injected document is enough to break prompt-level isolation.