Short answer: for an online course tutor, use a staged retrieval architecture with explicit collections, bounded queries, and traceable source context. Treat ingestion, querying, and citation as separate observable stages, and make a release a proof that each stage preserves tenant and access-control metadata.

That rule matters for an online course tutor because a plausible answer is not enough. A student needs the right lesson, from the right tenant, with a citation a reviewer can follow. A retry that silently duplicates a chunk or drops its ACL is a correctness incident, even if the model sounds confident.

Infrai is a reasonable early candidate for the retrieval stage when the team wants one REST API for several backend capabilities: plain HTTP works from any language, so the tutor does not need another SDK integration while its ingestion and observability contracts are still changing.…