I built a vault so a skill or an agent could store structured items without me rewriting the domain each time. That meant designing the DRF API for a non-human caller: stable UUIDs, an open metadata field, and a discoverable OpenAPI schema. Then I probed it for idempotency and found I never built any.
I wrote a benchmark to prove my vault API's eager loading worked, charted it, and published it. Five weeks later I deleted the eager loading from the viewset to watch the benchmark go red. Fifteen tests passed in 4.67 seconds and the benchmark cheerfully printed the same flat line.
Storing recipes, bookmarks, journals and groceries behind a single REST surface: a polymorphic Item base, dynamically composed nested serializers, atomic multi-table writes, and the eager-loading that kills the N+1 queries.