- Empty selections are 422 and duplicates run once in primary-key order
- A completed retry and an all-absent selection delete nothing and skip hooks
- Mixed, hook, cancel, and concurrent requests keep the batch atomic
- Record routes must enforce permission before ids or bodies and return D-10 envelopes
- Create, update, and delete run Before and After hooks once inside the transaction
- Out-of-scope and missing records are indistinguishable, and hook failure rolls back
