Stable key rule
Reuse the same idempotency key for every retry of the same logical mutation. A fresh key represents new work and can create a duplicate.Unconfirmed mutations
If the connection drops after sending a mutation:- Keep the original key.
- Read the known run or resource if an identifier was returned.
- Retry the same payload with the same key when the contract permits.
- Treat a digest mismatch as a reconciliation failure, not a signal to bypass it.