DMARC alignment
The domain match DMARC checks after SPF or DKIM passes.
DMARC does not only ask whether SPF or DKIM passed. It asks whether the passing domain aligns with the visible From domain. SPF alignment compares the Return-Path domain to the From domain. DKIM alignment compares the d= signing domain to the From domain.
reading this as teams building autonomous agents
An agent stack treats email as a two-way primitive. Inbound has to arrive as structured JSON a tool call can consume, sends have to be safe to retry when a model loop repeats itself, and every action needs an audit trail. A provider without inbound parsing only solves half the problem.
Applied to dmarc alignment, that means weighing inbound parsing, idempotency keys, webhook coverage, and operating track record ahead of the rest, against inbound parsing into tool calls and model-generated sends that must not duplicate.