Soft bounce
A temporary delivery failure.
A soft bounce means delivery failed for a temporary reason such as a full mailbox, greylisting, rate limiting, or a transient server issue. Providers usually retry soft bounces before converting them into final failures.
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 soft bounce, 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.