Durability and recovery

Durability preserves recorded facts across process failure. Consider an agent placing a replacement order: the service accepted the request, but the worker died before writing its final result. The durable conversation survives; the missing local result does not establish whether the service acted.

Three kinds of evidence

State	Next decision
A result was durably recorded and remains valid	Reuse it according to the configured replay contract
Work was not admitted or the service proves no effect	Continue under the applicable authority and retry policy
The external effect is unknown	Reconcile through a stable action identity or service receipt

An idempotency key identifies the downstream action. A receipt demonstrates what the downstream service accepted. The runtime checkpoint establishes what Cayu recorded. A correct recovery path compares these rather than inventing a success or retrying blindly.

Configure the boundary

Declare tool effects, choose appropriate stores, preserve stable service identities and make authorization reconstructible. The durable operations guide composes observation, proposal, approval, action, independent verification and recovery.

Recovery may preserve a pause or reject incompatible evidence. It need not turn every stopped session into an automatically running one. Inspect the reported recovery result and unresolved work. Read operating recovery and try the support-agent recipe.