One uses declarative workflows for durable coordination and explicit implementation contracts for domain computation.
Declarative workflow graphs
The canonical durable workflow is a bounded System IDL command/state graph. It contains named states, terminal states, operation and activity invocations, typed outcomes, timers, signals, compensation regions, approvals, seals, and transitions.
The graph is inspectable and versionable. It is not a hidden general-purpose programming language.
Programmatic descent
When a workflow cannot be represented honestly as a graph, an application can select a programmatic workflow implementation in native One, Rust, or another admitted profile.
The workflow contract still owns inputs, outputs, domain faults, activities, effects, history compatibility, and implementation identity. The program uses a restricted deterministic API and carries an exact executable revision and replay obligations.
Effects are more than retry labels
Effects distinguish:
- pure, read-only, reversible, compensatable, and irreversible behavior;
- intent, dispatch, confirmation, and outcome unknown;
- idempotency and deduplication scope;
- compensation and irreversibility points;
- reconciliation after uncertain external results.
Before dispatching a non-pure effect, One records an exact intent. If the external result is unknown, reconciliation occurs before unsafe repetition.
Compensation is forward work
A compensation is a new effect with its own authorization, failure, receipt, and evidence. It cannot erase that data was disclosed, an email was read, money moved, or a physical action occurred.
A rollback is likewise a new forward transition, not time travel.
Cancellation is not rollback
Dropping a future or cancelling a task does not prove an effect was not dispatched. Activities and calls state cancellation, deadline, retry, delivery, and unknown-outcome behavior explicitly.
Canonical owners: Authority, Execution, Components, and History.