State persists outside the runtime
Tasks store their objective, revision, plan, attempts and terminal result in durable state. Scheduling and leases coordinate execution. A worker restart does not make the language model’s last response the authority for deciding what work remains.
Distinguish failure from waiting
A missing human decision, a delayed external Process and a provider failure require different handling. Durable wait states let work resume when the expected condition arrives. Inspect the recorded state and incident rather than repeatedly submitting the same request.
Check effects before replay
For the internal Task runtime, durable effect checkpoints record the stages surrounding tool execution. Recovery distinguishes a confirmed effect from an uncertain outcome. Do not assume that every external harness implements the same checkpoint guarantees.
Correct the current mission
A correction changes the authoritative revision. Execution must respect the updated objective and avoid resuming reasoning against obsolete instructions. Review the current plan and result after a correction, especially when earlier steps already affected external resources.
Preserve work and reject stale writes
A Task’s original request and attachments remain separate from supplementary context. A new independent request does not interrupt other work, and a rejected amendment does not silently replace it.
In a document application, a Dataset write requires the expected revision. If data have changed, the write is rejected without automatic retry. The form can retain input and offer a new submission after reading the latest data.
Cancellation must reach execution
Stopping a Task should change its durable state and propagate to the active execution path. An external action that already completed may still require a separate corrective operation. Inspect the terminal outcome and any recorded effects after cancellation.
Requested and confirmed stopping
The contract distinguishes requested, confirmed and unknown stopping, with local or remote scope. Task replacement waits for the required evidence; an expired lease does not prove remote stopping. A durable inference can resume as a new attempt with possible additional cost. This is separate from recovering an existing file or its delivery.
Separate production and delivery
A deliverable may exist even when transport failed. The Working Set retains its resource and available evidence. Delivery recovery calls the authorised transport without generating the content again.
The effect-checkpoint guarantees described here concern the internal harness. For an external harness, inspect declared capabilities and adapter state. Process cancellation can also be full, best-effort or unavailable depending on the engine.