ADR-0004: Task, Run, Turn, and process are distinct

• Status: Accepted
• Date: 2026-09-10

Context

Providers use different execution shapes, including shared services and provider-assigned session IDs.

Decision

A Task can have many AgentRuns; a Run can have many AgentTurns; neither identity is an OS process.

Consequences

Process supervision stays inside adapter/execution infrastructure. Domain history remains stable across provider strategies.

Change rule

If implementation evidence proves this wrong, update the canonical architecture/product document first and then supersede/amend this ADR. The ADR is not allowed to keep current docs stale.