The extent to which learners conform to the structure, aims and linguistic demands of a task is often seen as the responsibility of the materials writer and/or teacher. Given a logical rubric, well-designed task and clear classroom instructions, it is often assumed that the task will be approached as intended. When a task is enacted differently, learner misunderstanding or confusion is often assumed. However, this conception of the relationship between task and enactment does not take into account the separate contribution learners make in bringing a task to life. This article reports on a study looking at examples of learner task adaptation. It concludes by arguing that a task cannot be considered as a static entity, but can only be evaluated by taking account of active learner decision-making, and the nature of classroom process.