Constitution of an Omission as Breach Through an Accepted Undertaking: How Accepting a Task Makes Not Doing It a Failure

This conceptual paper introduces Constitution of an Omission as Breach Through an Accepted Undertaking, a constitutive relation between accepted work and the status of an omission. Holding the unperformed task fixed, differences in what was undertaken can make the same omission a breach for one person and no breach for another. The paper assesses the undertaking’s scope, the material supplied, and the opportunity to perform. Accepted terms and applicable role requirements help determine what was owed. Private trust cannot enlarge the task. Outcomes may provide evidence about performance and affect consequences, but they do not themselves constitute the breach. The discussion connects the relation to Hart’s account of role-responsibility and examines Duncan v. Missouri Board for Architects, Professional Engineers and Land Surveyors (1988), arising from the Hyatt Regency walkway collapse. The case concerns an omitted review and the statutory responsibilities attached to the engineer’s act of sealing drawings. Part of the Power, Permission, and Obligation series within On Human Modeling, the paper examines who defines the task and who answers for its omission. Its framework can inform human–AI research on evaluating delegated tasks by their accepted scope, available inputs, and opportunity for performance, while distinguishing breach from resulting harm.