What problem does it solve? Deciding where to draw aggregate boundaries in a domain model is hard: too large and you get lock contention, too small and invariants break under concurrency. This Skill guides you through a structured, question-driven process to determine whether you need an aggregate at all, and if so, exactly what it should guard. ## Core Features & Use Cases - Fit Check Gate: Verifies the problem is genuinely a concurrency/consistency-boundary problem before any design work, stopping early for CRUD or read-only scenarios. - Command Extraction & Conflict Matrix: Classifies operations into commands, facts/events, and queries, then builds a pairwise conflict matrix surfacing self-conflicts, parameter-dependent conflicts, and time-range conflicts. - Sequencing Probe & Boundary Decision: Tests whether business processes already separate conflicting operations in time, then recommends one aggregate, multiple aggregates, a database constraint, or no aggregate. - Use Case: You are modeling a booking system where users reserve time slots. The Skill walks you through confirming concurrent write risk, extracting commands like ReserveSlot and CancelReservation, detecting time-range conflicts, and deciding whether a single aggregate or a database constraint best protects the no-double-booking invariant. ## Quick Start Ask the assistant to use the aggregate-designer skill to design consistency boundaries for your domain, providing a description of the state-changing operations and the rules that must never be broken.
