Activity

An activity is the generic name BPMN gives to any node where actual work happens. It is drawn as a rounded rectangle, and it is the only shape that consumes time and resources. Everything else on a diagram — events, gateways, flows — either routes the work or marks something that happens without work (a trigger, a decision, an outcome).

BPMN 2.0 splits activities into three concrete kinds: an atomic `task` that cannot be broken down further in the diagram, a `sub-process` that expands into its own internal flow, and a `call activity` that invokes a reusable global process defined elsewhere. Choosing between them is a scope decision, not a stylistic one — it tells the reader whether detail lives inside this diagram or in a separate one.

• The step takes measurable time or costs money — e.g. review an invoice, call the customer back, run the credit check.
• A person, a service, or a script is doing the work — not just a routing choice (that is a gateway) or a trigger (that is an event).
• You need to attach KPIs to it: duration, cost per execution, frequency, owner. Activities are the only nodes where those numbers belong.

When LucidFlow generates a BPMN from your document, every activity it produces carries three KPIs by default: estimated duration in minutes, estimated cost per execution in USD, and execution frequency. The bottleneck heatmap colours activities red→green by whichever KPI you pick, the process cost dashboard sums them across the diagram, and the ESSII framework evaluates each activity for elimination, simplification, standardization, integration, or AI-driven intelligization.