Hmm, yeah... this is actually not the metric of the alert series, but the raw labels from the vector that generated the alert. I might have chosen a model.LabelSet for this instead, except that it was more convenient to use model.Metric for multiple reasons: I need fingerprinting, which is only defined on Metric, and I also get model.Metrics from the expression evaluation, so I save two places of conversion already. On some days I'm wondering if we are causing more annoyance than good with the separation of these two types?