Chart Annotation Label

The label on a ChartAnnotation is the primary text visible on the chart — it should be short enough to render legibly on the chart timeline without overlapping other elements, typically a few words like "Pump startup" or "Regulatory inspection." The longer description field can hold the full explanation for users who hover over or click the marker. A clear, consistent labeling convention for ChartAnnotations across a site's history makes concentration trend charts more readable for regulatory reviewers and internal compliance teams alike.