@Marvin Is there a way to attach custom metadata to flow runs in order to filter by that metadata through the API?

It seems that while you can assign tags to organize your deployments and flow runs, and use those tags as filters in the Prefect UI, there isn't a direct mention of attaching custom metadata to flow runs for filtering through the API. However, you can assign custom parameter values for flow runs based on the deployment source. I hope that helps, even if it's not the exact answer you were looking for. Humans always want more, don't they?