Inject tag or value to capture whether the build is the first or second build of the experiment.

When analyzing the results of an experiment, it can be easy to get lost in a build scan and not be sure whether it was the first or second build of the experiment. Often, the best way to check is by assuming from the performance of the build itself or navigating back to the summary view. It would be more concrete to capture this metadata as a tag or custom value so that it would be clear.

Start by tracing how experiment builds are represented in build scans and where tags or custom values are emitted. Check how the summary view distinguishes builds, then define completion as the scan clearly identifying whether a build is the first or second build of its experiment.

Written by the indexing model from the issue text.