Right now to configure pull request tests via Evergreen, we use both task tag and task regex on the WiredTger Evergreen project Github config page (only admins have access). There are pros and cons for each of the 2 approaches, with notable ones being:

• Task tag needs labeling the task in evergreen.yml. It can be used to match a set of tasks in a pull request config entry. However, sometimes it unintentionally add a task in a builder (or builders) when a task is used in multiple builders. 
• Task regex does not need change to evergreen.yml. It's flexible to match a given task in a given builder using a config entry, but could lead to config entry bloating.

We should evaluate our use case and determine a balanced way to leverage the 2 options configuring WiredTiger pull request tests.