GrowthExperiments' Add Link feature relies on a pool of tasks fetched from a recommendation service, vetted, and added to the database and search index by a cron job. This pool could run dry if the task generation process cannot keep up with the rate at which tasks are consumed, or when task generation errors out. We should have some monitoring and maybe low-urgency alerts in place for noticing that in time.
For monitoring the service itself, see T276769: Create Grafana dashboard for link recommendation service and document it on wikitech.