Strategic planning is meaningless without boots on the ground to get things done. Depending on goals and needs, a company likely doesn’t just need a strategic partner; they also need a tactical one.
The only way to get a  sense of whether an agency can execute is if they provide strategic timelines with deliverables and hard deadlines. While an agency won’t have specifics, make sure to ask about what the timeline will look like.
But the opposite must also be true. An agency that gets itself far too into the weeds, focusing only on tactics won’t get the job done either. The strategy ultimately dictates what tactics to use, and it is possible for an agency to be too tactical. Long-term campaign success requires always having an eye towards the future without getting too caught up in the day-to-day.