Agatha of the Vile Cauldron has power 1 or greater.
Steps
At the beginning of your combat phase, Workshop Elders triggers, causing Basalt Monolith to become a 0/0 artifact creature, then putting four +1/+1 counters on it.
Activate Basalt Monolith's first ability by tapping it, adding ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) .
activate Basalt Monolith's second ability by paying at most ({2} magic symbol) , untapping it.