Parent State ID: 1
State Depth: 2
Action Taken: stack(d, b)
Action Reasoning: To reach the goal state, I need to place block `d` on block `b`. Currently, block `d` is in the hand, and block `b` is clear, so the best action is to stack `d` on `b`.
State Description: Block `d` is now on top of block `b` and is not clear. Block `a` is clear and on top of block `c`. Block `c` is on top of block `b`. Block `b` is on the table and supports block `d`. The hand is empty.
Action Path: ['unstack(d, a)', 'stack(d, b)']

INACTIVE REASON: deactivated because diagram generation failed or invalid action chosen: Block `b` is not clear, violating the precondition for stacking.
