Parent State ID: 12
State Depth: 4
Action Taken: stack(block_b, block_d)
Action Reasoning: The goal is to stack block B on block D. Since the hand is holding block B and block D is on the table and clear, we can directly stack block B on block D. This action aligns with the goal of stacking blocks correctly.
State Description: Block A is on the table and clear. Block B is on block D and clear. Block C is on the table and clear. Block D is on the table and not clear. The hand is empty.
Action Path: ['unstack(block_b, block_c)', 'stack(block_b, block_d)', 'unstack(block_b, block_d)', 'stack(block_b, block_d)']

INACTIVE REASON: action path invalid: The last action `stack(block_b, block_d)` is invalid because the precondition that the hand must hold block_b is not met. The hand is empty in the current state, violating the action's requirements.
