Parent State ID: 22
State Depth: 5
Action Taken: stack(block_d, block_c)
Action Reasoning: The goal is to have block C on the table, block D on top of block C, block B on top of block D, and block A on top of block B. Block C is already in the correct position. Next, we'll move block D on top of block C. As block C is clear, stack(block_d, block_c) is the best step to move toward the goal.
State Description: Block A is on the table and is clear. Block B is on block D and is clear. Block C is clear and on the table. Block D is not clear and is on block C. The hand is empty.
Action Path: ['unstack(block_b, block_c)', 'stack(block_b, block_d)', 'pick-up(block_a)', 'put-down(block_a)', 'stack(block_d, block_c)']

INACTIVE REASON: deactivated because diagram generation failed or invalid action chosen: The hand is not holding block_d, violating the precondition for the stack action.
