Parent State ID: 50
State Depth: 8
Action Taken: stack(block_b, block_d)
Action Reasoning: The goal is to build the stack C-D-B-A. Since the hand is currently holding block B, the next step is to stack block B on block D, which matches the desired order.
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, supporting block B, 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)', 'unstack(block_b, block_d)', 'stack(block_b, block_c)', 'unstack(block_b, block_c)', 'stack(block_b, block_d)']

INACTIVE REASON: action path invalid: The last action "stack(block_b, block_d)" violates the precondition that block_d must be clear. The current state description and visualization are accurate, but the action sequence is invalid due to this precondition violation.
