Parent State ID: 16
State Depth: 5
Action Taken: stack(a, d)
Action Reasoning: The next best action is to stack block 'a' on block 'd' because it directly achieves part of the goal state by placing block 'a' on top of block 'd', which is already on the table and clear.
State Description: Block 'a' is on top of block 'd', which is on the table. Block 'a' is clear, block 'd' is supporting 'a', and blocks 'b' and 'c' remain clear and on the table. The hand is empty.
Action Path: ['unstack(c, b)', 'put-down(c)', 'unstack(d, a)', 'put-down(d)', 'stack(a, d)']

INACTIVE REASON: deactivated because diagram generation failed or invalid action chosen: The precondition that the hand must be holding block 'a' is not satisfied.
