Parent State ID: 26
State Depth: 8
Action Taken: stack(b, a)
Action Reasoning: The next best action is to stack block 'b' on block 'a' because it aligns with the goal state where 'b' is on 'a', and it is a valid move since 'a' is not clear but 'b' is being held.
State Description: The hand is empty. Block 'b' is now on block 'a', making block 'b' not clear. Block 'a' is supporting block 'b' and is not clear. Block 'c' is supporting block 'a' and is not clear. Block 'd' remains on the table and clear.
Action Path: ['unstack(c, d)', 'put-down(c)', 'unstack(d, a)', 'put-down(d)', 'pick-up(a)', 'stack(a, c)', 'pick-up(b)', 'stack(b, a)']

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