Parent State ID: 1
State Depth: 2
Action Taken: stack(block_a, block_c)
Action Reasoning: To achieve the goal state, block 'a' must be placed on block 'c'. Currently, block 'a' is held by the hand. The next logical step is to stack block 'a' on block 'c', as block 'c' is clear and supports block 'b', which is not a constraint in the goal state.
State Description: Block 'a' is now on block 'c' and is clear. Block 'c' is supporting block 'a'. Block 'b' is supporting block 'd' and remains on block 'c'. Block 'd' is clear. The hand is empty.
Action Path: ['unstack(block_a, block_d)', 'stack(block_a, block_c)']

INACTIVE REASON: action path invalid: The last action `stack(block_a, block_c)` is invalid because `block_c` is not clear in the parent state, violating a precondition of the action. The current state's description and visualization are consistent with the effects of the action, but the action itself is not valid due to unmet preconditions.
