Attempt Number: 4
Error Message: Action not unique compared to other actions chosen from this state before. Choose a new action

Action Reasoning:
Pick up block 'a' to prepare for stacking it onto block 'c' later as part of building the goal state structure.

New State Description:
The hand is holding block 'a'. Block 'a' is no longer on the table and not clear. Blocks 'b', 'c', and 'd' are clear and remain on the table. The hand is not empty.

Action Chosen:
pick-up(a)
