I combined my thoughts from last night with what was the alternate description for the Spy I had yet to try out and wrote up a new alternate description of the piece. While writing it, I covered one detail with more precision that should also apply to the current version. A spy cannot capture a piece that could capture it, which for the Pawn means it must avoid moving as one of its own Pawns when capturing one. This was coded incorrectly in this case, and I fixed it in the code of the current games. Fortunately, this bug had not led to any illegal moves.
I combined my thoughts from last night with what was the alternate description for the Spy I had yet to try out and wrote up a new alternate description of the piece. While writing it, I covered one detail with more precision that should also apply to the current version. A spy cannot capture a piece that could capture it, which for the Pawn means it must avoid moving as one of its own Pawns when capturing one. This was coded incorrectly in this case, and I fixed it in the code of the current games. Fortunately, this bug had not led to any illegal moves.