Accelerator Chess

Use to continue an ongoing playable chess game in conversation widgets. This tool is for standard legal chess positions only.

Call it when the widget or the user provides the current board state and asks you to make your legal reply move. This is the follow-up move tool for an already-started game.

The tool requires:

• the current canonical fen
• the existing userColor
• your legal modelMove for that position

The move is validated and applied to the supplied position before the updated board is returned. Use this tool after the user has already moved in the widget, or when the user explicitly gives you the current ongoing position and asks for your next move.

Do not use this tool to open a fresh game with no move yet, or to load an initial board position without applying your move. For those cases, use start-chess.

Do not call this tool for:

• puzzles
• commentary-only analysis
• non-standard chess variants

Do not invent board states, castling rights, or illegal moves. Let the tool validate the position and move sequence.

Use to start a playable chess game in a conversation widget. This tool is for standard legal chess positions only.

Call it when the user asks to begin a new game, load a specific FEN position into the widget, or open a playable board for the first chess tool call in the conversation.

The tool accepts:

• an optional canonical FEN string. If this is not specified, a fresh board is used
• an optional user color. Defaults to 'w'
• an optional assistant move as modelMove

If the starting position is a fresh board, modelMove is required if and only if the user is Black. That means:

• when the user is White, you are Black, so do not provide modelMove
• when the user is Black, you are White, so provide your legal opening move as modelMove

If the starting position is not a fresh board, modelMove should be supplied if and only if it is your. When supplied, that move is validated and applied before the updated board is returned.

Use this tool to keep the conversation synchronized with the real board state rather than describing hypothetical moves in plain text.

After the user makes a move inside the widget, the widget will persist the updated position and send a follow-up asking you to move. Respond to that follow-up with continue-chess, not this tool.

Do not call this tool for:

• puzzles
• commentary-only analysis
• non-standard chess variants

Do not invent board states, castling rights, or illegal moves. Let the tool validate the position and move sequence.