A legal FEN is not a game: state identity in a browser chess extension

Описание и применение

Расширение ChessNavio использует комплексную проверку состояния доски, включая FEN, epoch, jobId и идентификатор игры, чтобы гарантировать, что подсказки движка отображаются только при реальной игре, избегая ложных срабатываний на лобби и повторных матчах.

Задача

A browser chess extension must reliably identify when a board represents a live game, avoiding false positives on lobbies, broadcasts, or rematches that share the same FEN.

Результат

By combining DOM signals, engine state, and platform identifiers, the extension now accurately distinguishes live games from non‑game boards, preventing misleading move suggestions.

Рабочий процесс

• 1. Verify the current URL matches a known game route for the site.
• 2. Ensure exactly one visible board of the expected type exists.
• 3. Check that the game has started (e.g., presence of move list or controls).
• 4. Retrieve the platform game ID if available.
• 5. Capture the board’s FEN, boardEpoch, configRevision, and jobId from the DOM and engine state.
• 6. Store a PresentationIdentity object with these values.
• 7. When the engine returns a bestmove, compare its FEN, epoch, jobId, and configRevision to the stored identity.
• 8. If all match, render the suggested move and caption; otherwise discard the result.

Доказательства

If any of that is missing, nothing renders. I'd rather the panel sit there doing nothing than draw an arrow on a lobby or a broadcast.

Источник

The type we compare at presentation time isn't a FEN and isn't a session snapshot: ...

Источник