Offline Chess Analyzer

The extension opens its own analysis page — it does not overlay chess.com or any other site — and runs the engine inside that page. Load a game and every move is graded; step through it, or stop anywhere and play your own line to see where the alternative would have gone.

• Whole-game review that classifies every move with an Expected Points model, running across a pool of engines.
• Real opening-book classification (Book) from an offline ECO database, not a guess from move numbers.
• Terminal positions decided by the rules — checkmate, stalemate and draws are scored directly instead of being handed to the engine.
• Evaluation bar and timeline scrubber, in pawns or expected points.

• Interactive what-if play from any position in the game, including underpromotion.
• An unbounded move tree — every alternative you play becomes a variation under the move it branched from.
• Live MultiPV analysis of the position on the board, with a best-move arrow.
• Board and piece themes, board flip, and a reset that drops back to the reference line.

• Trap finder — moves that are sound for you and that opponents at your rating tend to answer badly, found by crossing the Lichess opening explorer with the local engine.

• PGN paste, or a custom start FEN.
• Player Elo picked up from the PGN tags (WhiteElo / BlackElo) when they are there.
• One-click import from a chess.com archive.