--- a/src/chess/fen.h	Thu Sep 03 18:32:47 2026 +0200
+++ b/src/chess/fen.h	Fri Sep 04 13:49:48 2026 +0200
@@ -50,7 +50,18 @@
  * @param gamestate the current game state
  * @see #FEN_MAX_LENGTH
  */
-void fen_compute(char *str, GameState *gamestate);
+void fen_compute(char *str, const GameState *gamestate);
+
+/**
+ * Constructs a game state from a FEN string.
+ *
+ * Note that this cannot reconstruct a move history by design.
+ *
+ * @param str the FEN string
+ * @param gamestate uninitialized target structure
+ * @return zero on success, non-zero when the FEN is invalid
+ */
+int fen_parse(const char *str, GameState *gamestate);
 
 #ifdef __cplusplus
 } /* extern "C" */