diff --git a/packages/chess/src/schema.ts b/packages/chess/src/schema.ts
index ff287bd..11f0769 100644
--- a/packages/chess/src/schema.ts
+++ b/packages/chess/src/schema.ts
@@ -49,10 +49,25 @@ export interface ChessAttrMap {
   // Custom rule attributes (from RULES.md presets)
   Hp: number;
   PoisonedSquare: boolean;
+  // Modifier profile attributes
+  HpBonus: number;
+  RangeBonus: number;
+  DirectionAdditions: readonly string[];
+  CaptureFlags: number;
+  PromotionOverride: PieceType | "disabled";
+  DamageResistance: number;
 }
 
 export type ChessAttrKey = keyof ChessAttrMap;
 
+/** Capture behavior bitflags for the CaptureFlags modifier attribute. */
+export const CaptureFlag = {
+  CAN_CAPTURE_OWN: 1,
+  CANNOT_BE_CAPTURED: 2,
+  EN_PASSANT: 4,
+} as const;
+export type CaptureFlag = typeof CaptureFlag[keyof typeof CaptureFlag];
+
 /** A typed chess fact triple. */
 export interface ChessFact<K extends ChessAttrKey = ChessAttrKey> {
   readonly id: EntityId;