sync: update from private repo (dfadcd5f)

src/engine/tools/pieces.ts

@@ -58,6 +58,18 @@ function validatePiece(piece: any): string | null {
   if (typeof piece.max_movements !== 'number' || !Number.isFinite(piece.max_movements) || piece.max_movements <= 0) {
     return 'max_movements is required (positive integer, e.g. 50 for short tasks, 999 for open-ended ones)';
   }
+  // Piece-level shared tools (union into every movement). Optional; when
+  // present must be an array of non-empty strings. Kept in sync with the
+  // HTTP-layer validator in src/bridge/pieces-api.ts.
+  if (piece.shared_tools !== undefined) {
+    if (!Array.isArray(piece.shared_tools)) return 'shared_tools must be an array';
+    for (let i = 0; i < piece.shared_tools.length; i++) {
+      const t = piece.shared_tools[i];
+      if (typeof t !== 'string' || t.trim().length === 0) {
+        return `shared_tools[${i}] must be a non-empty string`;
+      }
+    }
+  }
   const names = new Set(piece.movements.map((m: any) => m.name));
   if (!names.has(piece.initial_movement)) return 'initial_movement must reference an existing movement';
   // Phase 6b: rules[].next only accepts existing movement names + WAIT_SUBTASKS.