diff --git a/.agents/rules/add_license_header.md b/.agents/rules/add_license_header.md
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+---
+trigger: glob
+description: Ensure standard Dart license header on newly created Dart files.
+globs: *.dart
+---
+
+# License Header Rule
+
+Whenever you create a new Dart (`.dart`) file in this repository, you MUST include the standard Dart project license header at the very top (line 1).
+
+Replace `<CURRENT_YEAR>` with the actual current year (e.g., 2026).
+
+```dart
+// Copyright (c) <CURRENT_YEAR>, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+```
+
+## Requirements
+- Insert at line 1.
+- Ensure a blank line follows the license header before any other code or comments.