diff --git a/backend/app/channels/goal_status.py b/backend/app/channels/goal_status.py
index 750b4a7849..c6ee706432 100644
--- a/backend/app/channels/goal_status.py
+++ b/backend/app/channels/goal_status.py
@@ -16,6 +16,7 @@ from __future__ import annotations
 import math
 from collections.abc import Mapping
 
+from app.channels.reply_locale import supported_locale
 from app.scheduler.notification_text import goal_reason_text
 from deerflow.persistence.scheduled_task_runs.finalization import CHECK_FAILURE_CODES
 from deerflow.runtime.goal import is_active_goal
@@ -65,6 +66,7 @@ _WAITING_KEYS = {"needs_user_input": "waiting_for_you", "external_wait": "waitin
 
 def goal_reply_text(key: str, locale: str) -> str:
     """A fixed ``/goal`` reply (``none``, ``cleared``, ``*_failed``) in ``locale``."""
+    locale = supported_locale(locale)
     return _TEXT[locale][key]
 
 
@@ -102,6 +104,7 @@ def goal_status_text(goal: object, outcome: object, *, running: bool, locale: st
 
     ``running`` says whether the thread has a run pending or in progress.
     """
+    locale = supported_locale(locale)
     text = _TEXT[locale]
     if is_active_goal_state(goal):
         lines = [text["goal"].format(objective=goal["objective"])]
diff --git a/backend/tests/test_goal_status.py b/backend/tests/test_goal_status.py
new file mode 100644
index 0000000000..8473873a0d
--- /dev/null
+++ b/backend/tests/test_goal_status.py
@@ -0,0 +1,25 @@
+"""Tests for ``/goal`` reply text locale handling.
+
+``goal_status.py`` hosts its own reply wording and, unlike the ``/connect``
+handshake, used to index its ``_TEXT`` table directly with the caller's locale.
+A locale outside ``NotificationLocale`` therefore raised ``KeyError`` instead of
+falling back, which is the opposite of ``connect_reply_text``. These tests pin
+the fallback behavior.
+"""
+
+from app.channels.goal_status import goal_reply_text, goal_status_text
+
+
+def test_goal_reply_text_unknown_locale_falls_back_to_default():
+    """A locale outside NotificationLocale must fall back, not raise KeyError."""
+    assert goal_reply_text("none", "ja-JP") == "No active goal."
+
+
+def test_goal_reply_text_known_zh_locale():
+    """A supported locale still selects its own wording."""
+    assert goal_reply_text("none", "zh-CN") == "当前没有目标。"
+
+
+def test_goal_status_text_unknown_locale_falls_back_to_default():
+    """The status reply also falls back for an unsupported locale."""
+    assert goal_status_text(None, None, running=False, locale="ja-JP") == "No active goal."