diff --git a/services/tts/tts_service.py b/services/tts/tts_service.py
index e724434cb..2120d7720 100644
--- a/services/tts/tts_service.py
+++ b/services/tts/tts_service.py
@@ -68,7 +68,7 @@ class TTSService:
         if provider == "local":
             kokoro = self._get_kokoro()
             return kokoro is not None and kokoro.available
-        if provider.startswith("endpoint:"):
+        if isinstance(provider, str) and provider.startswith("endpoint:"):
             return True  # assume reachable; errors surface at synthesis time
         return False
 
diff --git a/tests/test_tts_available_nonstring_provider.py b/tests/test_tts_available_nonstring_provider.py
new file mode 100644
index 000000000..632e1cd89
--- /dev/null
+++ b/tests/test_tts_available_nonstring_provider.py
@@ -0,0 +1,17 @@
+from services.tts.tts_service import TTSService
+
+
+def test_available_tolerates_non_string_provider(tmp_path):
+    """A hand-edited/corrupt data/settings.json can store a non-string
+    tts_provider (e.g. null or a number). available reads it and calls
+    provider.startswith("endpoint:"), which raised AttributeError on a
+    non-str. It must instead fall through and report unavailable."""
+    service = TTSService(cache_dir=str(tmp_path))
+    service._load_settings = lambda: {
+        "tts_enabled": True,
+        "tts_provider": 123,
+        "tts_model": "tts-1",
+        "tts_voice": "alloy",
+        "tts_speed": "1",
+    }
+    assert service.available is False