diff --git a/services/hwfit/image_models.py b/services/hwfit/image_models.py
index 088a00b..f47b602 100644
--- a/services/hwfit/image_models.py
+++ b/services/hwfit/image_models.py
@@ -288,7 +288,7 @@ def rank_image_models(system, search=None, sort="fit"):
 
     for model in IMAGE_MODEL_REGISTRY:
         # Filter by search
-        if search:
+        if isinstance(search, str) and search:
             s = search.lower()
             if s not in model["name"].lower() and s not in model["id"].lower() and s not in model.get("description", "").lower():
                 continue
diff --git a/tests/test_image_models_nonstring_search.py b/tests/test_image_models_nonstring_search.py
new file mode 100644
index 0000000..830e4ae
--- /dev/null
+++ b/tests/test_image_models_nonstring_search.py
@@ -0,0 +1,15 @@
+from services.hwfit.image_models import rank_image_models, IMAGE_MODEL_REGISTRY
+
+SYS = {"gpu_vram_gb": 0, "has_gpu": False}
+
+
+def test_rank_image_models_handles_non_string_search():
+    # search is a CLI/API filter arg; a non-string made search.lower() raise
+    # AttributeError. A non-string search should behave as "no filter".
+    out = rank_image_models(SYS, search=123)
+    assert len(out) == len(IMAGE_MODEL_REGISTRY)
+
+
+def test_rank_image_models_string_filter_still_applies():
+    out = rank_image_models(SYS, search="zzzznotarealmodelzzz")
+    assert out == []