fix: Support models slash prefix in model name extraction

Support "models/" prefix in model name extraction

PiperOrigin-RevId: 827557443

src/google/adk/utils/model_name_utils.py

@@ -27,8 +27,8 @@ def extract_model_name(model_string: str) -> str:
   """Extract the actual model name from either simple or path-based format.
 
   Args:
-    model_string: Either a simple model name like "gemini-2.5-pro" or
-                  a path-based model name like "projects/.../models/gemini-2.0-flash-001"
+    model_string: Either a simple model name like "gemini-2.5-pro" or a
+      path-based model name like "projects/.../models/gemini-2.0-flash-001"
 
   Returns:
     The extracted model name (e.g., "gemini-2.5-pro")
@@ -41,6 +41,10 @@ def extract_model_name(model_string: str) -> str:
   if match:
     return match.group(1)
 
+  # Handle 'models/' prefixed names like "models/gemini-2.5-pro"
+  if model_string.startswith('models/'):
+    return model_string[len('models/') :]
+
   # If it's not a path-based model, return as-is (simple model name)
   return model_string
 

tests/unittests/utils/test_model_name_utils.py

@@ -42,6 +42,11 @@ class TestExtractModelName:
     path_model_3 = 'projects/test-project/locations/europe-west1/publishers/google/models/claude-3-sonnet'
     assert extract_model_name(path_model_3) == 'claude-3-sonnet'
 
+  def test_extract_model_name_with_models_prefix(self):
+    """Test extraction of model names with 'models/' prefix."""
+    assert extract_model_name('models/gemini-2.5-pro') == 'gemini-2.5-pro'
+    assert extract_model_name('models/gemini-1.5-flash') == 'gemini-1.5-flash'
+
   def test_extract_model_name_invalid_path(self):
     """Test that invalid path formats return the original string."""
     invalid_paths = [