address greptile review feedback (greploop iteration 1)

- Restore backward compat for leading assistant(tool_calls) — always prepend user_continue
- Replace partial assertions with full list assertion in trailing tool-call test

Made-with: Cursor

litellm/litellm_core_utils/prompt_templates/common_utils.py

@@ -287,11 +287,9 @@ def _insert_user_continue_message(
     result_messages = messages.copy()  # Don't modify the input list
     continue_message = user_continue_message or DEFAULT_USER_CONTINUE_MESSAGE
 
-    # Handle first counted message if it's an assistant message
-    if (
-        result_messages[0]["role"] == "assistant"
-        and _counts_for_alternation(result_messages[0])
-    ):
+    # Handle first message if it's an assistant message — always prepend
+    # user_continue regardless of tool_calls, to preserve backward compatibility.
+    if result_messages[0]["role"] == "assistant":
         result_messages.insert(0, continue_message)
 
     # Handle consecutive assistant messages in the counted sequence

tests/llm_translation/test_prompt_factory.py

@@ -929,12 +929,25 @@ def test_ensure_alternating_roles_trailing_tool_call_assistant():
         ensure_alternating_roles=True,
     )
 
-    # Backward compat: trailing assistant (even with tool_calls) gets user_continue
-    # appended, then assistant_continue bridges the user→user gap.
-    assert transformed_messages[-1] == {"role": "user", "content": "Please continue."}
-    assert transformed_messages[0] == {"role": "user", "content": "What's the weather?"}
-    assert transformed_messages[1]["role"] == "assistant"
-    assert transformed_messages[1].get("tool_calls") is not None
+    assert transformed_messages == [
+        {"role": "user", "content": "What's the weather?"},
+        {
+            "role": "assistant",
+            "content": None,
+            "tool_calls": [
+                {
+                    "id": "call_abc",
+                    "type": "function",
+                    "function": {
+                        "name": "get_weather",
+                        "arguments": '{"location": "NYC"}',
+                    },
+                }
+            ],
+        },
+        {"role": "assistant", "content": "Please continue."},
+        {"role": "user", "content": "Please continue."},
+    ]
 
 
 def test_alternating_roles_e2e():