fix(gemini): return malformed Anthropic messages as an invalid request instead of raising from the token counter

litellm/llms/gemini/count_tokens/transformation.py

@@ -54,9 +54,12 @@ def build_count_tokens_payload(raw: AnthropicCountTokensInput) -> GeminiCountTok
     request: Final = _validated_request(raw)
     if isinstance(request, InvalidAnthropicRequest):
         return request
-    openai_request, _ = LiteLLMAnthropicMessagesAdapter().translate_anthropic_to_openai(
-        request, custom_llm_provider="gemini"
-    )
+    try:
+        openai_request, _ = LiteLLMAnthropicMessagesAdapter().translate_anthropic_to_openai(
+            request, custom_llm_provider="gemini"
+        )
+    except (KeyError, TypeError, ValueError) as e:
+        return InvalidAnthropicRequest(message=f"Invalid Anthropic Messages request: {e!r}")
     system_instruction, remaining_messages = _transform_system_message(
         supports_system_message=True, messages=openai_request["messages"]
     )

tests/test_litellm/llms/gemini/count_tokens/test_transformation.py

@@ -138,3 +138,12 @@ def test_tools_that_are_not_a_list_are_rejected_as_invalid():
 
     assert isinstance(result, InvalidAnthropicRequest), result
     assert "tools" in result.message, result.message
+
+
+def test_message_without_a_role_is_rejected_as_invalid_not_raised():
+    result = build_count_tokens_payload(
+        {"model": MODEL, "messages": [{"content": "hi"}], "system": None, "tools": None}
+    )
+
+    assert isinstance(result, InvalidAnthropicRequest), result
+    assert "role" in result.message, result.message