diff --git a/litellm/llms/anthropic/experimental_pass_through/messages/transformation.py b/litellm/llms/anthropic/experimental_pass_through/messages/transformation.py
index 9f318cf84b1..49dd758a8f3 100644
--- a/litellm/llms/anthropic/experimental_pass_through/messages/transformation.py
+++ b/litellm/llms/anthropic/experimental_pass_through/messages/transformation.py
@@ -225,8 +225,6 @@ class AnthropicMessagesConfig(BaseAnthropicMessagesConfig):
         stream: bool | None = None,
     ) -> str:
         api_base = AnthropicModelInfo.get_api_base(api_base) or "https://api.anthropic.com"
-        # Normalize like OpenAILikeAnthropicMessagesConfig: an api_base that
-        # already ends in /v1 must not become /v1/v1/messages.
         base = api_base.rstrip("/")
         if base.endswith("/v1/messages"):
             return base
diff --git a/tests/test_litellm/llms/anthropic/experimental_pass_through/messages/test_anthropic_messages_get_complete_url.py b/tests/test_litellm/llms/anthropic/experimental_pass_through/messages/test_anthropic_messages_get_complete_url.py
index 80f4fbd8f68..46082bb8198 100644
--- a/tests/test_litellm/llms/anthropic/experimental_pass_through/messages/test_anthropic_messages_get_complete_url.py
+++ b/tests/test_litellm/llms/anthropic/experimental_pass_through/messages/test_anthropic_messages_get_complete_url.py
@@ -13,24 +13,20 @@ def config() -> AnthropicMessagesConfig:
 @pytest.mark.parametrize(
     "api_base, expected",
     [
-        # default when no api_base is configured
         (None, "https://api.anthropic.com/v1/messages"),
-        # bases without a version suffix
         ("https://host", "https://host/v1/messages"),
         ("https://host/", "https://host/v1/messages"),
-        # bases that already carry /v1 must not become /v1/v1/messages
         ("https://host/v1", "https://host/v1/messages"),
         ("https://host/v1/", "https://host/v1/messages"),
         ("https://api.groq.com/openai/v1", "https://api.groq.com/openai/v1/messages"),
-        # full endpoint passes through untouched
         ("https://host/v1/messages", "https://host/v1/messages"),
-        # provider-prefixed path segments are preserved
         ("https://gateway.example.com/anthropic", "https://gateway.example.com/anthropic/v1/messages"),
         ("https://gateway.example.com/anthropic/v1", "https://gateway.example.com/anthropic/v1/messages"),
     ],
 )
 def test_get_complete_url_deduplicates_trailing_v1(config, api_base, expected, monkeypatch):
     monkeypatch.delenv("ANTHROPIC_API_BASE", raising=False)
+    monkeypatch.delenv("ANTHROPIC_BASE_URL", raising=False)
     url = config.get_complete_url(
         api_base=api_base,
         api_key="sk-test",