diff --git a/tests/proxy_e2e_anthropic_messages_tests/test_config.yaml b/tests/proxy_e2e_anthropic_messages_tests/test_config.yaml
index e9f7342df8..fbbb6d4114 100644
--- a/tests/proxy_e2e_anthropic_messages_tests/test_config.yaml
+++ b/tests/proxy_e2e_anthropic_messages_tests/test_config.yaml
@@ -40,6 +40,7 @@ model_list:
     litellm_params:
       model: "azure_ai/claude-opus-4.5"
       api_key: os.environ/AZURE_AI_API_KEY
+      api_base: os.environ/AZURE_AI_API_BASE
 
   # Vertex AI models
   - model_name: vertex-ai-claude-opus-4-6