MAINT: Adding URL validation for openai responses targets

pyrit/prompt_target/openai/openai_response_target.py

@@ -120,6 +120,9 @@ def __init__(
         super().__init__(api_version=api_version, temperature=temperature, top_p=top_p, **kwargs)
         self._max_output_tokens = max_output_tokens
 
+        # Validate endpoint URL for OpenAI Response API
+        self._validate_endpoint_url()
+
         # Reasoning parameters are not yet supported by PyRIT.
         # See https://platform.openai.com/docs/api-reference/responses/create#responses-create-reasoning
         # for more information.
@@ -136,6 +139,29 @@ def _set_openai_env_configuration_vars(self) -> None:
         self.api_key_environment_variable = "OPENAI_RESPONSES_KEY"
         return
 
+    def _validate_endpoint_url(self) -> None:
+        """
+        Validate that the endpoint URL ends with the correct path for OpenAI Response API.
+
+        Prints a warning if the endpoint doesn't end with '/openai/responses' for OpenAI or Azure OpenAI endpoints.
+        This validation helps ensure the endpoint is configured correctly for the Response API.
+        """
+        if not self._endpoint:
+            return
+
+        endpoint_lower = self._endpoint.lower()
+
+        # Check if this is an OpenAI or Azure OpenAI endpoint
+        is_openai_endpoint = False
+        if "openai.com" in endpoint_lower or "openai.azure.com" in endpoint_lower or "azure.com" in endpoint_lower:
+            is_openai_endpoint = True
+
+        if is_openai_endpoint and not self._endpoint.endswith("/openai/responses"):
+            logger.warning(
+                f"Warning: Expected endpoint to end with '/openai/responses'. "
+                f"Please verify your endpoint: Your endpoint is '{self._endpoint}'."
+            )
+
     # Helpers kept on the class for reuse + testability
     def _flush_message(self, role: Optional[str], content: List[Dict[str, Any]], output: List[Dict[str, Any]]) -> None:
         """