diff --git a/litellm/llms/parallel_ai/search/transformation.py b/litellm/llms/parallel_ai/search/transformation.py
index 3092674363b..bf4b19b1d09 100644
--- a/litellm/llms/parallel_ai/search/transformation.py
+++ b/litellm/llms/parallel_ai/search/transformation.py
@@ -214,6 +214,10 @@ class ParallelAISearchConfig(BaseSearchConfig):
         # unified-spec param with no v1 equivalent
         params.pop("max_tokens_per_page", None)
 
+        # reserved for the provider's own reported usage, which prices the request;
+        # a caller-supplied value would otherwise set its own cost
+        params.pop(PARALLEL_AI_USAGE_PARAM, None)
+
         return {**request_data, **params}
 
     def transform_search_response(
@@ -237,11 +241,12 @@ class ParallelAISearchConfig(BaseSearchConfig):
         """
         parsed: Final = _ParallelAIV1SearchResponse.model_validate(raw_response.json())
 
-        if parsed.usage is not None:
-            logging_obj.optional_params = {
-                **logging_obj.optional_params,
-                PARALLEL_AI_USAGE_PARAM: parsed.usage,
-            }
+        # written unconditionally: leaving a caller-supplied value in place when the
+        # provider reports no usage would let the caller price its own request
+        logging_obj.optional_params = {
+            **logging_obj.optional_params,
+            PARALLEL_AI_USAGE_PARAM: parsed.usage,
+        }
 
         results: Final = tuple(
             SearchResult.model_validate(
diff --git a/tests/test_litellm/llms/parallel_ai/test_parallel_ai_search.py b/tests/test_litellm/llms/parallel_ai/test_parallel_ai_search.py
index 38846c741cc..337d2314831 100644
--- a/tests/test_litellm/llms/parallel_ai/test_parallel_ai_search.py
+++ b/tests/test_litellm/llms/parallel_ai/test_parallel_ai_search.py
@@ -472,3 +472,27 @@ class TestParallelAISearch:
             )
 
             assert response._hidden_params["response_cost"] == pytest.approx(0.005)
+
+    @pytest.mark.asyncio
+    async def test_caller_cannot_supply_provider_usage(self, bundled_cost_map):
+        """`_parallel_ai_usage` prices the request, so a caller must not be able to set it.
+
+        The provider reports no usage here, which is the case where a caller-supplied
+        value would otherwise survive into the cost calculation.
+        """
+        response_payload = {k: v for k, v in MOCK_V1_RESPONSE.items() if k != "usage"}
+        with patch(
+            "litellm.llms.custom_httpx.http_handler.AsyncHTTPHandler.post",
+            new_callable=AsyncMock,
+        ) as mock_post:
+            mock_post.return_value = _mock_response(response_payload)
+
+            response = await litellm.asearch(
+                query="AI developments",
+                search_provider="parallel_ai",
+                mode="basic",
+                _parallel_ai_usage=[{"name": "sku_search", "count": 0}],
+            )
+
+            assert response._hidden_params["response_cost"] == pytest.approx(0.005)
+            assert "_parallel_ai_usage" not in mock_post.call_args.kwargs["json"]