diff --git a/backend/internal/service/openai_gateway_chat_completions_raw.go b/backend/internal/service/openai_gateway_chat_completions_raw.go
index 7427c6fc9c..9d7234dd96 100644
--- a/backend/internal/service/openai_gateway_chat_completions_raw.go
+++ b/backend/internal/service/openai_gateway_chat_completions_raw.go
@@ -156,6 +156,10 @@ func (s *OpenAIGatewayService) forwardAsRawChatCompletions(
 		if err != nil {
 			return nil, fmt.Errorf("normalize Grok chat reasoning effort: %w", err)
 		}
+		upstreamBody, err = sanitizeGrokUnsupportedFields(upstreamBody)
+		if err != nil {
+			return nil, fmt.Errorf("sanitize Grok unsupported fields: %w", err)
+		}
 	}
 	upstreamBody = applyOllamaCloudRawChatCompletionsRequest(account, upstreamBody)
 
diff --git a/backend/internal/service/openai_gateway_grok.go b/backend/internal/service/openai_gateway_grok.go
index 21c7342356..34fdc82e67 100644
--- a/backend/internal/service/openai_gateway_grok.go
+++ b/backend/internal/service/openai_gateway_grok.go
@@ -752,11 +752,14 @@ func grokSupportsReasoningEffort(model string) bool {
 	}
 }
 
-var grokResponsesUnsupportedRecursiveFields = map[string]struct{}{
+// grokUnsupportedRecursiveFields 定义 Grok 平台（Responses 和 Chat Completions）不支持的字段
+var grokUnsupportedRecursiveFields = map[string]struct{}{
 	"external_web_access": {},
 }
 
-func sanitizeGrokResponsesUnsupportedFields(body []byte) ([]byte, error) {
+// sanitizeGrokUnsupportedFields 递归移除 Grok 平台不支持的字段
+// 适用于 Responses API 和 Chat Completions API
+func sanitizeGrokUnsupportedFields(body []byte) ([]byte, error) {
 	if !bytes.Contains(body, []byte(`"external_web_access"`)) {
 		return body, nil
 	}
@@ -765,12 +768,15 @@ func sanitizeGrokResponsesUnsupportedFields(body []byte) ([]byte, error) {
 	if err := decodeOpenAIJSONUseNumber(body, &payload); err != nil {
 		return nil, err
 	}
-	if !deleteJSONFields(payload, grokResponsesUnsupportedRecursiveFields) {
+	if !deleteJSONFields(payload, grokUnsupportedRecursiveFields) {
 		return body, nil
 	}
 	return marshalOpenAIUpstreamJSON(payload)
 }
 
+// sanitizeGrokResponsesUnsupportedFields 保留旧函数名作为别名，向后兼容
+var sanitizeGrokResponsesUnsupportedFields = sanitizeGrokUnsupportedFields
+
 func deleteJSONFields(value any, fields map[string]struct{}) bool {
 	switch typed := value.(type) {
 	case map[string]any: