diff --git a/open-sse/handlers/chatCore.ts b/open-sse/handlers/chatCore.ts
index b66aab7362..024cca1839 100644
--- a/open-sse/handlers/chatCore.ts
+++ b/open-sse/handlers/chatCore.ts
@@ -1776,8 +1776,8 @@ export async function handleChatCore({
     // Sanitize response for OpenAI SDK compatibility
     // Strips non-standard fields (x_groq, usage_breakdown, service_tier, etc.)
     // Extracts <think> and <thinking> tags into reasoning_content
-    // Target format determines output shape. If we are outputting OpenAI shape or pseudo-OpenAI shape, sanitize.
-    if (targetFormat === FORMATS.OPENAI || targetFormat === FORMATS.OPENAI_RESPONSES) {
+    // Source format determines output shape. If we are outputting OpenAI shape or pseudo-OpenAI shape, sanitize.
+    if (sourceFormat === FORMATS.OPENAI || sourceFormat === FORMATS.OPENAI_RESPONSES) {
       translatedResponse = sanitizeOpenAIResponse(translatedResponse);
     }
 
diff --git a/open-sse/utils/stream.ts b/open-sse/utils/stream.ts
index e5f264f34c..c17c00cc33 100644
--- a/open-sse/utils/stream.ts
+++ b/open-sse/utils/stream.ts
@@ -585,9 +585,9 @@ export function createSSEStream(options: StreamOptions = {}) {
               // Content for call log is accumulated only from parsed (above) to avoid double-counting;
               // do not add again from item here.
 
-              // #723, #727: Sanitize intermediate stream chunks if target is OpenAI format loop
+              // #723, #727: Sanitize intermediate stream chunks if source (client) is OpenAI format
               let itemSanitized: Record<string, unknown> = item;
-              if (targetFormat === FORMATS.OPENAI || targetFormat === FORMATS.OPENAI_RESPONSES) {
+              if (sourceFormat === FORMATS.OPENAI || sourceFormat === FORMATS.OPENAI_RESPONSES) {
                 itemSanitized = sanitizeStreamingChunk(itemSanitized) as Record<string, unknown>;
 
                 // Extract reasoning tags from content if translation generated them