diff --git a/src/model/openai.ts b/src/model/openai.ts
index b46dd88..f89a7a2 100644
--- a/src/model/openai.ts
+++ b/src/model/openai.ts
@@ -49,15 +49,17 @@ export class OpenAIResponsesClient implements ModelClient {
         : []
     );
 
+    const outputText = response.output_text ?? "";
+
     await this.events?.emit("model.response", {
       outputItems: response.output.length,
       toolCalls: toolCalls.map((toolCall) => toolCall.name),
-      hasText: response.output_text.length > 0
+      hasText: outputText.length > 0
     });
 
     return {
-      output: response.output,
-      outputText: response.output_text,
+      output: sanitizeOutputItems(response.output),
+      outputText,
       toolCalls
     };
   }
@@ -105,16 +107,29 @@ export class OpenAIResponsesClient implements ModelClient {
         : []
     );
 
+    const outputText = response.output_text ?? "";
+
     await this.events?.emit("model.response", {
       outputItems: response.output.length,
       toolCalls: toolCalls.map((toolCall) => toolCall.name),
-      hasText: response.output_text.length > 0
+      hasText: outputText.length > 0
     });
 
     return {
-      output: response.output,
-      outputText: response.output_text,
+      output: sanitizeOutputItems(response.output),
+      outputText,
       toolCalls
     };
   }
 }
+
+function sanitizeOutputItems(items: unknown[]): unknown[] {
+  return JSON.parse(
+    JSON.stringify(items, (key, value) => {
+      if (key === "parsed_arguments") {
+        return undefined;
+      }
+      return value;
+    })
+  ) as unknown[];
+}