diff --git a/‎src/triframe_inspect/util/choices.py‎
Lines changed: 6 additions & 4 deletions b/‎src/triframe_inspect/util/choices.py‎
Lines changed: 6 additions & 4 deletions
@@ -15,7 +15,7 @@ async def generate_choices(
     settings: TriframeSettings,
     desired_choices: int = 3,
 ) -> List[ModelOutput]:
-    """Generate multiple model responses, handling Anthropic models specially.
+    """Generate multiple model responses, handling Anthropic and OAI reasoning models specially.
 
     Args:
         model: The model to use for generation
@@ -28,9 +28,11 @@ async def generate_choices(
         List of ModelOutput objects containing all generated results
     """
     is_anthropic = model.name.startswith("claude")
+    is_o_series = model.name.startswith("o3") or model.name.startswith("o1")
 
-    if is_anthropic:
-        # For Anthropic, make multiple single-choice requests
+    if is_anthropic or is_o_series:
+        # For Anthropic and o-series models, make multiple single-choice requests
+        # o-series models use Responses API which doesn't support num_choices
         config = GenerateConfig(
             **{k: v for k, v in settings.items() if k != "num_choices"}
         )
@@ -40,7 +42,7 @@ async def generate_choices(
         ]
         return await asyncio.gather(*requests)
 
-    # For non-Anthropic models, use num_choices parameter
+    # For other models, use num_choices parameter
     config = GenerateConfig(**{**settings, "num_choices": desired_choices})
     result = await model.generate(input=messages, tools=tools, config=config)
     return [result]