diff --git a/scripts/batch_o3_prompts.py b/scripts/batch_o3_prompts.py
index 044ec19..df6ad8b 100644
--- a/scripts/batch_o3_prompts.py
+++ b/scripts/batch_o3_prompts.py
@@ -46,13 +46,19 @@ def write_output(path: Path, record: Dict[str, Any]) -> None:
 
 
 def call_o3(prompt: str) -> str:
-    response = client.completions.create(
+    """
+    Send the prompt to the chat-completions endpoint (OpenAI ≥ 1.0.0).
+
+    The prompt is wrapped in a single user message so the new API remains
+    compatible with the existing template-based workflow.
+    """
+    response = client.chat.completions.create(
         model=MODEL,
-        prompt=prompt,
+        messages=[{"role": "user", "content": prompt}],
         max_tokens=1024,
         temperature=0.7,
     )
-    return response.choices[0].text.strip()
+    return response.choices[0].message.content.strip()
 
 
 def main(argv: list[str] | None = None) -> None: