diff --git a/slime/utils/arguments.py b/slime/utils/arguments.py
index 4a7f608f1..964bf00d3 100644
--- a/slime/utils/arguments.py
+++ b/slime/utils/arguments.py
@@ -1575,13 +1575,12 @@ def slime_validate_args(args):
         )
         args.eval_max_context_len = args.rollout_max_context_len
 
-    if args.rollout_max_prompt_len is None and args.rollout_max_context_len is not None:
-        logger.info(
-            f"args.rollout_max_prompt_len is not set. Use args.rollout_max_context_len - 1 ({args.rollout_max_context_len} - 1) as default value so that there is at least one generated token to compute loss."
-        )
-        args.rollout_max_prompt_len = args.rollout_max_context_len - 1
-
-    if args.rollout_max_prompt_len is not None and args.rollout_max_context_len is not None:
+    if args.rollout_max_context_len is not None:
+        if args.rollout_max_prompt_len is None:
+            args.rollout_max_prompt_len = args.rollout_max_context_len - 1
+            logger.info(
+                f"args.rollout_max_prompt_len is not set. Use args.rollout_max_context_len - 1 ({args.rollout_max_context_len} - 1) as default value so that there is at least one generated token to compute loss."
+            )
         assert (
             args.rollout_max_prompt_len <= args.rollout_max_context_len - 1
         ), f"args.rollout_max_prompt_len ({args.rollout_max_prompt_len}) must be smaller than args.rollout_max_context_len ({args.rollout_max_context_len}) so that there is at least one generated token to compute loss."