diff --git a/python/sglang/srt/constrained/reasoner_grammar_backend.py b/python/sglang/srt/constrained/reasoner_grammar_backend.py
index 5fe7b0c8c00a..0179d3426001 100644
--- a/python/sglang/srt/constrained/reasoner_grammar_backend.py
+++ b/python/sglang/srt/constrained/reasoner_grammar_backend.py
@@ -51,6 +51,9 @@ def accept_token(self, token: int):
             self.grammar.accept_token(token)
         self.transfer_state(token)
 
+    def is_terminated(self):
+        return self.grammar.is_terminated()
+
     def rollback(self, k):
         steps_after_think = min(k, self.tokens_after_think_end)
         if steps_after_think > 0: