diff --git a/agent/error_classifier.py b/agent/error_classifier.py
index 3489c66c949b1..84438e087ab23 100644
--- a/agent/error_classifier.py
+++ b/agent/error_classifier.py
@@ -661,7 +661,8 @@ def _result(reason: FailoverReason, **overrides) -> ClassifiedError:
     if (
         status_code == 400
         and (
-            "error parsing grammar" in error_msg
+            "failed to parse grammar" in error_msg
+            or "error parsing grammar" in error_msg
             or "json-schema-to-grammar" in error_msg
             or (
                 "unable to generate parser" in error_msg
diff --git a/tests/agent/test_error_classifier.py b/tests/agent/test_error_classifier.py
index 6c533089986ce..6f36f441e1a6f 100644
--- a/tests/agent/test_error_classifier.py
+++ b/tests/agent/test_error_classifier.py
@@ -857,6 +857,17 @@ def test_llama_cpp_grammar_parse_error(self):
         assert result.retryable is True
         assert result.should_compress is False
 
+    def test_llama_cpp_failed_to_parse_grammar(self):
+        """Newer llama.cpp builds return 'Failed to initialize samplers: failed to parse grammar'."""
+        e = MockAPIError(
+            "Failed to initialize samplers: failed to parse grammar",
+            status_code=400,
+        )
+        result = classify_api_error(e, provider="openai-compatible")
+        assert result.reason == FailoverReason.llama_cpp_grammar_pattern
+        assert result.retryable is True
+        assert result.should_compress is False
+
     def test_llama_cpp_unable_to_generate_parser(self):
         """Older llama.cpp builds surface the error as 'unable to generate parser'."""
         e = MockAPIError(