diff --git a/dlrover/python/diagnosis/common/constants.py b/dlrover/python/diagnosis/common/constants.py
index a0309562e..a55a2a864 100644
--- a/dlrover/python/diagnosis/common/constants.py
+++ b/dlrover/python/diagnosis/common/constants.py
@@ -33,6 +33,7 @@ class InferenceConfigKey(object):
 
 class DiagnosisConstant(object):
     MASTER_DIAGNOSIS_OBSERVING_INTERVAL_SECS = 180
+    # the minimum diagnosis interval is 5 seconds
     AGENT_PERIODICALLY_DIAGNOSIS_INTERVAL_SECS = 5
     AGENT_PERIODICALLY_REPORT_INTERVAL_SECS = 15
     MASTER_INSTANCE = -1
diff --git a/dlrover/python/diagnosis/inferencechain/inferenceoperator/resolver/resolve_gpu_errors_operator.py b/dlrover/python/diagnosis/inferencechain/inferenceoperator/resolver/resolve_gpu_errors_operator.py
index a604e74d1..3bf2f3c56 100644
--- a/dlrover/python/diagnosis/inferencechain/inferenceoperator/resolver/resolve_gpu_errors_operator.py
+++ b/dlrover/python/diagnosis/inferencechain/inferenceoperator/resolver/resolve_gpu_errors_operator.py
@@ -32,7 +32,9 @@
 
 class ResolveGPUErrorsOperator(InferenceOperator):
     """
-    ResolveGPUErrorsOperator is to diagnose GPU errors
+    ResolveGPUErrorsOperator is to diagnose GPU errors like:
+    1. GPU lost. This error will be reported to the master and
+    the master will expose this error at this moment.
     """
 
     def __init__(self):
diff --git a/dlrover/python/elastic_agent/diagnosis/diagnosis_agent.py b/dlrover/python/elastic_agent/diagnosis/diagnosis_agent.py
index 35b1a107a..f0808b18b 100644
--- a/dlrover/python/elastic_agent/diagnosis/diagnosis_agent.py
+++ b/dlrover/python/elastic_agent/diagnosis/diagnosis_agent.py
@@ -57,10 +57,10 @@
 
 class DiagnosisAgent(Singleton):
     def __init__(
-            self,
-            training_log_file="",
-            errors="",
-            rank=-1,
+        self,
+        training_log_file="",
+        errors="",
+        rank=-1,
     ):
         self._client = MasterClient.singleton_instance()
         self._training_log_file = training_log_file
@@ -168,7 +168,7 @@ def _observe(self, observe_problems: List[Inference]) -> List[Inference]:
                 logger.error(f"fail to observe problem {problem}: {e}")
         new_obs: List[Inference] = []
         for ob in observations:
-            if not is_inference_included(self._observe_problems, ob):
+            if not is_inference_included(observe_problems, ob):
                 new_obs.append(ob)
         return new_obs