diff --git a/src/interface.jl b/src/interface.jl
index 3fb3bcf..1876597 100644
--- a/src/interface.jl
+++ b/src/interface.jl
@@ -33,7 +33,7 @@ using ..type, ..mcts, ..util
     a known state. 1.0 balance between exploration and exploitation like 50%-50%. 2.0 makes MCTS
     aggressively explore new state (default: 1.0)
   - `earlystop::Union{Function,Nothing}`
-    optional function to check early stopping condition (default: nothing)
+    optional function to check early stopping condition if it is satisfied, MCTS will break iterations (default: nothing)
   - `saveSimulatedNode::Bool`
     whether to save nodes created during simulation phase (default: false)
   - `multithread::Bool`