diff --git a/src/interface.jl b/src/interface.jl
index ea69ca2..b54b947 100644
--- a/src/interface.jl
+++ b/src/interface.jl
@@ -32,8 +32,8 @@ using ..type, ..mcts
     aggressively explore new state.
 
 # Return
-  - `plan::Vector{Dict}`
-    best plan
+  - `(bestNextState, BestFinalState)::Tuple`
+    the best next state and the best final state
 
 # Example
 ```jldoctest
@@ -41,8 +41,7 @@ julia>
 ```
 
 # TODO
-  [x] update docstring
-  [] return best action
+  [] update example
 
 # Signature
 """
@@ -55,7 +54,7 @@ function runMCTS(
   maxdepth::Integer=3, 
   maxiterations::Integer=10, 
   explorationweight::Number=1.0,
-  )
+  )::Tuple
   
   root = MCTSNode("root", initialstate, 0, 0, 0, 0, false, nothing, Dict{String, MCTSNode}())