diff --git a/src/interface.jl b/src/interface.jl
index c42ab8a..7dfc94e 100644
--- a/src/interface.jl
+++ b/src/interface.jl
@@ -23,7 +23,7 @@ using LLMMCTS, GeneralUtils
     A number to limit how many attempt will be made.
   
 # Return
-  - `(response, errormsg, success)::@NamedTuple{response::String, errormsg::String, success::Bool}`
+  - `NamedTuple{(:result, :errormsg, :success), Tuple{Union{String, Nothing}, Union{String, Nothing}, Bool}}`
     if success=`true`, response is a valid JSON string. otherwise, check errormsg. 
 
 # Example
@@ -92,7 +92,7 @@ julia> println(result)
 # Signature
 """
 function jsoncorrection(jsonstring::T, example::String, commfunction::Function; maxattempt=3
-  )::@NamedTuple{response::String, errormsg::String, success::Bool} where {T<:AbstractString}
+)::NamedTuple{(:result, :errormsg, :success), Tuple{Union{String, Nothing}, Union{String, Nothing}, Bool}} where {T<:AbstractString}
 
   initialstate = Dict{Symbol, Any}(
     :reward=> 0,
@@ -116,9 +116,9 @@ function jsoncorrection(jsonstring::T, example::String, commfunction::Function;
                           totalsample=1, maxdepth=(maxattempt-1), maxiterations=1, explorationweight=1.0)
 
   if result[:isterminal] == true
-    return (response=result[:code], errormsg="nothing", success=true)
+    return (result=result[:code], errormsg=nothing, success=true)
   else
-    return (response="nothing", errormsg=result[:errorexplain], success=false)
+    return (result=nothing, errormsg=result[:errorexplain], success=false)
   end
 end