diff --git a/src/interface.jl b/src/interface.jl
index 12dad7f..e9f0be9 100644
--- a/src/interface.jl
+++ b/src/interface.jl
@@ -110,9 +110,9 @@ function conversation(a::T, userinput::Dict) where {T<:agent}
     else    #[WORKING] new thinking 
       initialState = Dict(
         :info=> Dict(),           # keyword info
-        :thought=> nothing,
-        :action=> nothing,
-        :observation=> nothing,
+        :thoughtHistory=> Dict( # contain question, thought_1, action_1, observation_1, thought_2, ...
+          :question=> userinput[:text],
+        )  
       )
       bestplan = runMCTS(initialState, decisionMaker, stateValueEstimator, reflector,
                   3, 10, 1000, 1.0)
diff --git a/src/mcts.jl b/src/mcts.jl
index 9f59408..e2f47e9 100644
--- a/src/mcts.jl
+++ b/src/mcts.jl
@@ -17,11 +17,24 @@ using GeneralUtils
   Arguments\n
   -----
     state::T
-      Represent a state of a game. Can be a Dict or something else.
+      a state of a game. Can be a Dict or something else. 
+      For example:
+      state = Dict(
+        :info=> Dict(),           # keyword info
+        :thoughtHistory=> Dict(
+          :question=> _,
+          :thought_1=> _, 
+          :action_1=> _, 
+          :observation_1=> _, 
+          :thought_2=> _,
+          ...
+        )  
+      )
     visits::Integer 
       number of time the game visits this state
     stateValue::Float64
-    
+      state value
+
   Return\n
   -----
 
@@ -46,7 +59,7 @@ struct MCTSNode{T}
   children::Dict{T, MCTSNode}
 end
 
-"""
+""" Select a node based on UCT score
 
   Arguments\n
   -----
@@ -87,10 +100,16 @@ function select(node::MCTSNode, w::Float64)
     return selectedNode
 end
 
-"""
+""" Expand selected node 
 
   Arguments\n
   -----
+    node::MCTSNode
+      MCTS node
+    state::T
+      a state of a game. Can be a Dict or something else.
+    decisionMaker::Function
+      
     
   Return\n
   -----
@@ -114,6 +133,7 @@ function expand(node::MCTSNode, state::T, decisionMaker::Function, stateValueEst
 
   # sampling action from decisionMaker
   for sample in 1:n
+    result = decisionMaker(state)
     newState = transition(node.state, action)  #[] Implement your transition function
     if newState ∉ keys(node.children)
         node.children[newState] = MCTSNode(newState, 0, 0.0, Dict{T, MCTSNode}())
@@ -262,7 +282,7 @@ isLeaf(node::MCTSNode)::Bool = isempty(node.children)
   -----
     [] update docstring
     [] implement the function
-    [] implement RAG to pull similar experience
+    [WORKING] implement RAG to pull similar experience
 
   Signature\n
   -----
@@ -350,6 +370,32 @@ function isTerminal()
 
 end
 
+"""
+
+  Arguments\n
+  -----
+    
+  Return\n
+  -----
+
+  Example\n
+  -----
+  ```jldoctest
+  julia> 
+  ```
+
+  TODO\n
+  -----
+    [] update docstring
+    [WORKING] implement the function
+
+  Signature\n
+  -----
+"""
+function executeLLMFunction()
+
+end
+
 
 # ------------------------------------------------------------------------------------------------ #
 #                    Create a complete example using the defined MCTS functions                    #
diff --git a/src/util.jl b/src/util.jl
index aff186d..dff6540 100644
--- a/src/util.jl
+++ b/src/util.jl
@@ -1,6 +1,6 @@
 module util
 
-export clearhistory, addNewMessage
+export clearhistory, addNewMessage, formatLLMtext, formatLLMtext_llama3instruct
 
 using UUIDs, Dates, DataStructures, HTTP, MQTTClient, JSON3
 using GeneralUtils
@@ -101,22 +101,114 @@ end
   Signature\n
   -----
 """
-function addNewMessage(a::T1, role::String, text::T2; 
+function addNewMessage(a::T1, name::String, text::T2; 
                       maximumMsg::Integer=20) where {T1<:agent, T2<:AbstractString}
-  if role ∉ ["system", "user", "assistant"]   # guard against typo
-    error("role is not in agent.availableRole $(@__LINE__)")
+  if name ∉ ["system", "user", "assistant"]   # guard against typo
+    error("name is not in agent.availableRole $(@__LINE__)")
   end
 
   #[] summarize the oldest 10 message
   if length(a.chathistory) > maximumMsg
     summarize(a.chathistory)
   else
-    d = Dict(:role=> role, :text=> text, :timestamp=> Dates.now())
+    d = Dict(:name=> name, :text=> text, :timestamp=> Dates.now())
     push!(a.chathistory, d)
   end
 end
 
 
+""" Convert a chat dictionary into LLM model instruct format.
+
+  Arguments\n
+  -----
+    name::T
+      message owner name e.f. "system", "user" or "assistant"
+    text::T
+
+  Return\n
+  -----
+    formattedtext::String
+      text formatted to model format
+
+  Example\n
+  -----
+  ```jldoctest
+  julia> using Revise
+  julia> d = Dict(:name=> "system",:text=> "You are a helpful, respectful and honest assistant.",)
+  julia> formattedtext = formatLLMtext_llama3instruct(d[:name], d[:text])
+  ```
+
+  Signature\n
+  -----
+"""
+function formatLLMtext_llama3instruct(name::T, text::T) where {T<:AbstractString}
+  formattedtext = 
+  if name == "system"
+    """<|begin_of_text|>
+      <|start_header_id|>$name<|end_header_id|>
+      $text
+      <|eot_id|>
+    """
+  else
+    """
+      <|start_header_id|>$name<|end_header_id|>
+      $text
+      <|eot_id|>
+    """
+  end
+
+  return formattedtext
+end
+
+
+
+""" Convert a chat messages in vector of dictionary into LLM model instruct format.
+
+  Arguments\n
+  -----
+    messages::Vector{Dict{Symbol, T}}
+      message owner name e.f. "system", "user" or "assistant"
+    formatname::T
+      format name to be used
+
+  Return\n
+  -----
+    formattedtext::String
+      text formatted to model format
+
+  Example\n
+  -----
+  ```jldoctest
+  julia> using Revise
+  julia> chatmessage = [
+            Dict(:name=> "system",:text=> "You are a helpful, respectful and honest assistant.",),
+            Dict(:name=> "user",:text=> "list me all planets in our solar system.",),
+          ]
+  julia> formattedtext = formatLLMtext(chatmessage, "llama3instruct")
+  ```
+
+  Signature\n
+  -----
+"""
+function formatLLMtext(messages::Vector{Dict{Symbol, T}}, 
+                      formatname::String="llama3instruct") where {T<:Any}
+  f = if formatname == "llama3instruct"
+    formatLLMtext_llama3instruct
+  elseif formatname == "mistral"
+    # not define yet
+  else
+    error("$formatname template not define yet")
+  end
+
+  str = ""
+  for t in messages
+    str *= f(t[:name], t[:text])
+  end
+
+  return str
+end
+
+
 
 
 
@@ -168,7 +260,6 @@ end
 
 
 
-
 
 
 end # module util
\ No newline at end of file