diff --git a/lua/fittencode/actions/identify_programming_language.lua b/lua/fittencode/actions/identify_programming_language.lua
index 48c5657..b42532f 100644
--- a/lua/fittencode/actions/identify_programming_language.lua
+++ b/lua/fittencode/actions/identify_programming_language.lua
@@ -7,12 +7,12 @@ local Log = require('fittencode.log')
 
 local M = {}
 
-local DEFER = 1000
+local DEFER = 2000
 
 -- milliseconds
-local IPL_DEBOUNCE_TIME = 500
+local IPL_DEBOUNCE_TIME = 1000
 
----@type uv_timer_t
+---@type uv_timer_t?
 local ipl_timer = nil
 
 local function _identify_current_buffer()
@@ -46,19 +46,26 @@ local function _identify_current_buffer()
   API.identify_programming_language({
     headless = true,
     content = content,
+    preprocess_format = {
+      condense_blank_line = {
+        convert_whitespace_to_blank = true,
+      },
+      trim_trailing_whitespace = true,
+      filter = {
+        count = 1,
+        exclude_markdown_code_blocks_marker = true,
+        remove_blank_lines = true,
+      }
+    },
     on_success = function(suggestions)
       if not suggestions or #suggestions == 0 then
         return
       end
       local lang = suggestions[1]
-      if #lang == 0 then
+      if #lang > 10 then
         return
       end
       lang = lang:lower()
-      lang = lang:gsub('^%s*(.-)%s*$', '%1')
-      if #lang == 0 then
-        return
-      end
       lang = lang:gsub('c%+%+', 'cpp')
       lang = lang:match('^(%w+)')
       api.nvim_set_option_value('filetype', lang, {
@@ -70,7 +77,7 @@ local function _identify_current_buffer()
 end
 
 local function _ipl_wrap()
-  Base.debounce(ipl_timer, function()
+  ipl_timer = Base.debounce(ipl_timer, function()
     _identify_current_buffer()
   end, IPL_DEBOUNCE_TIME)
 end
@@ -79,7 +86,7 @@ local function register_identify_current_buffer()
   api.nvim_create_autocmd({ 'TextChangedI', 'BufReadPost' }, {
     group = Base.augroup('Actions', 'IdentifyProgrammingLanguage'),
     pattern = '*',
-    callback = function(params)
+    callback = function()
       if not API.ready_for_generate() then
         vim.defer_fn(function()
           _ipl_wrap()
diff --git a/lua/fittencode/base.lua b/lua/fittencode/base.lua
index 4f26a1c..f02846b 100644
--- a/lua/fittencode/base.lua
+++ b/lua/fittencode/base.lua
@@ -73,14 +73,10 @@ function M.get_cursor(window)
 end
 
 -- Debounce a function call.
--- * If a timer is already running, reset it.
--- * If a timer is not running, start a new timer with the given `wait` time.
--- * When the timer expires, call the `callback` function.
--- * If an error occurs, call `on_error` with the error message.
----@param timer uv_timer_t|nil
+---@param timer? uv_timer_t
 ---@param callback function
 ---@param wait integer
----@param on_error function|nil
+---@param on_error? function
 function M.debounce(timer, callback, wait, on_error)
   if type(wait) ~= 'number' or wait < 0 then
     return
@@ -88,7 +84,7 @@ function M.debounce(timer, callback, wait, on_error)
     callback()
     return
   end
-  local function destroy_timer()
+  local _destroy_timer = function()
     if timer then
       if timer:has_ref() then
         timer:stop()
@@ -99,7 +95,7 @@ function M.debounce(timer, callback, wait, on_error)
       timer = nil
     end
   end
-  if not timer then
+  local _create_timer = function()
     timer = uv.new_timer()
     if timer == nil then
       if on_error then
@@ -111,13 +107,18 @@ function M.debounce(timer, callback, wait, on_error)
       wait,
       0,
       vim.schedule_wrap(function()
-        destroy_timer()
+        _destroy_timer()
         callback()
       end)
     )
+  end
+  if not timer then
+    _create_timer()
   else
-    timer:again()
+    _destroy_timer()
+    _create_timer()
   end
+  return timer
 end
 
 local function sysname()
diff --git a/lua/fittencode/commands.lua b/lua/fittencode/commands.lua
index 498fbe8..ffd130e 100644
--- a/lua/fittencode/commands.lua
+++ b/lua/fittencode/commands.lua
@@ -174,7 +174,7 @@ function M.setup()
       table.remove(actions, 1)
       return cmd(unpack(actions))
     end
-    Log.debug('Invalid command fargs: {}', line.fargs)
+    -- Log.debug('Invalid command fargs: {}', line.fargs)
   end, {
     complete = function(_, line)
       local args = vim.split(vim.trim(line), '%s+')
diff --git a/lua/fittencode/engines/actions/content.lua b/lua/fittencode/engines/actions/content.lua
index c1c4d6c..627d09e 100644
--- a/lua/fittencode/engines/actions/content.lua
+++ b/lua/fittencode/engines/actions/content.lua
@@ -3,11 +3,11 @@ local Log = require('fittencode.log')
 
 ---@class ActionsContent
 ---@field chat Chat
----@field buffer_content string[][]
 ---@field conversations Conversation[]
 ---@field has_suggestions boolean[]
 ---@field current_eval number
 ---@field cursors table[]
+---@field last_lines string[]?
 ---@field on_start function
 ---@field on_suggestions function
 ---@field on_status function
@@ -26,95 +26,70 @@ local ViewBlock = {
 function M:new(chat)
   local obj = {
     chat = chat,
-    buffer_content = {},
     conversations = {},
     current_eval = nil,
     cursors = {},
     has_suggestions = {},
+    last_lines = nil,
   }
   self.__index = self
   return setmetatable(obj, self)
 end
 
 ---@class ChatCommitFormat
----@field firstlinebreak? boolean
----@field firstlinecompress? boolean
----@field fenced_code? boolean
+---@field start_space? boolean
 
 ---@class ChatCommitOptions
 ---@field lines? string|string[]
 ---@field format? ChatCommitFormat
 
-local fenced_code_open = false
-
----@param opts? ChatCommitOptions|string
----@param content string[]
----@return string[]?
-local function format_lines(opts, content)
-  if not opts then
-    return
-  end
-
-  if type(opts) == 'string' then
-    ---@diagnostic disable-next-line: param-type-mismatch
-    opts = { lines = vim.split(opts, '\n') }
-  end
+---@param line string
+local function _end(line)
+  return line:match('```$')
+end
 
-  ---@type string[]
-  ---@diagnostic disable-next-line: assign-type-mismatch
-  local lines = opts.lines or {}
-  local firstlinebreak = opts.format and opts.format.firstlinebreak
-  local fenced_code = opts.format and opts.format.fenced_code
-  local firstlinecompress = opts.format and opts.format.firstlinecompress
+---@param line string
+local function _start(line)
+  return line:match('^```')
+end
 
-  if #lines == 0 then
-    return
+local function format_lines(last_lines, lines, format)
+  if not format then
+    return lines
   end
-
-  vim.tbl_map(function(x)
-    if x:match('^```') or x:match('```$') then
-      fenced_code_open = not fenced_code_open
-    end
-  end, lines)
-
-  local fenced_sloved = false
-  if fenced_code_open then
-    if fenced_code then
-      if lines[1] ~= '' then
+  local last = last_lines[#last_lines]
+  local first = lines[1]
+  if format.start_space then
+    if not _end(last) then
+      table.insert(lines, 1, '')
+      if not _start(first) and first ~= '' then
+        table.insert(lines, 1, '')
+      end
+    else
+      if first ~= '' then
         table.insert(lines, 1, '')
       end
-      table.insert(lines, 2, '```')
-      fenced_code_open = false
-      fenced_sloved = true
-    end
-  end
-
-  if not fenced_code_open and not fenced_sloved and firstlinebreak and
-      #content > 0 and #lines > 1 then
-    local last_lines = content[#content]
-    local last_line = last_lines[#last_lines]
-    if not string.match(lines[1], '^```') and not string.match(lines[2], '^```') and not string.match(last_line, '^```') then
-      table.insert(lines, 1, '')
-    end
-  end
-
-  if firstlinecompress and #lines > 1 then
-    if lines[1] == '' and string.match(lines[2], '^```') then
-      table.remove(lines, 1)
     end
   end
-
   return lines
 end
 
 ---@param opts? ChatCommitOptions|string
 function M:commit(opts)
-  local lines = format_lines(opts, self.buffer_content)
-  if not lines then
+  if not opts then
     return
   end
-
-  table.insert(self.buffer_content, lines)
+  local lines = nil
+  local format = nil
+  if type(opts) == 'string' then
+    ---@diagnostic disable-next-line: param-type-mismatch
+    lines = vim.split(opts, '\n')
+  elseif type(opts) == 'table' then
+    lines = opts.lines
+    format = opts.format
+  end
+  lines = format_lines(self.last_lines, lines, format)
+  self.last_lines = lines
   return self.chat:commit(lines)
 end
 
@@ -123,20 +98,12 @@ function M:on_start(opts)
     return
   end
   self.current_eval = opts.current_eval
-  self.current_action = opts.current_action
   self.conversations[self.current_eval] = Conversation:new(self.current_eval, opts.action)
-  self.conversations[self.current_eval].current_action = opts.current_action
   self.conversations[self.current_eval].location = opts.location
   self.conversations[self.current_eval].prompt = opts.prompt
-  self.conversations[self.current_eval].headless = opts.headless
-
-  if self.conversations[self.current_eval].headless then
-    self.cursors[self.current_eval] = nil
-    return
-  end
 
   local source_info = ' (' .. opts.location[1] .. ' ' .. opts.location[2] .. ':' .. opts.location[3] .. ')'
-  local c_in = '# In`[' .. self.current_action .. ']`:= ' .. opts.action .. source_info
+  local c_in = '# In`[' .. self.current_eval .. ']`:= ' .. opts.action .. source_info
   if not self.chat:is_empty() then
     self:commit('\n\n')
   end
@@ -163,18 +130,12 @@ function M:on_start(opts)
       '',
     }
   })
-  local c_out = '# Out`[' .. self.current_action .. ']`='
+  local c_out = '# Out`[' .. self.current_eval .. ']`='
   cursor = self:commit({
     lines = {
       c_out,
     }
   })
-  self:commit({
-    lines = {
-      '',
-      '',
-    }
-  })
   self.cursors[self.current_eval][ViewBlock.OUT] = cursor
 end
 
@@ -185,26 +146,16 @@ function M:on_end(opts)
 
   self.conversations[self.current_eval].elapsed_time = opts.elapsed_time
   self.conversations[self.current_eval].depth = opts.depth
+  self.conversations[self.current_eval].suggestions = opts.suggestions
 
-  if self.conversations[self.current_eval].headless then
-    return
-  end
-
-  self:commit({
-    lines = {
-      '',
-      '',
-    },
-    format = {
-      firstlinebreak = true,
-      fenced_code = true,
-    }
-  })
   local qed = '> Q.E.D.' .. '(' .. opts.elapsed_time .. ' ms)'
   local cursor = self:commit({
     lines = {
       qed,
     },
+    format = {
+      start_space = true,
+    }
   })
   self.cursors[self.current_eval][ViewBlock.QED] = cursor
 end
@@ -220,18 +171,12 @@ function M:on_suggestions(suggestions)
   if not suggestions then
     return
   end
-  self.conversations[self.current_eval].suggestions[#self.conversations[self.current_eval].suggestions + 1] = suggestions
-
-  if self.conversations[self.current_eval].headless then
-    return
-  end
-
   if not self.has_suggestions[self.current_eval] then
     self.has_suggestions[self.current_eval] = true
     local cursor = self:commit({
       lines = suggestions,
       format = {
-        firstlinecompress = true,
+        start_space = true,
       }
     })
     self.cursors[self.current_eval][ViewBlock.OUT_CONTENT] = cursor
@@ -248,9 +193,6 @@ function M:on_status(msg)
   if not msg then
     return
   end
-  if self.conversations[self.current_eval].headless then
-    return
-  end
   self:commit({
     lines = {
       '```',
@@ -258,28 +200,13 @@ function M:on_status(msg)
       '```',
     },
     format = {
-      firstlinebreak = true,
-      fenced_code = true,
+      start_space = true,
     }
   })
 end
 
-local function merge_lines(suggestions)
-  local merged = {}
-  for _, lines in ipairs(suggestions) do
-    for i, line in ipairs(lines) do
-      if i == 1 and #merged ~= 0 then
-        merged[#merged] = merged[#merged] .. line
-      else
-        merged[#merged + 1] = line
-      end
-    end
-  end
-  return merged
-end
-
 function M:get_current_suggestions()
-  return merge_lines(self.conversations[self.current_eval].suggestions)
+  return self.conversations[self.current_eval].suggestions
 end
 
 function M:get_conversation_index(row, col)
@@ -297,29 +224,16 @@ function M:get_conversations_range(direction, row, col)
   if not i then
     return
   end
-  if direction == 'current' then
+  if direction == 'forward' then
+    i = i + 1
+  elseif direction == 'backward' then
+    i = i - 1
+  end
+  if self.cursors[i] then
     return {
       { self.cursors[i][ViewBlock.IN][1][1],  0 },
       { self.cursors[i][ViewBlock.QED][2][1], 0 }
     }
-  elseif direction == 'forward' then
-    for j = i + 1, #self.cursors do
-      if self.cursors[j] and #self.cursors[j] == 5 then
-        return {
-          { self.cursors[j][ViewBlock.IN][1][1],  0 },
-          { self.cursors[j][ViewBlock.QED][1][1], 0 }
-        }
-      end
-    end
-  elseif direction == 'backward' then
-    for j = i - 1, 1, -1 do
-      if self.cursors[j] and #self.cursors[j] == 5 then
-        return {
-          { self.cursors[j][ViewBlock.IN][1][1],  0 },
-          { self.cursors[j][ViewBlock.QED][2][1], 0 }
-        }
-      end
-    end
   end
 end
 
diff --git a/lua/fittencode/engines/actions/conversation.lua b/lua/fittencode/engines/actions/conversation.lua
index 1f3ff9e..e8639b3 100644
--- a/lua/fittencode/engines/actions/conversation.lua
+++ b/lua/fittencode/engines/actions/conversation.lua
@@ -3,12 +3,10 @@
 ---@field action string
 ---@field references integer[]
 ---@field prompt string[]
----@field suggestions string[]
+---@field suggestions Suggestions
 ---@field elapsed_time integer
 ---@field depth integer
 ---@field location table -- [filename, row_start, row_end]
----@field headless boolean
----@field current_action integer
 local M = {}
 
 function M:new(id, actions, references)
diff --git a/lua/fittencode/engines/actions/init.lua b/lua/fittencode/engines/actions/init.lua
index ee77fee..485bd4e 100644
--- a/lua/fittencode/engines/actions/init.lua
+++ b/lua/fittencode/engines/actions/init.lua
@@ -6,11 +6,12 @@ local Chat = require('fittencode.views.chat')
 local Config = require('fittencode.config')
 local Content = require('fittencode.engines.actions.content')
 local Log = require('fittencode.log')
+local Merge = require('fittencode.preprocessing.merge')
 local Promise = require('fittencode.concurrency.promise')
 local PromptProviders = require('fittencode.prompt_providers')
 local Sessions = require('fittencode.sessions')
 local Status = require('fittencode.status')
-local SuggestionsPreprocessing = require('fittencode.suggestions_preprocessing')
+local Preprocessing = require('fittencode.preprocessing')
 local TaskScheduler = require('fittencode.tasks')
 local Unicode = require('fittencode.unicode')
 
@@ -19,13 +20,6 @@ local schedule = Base.schedule
 local SC = Status.C
 
 ---@class ActionsEngine
----@field chat Chat
----@field tasks TaskScheduler
----@field status Status
----@field lock boolean
----@field elapsed_time number
----@field depth number
----@field current_eval number
 ---@field start_chat function
 ---@field document_code function
 ---@field edit_code function
@@ -60,7 +54,7 @@ local ACTIONS = {
 }
 
 local current_eval = 1
-local current_action = 1
+local current_headless = 1
 
 ---@type Chat
 local chat = nil
@@ -68,14 +62,14 @@ local chat = nil
 ---@type ActionsContent
 local content = nil
 
----@class TaskScheduler
-local tasks = nil
+local TASK_DEFAULT = 1
+local TASK_HEADLESS = 2
+---@type table<integer, TaskScheduler>
+local tasks = {}
 
 -- One by one evaluation
 local lock = false
 
-local elapsed_time = 0
-local depth = 0
 local MAX_DEPTH = 20
 
 ---@type Status
@@ -86,6 +80,8 @@ local status = nil
 ---@field content? string
 ---@field language? string
 ---@field headless? boolean
+---@field silence? boolean
+---@field preprocess_format? SuggestionsPreprocessingFormat
 ---@field on_success? function
 ---@field on_error? function
 
@@ -116,35 +112,44 @@ end
 ---@param task_id integer
 ---@param suggestions Suggestions
 ---@return Suggestions?, integer?
-local function filter_suggestions(window, buffer, task_id, suggestions)
-  local matched, ms = tasks:match_clean(task_id, 0, 0)
-  if not matched then
-    Log.debug('Action request is outdated, discarding task: {}', task_id)
+local function preprocessing(presug, task_id, headless, preprocess_format, suggestions)
+  local match = headless and tasks[TASK_HEADLESS]:match_clean(task_id, nil, nil, false) or
+      tasks[TASK_DEFAULT]:match_clean(task_id, nil, nil)
+  local ms = match[2]
+  if not match[1] or not suggestions or #suggestions == 0 then
     return nil, ms
   end
-  if not suggestions then
-    return nil, ms
-  end
-  return SuggestionsPreprocessing.run({
-    window = window,
-    buffer = buffer,
+  local opts = {
+    prefix = presug,
     suggestions = suggestions,
-    condense_nl = 'all'
-  }), ms
+    condense_blank_line = {
+      mode = 'all'
+    },
+    replace_slash = true,
+    markdown_prettify = {
+      separate_code_block_marker = true,
+    },
+  }
+  opts = vim.tbl_deep_extend('force', opts, preprocess_format or {})
+  return Preprocessing.run(opts), ms
 end
 
-local function on_stage_end(is_error, headless, on_success, on_error)
+local function on_stage_end(is_error, headless, elapsed_time, depth, suggestions, on_success, on_error)
   local ready = false
   if is_error then
     status:update(SC.ERROR)
-    local err_msg = 'Error: fetch failed.'
-    content:on_status(err_msg)
+    if not headless then
+      local err_msg = 'Error: fetch failed.'
+      content:on_status(err_msg)
+    end
     schedule(on_error)
   else
     if depth == 0 then
       status:update(SC.NO_MORE_SUGGESTIONS)
-      local msg = 'No more suggestions.'
-      content:on_status(msg)
+      if not headless then
+        local msg = 'No more suggestions.'
+        content:on_status(msg)
+      end
       schedule(on_success)
     else
       status:update(SC.SUGGESTIONS_READY)
@@ -152,47 +157,71 @@ local function on_stage_end(is_error, headless, on_success, on_error)
     end
   end
 
-  content:on_end({
-    elapsed_time = elapsed_time,
-    depth = depth,
-  })
-
   if ready then
-    schedule(on_success, content:get_current_suggestions())
+    schedule(on_success, suggestions)
   end
 
-  current_eval = current_eval + 1
-  if not headless then
-    current_action = current_action + 1
+  if headless then
+    current_headless = current_headless + 1
+  else
+    content:on_end({
+      suggestions = suggestions,
+      elapsed_time = elapsed_time,
+      depth = depth,
+    })
+    current_eval = current_eval + 1
+    lock = false
   end
-  lock = false
 end
 
 ---@param action integer
 ---@param solved_prefix string
 ---@param on_error function
-local function chain_actions(window, buffer, action, solved_prefix, headless, on_success, on_error)
+local function chain_actions(presug, action, solved_prefix, headless, elapsed_time, depth, preprocess_format, on_success,
+                             on_error)
   if not solved_prefix or depth >= MAX_DEPTH then
-    on_stage_end(false, headless, on_success, on_error)
+    on_stage_end(false, headless, elapsed_time, depth, presug, on_success, on_error)
     return
   end
-  local task_id = tasks:create(0, 0)
-  Sessions.request_generate_one_stage(task_id, {
-    prompt_ty = get_action_type(action),
-    solved_prefix = solved_prefix,
-  }, function(_, prompt, suggestions)
-    local lines, ms = filter_suggestions(window, buffer, task_id, suggestions)
-    if not lines or #lines == 0 then
-      on_stage_end(false, headless, on_success, on_error)
+  Promise:new(function(resolve, reject)
+    local task_id = nil
+    if headless then
+      task_id = tasks[TASK_HEADLESS]:create()
     else
-      elapsed_time = elapsed_time + ms
-      depth = depth + 1
-      content:on_suggestions(lines)
-      local new_solved_prefix = prompt.prefix .. table.concat(lines, '\n')
-      chain_actions(window, buffer, action, new_solved_prefix, headless, on_success, on_error)
+      task_id = tasks[TASK_DEFAULT]:create()
     end
-  end, function()
-    on_stage_end(true, headless, on_success, on_error)
+    Sessions.request_generate_one_stage(task_id, {
+      prompt_ty = get_action_type(action),
+      solved_prefix = solved_prefix,
+    }, function(_, prompt, suggestions)
+      local lines, ms = preprocessing(presug, task_id, headless, preprocess_format, suggestions)
+      elapsed_time = elapsed_time + ms
+      if not lines or #lines == 0 then
+        reject({ false, presug })
+      else
+        depth = depth + 1
+        local new_presug = Merge.run(presug, lines, true)
+        if not headless then
+          content:on_suggestions(vim.deepcopy(lines))
+        end
+        local new_solved_prefix = prompt.prefix .. table.concat(lines, '\n')
+        chain_actions(new_presug, action, new_solved_prefix, headless, elapsed_time, depth, preprocess_format, on_success,
+          on_error)
+      end
+    end, function()
+      reject({ true, presug })
+    end)
+  end):forward(nil, function(pair)
+    local is_error, prefix = unpack(pair)
+    local lines = Preprocessing.run({
+      prefix = prefix,
+      suggestions = { '' },
+      markdown_prettify = {
+        fenced_code_blocks = 'start'
+      }
+    })
+    local new_presug = Merge.run(prefix, lines, true)
+    on_stage_end(is_error, headless, elapsed_time, depth, new_presug, on_success, on_error)
   end)
 end
 
@@ -202,11 +231,8 @@ local function find_nospace(line)
   if not line then
     return
   end
-  for i = 1, #line do
-    if line:sub(i, i) ~= ' ' then
-      return i
-    end
-  end
+  local _, index = string.find(line, '%S')
+  return index
 end
 
 ---@param buffer number
@@ -298,23 +324,31 @@ end
 local function make_range(buffer)
   local in_v = false
   local region = nil
+  ---@type integer[][][]
+  local pos = nil
 
   local mode = api.nvim_get_mode().mode
-  Log.debug('Action mode: {}', mode)
   if VMODE[mode] then
     in_v = true
     if fn.has('nvim-0.10') == 1 then
       region = fn.getregion(fn.getpos('.'), fn.getpos('v'), { type = fn.mode() })
+      -- [bufnum, lnum, col, off]
+      pos = fn.getregionpos(fn.getpos('.'), fn.getpos('v'))
     end
   end
 
-  if not region then
+  local start = { 0, 0 }
+  local end_ = { 0, 0 }
+
+  if pos then
+    start = { pos[1][1][2], pos[1][1][3] }
+    end_ = { pos[#pos][2][2], pos[#pos][2][3] }
+  else
     api.nvim_feedkeys(api.nvim_replace_termcodes('<ESC>', true, true, true), 'nx', false)
+    start = api.nvim_buf_get_mark(buffer, '<')
+    end_ = api.nvim_buf_get_mark(buffer, '>')
   end
 
-  local start = api.nvim_buf_get_mark(buffer, '<')
-  local end_ = api.nvim_buf_get_mark(buffer, '>')
-
   ---@type ActionRange
   local range = {
     start = start,
@@ -329,9 +363,7 @@ end
 
 local function make_filetype(buffer, range)
   local filetype = api.nvim_get_option_value('filetype', { buf = buffer })
-  Log.debug('Action option filetype: {}', filetype)
   local langs = get_tslangs(buffer, range)
-  Log.debug('Action langs: {}', langs)
   -- Markdown contains blocks of code
   -- JS or CSS is embedded in the HTML
   if #langs >= 2 then
@@ -340,81 +372,64 @@ local function make_filetype(buffer, range)
   return filetype
 end
 
-local function _start_action(window, buffer, action, opts, headless, on_success, on_error)
+local function _start_action(action, opts, headless, elapsed_time, depth, preprocess_format, on_success, on_error)
   Promise:new(function(resolve, reject)
-    local task_id = tasks:create(0, 0)
+    local task_id = nil
+    if headless then
+      task_id = tasks[TASK_HEADLESS]:create()
+    else
+      task_id = tasks[TASK_DEFAULT]:create()
+    end
     Sessions.request_generate_one_stage(task_id, opts, function(_, prompt, suggestions)
-      local lines, ms = filter_suggestions(window, buffer, task_id, suggestions)
+      local lines, ms = preprocessing(nil, task_id, headless, preprocess_format, suggestions)
       elapsed_time = elapsed_time + ms
       if not lines or #lines == 0 then
-        resolve()
+        resolve({ nil, lines })
       else
         depth = depth + 1
-        content:on_suggestions(lines)
+        if not headless then
+          content:on_suggestions(vim.deepcopy(lines))
+        end
         local solved_prefix = prompt.prefix .. table.concat(lines, '\n')
-        resolve(solved_prefix)
+        resolve({ solved_prefix, lines })
       end
     end, function()
       reject()
     end)
-  end):forward(function(solved_prefix)
-    chain_actions(window, buffer, action, solved_prefix, headless, on_success, on_error)
+  end):forward(function(pair)
+    local solved_prefix, new_presug = unpack(pair)
+    chain_actions(new_presug, action, solved_prefix, headless, elapsed_time, depth, preprocess_format, on_success,
+      on_error)
   end, function()
-    on_stage_end(true, headless, on_success, on_error)
+    on_stage_end(true, headless, elapsed_time, depth, nil, on_success, on_error)
   end)
 end
 
-local function start_content(action_name, prompt_opts, range)
-  local prompt_preview = PromptProviders.get_prompt_one(prompt_opts)
-  if #prompt_preview.filename == 0 then
-    prompt_preview.filename = 'unnamed'
+local function start_content(action_name, ctx, range)
+  local preview = PromptProviders.get_prompt_one(ctx)
+  if not preview then
+    return false
+  end
+  if #preview.display_filename == 0 then
+    preview.display_filename = 'unnamed'
   end
   content:on_start({
     current_eval = current_eval,
-    current_action = current_action,
     action = action_name,
-    prompt = vim.split(prompt_preview.content, '\n'),
-    headless = prompt_opts.action.headless,
+    prompt = vim.split(preview.content, '\n'),
     location = {
-      prompt_preview.filename,
+      preview.display_filename,
       range.start[1],
       range['end'][1],
     }
   })
+  return true
 end
 
----@param action integer
----@param opts? ActionOptions
----@return nil
-function ActionsEngine.start_action(action, opts)
-  opts = opts or {}
-
-  local action_name = get_action_name(action)
-  if not action_name then
-    Log.error('Invalid Action: {}', action)
-    return
-  end
-
-  local headless = opts.headless == true
-
-  if lock then
-    return
-  end
-
-  lock = true
-  elapsed_time = 0
-  depth = 0
-
+---@param opts ActionOptions
+local function _start_action_wrap(window, buffer, action, action_name, headless, opts)
   status:update(SC.GENERATING)
 
-  local window = api.nvim_get_current_win()
-  local buffer = api.nvim_win_get_buf(window)
-
-  if not headless then
-    chat:show()
-    fn.win_gotoid(window)
-  end
-
   local range = {
     start = { 0, 0 },
     ['end'] = { 0, 0 },
@@ -427,7 +442,7 @@ function ActionsEngine.start_action(action, opts)
   end
 
   ---@type PromptContext
-  local prompt_opts = {
+  local prompt_ctx = {
     window = window,
     buffer = buffer,
     range = range,
@@ -439,8 +454,48 @@ function ActionsEngine.start_action(action, opts)
     action = opts,
   }
 
-  start_content(action_name, prompt_opts, range)
-  _start_action(chat.window, chat.buffer, action, prompt_opts, headless, opts.on_success, opts.on_error)
+  if not headless then
+    if not start_content(action_name, prompt_ctx, range) then
+      return false
+    end
+  end
+  _start_action(action, prompt_ctx, headless, 0, 0, opts.preprocess_format, opts.on_success, opts.on_error)
+  return true
+end
+
+---@param action integer
+---@param opts? ActionOptions
+---@return nil
+function ActionsEngine.start_action(action, opts)
+  opts = opts or {}
+
+  local action_name = get_action_name(action)
+  if not action_name then
+    return
+  end
+
+  local window = api.nvim_get_current_win()
+  local buffer = api.nvim_win_get_buf(window)
+
+  local headless = opts.headless == true
+  if headless then
+    _start_action_wrap(window, buffer, action, action_name, true, opts)
+    return
+  end
+
+  if lock then
+    return
+  end
+  lock = true
+
+  if not opts.silence then
+    chat:show()
+    fn.win_gotoid(window)
+  end
+
+  if not _start_action_wrap(window, buffer, action, action_name, false, opts) then
+    lock = false
+  end
 end
 
 ---@param opts? ActionOptions
@@ -458,10 +513,8 @@ function ActionsEngine.edit_code(opts)
     local input_opts = { prompt = 'Prompt for FittenCode EditCode: ', default = '', }
     vim.ui.input(input_opts, function(prompt)
       if not prompt or #prompt == 0 then
-        Log.debug('No Prompt for FittenCode EditCode')
         return
       end
-      Log.debug('Prompt for FittenCode EditCode: ' .. prompt)
       ActionsEngine.start_action(ACTIONS.EditCode, {
         prompt = prompt,
         content = merged.content
@@ -572,10 +625,8 @@ function ActionsEngine.generate_code(opts)
     local input_opts = { prompt = 'Enter instructions: ', default = '', }
     vim.ui.input(input_opts, function(content)
       if not content or #content == 0 then
-        Log.debug('No Content for FittenCode GenerateCode')
         return
       end
-      Log.debug('Enter instructions: ' .. content)
       ActionsEngine.start_action(ACTIONS.GenerateCode, {
         content = content }
       )
@@ -594,10 +645,8 @@ function ActionsEngine.start_chat(opts)
     local input_opts = { prompt = 'Ask... (Fitten Code Fast): ', default = '', }
     vim.ui.input(input_opts, function(content)
       if not content or #content == 0 then
-        Log.debug('No Content for FittenCode StartChat')
         return
       end
-      Log.debug('Ask... (Fitten Code Fast): ' .. content)
       ActionsEngine.start_action(ACTIONS.StartChat, {
         content = content }
       )
@@ -670,8 +719,10 @@ function ActionsEngine.setup()
   chat = Chat:new(CHAT_MODEL)
   chat:create()
   content = Content:new(chat)
-  tasks = TaskScheduler:new()
-  tasks:setup()
+  tasks[TASK_DEFAULT] = TaskScheduler:new('ActionsEngine/Default')
+  tasks[TASK_DEFAULT]:setup()
+  tasks[TASK_HEADLESS] = TaskScheduler:new('ActionsEngine/Headless')
+  tasks[TASK_HEADLESS]:setup()
   status = Status:new({
     tag = 'ActionsEngine',
     ready_idle = true,
diff --git a/lua/fittencode/engines/inline/suggestions_cache.lua b/lua/fittencode/engines/inline/cache.lua
similarity index 100%
rename from lua/fittencode/engines/inline/suggestions_cache.lua
rename to lua/fittencode/engines/inline/cache.lua
diff --git a/lua/fittencode/engines/inline/init.lua b/lua/fittencode/engines/inline/init.lua
index 8105554..36dfd0c 100644
--- a/lua/fittencode/engines/inline/init.lua
+++ b/lua/fittencode/engines/inline/init.lua
@@ -8,7 +8,7 @@ local Log = require('fittencode.log')
 local Model = require('fittencode.engines.inline.model')
 local Sessions = require('fittencode.sessions')
 local Status = require('fittencode.status')
-local SuggestionsPreprocessing = require('fittencode.suggestions_preprocessing')
+local Preprocessing = require('fittencode.preprocessing')
 local TaskScheduler = require('fittencode.tasks')
 local PromptProviders = require('fittencode.prompt_providers')
 
@@ -32,7 +32,7 @@ local IDS_PROMPT = 2
 ---@type integer[][]
 local extmark_ids = { {}, {} }
 
----@type uv_timer_t
+---@type uv_timer_t?
 local generate_one_stage_timer = nil
 
 local ignore_event = false
@@ -40,33 +40,40 @@ local ignore_event = false
 -- milliseconds
 local CURSORMOVED_DEBOUNCE_TIME = 120
 
----@type uv_timer_t
+---@type uv_timer_t?
 local cursormoved_timer = nil
 
 local function suggestions_modify_enabled()
   return M.is_inline_enabled() and M.has_suggestions()
 end
 
+---@param ctx PromptContext
 ---@param task_id integer
 ---@param suggestions? Suggestions
 ---@return Suggestions?
-local function process_suggestions(task_id, suggestions)
-  local window = api.nvim_get_current_win()
-  local buffer = api.nvim_win_get_buf(window)
-  local row, col = Base.get_cursor(window)
-  if not tasks:match_clean(task_id, row, col) then
+local function preprocessing(ctx, task_id, suggestions)
+  local row, col = Base.get_cursor(ctx.window)
+  local match = tasks:match_clean(task_id, row, col)
+  if not match[1] then
     return
   end
-
   if not suggestions or #suggestions == 0 then
     return
   end
-
-  return SuggestionsPreprocessing.run({
-    window = window,
-    buffer = buffer,
+  local format = PromptProviders.get_suggestions_preprocessing_format(ctx)
+  ---@type SuggestionsPreprocessingOptions
+  local opts = {
     suggestions = suggestions,
-  })
+    condense_blank_line = {
+      mode = 'first'
+    },
+    replace_slash = true,
+    markdown_prettify = {
+      separate_code_block_marker = true,
+    }
+  }
+  opts = vim.tbl_deep_extend('force', opts, format or {})
+  return Preprocessing.run(opts)
 end
 
 ---@param ss SuggestionsSegments
@@ -155,16 +162,17 @@ local function _generate_one_stage(row, col, on_success, on_error)
   status:update(SC.GENERATING)
 
   local task_id = tasks:create(row, col)
-  Sessions.request_generate_one_stage(task_id, PromptProviders.get_current_prompt_ctx(), function(id, _, suggestions)
-    local processed = process_suggestions(id, suggestions)
-    if processed then
+  local ctx = PromptProviders.get_current_prompt_ctx(row, col)
+  Sessions.request_generate_one_stage(task_id, ctx, function(id, _, suggestions)
+    local results = preprocessing(ctx, id, suggestions)
+    if results then
       status:update(SC.SUGGESTIONS_READY)
-      apply_new_suggestions(task_id, row, col, processed)
-      schedule(on_success, processed)
+      apply_new_suggestions(task_id, row, col, results)
+      schedule(on_success, results)
     else
       status:update(SC.NO_MORE_SUGGESTIONS)
       schedule(on_success)
-      Log.debug('No More Suggestions')
+      -- Log.debug('No More Suggestions')
     end
   end, function()
     status:update(SC.ERROR)
@@ -183,10 +191,10 @@ function M.generate_one_stage(row, col, force, delaytime, on_success, on_error)
     status:update(SC.SUGGESTIONS_READY)
     render_virt_text_segments(model:get_suggestions_segments())
     schedule(on_success, model:make_new_trim_commmited_suggestions())
-    Log.debug('CACHE HIT')
+    -- Log.debug('Cache hit')
     return
   else
-    Log.debug('NO CACHE HIT')
+    -- Log.debug('Cache miss')
   end
 
   if suggestions_modify_enabled() then
@@ -195,7 +203,7 @@ function M.generate_one_stage(row, col, force, delaytime, on_success, on_error)
   model:reset()
 
   if not Sessions.ready_for_generate() then
-    Log.debug('Not ready for generate')
+    -- Log.debug('Not ready for generate')
     schedule(on_error)
     return
   end
@@ -203,9 +211,11 @@ function M.generate_one_stage(row, col, force, delaytime, on_success, on_error)
   if delaytime == nil then
     delaytime = Config.options.delay_completion.delaytime
   end
-  Log.debug('Delay completion request for delaytime: {} ms', delaytime)
+  if delaytime > 0 then
+    Log.debug('Delay completion request for delaytime: {} ms', delaytime)
+  end
 
-  Base.debounce(generate_one_stage_timer, function()
+  generate_one_stage_timer = Base.debounce(generate_one_stage_timer, function()
     _generate_one_stage(row, col, on_success, on_error)
   end, delaytime)
 end
@@ -502,7 +512,7 @@ function M.on_cursor_moved()
   if ignore_event then
     return
   end
-  Base.debounce(cursormoved_timer, function()
+  cursormoved_timer = Base.debounce(cursormoved_timer, function()
     _on_cursor_moved()
   end, CURSORMOVED_DEBOUNCE_TIME)
 end
@@ -578,7 +588,7 @@ end
 
 function M.setup()
   model = Model:new()
-  tasks = TaskScheduler:new()
+  tasks = TaskScheduler:new('InlineEngine')
   tasks:setup()
   status = Status:new({ tag = 'InlineEngine' })
   if Config.options.completion_mode == 'inline' then
diff --git a/lua/fittencode/engines/inline/model.lua b/lua/fittencode/engines/inline/model.lua
index 8b404e5..555ae06 100644
--- a/lua/fittencode/engines/inline/model.lua
+++ b/lua/fittencode/engines/inline/model.lua
@@ -2,7 +2,7 @@ local api = vim.api
 
 local Base = require('fittencode.base')
 local Log = require('fittencode.log')
-local SuggestionsCache = require('fittencode.engines.inline.suggestions_cache')
+local SuggestionsCache = require('fittencode.engines.inline.cache')
 local Unicode = require('fittencode.unicode')
 
 ---@alias AcceptMode 'stage' | 'commit'
diff --git a/lua/fittencode/key_storage.lua b/lua/fittencode/key_storage.lua
index 0d1d3bd..8989d2e 100644
--- a/lua/fittencode/key_storage.lua
+++ b/lua/fittencode/key_storage.lua
@@ -33,24 +33,24 @@ end
 ---@param on_success function|nil
 ---@param on_error function|nil
 function KeyStorage:load(on_success, on_error)
-  Log.debug('Loading key file: {}', self.path)
+  -- Log.debug('Loading key file: {}', self.path)
   if not FS.exists(self.path) then
-    Log.error('Key file not found')
+    -- Log.error('Key file not found')
     schedule(on_error)
     return
   end
   FS.read(self.path, function(data)
     local success, result = pcall(fn.json_decode, data)
     if success == false then
-      Log.error('Failed to parse key file; error: {}', result)
+      -- Log.error('Failed to parse key file; error: {}', result)
       schedule(on_error)
       return
     end
     self.keys = result
-    Log.debug('Key file loaded successful')
+    -- Log.debug('Key file loaded successful')
     schedule(on_success, self.keys.name)
   end, function(err)
-    Log.error('Failed to load Key file; error: {}', err)
+    -- Log.error('Failed to load Key file; error: {}', err)
     schedule(on_error)
   end)
 end
@@ -58,18 +58,18 @@ end
 ---@param on_success function|nil
 ---@param on_error function|nil
 function KeyStorage:save(on_success, on_error)
-  Log.debug('Saving key file: {}', self.path)
+  -- Log.debug('Saving key file: {}', self.path)
   local success, encode_keys = pcall(fn.json_encode, self.keys)
   if not success then
-    Log.error('Failed to encode key file; error: {}', encode_keys)
+    -- Log.error('Failed to encode key file; error: {}', encode_keys)
     schedule(on_error)
     return
   end
   FS.write_mkdir(encode_keys, self.path, function()
-    Log.info('Key file saved successful')
+    -- Log.info('Key file saved successful')
     schedule(on_success)
   end, function(err)
-    Log.error('Failed to save key file; error: {}', err)
+    -- Log.error('Failed to save key file; error: {}', err)
     schedule(on_error)
   end)
 end
@@ -77,14 +77,14 @@ end
 ---@param on_success function|nil
 ---@param on_error function|nil
 function KeyStorage:clear(on_success, on_error)
-  Log.debug('Clearing key file: {}', self.path)
+  -- Log.debug('Clearing key file: {}', self.path)
   self.keys = {}
   uv.fs_unlink(self.path, function(err)
     if err then
-      Log.error('Failed to delete key file; error: {}', err)
+      -- Log.error('Failed to delete key file; error: {}', err)
       schedule(on_error)
     else
-      Log.info('Delete key file successful')
+      -- Log.info('Delete key file successful')
       schedule(on_success)
     end
   end)
diff --git a/lua/fittencode/preprocessing/condense_blank_line.lua b/lua/fittencode/preprocessing/condense_blank_line.lua
new file mode 100644
index 0000000..b5ebc26
--- /dev/null
+++ b/lua/fittencode/preprocessing/condense_blank_line.lua
@@ -0,0 +1,108 @@
+---@class PreprocessingCondensedBlankLineOptions
+---@field mode? string
+---@field convert_whitespace_to_blank? boolean
+
+local function is_all_blank(lines)
+  for _, line in ipairs(lines) do
+    if #line ~= 0 then
+      return false
+    end
+  end
+  return true
+end
+
+local function find_last_non_blank_line(lines)
+  for i = #lines, 1, -1 do
+    if #lines[i] ~= 0 then
+      return i
+    end
+  end
+end
+
+local function remove_lines_after(lines, row)
+  for i = row + 1, #lines do
+    table.remove(lines, row)
+  end
+end
+
+local function is_remove_all(prefix)
+  if not prefix or #prefix == 0 then
+    return true
+  end
+  local cur_line = prefix[#prefix]
+  local prev_line = nil
+  if #prefix > 1 then
+    prev_line = prefix[#prefix - 1]
+  end
+  if #cur_line == 0 then
+    if not prev_line or #prev_line == 0 then
+      return true
+    end
+  end
+  return false
+end
+
+local function condense(mode, prefix, lines)
+  local remove_all = is_remove_all(prefix)
+  local condensed = {}
+  local is_processed = false
+  for i, line in ipairs(lines) do
+    if #line == 0 then
+      if remove_all and (mode == 'all' or (mode == 'first' and not is_processed)) then
+        -- ignore
+      elseif i ~= 1 then
+        -- ignore
+      else
+        table.insert(condensed, line)
+      end
+    else
+      is_processed = true
+      table.insert(condensed, line)
+    end
+  end
+  return condensed
+end
+
+local function condense_reverse(lines)
+  local non_blank = find_last_non_blank_line(lines)
+  if non_blank then
+    remove_lines_after(lines, non_blank + 2)
+  end
+  return lines
+end
+
+local function _convert_whitespace_to_blank(lines, convert)
+  if not convert then
+    return lines
+  end
+  local new_lines = {}
+  for _, line in ipairs(lines) do
+    if line:match('^%s*$') then
+      line = ''
+    end
+    table.insert(new_lines, line)
+  end
+  return new_lines
+end
+
+---@param prefix? string[]
+---@param lines string[]
+---@param opts? PreprocessingCondensedBlankLineOptions
+---@return string[]?
+local function condense_blank_line(prefix, lines, opts)
+  if not opts then
+    return lines
+  end
+  if is_all_blank(lines) then
+    return
+  end
+  local convert_whitespace_to_blank = opts.convert_whitespace_to_blank or false
+  lines = _convert_whitespace_to_blank(lines, convert_whitespace_to_blank)
+  lines = condense_reverse(lines)
+  lines = condense(opts.mode or 'first', prefix, lines)
+  return lines
+end
+
+return {
+  run = condense_blank_line,
+}
diff --git a/lua/fittencode/preprocessing/filter.lua b/lua/fittencode/preprocessing/filter.lua
new file mode 100644
index 0000000..bf0ec0a
--- /dev/null
+++ b/lua/fittencode/preprocessing/filter.lua
@@ -0,0 +1,69 @@
+local Log = require('fittencode.log')
+
+local function is_marker(line)
+  return line:match('^```') or line:match('```$')
+end
+
+local function _filter_pattern(lines, pattern)
+  if not pattern then
+    return lines
+  end
+  local filtered_lines = vim.tbl_filter(function(line)
+    return line:match(pattern)
+  end, lines)
+  return filtered_lines
+end
+
+local function _filter_exclude_markdown_code_blocks_marker(lines, exclude)
+  if not exclude then
+    return lines
+  end
+  local filtered_lines = vim.tbl_filter(function(line)
+    return not is_marker(line)
+  end, lines)
+  return filtered_lines
+end
+
+local function _filter_remove_blank_lines(lines, remove)
+  if not remove then
+    return lines
+  end
+  local filtered_lines = vim.tbl_filter(function(line)
+    return line ~= ''
+  end, lines)
+  return filtered_lines
+end
+
+local function _filter_count(lines, count)
+  if count >= #lines then
+    return lines
+  end
+  local filtered_lines = {}
+  for i = 1, count do
+    filtered_lines[#filtered_lines + 1] = lines[i]
+  end
+  return filtered_lines
+end
+
+---@param prefix? string[]
+---@param lines string[]
+---@param opts? PreprocessingFilterOptions
+---@return string[]?
+local function filter_lines(prefix, lines, opts)
+  if not opts then
+    return lines
+  end
+  local count = opts.count or #lines
+  local pattern = opts.pattern
+  local exclude_markdown_code_blocks_marker = opts.exclude_markdown_code_blocks_marker or false
+  local remove_blank_lines = opts.remove_blank_lines or false
+  lines = _filter_pattern(lines, pattern)
+  lines = _filter_exclude_markdown_code_blocks_marker(lines, exclude_markdown_code_blocks_marker)
+  lines = _filter_remove_blank_lines(lines, remove_blank_lines)
+  lines = _filter_count(lines, count)
+  return lines
+end
+
+return {
+  run = filter_lines
+}
diff --git a/lua/fittencode/preprocessing/init.lua b/lua/fittencode/preprocessing/init.lua
new file mode 100644
index 0000000..9a4b64f
--- /dev/null
+++ b/lua/fittencode/preprocessing/init.lua
@@ -0,0 +1,67 @@
+local api = vim.api
+
+local Base = require('fittencode.base')
+local Log = require('fittencode.log')
+
+local M = {}
+
+---@class PreprocessingMarkdownPrettifyOptions
+---@field fenced_code_blocks? 'start'|'end'
+---@field separate_code_block_marker? boolean
+
+---@class PreprocessingNormalizeIndentOptions
+---@field tabstop integer
+---@field expandtab boolean
+
+---@class PreprocessingFilterOptions
+---@field count? integer
+---@field pattern? string
+---@field exclude_markdown_code_blocks_marker? boolean
+---@field remove_blank_lines? boolean
+
+---@class SuggestionsPreprocessingFormat
+---@field prefix? string[]
+---@field condense_blank_line? PreprocessingCondensedBlankLineOptions
+---@field normalize_indent? PreprocessingNormalizeIndentOptions
+---@field replace_slash? boolean
+---@field trim_trailing_whitespace? boolean
+---@field markdown_prettify? PreprocessingMarkdownPrettifyOptions
+---@field filter? PreprocessingFilterOptions
+---@field merge? boolean
+
+---@class SuggestionsPreprocessingOptions:SuggestionsPreprocessingFormat
+---@field suggestions string[]
+
+local PIPELINES = {
+  'condense_blank_line',
+  'normalize_indent',
+  'replace_slash',
+  'trim_trailing_whitespace',
+  'markdown_prettify',
+  'filter',
+  'merge'
+}
+
+---@param opts SuggestionsPreprocessingOptions
+---@return Suggestions?
+function M.run(opts)
+  if not opts then
+    return
+  end
+  ---@type string[]?
+  local suggestions = opts.suggestions
+  local prefix = opts.prefix or {}
+  if not suggestions or #suggestions == 0 then
+    return
+  end
+  for _, pipeline in ipairs(PIPELINES) do
+    local run = require('fittencode.preprocessing.' .. pipeline).run
+    suggestions = run(prefix, suggestions, opts[pipeline])
+    if not suggestions or #suggestions == 0 then
+      break
+    end
+  end
+  return suggestions
+end
+
+return M
diff --git a/lua/fittencode/preprocessing/markdown_prettify.lua b/lua/fittencode/preprocessing/markdown_prettify.lua
new file mode 100644
index 0000000..caad2a6
--- /dev/null
+++ b/lua/fittencode/preprocessing/markdown_prettify.lua
@@ -0,0 +1,70 @@
+local Merge = require('fittencode.preprocessing.merge')
+
+---@param lines string[]
+local function _separate_code_block_marker(lines)
+  local formated_lines = {}
+  for i, line in ipairs(lines) do
+    local start, _end = string.find(line, '```', 1, true)
+    if not start then
+      table.insert(formated_lines, line)
+    else
+      local prefix = line:sub(1, start - 1)
+      local suffix = line:sub(_end + 1)
+      if suffix == '' or suffix:match('^%w+$') then
+        table.insert(formated_lines, prefix)
+        table.insert(formated_lines, '```' .. suffix)
+      else
+        table.insert(formated_lines, line)
+      end
+    end
+  end
+  return formated_lines
+end
+
+local function _fenced_code(prefix, lines, fenced_code_blocks)
+  local fenced_code_open = false
+  local check = prefix
+  if fenced_code_blocks == 'end' then
+    check = Merge.run(prefix, lines)
+  end
+  vim.tbl_map(function(x)
+    if x:match('^```') or x:match('```$') then
+      fenced_code_open = not fenced_code_open
+    end
+  end, check)
+  if fenced_code_open then
+    if fenced_code_blocks == 'start' then
+      if lines[1] ~= '' then
+        table.insert(lines, 1, '')
+      end
+      table.insert(lines, 2, '```')
+    elseif fenced_code_blocks == 'end' then
+      lines[#lines + 1] = '```'
+    end
+  end
+  return lines
+end
+
+---@param prefix string[]
+---@param lines string[]
+---@param opts? PreprocessingMarkdownPrettifyOptions
+local function markdown_prettify(prefix, lines, opts)
+  if not opts then
+    return lines
+  end
+  local fenced_code_blocks = opts.fenced_code_blocks
+  local separate_code_block_marker = opts.separate_code_block_marker or true
+
+  if separate_code_block_marker then
+    lines = _separate_code_block_marker(lines)
+  end
+  if fenced_code_blocks then
+    lines = _fenced_code(prefix, lines, fenced_code_blocks)
+  end
+
+  return lines
+end
+
+return {
+  run = markdown_prettify
+}
diff --git a/lua/fittencode/preprocessing/merge.lua b/lua/fittencode/preprocessing/merge.lua
new file mode 100644
index 0000000..6d02e14
--- /dev/null
+++ b/lua/fittencode/preprocessing/merge.lua
@@ -0,0 +1,27 @@
+local function merge_multi(suggestions)
+  local merged = {}
+  for _, lines in ipairs(suggestions) do
+    for i, line in ipairs(lines) do
+      if i == 1 and #merged ~= 0 then
+        merged[#merged] = merged[#merged] .. line
+      else
+        merged[#merged + 1] = line
+      end
+    end
+  end
+  return merged
+end
+
+local function merge_lines(prefix, lines, opts)
+  if not opts then
+    return lines
+  end
+  if not prefix or #prefix == 0 then
+    return lines
+  end
+  return merge_multi({ prefix, lines })
+end
+
+return {
+  run = merge_lines,
+}
diff --git a/lua/fittencode/preprocessing/normalize_indent.lua b/lua/fittencode/preprocessing/normalize_indent.lua
new file mode 100644
index 0000000..7864a52
--- /dev/null
+++ b/lua/fittencode/preprocessing/normalize_indent.lua
@@ -0,0 +1,24 @@
+---@param prefix? string[]
+---@param lines string[]
+---@param opts? PreprocessingNormalizeIndentOptions
+---@return string[]?
+local function normalize_indent(prefix, lines, opts)
+  if not opts then
+    return lines
+  end
+  local expandtab = opts.expandtab
+  local tabstop = opts.tabstop
+  if not expandtab or not tabstop or tabstop <= 0 then
+    return
+  end
+  local normalized_lines = {}
+  for i, line in ipairs(lines) do
+    line = line:gsub('\t', string.rep(' ', tabstop))
+    normalized_lines[#normalized_lines + 1] = line
+  end
+  return normalized_lines
+end
+
+return {
+  run = normalize_indent
+}
diff --git a/lua/fittencode/preprocessing/replace_slash.lua b/lua/fittencode/preprocessing/replace_slash.lua
new file mode 100644
index 0000000..973cd88
--- /dev/null
+++ b/lua/fittencode/preprocessing/replace_slash.lua
@@ -0,0 +1,17 @@
+---@param prefix? string[]
+---@param lines string[]
+local function replace_slash(prefix, lines, opts)
+  if not opts then
+    return lines
+  end
+  local slash = {}
+  for i, line in ipairs(lines) do
+    line = line:gsub('\\"', '"')
+    slash[#slash + 1] = line
+  end
+  return slash
+end
+
+return {
+  run = replace_slash
+}
diff --git a/lua/fittencode/preprocessing/trim_trailing_whitespace.lua b/lua/fittencode/preprocessing/trim_trailing_whitespace.lua
new file mode 100644
index 0000000..031415a
--- /dev/null
+++ b/lua/fittencode/preprocessing/trim_trailing_whitespace.lua
@@ -0,0 +1,17 @@
+local Log = require('fittencode.log')
+
+---@param lines string[]
+---@return string[]
+local function trim_trailing_whitespace(prefix, lines, opts)
+  if not opts then
+    return lines
+  end
+  for i, line in ipairs(lines) do
+    lines[i] = vim.trim(line)
+  end
+  return lines
+end
+
+return {
+  run = trim_trailing_whitespace
+}
diff --git a/lua/fittencode/prompt_providers/actions.lua b/lua/fittencode/prompt_providers/actions.lua
index dcdbf2f..b233250 100644
--- a/lua/fittencode/prompt_providers/actions.lua
+++ b/lua/fittencode/prompt_providers/actions.lua
@@ -187,8 +187,10 @@ function M:execute(ctx)
   local instruction_type = make_instruction_type(name)
 
   local filename = ''
+  local display_filename = ''
   if ctx.buffer then
     filename = Path.name(ctx.buffer, no_lang)
+    display_filename = Path.name(ctx.buffer, false)
   end
   local within_the_line = false
   local content = ''
@@ -212,6 +214,7 @@ function M:execute(ctx)
     name = self.name,
     priority = self.priority,
     filename = filename,
+    display_filename = display_filename,
     content = content,
     prefix = prefix,
     suffix = suffix,
diff --git a/lua/fittencode/prompt_providers/default.lua b/lua/fittencode/prompt_providers/default.lua
index 01a76d8..cc8889c 100644
--- a/lua/fittencode/prompt_providers/default.lua
+++ b/lua/fittencode/prompt_providers/default.lua
@@ -71,4 +71,23 @@ function M:execute(ctx)
   }
 end
 
+local function make_prefix(buffer, row)
+  local prefix = {}
+  local cur_line = api.nvim_buf_get_lines(buffer, row, row + 1, false)[1]
+  if row > 1 then
+    local prev_line = api.nvim_buf_get_lines(buffer, row - 1, row, false)[1]
+    prefix[#prefix + 1] = prev_line
+  end
+  prefix[#prefix + 1] = cur_line
+  return prefix
+end
+
+---@return SuggestionsPreprocessingFormat?
+function M:get_suggestions_preprocessing_format(ctx)
+  ---@type SuggestionsPreprocessingFormat
+  return {
+    prefix = make_prefix(ctx.buffer, ctx.row)
+  }
+end
+
 return M
diff --git a/lua/fittencode/prompt_providers/init.lua b/lua/fittencode/prompt_providers/init.lua
index fd39f14..32c000f 100644
--- a/lua/fittencode/prompt_providers/init.lua
+++ b/lua/fittencode/prompt_providers/init.lua
@@ -9,6 +9,7 @@ local M = {}
 ---@field name string
 ---@field priority integer
 ---@field filename string
+---@field display_filename string
 ---@field prefix string
 ---@field suffix string
 ---@field content string
@@ -23,6 +24,8 @@ local M = {}
 ---@field col? integer
 ---@field range? ActionRange
 ---@field prompt? string
+---@field filename? string
+---@field display_filename? string
 ---@field solved_prefix? string
 ---@field solved_content? string
 ---@field action? ActionOptions
@@ -32,6 +35,7 @@ local M = {}
 ---@field get_name fun(self): string
 ---@field get_priority fun(self): integer
 ---@field execute fun(self, PromptContext): Prompt?
+---@field get_suggestions_preprocessing_format fun(self, PromptContext): SuggestionsPreprocessingFormat?
 
 ---@class PromptFilter
 ---@field count integer
@@ -63,7 +67,6 @@ end
 ---@return Prompt[]?
 function M.get_prompts(ctx, filter)
   if not ctx or not ctx.prompt_ty then
-    Log.error('Invalid prompt context')
     return
   end
   filter = filter or {}
@@ -84,15 +87,23 @@ function M.get_prompts(ctx, filter)
   return prompts
 end
 
-function M.get_prompt_one(opts)
-  return M.get_prompts(opts, { count = 1 })[1]
+---@param ctx PromptContext
+---@return Prompt?
+function M.get_prompt_one(ctx)
+  local prompts = M.get_prompts(ctx, { count = 1 })
+  if not prompts or #prompts == 0 then
+    return
+  end
+  return prompts[1]
 end
 
 ---@return PromptContext
-function M.get_current_prompt_ctx()
+function M.get_current_prompt_ctx(row, col)
   local window = api.nvim_get_current_win()
   local buffer = api.nvim_win_get_buf(window)
-  local row, col = Base.get_cursor(window)
+  if not row or not col then
+    row, col = Base.get_cursor(window)
+  end
   ---@type PromptContext
   return {
     window = window,
@@ -105,4 +116,17 @@ function M.get_current_prompt_ctx()
   }
 end
 
+---@param ctx PromptContext
+---@return SuggestionsPreprocessingFormat?
+function M.get_suggestions_preprocessing_format(ctx)
+  local format = nil
+  for _, provider in ipairs(providers) do
+    if provider:is_available(ctx.prompt_ty) and provider.get_suggestions_preprocessing_format then
+      format = provider:get_suggestions_preprocessing_format(ctx)
+      break
+    end
+  end
+  return format
+end
+
 return M
diff --git a/lua/fittencode/prompt_providers/telescope.lua b/lua/fittencode/prompt_providers/telescope.lua
index 369e137..14bf6a1 100644
--- a/lua/fittencode/prompt_providers/telescope.lua
+++ b/lua/fittencode/prompt_providers/telescope.lua
@@ -92,4 +92,15 @@ function M:execute(ctx)
   }
 end
 
+---@return SuggestionsPreprocessingFormat?
+function M:get_suggestions_preprocessing_format()
+  ---@type SuggestionsPreprocessingFormat
+  return {
+    filter = {
+      count = 1,
+      exclude_markdown_code_blocks_marker = true,
+    }
+  }
+end
+
 return M
diff --git a/lua/fittencode/sessions.lua b/lua/fittencode/sessions.lua
index bbbef50..4a89236 100644
--- a/lua/fittencode/sessions.lua
+++ b/lua/fittencode/sessions.lua
@@ -71,7 +71,7 @@ function M.logout()
 end
 
 function M.load_last_session()
-  Log.info('Loading last session...')
+  -- Log.info('Loading last session...')
   key_storage:load(function(name)
     current_username = name
     Log.info('Last session for user {} loaded successful', name)
@@ -134,10 +134,9 @@ end
 ---@param on_success function|nil
 ---@param on_error function|nil
 function M.request_generate_one_stage(task_id, opts, on_success, on_error)
-  Log.debug('Requesting generate one stage...')
   local api_key = key_storage:get_key_by_name(current_username)
   if api_key == nil then
-    Log.debug('Key is not found')
+    -- Log.debug('Key is not found')
     schedule(on_error)
     return
   end
@@ -154,7 +153,7 @@ end
 
 function M.setup()
   client = Client:new()
-  Log.debug('FittenClient rest implementation is: {}', client:get_restimpl_name())
+  -- Log.debug('FittenClient rest implementation is: {}', client:get_restimpl_name())
   key_storage = KeyStorage:new({
     path = KEY_STORE_PATH,
   })
diff --git a/lua/fittencode/sources/cmp/source.lua b/lua/fittencode/sources/cmp/source.lua
index ba17169..b311289 100644
--- a/lua/fittencode/sources/cmp/source.lua
+++ b/lua/fittencode/sources/cmp/source.lua
@@ -106,9 +106,9 @@ function source:complete(request, callback)
       character = character,
       reason = request.option.reason,
     }
-    Log.debug('Source(cmp) request: {}', info)
+    -- Log.debug('Source(cmp) request: {}', info)
     local response = convert_to_lsp_completion_response(line, character, cursor_before_line, suggestions)
-    Log.debug('LSP CompletionResponse: {}', response)
+    -- Log.debug('LSP CompletionResponse: {}', response)
     callback(response)
   end, function()
     callback()
diff --git a/lua/fittencode/status.lua b/lua/fittencode/status.lua
index 930fe0b..2a59d10 100644
--- a/lua/fittencode/status.lua
+++ b/lua/fittencode/status.lua
@@ -7,7 +7,7 @@ local Log = require('fittencode.log')
 ---@field ready_idle boolean
 ---@field tag string
 ---@field current integer
----@field idle_timer uv_timer_t
+---@field idle_timer? uv_timer_t
 ---@field IDLE_CYCLE integer
 ---@field update function
 ---@field get_current function
@@ -52,16 +52,15 @@ end
 function M:update(status)
   local name = get_status_name(status)
   if not name then
-    Log.error('Invalid status code: {}', status)
     return
   end
   if status ~= self.current then
     self.current = status
     -- Force `lualine` to update statusline
     -- vim.cmd('redrawstatus')
-    Log.debug('{} status updated to {}', self.tag, name)
+    Log.debug('{} -> {}', self.tag, name)
   end
-  Base.debounce(self.idle_timer, function()
+  self.idle_timer = Base.debounce(self.idle_timer, function()
     if vim.tbl_contains(self.filters, self.current) then
       self:update(C.IDLE)
     end
diff --git a/lua/fittencode/suggestions_preprocessing.lua b/lua/fittencode/suggestions_preprocessing.lua
deleted file mode 100644
index 882e2bd..0000000
--- a/lua/fittencode/suggestions_preprocessing.lua
+++ /dev/null
@@ -1,188 +0,0 @@
-local api = vim.api
-
-local Base = require('fittencode.base')
-local Log = require('fittencode.log')
-
-local M = {}
-
----@class SuggestionsPreprocessingOptions
----@field window number
----@field buffer number
----@field suggestions string[]
----@field condense_nl? string
-
----@param opts SuggestionsPreprocessingOptions
-local function condense_nl(opts)
-  local window = opts.window
-  local buffer = opts.buffer
-  local suggestions = opts.suggestions
-  local mode = opts.condense_nl
-
-  if not suggestions or #suggestions == 0 then
-    return
-  end
-
-  local is_all_empty = true
-  for _, suggestion in ipairs(suggestions) do
-    if #suggestion ~= 0 then
-      is_all_empty = false
-      break
-    end
-  end
-  if is_all_empty then
-    return {}
-  end
-
-  local non_empty = 0
-  for i = #suggestions, 1, -1 do
-    if #suggestions[i] ~= 0 then
-      non_empty = i
-      break
-    end
-  end
-  for i = non_empty + 3, #suggestions do
-    table.remove(suggestions, non_empty + 3)
-  end
-
-  local nls = {}
-  local remove_all = false
-  local keep_first = true
-
-  local filetype = api.nvim_get_option_value('filetype', { buf = buffer })
-  if filetype == 'TelescopePrompt' then
-    remove_all = true
-  end
-
-  if window and buffer and api.nvim_buf_is_valid(buffer) and api.nvim_win_is_valid(window) then
-    local row, col = Base.get_cursor(window)
-    local prev_line = nil
-    local cur_line = api.nvim_buf_get_lines(buffer, row, row + 1, false)[1]
-    if row > 1 then
-      prev_line = api.nvim_buf_get_lines(buffer, row - 1, row, false)[1]
-    end
-
-    if #cur_line == 0 then
-      if not prev_line or #prev_line == 0 then
-        remove_all = true
-      end
-    end
-  end
-
-  mode = mode or 'first'
-
-  if mode == 'all' then
-    for i, suggestion in ipairs(suggestions) do
-      if #suggestion == 0 then
-        if remove_all then
-          -- ignore
-        elseif keep_first and i ~= 1 then
-          -- ignore
-        else
-          table.insert(nls, suggestion)
-        end
-      else
-        table.insert(nls, suggestion)
-      end
-    end
-  elseif mode == 'per-segments' then
-    local count = 0
-    for i, suggestion in ipairs(suggestions) do
-      if #suggestion == 0 then
-        if remove_all then
-          -- ignore
-        elseif keep_first and count ~= 0 then
-          -- ignore
-        else
-          table.insert(nls, suggestion)
-        end
-        count = count + 1
-      else
-        count = 0
-        table.insert(nls, suggestion)
-      end
-    end
-  elseif mode == 'first' then
-    local is_processed = false
-    for i, suggestion in ipairs(suggestions) do
-      if #suggestion == 0 and not is_processed then
-        if remove_all then
-          -- ignore
-        elseif keep_first and i ~= 1 then
-          -- ignore
-        else
-          table.insert(nls, suggestion)
-        end
-      else
-        is_processed = true
-        table.insert(nls, suggestion)
-      end
-    end
-  end
-
-  if filetype == 'TelescopePrompt' then
-    nls = { nls[1] }
-  end
-
-  return nls
-end
-
----@param suggestions string[]
-local function normalize_indent(buffer, suggestions)
-  if not suggestions or #suggestions == 0 then
-    return
-  end
-  local expandtab = api.nvim_get_option_value('expandtab', { buf = buffer })
-  local tabstop = api.nvim_get_option_value('tabstop', { buf = buffer })
-  if not expandtab then
-    return
-  end
-  local nor = {}
-  for i, suggestion in ipairs(suggestions) do
-    -- replace `\t` with space
-    suggestion = suggestion:gsub('\t', string.rep(' ', tabstop))
-    nor[i] = suggestion
-  end
-  return nor
-end
-
-local function replace_slash(suggestions)
-  if not suggestions or #suggestions == 0 then
-    return
-  end
-  local slash = {}
-  for i, suggestion in ipairs(suggestions) do
-    suggestion = suggestion:gsub('\\"', '"')
-    slash[i] = suggestion
-  end
-  return slash
-end
-
----@param opts SuggestionsPreprocessingOptions
-function M.run(opts)
-  local buffer = opts.buffer
-  local suggestions = opts.suggestions
-
-  local nls = condense_nl(opts)
-  if nls then
-    suggestions = nls
-  end
-
-  local nor = normalize_indent(buffer, suggestions)
-  if nor then
-    suggestions = nor
-  end
-
-  local slash = replace_slash(suggestions)
-  if slash then
-    suggestions = slash
-  end
-
-  if #suggestions == 0 then
-    return
-  end
-
-  Log.debug('Processed suggestions: {}', suggestions)
-  return suggestions
-end
-
-return M
diff --git a/lua/fittencode/tasks.lua b/lua/fittencode/tasks.lua
index 6e8ca5d..bff3b8c 100644
--- a/lua/fittencode/tasks.lua
+++ b/lua/fittencode/tasks.lua
@@ -8,6 +8,7 @@ local Log = require('fittencode.log')
 ---@field timestamp integer @timestamp of the task when it was created, in nanoseconds, since the Unix epoch
 
 ---@class TaskScheduler
+---@field tag string
 ---@field list table<integer, Task> @list of tasks
 ---@field threshold? integer @threshold for clean up
 ---@field timeout_recycling_timer? uv_timer_t @timer for recycling timeout tasks
@@ -21,12 +22,15 @@ local MS_TO_NS = 1000000
 local TASK_TIMEOUT = 6000 * MS_TO_NS
 local RECYCLING_CYCLE = 100
 
-function TaskScheduler.new()
-  local self = setmetatable({}, { __index = TaskScheduler })
-  self.list = {}
-  self.threshold = nil
-  self.timeout_recycling_timer = nil
-  return self
+function TaskScheduler:new(tag)
+  local obj = {
+    tag = tag,
+    list = {},
+    threshold = nil,
+    timeout_recycling_timer = nil,
+  }
+  self.__index = self
+  return setmetatable(obj, self)
 end
 
 function TaskScheduler:setup()
@@ -41,13 +45,17 @@ function TaskScheduler:setup()
   end
 end
 
----@param row integer
----@param col integer
+---@param row? integer
+---@param col? integer
 ---@return integer
 function TaskScheduler:create(row, col)
   local timestamp = uv.hrtime()
   table.insert(self.list, #self.list + 1, { row = row, col = col, timestamp = timestamp })
-  Log.debug('TASK CREATED: {}', self.list[#self.list])
+  if row and col then
+    Log.debug('Task<{}>: {} Created at ({}, {})', self.tag, string.format('%x', timestamp), row, col)
+  else
+    Log.debug('Task<{}>: {} Created', self.tag, string.format('%x', timestamp))
+  end
   return timestamp
 end
 
@@ -60,23 +68,26 @@ function TaskScheduler:schedule_clean(task_id)
 end
 
 ---@param task_id integer
----@param row integer
----@param col integer
----@return boolean, integer
-function TaskScheduler:match_clean(task_id, row, col)
+---@param row? integer
+---@param col? integer
+---@return table<boolean, integer>
+function TaskScheduler:match_clean(task_id, row, col, clean)
   local match_found = false
   local ms = 0
+  clean = clean == false and false or true
   for i = #self.list, 1, -1 do
     local task = self.list[i]
     if task.timestamp == task_id and task.row == row and task.col == col then
       ms = math.floor((uv.hrtime() - task.timestamp) / MS_TO_NS)
-      Log.debug('TASK MATCHED, time elapsed: {} ms, task: {}', ms, task)
+      Log.debug('Task<{}>: {} Matched, Time elapsed: {} ms', self.tag, string.format('%x', task_id), ms)
       match_found = true
       break
     end
   end
-  self:schedule_clean(task_id)
-  return match_found, ms
+  if clean then
+    self:schedule_clean(task_id)
+  end
+  return { match_found, ms }
 end
 
 ---@param timestamp integer
diff --git a/lua/fittencode/views/chat.lua b/lua/fittencode/views/chat.lua
index 9c244b3..0954df3 100644
--- a/lua/fittencode/views/chat.lua
+++ b/lua/fittencode/views/chat.lua
@@ -132,7 +132,7 @@ function M:create(opts)
       if Fx[value] then
         Fx[value]()
       end
-    end, { buffer = self.buffer })
+    end, { buffer = self.buffer, nowait = true })
   end
 
   if Config.options.chat.highlight_conversation_at_cursor then
diff --git a/tests/init.lua b/tests/init.lua
index c3aa083..e204c4f 100644
--- a/tests/init.lua
+++ b/tests/init.lua
@@ -17,7 +17,10 @@ vim.opt.runtimepath:append(root('tests'))
 -- require('tests.CATCHME.inline_model.word6')
 -- require('tests.CATCHME.inline_model.line')
 
-require('tests.CATCHME.concurrency.promise_tests')
+-- require('tests.CATCHME.concurrency.promise_tests')
+
+require('tests.CATCHME.preprocessing.condense_blank_line')
+-- require('tests.CATCHME.preprocessing.markdown_prettify')
 
 -- vim.cmd([[
 --   sleep 1000m