diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..8ad5459
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+utils/stylua
diff --git a/README.md b/README.md
index a797535..7aa5491 100644
--- a/README.md
+++ b/README.md
@@ -173,26 +173,32 @@ mapping = {
 You can specify your own custom mapping function.
 
 ```lua
-local check_back_space = function()
-  local line, col = unpack(vim.api.nvim_win_get_cursor(0))
-  return col == 0 or vim.api.nvim_buf_get_lines(0, line - 1, line, true)[1]:sub(col, col):match('%s') ~= nil
-end
-
 mapping = {
   ['<Tab>'] = function(fallback)
-    if vim.fn.pumvisible() == 1 then
-      vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes('<C-n>', true, true, true), 'n', true)
-    elseif check_back_space() then
-      vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes('<Tab>', true, true, true), 'n', true)
-    elseif vim.fn['vsnip#available']() == 1 then
-      vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes('<Plug>(vsnip-expand-or-jump)', true, true, true), '', true)
+    if ...some_condition... then
+      vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes('...', true, true, true), 'n', true)
     else
-      fallback()
+      fallback() -- The fallback function is treated as original mapped key. In this case, it might be `<Tab>`.
     end
   end,
 }
 ```
 
+#### enabled (type: fun(): boolean|boolean)
+
+The function or boolean value to specify all cmp's features enabled or not.
+
+Default:
+
+```lua
+function()
+  local enabled = true
+  enabled = enabled and vim.api.nvim_buf_get_option(0, 'buftype') ~= 'prompt'
+  enabled = enabled and string.sub(vim.api.nvim_get_mode().mode, 1, 1) == 'i'
+  return enabled
+end
+```
+
 #### sources (type: table<cmp.SourceConfig>)
 
 Globals source lists are listed in the `source` table. These are applied to all
@@ -468,24 +474,28 @@ cmp.setup {
 }
 ```
 
+#### How to disable nvim-cmp on the specific buffer?
+
+You can specify `enabled = false` like this.
+
+```vim
+autocmd FileType TelescopePrompt lua require('cmp').setup.buffer { enabled = false }
+```
+
 #### nvim-cmp is slow.
 
 I've optimized `nvim-cmp` as much as possible, but there are currently some known / unfixable issues.
 
 1. `cmp-buffer` source and too large buffer.
-The `cmp-buffer` source makes an index of the current buffer so if the current buffer is too large, it will slowdown the main UI thread.
+  The `cmp-buffer` source makes an index of the current buffer so if the current buffer is too large, it will slowdown the main UI thread.
 
 1. Some language servers.
-For example, `typescript-language-server` will returns 15k items to the client.
-In such a case, it will take 100ms just to parse payloads as JSON.
+  For example, `typescript-language-server` will returns 15k items to the client.
+  In such a case, it will take 100ms just to parse payloads as JSON.
 
 1. You set `vim.lsp.set_log_level` up by yourself.
-This setting will cause the filesystem operation for each LSP payload.
-This will greatly slow down nvim-cmp (and other LSP related features).
-
-#### How to setup supertab-like mapping?
-
-You can found the solution in [Example mappings](https://github.com/hrsh7th/nvim-cmp/wiki/Example-mappings).
+  This setting will cause the filesystem operation for each LSP payload.
+  This will greatly slow down nvim-cmp (and other LSP related features).
 
 #### How to show name of item kind and source (like compe)?
 
@@ -508,6 +518,10 @@ formatting = {
 },
 ```
 
+#### How to setup supertab-like mapping?
+
+You can found the solution in [Example mappings](https://github.com/hrsh7th/nvim-cmp/wiki/Example-mappings).
+
 
 Source creation
 ====================
diff --git a/lua/cmp/config.lua b/lua/cmp/config.lua
index eae3c19..f6f26b2 100644
--- a/lua/cmp/config.lua
+++ b/lua/cmp/config.lua
@@ -40,6 +40,15 @@ config.get = function()
   end)
 end
 
+---Return cmp is enabled or not.
+config.enabled = function()
+  local enabled = config.get().enabled
+  if type(enabled) == 'function' then
+    return enabled()
+  end
+  return not not enabled
+end
+
 ---Return source config
 ---@param name string
 ---@return cmp.SourceConfig
diff --git a/lua/cmp/config/default.lua b/lua/cmp/config/default.lua
index ec85a09..9852273 100644
--- a/lua/cmp/config/default.lua
+++ b/lua/cmp/config/default.lua
@@ -6,6 +6,12 @@ local WIDE_HEIGHT = 40
 ---@return cmp.ConfigSchema
 return function()
   return {
+    enabled = function()
+      local enabled = true
+      enabled = enabled and vim.api.nvim_buf_get_option(0, 'buftype') ~= 'prompt'
+      enabled = enabled and string.sub(vim.api.nvim_get_mode().mode, 1, 1) == 'i'
+      return enabled
+    end,
     completion = {
       autocomplete = {
         types.cmp.TriggerEvent.TextChanged,
diff --git a/lua/cmp/init.lua b/lua/cmp/init.lua
index a19fcfc..0ba4e75 100644
--- a/lua/cmp/init.lua
+++ b/lua/cmp/init.lua
@@ -126,16 +126,25 @@ cmp.setup = setmetatable({
 
 ---Handle events
 autocmd.subscribe('InsertEnter', function()
-  core.prepare()
-  core.on_change('InsertEnter')
+  -- Avoid unexpected mode detection (mode() function will returns `normal mode` on the InsertEnter event.)
+  vim.schedule(function()
+    if config.enabled() then
+      core.prepare()
+      core.on_change('InsertEnter')
+    end
+  end)
 end)
 
 autocmd.subscribe('TextChanged', function()
-  core.on_change('TextChanged')
+  if config.enabled() then
+    core.on_change('TextChanged')
+  end
 end)
 
 autocmd.subscribe('InsertLeave', function()
-  core.reset()
+  if config.enabled() then
+    core.reset()
+  end
 end)
 
 return cmp
diff --git a/lua/cmp/menu.lua b/lua/cmp/menu.lua
index 2135764..4f74292 100644
--- a/lua/cmp/menu.lua
+++ b/lua/cmp/menu.lua
@@ -4,7 +4,6 @@ local async = require('cmp.utils.async')
 local float = require('cmp.float')
 local config = require('cmp.config')
 local autocmd = require('cmp.utils.autocmd')
-local check = require('cmp.utils.check')
 
 ---@class cmp.MenuOption
 ---@field on_select fun(e: cmp.Entry)
@@ -70,7 +69,7 @@ end
 ---@param ctx cmp.Context
 ---@param sources cmp.Source[]
 ---@return cmp.Menu
-menu.update = check.wrap(function(self, ctx, sources)
+menu.update = function(self, ctx, sources)
   local entries = {}
 
   -- check the source triggered by character
@@ -138,11 +137,11 @@ menu.update = check.wrap(function(self, ctx, sources)
   self.preselect = preselect
   self.context = ctx
   self:show()
-end)
+end
 
 ---Restore previous menu
 ---@param ctx cmp.Context
-menu.restore = check.wrap(function(self, ctx)
+menu.restore = function(self, ctx)
   if not ctx.pumvisible then
     if #self.items > 0 then
       if self.offset <= ctx.cursor.col then
@@ -151,7 +150,7 @@ menu.restore = check.wrap(function(self, ctx)
       end
     end
   end
-end)
+end
 
 ---Show completion item
 menu.show = function(self)
diff --git a/lua/cmp/types/cmp.lua b/lua/cmp/types/cmp.lua
index 6a88569..aa68f2a 100644
--- a/lua/cmp/types/cmp.lua
+++ b/lua/cmp/types/cmp.lua
@@ -47,6 +47,7 @@ cmp.PreselectMode.None = 'none'
 
 ---@class cmp.ConfigSchema
 ---@field private revision number
+---@field public enabled fun():boolean|boolean
 ---@field public preselect cmp.PreselectMode
 ---@field public completion cmp.CompletionConfig
 ---@field public documentation cmp.DocumentationConfig|"false"
diff --git a/lua/cmp/utils/check.lua b/lua/cmp/utils/check.lua
deleted file mode 100644
index e5a9cbe..0000000
--- a/lua/cmp/utils/check.lua
+++ /dev/null
@@ -1,18 +0,0 @@
-local check = {}
-
-check.ok = function()
-  local ng = false
-  ng = ng or vim.api.nvim_buf_get_option(0, 'buftype') == 'prompt'
-  ng = ng or string.sub(vim.api.nvim_get_mode().mode, 1, 1) ~= 'i'
-  return not ng
-end
-
-check.wrap = function(callback)
-  return function(...)
-    if check.ok() then
-      callback(...)
-    end
-  end
-end
-
-return check
diff --git a/utils/install_stylua.sh b/utils/install_stylua.sh
old mode 100644
new mode 100755