diff --git a/docs/content/en/Development-API/_index.md b/docs/content/en/Development-API/_index.md
index 89eface6..e559c2b4 100644
--- a/docs/content/en/Development-API/_index.md
+++ b/docs/content/en/Development-API/_index.md
@@ -33,6 +33,70 @@ Command entry point. Each command file should contain this macro somewhere in th
   )
 ```
 
+# 🚩 Environment
+
+## 🔍 Variable: eask-has-colors
+
+Return non-nil if the terminal supports colors.
+
+```elisp
+(when eask-has-colors ...
+```
+
+## 🔍 Variable: eask-homedir
+
+Eask's home directory path.
+
+```elisp
+(message "%s" eask-homedir)
+```
+
+## 🔍 Variable: eask-invocation
+
+Eask's invocation program path.
+
+```elisp
+(message "%s" eask-invocation)
+```
+
+It could be the `node` executable or the `eask` executable itself.
+
+## 🔍 Variable: eask-is-pkg
+
+Return non-nil if Eask is packaged.
+
+```elisp
+(when eask-is-pkg ...
+```
+
+## 🔍 Variable: eask-rest
+
+Eask's arguments after command separator `--'; return a list.
+
+```sh
+$ eask <command> -- args0 args1
+```
+
+Output:
+
+```elisp
+(message "%s" eask-rest)  ; '(args0 args1)
+```
+
+## 🔍 Function: eask-rest ()
+
+Eask's arguments after command separator `--'; return a string.
+
+```sh
+$ eask <command> -- args0 args1
+```
+
+Output:
+
+```elisp
+(message "%s" (eask-rest))  ; "args0 args1"
+```
+
 # 🚩 Core
 
 ## 🔍 Variable: eask-lisp-root
@@ -45,9 +109,7 @@ Points to `lisp` directory from the project root.
 
 ## 🔍 Function: eask-command ()
 
-Return the current command in string.
-
-Suppose the command is:
+Return the current command in string. Suppose the command is:
 
 ```sh
 $ eask init
diff --git a/docs/content/zh-TW/Development-API/_index.md b/docs/content/zh-TW/Development-API/_index.md
index 7de4278c..17e811e5 100644
--- a/docs/content/zh-TW/Development-API/_index.md
+++ b/docs/content/zh-TW/Development-API/_index.md
@@ -32,6 +32,70 @@ weight: 700
   )
 ```
 
+# 🚩 環境
+
+## 🔍 變數: eask-has-colors
+
+如果終端支援顏色，則傳回非零。
+
+```elisp
+(when eask-has-colors ...
+```
+
+## 🔍 變數: eask-homedir
+
+Eask 的主目錄路徑。
+
+```elisp
+(message "%s" eask-homedir)
+```
+
+## 🔍 變數: eask-invocation
+
+Eask的呼叫程式路徑。
+
+```elisp
+(message "%s" eask-invocation)
+```
+
+它可以是 `node` 可執行檔或 `eask` 執行檔本身。
+
+## 🔍 變數: eask-is-pkg
+
+如果 Eask 已打包，則傳回非零。
+
+```elisp
+(when eask-is-pkg ...
+```
+
+## 🔍 變數: eask-rest
+
+命令分隔符號 `--` 之後的 Eask 參數；傳回一個列表。
+
+```sh
+$ eask <command> -- args0 args1
+```
+
+輸出:
+
+```elisp
+(message "%s" eask-rest)  ; '(args0 args1)
+```
+
+## 🔍 函式: eask-rest ()
+
+命令分隔符號 `--` 之後的 Eask 參數；傳回一個字串。
+
+```sh
+$ eask <command> -- args0 args1
+```
+
+輸出:
+
+```elisp
+(message "%s" (eask-rest))  ; "args0 args1"
+```
+
 # 🚩 核心
 
 ## 🔍 變數: eask-lisp-root
@@ -44,9 +108,7 @@ weight: 700
 
 ## 🔍 函式: eask-command ()
 
-返回字符串中的當前命令。
-
-假設命令是：
+返回字符串中的當前命令。假設命令是：
 
 ```sh
 $ eask init
diff --git a/lisp/_prepare.el b/lisp/_prepare.el
index c9532f72..8197c273 100644
--- a/lisp/_prepare.el
+++ b/lisp/_prepare.el
@@ -42,7 +42,7 @@
 (declare-function ansi-white "ext:ansi.el")
 
 ;;
-;;; Environments
+;;; Environment
 
 ;; Determine the underlying operating system
 (defconst eask-is-windows (memq system-type '(cygwin windows-nt ms-dos))
@@ -79,29 +79,29 @@ Arguments FNC and ARGS are used for advice `:around'."
 (advice-add 'load :around #'eask--load--adv)
 
 (defconst eask-has-colors (getenv "EASK_HASCOLORS")
-  "Return non-nil if terminal support colors.")
+  "Return non-nil if terminal supports colors.")
 
 (defconst eask-homedir (getenv "EASK_HOMEDIR")
-  "Eask temporary storage.")
+  "Eask's home directory path.")
 
 (defconst eask-invocation (getenv "EASK_INVOCATION")
-  "Eask invocation program.")
+  "Eask's invocation program path.")
 
 (defconst eask-is-pkg (getenv "EASK_IS_PKG")
-  "Eask is pkg.")
+  "Return non-nil if Eask is packaged.")
 
 (defconst eask-rest
   (let ((args (getenv "EASK_REST_ARGS")))
     (setq args (ignore-errors (split-string args ",")))
     args)
-  "Eask arguments in list after command separator `--'.
+  "Eask's arguments after command separator `--'; return a list.
 
-If the argument is `-- hello world'; it will return `(hello world)'.")
+If the argument is `-- arg0 arg1'; it will return `(arg0 arg1)'.")
 
 (defun eask-rest ()
-  "Eask arguments in string after command separator `--'.
+  "Eask's arguments after command separator `--'; return a string.
 
-If the argument is `-- hello world'; it will return `hello world'."
+If the argument is `-- arg0 arg1'; it will return `arg0 arg1'."
   (mapconcat #'identity eask-rest " "))
 
 (defcustom eask-import-timeout 10