diff --git a/core/fg42/core.el b/core/fg42/core.el
index f3ca462..b4fd71b 100644
--- a/core/fg42/core.el
+++ b/core/fg42/core.el
@@ -22,11 +22,16 @@
 ;;; Commentary:
 ;;; Code:
 
+(defgroup fg42 nil
+  "Customize your FG42 instance via this group of configurations.")
+
+
 (defvar fg42-home (getenv "FG42_HOME")
   "The pass to fg42-home.")
 
+
 (defvar fg42-tmp (concat fg42-home "/tmp"))
 
 
 (provide 'fg42/core)
-;; core.el ends here
+;;; core.el ends here
diff --git a/core/fg42/flags.el b/core/fg42/flags.el
new file mode 100644
index 0000000..d348f80
--- /dev/null
+++ b/core/fg42/flags.el
@@ -0,0 +1,106 @@
+;;; Flags --- Flags library of FG42 -*- lexical-binding: t; -*-
+;;
+;; Copyright (c) 2010-2021 Sameer Rahmani & Contributors
+;;
+;; Author: Sameer Rahmani <lxsameer@gnu.org>
+;; URL: https://gitlab.com/FG42/FG42
+;; Version: 3.0.0
+;;
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+;;
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+;;
+;;; Commentary:
+;;; Code:
+
+(require 'seq)
+(require 'fg42/core)
+
+
+(defvar fg42/available-flags nil
+  "A list of defined flags.
+
+Only use \\[defflag] to add a new flag to this list")
+
+
+(defcustom fg42/flags nil
+  "A set of flags to mark the functionalities that expected from FG42.
+Flags are defined using the \\[defflag] through out the source code.
+
+To see a list of available flags use \\[fg42/show-all-flags] and to see
+the documentation of each flag simply use \\[describe-flag]."
+  :group fg42
+  :package-version '(FG42 . "3.x")
+  :type '(symbol)
+  :tag "FG42 Flags")
+
+
+(defmacro use-flags (&rest flags)
+  "Set the given FLAGS to activate their functionalities in FG42."
+  (setq fg42/flags flags))
+
+
+(defun fg42/-merge-flags (flags-set &rest new-flags)
+  "Merge the given NEW-FLAGS into the FLAGS-SET and return the result."
+  (remove-duplicates
+   (seq-reduce
+    (lambda (result flag)
+      (let ((flag-str (symbol-name flag)))
+        (if (string-prefix-p "-" flag-str)
+            (let ((actual-flag (intern (substring flag-str 1))))
+              (if (member actual-flag result)
+                  (remove actual-flag result)
+                result))
+          ;; We don't want to check for duplicates here since we remove them
+          ;; later
+          (cons flag result))))
+    new-flags
+    flags-set)))
+
+
+(defmacro fg42/merge-flags (flags-set &rest new-flags)
+    "Merge the given NEW-FLAGS into the FLAGS-SET and return the result.
+
+If any flag name in NEW-FLAGS list starts with `-' (a dash) it implies that
+that functionality has to be disabled and removed from FLAGS-SET.  For example,
+`-lsp' implies that we DO NOT want to have `lsp' flag enabled and it should not
+exist in the return value.
+
+For example, `(fg42/merge-flags (list f1 f2 f3) f4 -f2)' will return `(f1 f3 f4)'"
+    `(fg42/-merge-flags ,flags-set ,@(mapcar (lambda (x) `',x) new-flags)))
+
+
+(defmacro defflag (flag-name docstring)
+  "Define a new flag FLAG-NAME with the given DOCSTRING."
+  (let ((var-name (format "fg42/-flag-%s" flag-name)))
+    `(if (boundp ,var-name)
+         (warn (foramt "Flag name `%s' already defined" ,flag-name))
+       (progn
+         (defvar ,var-name t)
+         (add-to-list 'fg42/available-flags ,flag-name)))))
+
+
+(defmacro when-flag (flag &rest body)
+  "Evaluate the BODY only if the given FLAG is active."
+
+  ;; The `cube-local-flags' variable here is going to be
+  ;; defined in cubes to hold the local flags for each cube
+  (if (and (boundp 'cube-local-flags)
+           (member flag cube-local-flags))
+      `,@body
+    (if (member flag fg42/flags)
+        `,@body
+      nil)))
+
+
+(provide 'fg42/flags)
+;;; flags.el ends here
diff --git a/dev.org b/dev.org
index fac60c2..7d9029d 100644
--- a/dev.org
+++ b/dev.org
@@ -38,6 +38,7 @@ On the first level, I should feel comfortable with it.
 
 * Tasks
 ** TODO Reformat the modeline
+** TODO Create a macro similar to `with-ability` to run a block of code only if the given cube was active
 
 * Things that didn't work out
 - rbenv