diff --git a/README.md b/README.md
index 0c97b74..8d25dc2 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ to your questions, right within the editor.
 This package is available from [JCS-ELPA](https://jcs-emacs.github.io/jcs-elpa/).
 Install from these repositories then you should be good to go!
 
-Normall, you don't need to add `(require 'codegpt)` to your confiugration since
+Normally, you don't need to add `(require 'codegpt)` to your confiugration since
 most `codegpt` commands are autoload and can be called without loading the module!
 
 #### use-package
@@ -86,6 +86,14 @@ List of supported commands,
 | `codegpt-explain` | Explain the selected code                       |
 | `codegpt-improve` | Improve, refactor or optimize it                |
 
+## 📝 Customization
+
+#### 🧪 Variables
+
+- `codegpt-model` - ID of the model to use.
+- `codegpt-max-tokens` - The maximum number of tokens to generate in the completion.
+- `codegpt-temperature` - What sampling temperature to use.
+
 ## Contribute
 
 [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](http://makeapullrequest.com)
diff --git a/codegpt.el b/codegpt.el
index b463b57..cc42ec1 100644
--- a/codegpt.el
+++ b/codegpt.el
@@ -58,6 +58,21 @@
   :type 'list
   :group 'codegpt)
 
+(defcustom codegpt-model "text-davinci-003"
+  "ID of the model to use."
+  :type 'string
+  :group 'codegpt)
+
+(defcustom codegpt-max-tokens 4000
+  "The maximum number of tokens to generate in the completion."
+  :type 'integer
+  :group 'codegpt)
+
+(defcustom codegpt-temperature 1.0
+  "What sampling temperature to use."
+  :type 'number
+  :group 'openai)
+
 ;;
 ;;; Application
 
@@ -91,7 +106,10 @@ boundaries of that region in buffer."
              (insert (string-trim result) "\n")
              (fill-region original-point (point))))
          (unless codegpt-focus-p
-           (select-window original-window))))
+           (select-window original-window)))
+       :model codegpt-model
+       :max-tokens codegpt-max-tokens
+       :temperature codegpt-temperature)
       (unless codegpt-focus-p
         (select-window original-window)))))