diff --git a/README.org b/README.org
index 10931db..188ebf9 100644
--- a/README.org
+++ b/README.org
@@ -376,6 +376,8 @@ the contents of packages and allows to update packages to the latest version.
 #+begin_src emacs-lisp -n :results silent
 (when (require 'treesit nil 'noerror)
   (setopt
+   ;; Set `tab-width' in `after-change-major-mode-hook' function too.
+   go-ts-mode-indent-offset 2
    treesit-language-source-alist
    '((bash "https://github.com/tree-sitter/tree-sitter-bash" "master" "src")
      (c "https://github.com/tree-sitter/tree-sitter-c" "master" "src")
@@ -383,7 +385,9 @@ the contents of packages and allows to update packages to the latest version.
      (cpp "https://github.com/tree-sitter/tree-sitter-cpp" "master" "src")
      (css "https://github.com/tree-sitter/tree-sitter-css" "master" "src")
      (glsl "https://github.com/theHamsta/tree-sitter-glsl" "master" "src")
+     ;; go-ts-mode requires libtree-sitter-go and libtree-sitter-gomode.
      (go "https://github.com/tree-sitter/tree-sitter-go" "master" "src")
+     (gomod "https://github.com/camdencheek/tree-sitter-go-mod" "main" "src")
      (html "https://github.com/tree-sitter/tree-sitter-html" "master" "src")
      (java "https://github.com/tree-sitter/tree-sitter-java" "master" "src")
      (javascript "https://github.com/tree-sitter/tree-sitter-javascript"
@@ -405,8 +409,11 @@ the contents of packages and allows to update packages to the latest version.
                  "master" "typescript/src")
      (yaml "https://github.com/ikatyang/tree-sitter-yaml" "master" "src")))
 
-  (add-to-list 'auto-mode-alist
-               `(,(rx ".py" (opt (any "iw")) eos) . python-ts-mode)))
+  (add-hook 'after-change-major-mode-hook
+            (defun on-go-ts-mode-hook ()
+              (when (derived-mode-p 'go-ts-mode 'go-mod-ts-mode)
+                (setq-local tab-width 2))))
+  (add-to-list 'auto-mode-alist `(,(rx ".go" eos) . go-ts-mode)))
 #+end_src
 
 * [[info:emacs#Faces][Text faces or styles (info)]]