In order for format-all picks up terraform-fmt formatter of Terraform files, when using Tree Sitter with terraform-ts-mode, the mode should be registered in language-id package like this:

(when-let ((terraform-def (assoc "Terraform" language-id--definitions)))
   (setcdr terraform-def '(terraform-mode terraform-ts-mode)))

Added to Pavel's Emacs Configuration v3 to (use-package format-all) block.

At work I work with Terraform, so need to edit quite a lot of tf files in GNU Emacs. There's no built-in terraform-ts-mode Emacs package and I don't want to install regexp-based terraform-mode package

Existing terraform-ts-mode is this: kgrotel/terraform-ts-mode, which claims being experimental. So it's a good opportunity to learn how to create major modes using Tree Sitter and on <2026-05-05 Tue> I built my own with Claude Code.

Installation: put terraform-ts-mode.el to load-path.

Usage:

(use-package terraform-ts-mode :ensure nil
  :init
  (add-to-list 'major-mode-remap-alist '(terraform-mode . terraform-ts-mode)))

With this knowledge, the next step is [TK: try mickeynp/combobulate package].