[codex] Add helper to generate commit messages from git diffs (generic + dotfiles variant)

[0xdevalias]

Overview

Introduce a shell alias/function/helper that can take git diff output, feed it into Codex with a suitable prompt, and return a well-structured commit message.

The tool should be written generically so it can work in any Git repo, and then extended with a dotfiles-specific wrapper that defaults to ~/.dotfiles.

Example

Generic usage:

⇒ git -C /path/to/repo diff repoPath/to/file | codex "Generate a concise commit message for this diff"

Dotfiles-specific wrapper:

⇒ git -C ~/.dotfiles/bin diff dotfiles-create-bin | codex "Generate a concise commit message for this dotfiles change"

Goals

• Provide a smooth workflow for drafting commit messages without copy/pasting diffs.
• Ensure generated commit messages are consistent, scoped, and conventional.
• Make the generic helper reusable across repos.
• Provide a dotfiles-scoped alias/function that builds on the generic helper.

Proposed Approach

• Implement a generic helper script/alias (e.g., codex-git-commit-msg):

  • Runs git diff (or accepts an existing diff via pipe).
  • Pipes the diff into Codex with a commit-message prompt.
  • Outputs the proposed commit message.

• Add a dotfiles wrapper (e.g., codex-dotfiles-commit-msg) that:

  • Uses git -C ~/.dotfiles automatically.
  • Provides a dotfiles-specific prompt context.

References

• Codex CLI docs: codex -h