Shell

Homebrew bash 5 is the login shell. The whole configuration is one file.

~/.bashrc

export PATH="$HOME/.local/share/mise/shims:$HOME/.local/bin:$HOME/.bun/bin:/opt/homebrew/bin:/opt/homebrew/sbin:$PATH"
export EDITOR="code --wait"
export VISUAL="$EDITOR"
export HOMEBREW_NO_ENV_HINTS=1
export IOS_SIMULATOR_POOL_SIZE="${IOS_SIMULATOR_POOL_SIZE:-3}"

for f in "$HOME/.config/secrets.env" "$HOME/.codex/secrets/linear.env"; do
  [ -r "$f" ] && . "$f"
done

case $- in *i*)
  alias claude='command claude --dangerously-skip-permissions'
  alias maude='clear; ssh -t maude cc'
  ;;
esac

• mise shims come first so every tool resolves without mise activate, including in bash -c.
• ~/.config/secrets.env is where API keys go. It is untracked and mode 600. The Codex secrets file is sourced too so both agents see the same variables.
• The two aliases are the only interactive-only lines.

~/.bash_profile sources ~/.bashrc, so login shells and interactive shells are identical.

~/.zshenv

emulate sh -c '. "$HOME/.bashrc"'

Anything that still runs zsh -c gets the same PATH and secrets. There is no .zshrc.

How agents pick the shell

• Codex reads the login shell from the user record. After chsh it uses bash immediately.
• Claude Code uses $SHELL. CLAUDE_CODE_SHELL is pinned to /opt/homebrew/bin/bash in its settings so it does not depend on the parent process.
• T3 Code and other GUI apps inherit SHELL from the login session. run_once_after_set-login-shell sets it with launchctl setenv so apps launched after the switch get bash without logging out.

Login shell on a new machine

run_once_after_set-login-shell adds /opt/homebrew/bin/bash to /etc/shells, runs chsh, and sets the launchd variable. It asks for sudo once.