diff --git a/zsh/.mac_config.zsh_mac.example b/zsh/.mac_config.zsh_mac.example
index 7341fd2..82a0a8b 100644
--- a/zsh/.mac_config.zsh_mac.example
+++ b/zsh/.mac_config.zsh_mac.example
@@ -8,11 +8,11 @@ defaults write .GlobalPreferences AppleLocale en_DE
 
 ARCH=`uname -m`
 if [[ $ARCH == "arm64" ]]; then
-    HOMEBREWPREFIX="/opt/homebrew"
+    export HOMEBREW_PREFIX="/opt/homebrew"
 else
-    HOMEBREWPREFIX="/usr/local"
+    export HOMEBREW_PREFIX="/usr/local"
 fi
-export PATH="$HOMEBREWPREFIX/opt/coreutils/libexec/gnubin:$HOME/.local/bin:$HOMEBREWPREFIX/bin:$PATH:$HOMEBREWPREFIX/sbin"
+export PATH="$HOMEBREW_PREFIX/opt/coreutils/libexec/gnubin:$HOME/.local/bin:$HOMEBREW_PREFIX/bin:$PATH:$HOMEBREW_PREFIX/sbin"
 
 # test -e "${HOME}/.iterm2_shell_integration.zsh" && source "${HOME}/.iterm2_shell_integration.zsh"
 
@@ -27,9 +27,9 @@ if [ -f "$HOMEBREW_COMMAND_NOT_FOUND_HANDLER" ]; then
   source "$HOMEBREW_COMMAND_NOT_FOUND_HANDLER";
 fi
 
-export DYLD_FALLBACK_LIBRARY_PATH="$HOMEBREW_PREFIX/lib:${DYLD_FALLBACK_LIBRARY_PATH}"
-export GI_TYPELIB_PATH="$HOMEBREW_PREFIX/lib/girepository-1.0:${GI_TYPELIB_PATH}"
-export PKG_CONFIG_PATH="$HOMEBREW_PREFIX/lib/pkgconfig:$HOMEBREW_PREFIX/share/pkgconfig:${PKG_CONFIG_PATH}"
+export DYLD_FALLBACK_LIBRARY_PATH="$HOMEBREW_PREFIX/lib${DYLD_FALLBACK_LIBRARY_PATH:+:$DYLD_FALLBACK_LIBRARY_PATH}"
+export GI_TYPELIB_PATH="$HOMEBREW_PREFIX/lib/girepository-1.0${GI_TYPELIB_PATH:+:$GI_TYPELIB_PATH}"
+export PKG_CONFIG_PATH="$HOMEBREW_PREFIX/lib/pkgconfig:$HOMEBREW_PREFIX/share/pkgconfig${PKG_CONFIG_PATH:+:$PKG_CONFIG_PATH}"
 alias claude="workon claude; claude; deactivate"
 alias python="python3"
 
diff --git a/zsh/.zshrc b/zsh/.zshrc
index 41dcff3..39f706d 100644
--- a/zsh/.zshrc
+++ b/zsh/.zshrc
@@ -146,9 +146,9 @@ delzip() {
 export MITMPROXY_SSLKEYLOGFILE="~/.mitmproxy/sslkeylogfile.txt"
 
 [[ -f ~/.zsh/.mac_config.zsh ]] && source ~/.zsh/.mac_config.zsh
-if `which go &>/dev/null`; then
-    export PATH="$PATH:$(go env GOPATH)/bin"
-    export GOPATH=$(go env GOPATH)
+if (( $+commands[go] )); then
+    export GOPATH="$(go env GOPATH 2>/dev/null)"
+    [[ -n "$GOPATH" ]] && path+=("$GOPATH/bin")
 fi
 
 # Use safecp/safemv from the tools-repo when available (after ~/.local/bin is on PATH)
@@ -205,8 +205,9 @@ zstyle :bracketed-paste-magic paste-finish pastefinish
 
 # https://github.com/zsh-users/zsh-autosuggestions/issues/351
 ZSH_AUTOSUGGEST_CLEAR_WIDGETS+=(bracketed-paste)
-export PATH=$PATH:/Users/ising/.runai/bin
-runai_bin=/Users/ising/.runai/bin/runai
+[[ -d "$HOME/.lmstudio/bin" ]] && path+=("$HOME/.lmstudio/bin")
+[[ -d "$HOME/.runai/bin" ]] && path+=("$HOME/.runai/bin")
+runai_bin="$HOME/.runai/bin/runai"
 runai_completion=${ZDOTDIR:-$HOME}/.cache/zsh/runai-completion.zsh
 if [[ -x "$runai_bin" ]]; then
     if [[ ! -s "$runai_completion" || "$runai_bin" -nt "$runai_completion" ]]; then
@@ -226,7 +227,7 @@ fi
 # in via `-e VIRTUAL_ENV=...`, see .tmux.conf) we source the venv's activate
 # script here rather than in .virtual_env_config.zsh. activate snapshots the
 # current PATH into _OLD_VIRTUAL_PATH and restores it on `deactivate`; if we
-# activated earlier (before .mac_config.zsh, go, runai below all prepend to
+# activated earlier (before .mac_config.zsh, Go, Run:AI, and LM Studio mutate
 # PATH) that snapshot would be incomplete and `deactivate` would strip
 # ~/.local/bin & friends — dropping claude and co. off PATH. Keeping this last
 # guarantees the snapshot is the fully-built PATH.
@@ -235,6 +236,7 @@ fi
 #
 # A new tmux window clears the var to empty (`bind c ... -e VIRTUAL_ENV=`) to
 # force the base environment; drop that empty value so nothing sees a bogus venv.
+typeset -U path PATH
 [ -z "${VIRTUAL_ENV:-}" ] && unset VIRTUAL_ENV
 if [ -n "$VIRTUAL_ENV" ] && [ -f "$VIRTUAL_ENV/bin/activate" ]; then
     # Guard against double-activation on a manual `source ~/.zshrc`.