diff --git a/completions/_omz b/completions/_omz
new file mode 100644
index 000000000..97112678d
--- /dev/null
+++ b/completions/_omz
@@ -0,0 +1,90 @@
+#compdef omz
+
+local -a cmds subcmds
+cmds=(
+  'changelog:Print the changelog'
+  'help:Usage information'
+  'plugin:Manage plugins'
+  'pr:Manage Oh My Zsh Pull Requests'
+  'reload:Reload the current zsh session'
+  'shop:Open the Oh My Zsh shop'
+  'theme:Manage themes'
+  'update:Update Oh My Zsh'
+  'version:Show the version'
+)
+
+if (( CURRENT == 2 )); then
+  _describe 'command' cmds
+elif (( CURRENT == 3 )); then
+  case "$words[2]" in
+    changelog) local -a refs
+      refs=("${(@f)$(builtin cd -q "$ZSH"; command git for-each-ref --format="%(refname:short):%(subject)" refs/heads refs/tags)}")
+      _describe 'command' refs ;;
+    plugin) subcmds=(
+      'disable:Disable plugin(s)'
+      'enable:Enable plugin(s)'
+      'info:Get plugin information'
+      'list:List plugins'
+      'load:Load plugin(s)'
+    )
+      _describe 'command' subcmds ;;
+    pr) subcmds=('clean:Delete all Pull Request branches' 'test:Test a Pull Request')
+      _describe 'command' subcmds ;;
+    theme) subcmds=('list:List themes' 'set:Set a theme in your .zshrc file' 'use:Load a theme')
+      _describe 'command' subcmds ;;
+  esac
+elif (( CURRENT == 4 )); then
+  case "${words[2]}::${words[3]}" in
+    plugin::(disable|enable|load))
+      local -aU valid_plugins
+
+      if [[ "${words[3]}" = disable ]]; then
+        # if command is "disable", only offer already enabled plugins
+        valid_plugins=($plugins)
+      else
+        valid_plugins=("$ZSH"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t) "$ZSH_CUSTOM"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t))
+        # if command is "enable", remove already enabled plugins
+        [[ "${words[3]}" = enable ]] && valid_plugins=(${valid_plugins:|plugins})
+      fi
+
+      _describe 'plugin' valid_plugins ;;
+    plugin::info)
+      local -aU plugins
+      plugins=("$ZSH"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t) "$ZSH_CUSTOM"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t))
+      _describe 'plugin' plugins ;;
+    plugin::list)
+      local -a opts
+      opts=('--enabled:List enabled plugins only')
+      _describe -o 'options' opts ;;
+    theme::(set|use))
+      local -aU themes
+      themes=("$ZSH"/themes/*.zsh-theme(-.N:t:r) "$ZSH_CUSTOM"/**/*.zsh-theme(-.N:r:gs:"$ZSH_CUSTOM"/themes/:::gs:"$ZSH_CUSTOM"/:::))
+      _describe 'theme' themes ;;
+  esac
+elif (( CURRENT > 4 )); then
+  case "${words[2]}::${words[3]}" in
+    plugin::(enable|disable|load))
+      local -aU valid_plugins
+
+      if [[ "${words[3]}" = disable ]]; then
+        # if command is "disable", only offer already enabled plugins
+        valid_plugins=($plugins)
+      else
+        valid_plugins=("$ZSH"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t) "$ZSH_CUSTOM"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t))
+        # if command is "enable", remove already enabled plugins
+        [[ "${words[3]}" = enable ]] && valid_plugins=(${valid_plugins:|plugins})
+      fi
+
+      # Remove plugins already passed as arguments
+      # NOTE: $(( CURRENT - 1 )) is the last plugin argument completely passed, i.e. that which
+      # has a space after them. This is to avoid removing plugins partially passed, which makes
+      # the completion not add a space after the completed plugin.
+      local -a args
+      args=(${words[4,$(( CURRENT - 1))]})
+      valid_plugins=(${valid_plugins:|args})
+
+      _describe 'plugin' valid_plugins ;;
+  esac
+fi
+
+return 0
diff --git a/lib/cli.zsh b/functions/omz
similarity index 86%
rename from lib/cli.zsh
rename to functions/omz
index a86434411..5a75fcb84 100644
--- a/lib/cli.zsh
+++ b/functions/omz
@@ -1,5 +1,3 @@
-#!/usr/bin/env zsh
-
 function omz {
   setopt localoptions noksharrays
   [[ $# -gt 0 ]] || {
@@ -20,102 +18,6 @@ function omz {
   _omz::$command "$@"
 }
 
-function _omz {
-  local -a cmds subcmds
-  cmds=(
-    'changelog:Print the changelog'
-    'help:Usage information'
-    'plugin:Manage plugins'
-    'pr:Manage Oh My Zsh Pull Requests'
-    'reload:Reload the current zsh session'
-    'shop:Open the Oh My Zsh shop'
-    'theme:Manage themes'
-    'update:Update Oh My Zsh'
-    'version:Show the version'
-  )
-
-  if (( CURRENT == 2 )); then
-    _describe 'command' cmds
-  elif (( CURRENT == 3 )); then
-    case "$words[2]" in
-      changelog) local -a refs
-        refs=("${(@f)$(builtin cd -q "$ZSH"; command git for-each-ref --format="%(refname:short):%(subject)" refs/heads refs/tags)}")
-        _describe 'command' refs ;;
-      plugin) subcmds=(
-        'disable:Disable plugin(s)'
-        'enable:Enable plugin(s)'
-        'info:Get plugin information'
-        'list:List plugins'
-        'load:Load plugin(s)'
-      )
-        _describe 'command' subcmds ;;
-      pr) subcmds=('clean:Delete all Pull Request branches' 'test:Test a Pull Request')
-        _describe 'command' subcmds ;;
-      theme) subcmds=('list:List themes' 'set:Set a theme in your .zshrc file' 'use:Load a theme')
-        _describe 'command' subcmds ;;
-    esac
-  elif (( CURRENT == 4 )); then
-    case "${words[2]}::${words[3]}" in
-      plugin::(disable|enable|load))
-        local -aU valid_plugins
-
-        if [[ "${words[3]}" = disable ]]; then
-          # if command is "disable", only offer already enabled plugins
-          valid_plugins=($plugins)
-        else
-          valid_plugins=("$ZSH"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t) "$ZSH_CUSTOM"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t))
-          # if command is "enable", remove already enabled plugins
-          [[ "${words[3]}" = enable ]] && valid_plugins=(${valid_plugins:|plugins})
-        fi
-
-        _describe 'plugin' valid_plugins ;;
-      plugin::info)
-        local -aU plugins
-        plugins=("$ZSH"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t) "$ZSH_CUSTOM"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t))
-        _describe 'plugin' plugins ;;
-      plugin::list)
-        local -a opts
-        opts=('--enabled:List enabled plugins only')
-        _describe -o 'options' opts ;;
-      theme::(set|use))
-        local -aU themes
-        themes=("$ZSH"/themes/*.zsh-theme(-.N:t:r) "$ZSH_CUSTOM"/**/*.zsh-theme(-.N:r:gs:"$ZSH_CUSTOM"/themes/:::gs:"$ZSH_CUSTOM"/:::))
-        _describe 'theme' themes ;;
-    esac
-  elif (( CURRENT > 4 )); then
-    case "${words[2]}::${words[3]}" in
-      plugin::(enable|disable|load))
-        local -aU valid_plugins
-
-        if [[ "${words[3]}" = disable ]]; then
-          # if command is "disable", only offer already enabled plugins
-          valid_plugins=($plugins)
-        else
-          valid_plugins=("$ZSH"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t) "$ZSH_CUSTOM"/plugins/*/{_*,*.plugin.zsh}(-.N:h:t))
-          # if command is "enable", remove already enabled plugins
-          [[ "${words[3]}" = enable ]] && valid_plugins=(${valid_plugins:|plugins})
-        fi
-
-        # Remove plugins already passed as arguments
-        # NOTE: $(( CURRENT - 1 )) is the last plugin argument completely passed, i.e. that which
-        # has a space after them. This is to avoid removing plugins partially passed, which makes
-        # the completion not add a space after the completed plugin.
-        local -a args
-        args=(${words[4,$(( CURRENT - 1))]})
-        valid_plugins=(${valid_plugins:|args})
-
-        _describe 'plugin' valid_plugins ;;
-    esac
-  fi
-
-  return 0
-}
-
-# If run from a script, do not set the completion function
-if (( ${+functions[compdef]} )); then
-  compdef _omz omz
-fi
-
 ## Utility functions
 
 function _omz::confirm {
@@ -942,3 +844,5 @@ function _omz::version {
     printf "%s (%s)\n" "$version" "$commit"
   )
 }
+
+omz "$@"
diff --git a/lib/diagnostics.zsh b/functions/omz_diagnostic_dump
similarity index 99%
rename from lib/diagnostics.zsh
rename to functions/omz_diagnostic_dump
index 29929f3fc..41d7a477d 100644
--- a/lib/diagnostics.zsh
+++ b/functions/omz_diagnostic_dump
@@ -1,4 +1,4 @@
-# diagnostics.zsh
+# omz_diagnostic_dump
 #
 # Diagnostic and debugging support for oh-my-zsh
 
@@ -351,3 +351,5 @@ function _omz_diag_dump_os_specific_version() {
   done
 }
 
+
+omz_diagnostic_dump "$@"
diff --git a/oh-my-zsh.sh b/oh-my-zsh.sh
index b4e95e0ff..e8b8cdc63 100644
--- a/oh-my-zsh.sh
+++ b/oh-my-zsh.sh
@@ -78,6 +78,9 @@ fpath=($ZSH/{functions,completions} $ZSH_CUSTOM/{functions,completions} $fpath)
 # Load all stock functions (from $fpath files) called below.
 autoload -U compaudit compinit zrecompile
 
+# The omz CLI and omz_diagnostic_dump are loaded on first use
+autoload -Uz omz omz_diagnostic_dump
+
 is_plugin() {
   local base_dir=$1
   local name=$2