wezterm/docs/config/lua/window/composition_status.md

wezterm:composition_status()

Since: nightly builds only

Returns a string holding the current dead key or IME composition text, or nil if the input layer is not in a composition state.

This is the same text that is shown at the cursor position when composing.

This example shows how to show the composition status in the status area. The cursor color is also changed to orange when in this state.

local wezterm = require 'wezterm';

wezterm.on("update-right-status", function(window, pane)
  local compose = window:composition_status()
  if compose then
    compose = "COMPOSING: " .. compose
  end
  window:set_right_status(compose)
end);

return {
  colors = {
    compose_cursor = "orange",
  },
}

See also: window:leader_is_active().