diff --git a/README.md b/README.md
index 1dfa05c..a54d5d4 100644
--- a/README.md
+++ b/README.md
@@ -143,7 +143,11 @@ from the build tree:
 build-tree daemon in the background, and returns to the shell. It requires
 `pkill` from procps. Startup and frontend failures remain visible on the
 caller's standard error. A service supervisor should instead run
-`./strans map` directly in the foreground.
+`./strans map` directly in the foreground, with the session's
+`XDG_RUNTIME_DIR` and `DISPLAY`: the GTK module finds the daemon at
+`$XDG_RUNTIME_DIR/strans.sock` (else `/tmp/strans.UID`), and IBus clients
+through the address file libibus expects under `~/.config/ibus/bus/`,
+which strans writes as `ibus-daemon` would.
 
 The build does not copy or install the daemon or its data. `./strans DIR`
 opens `hira.map`, `kata.map`, `telex.map`, `kanji.dict`, `emoji.dict`, and