diff --git a/bin/brightness-i2c b/bin/brightness-i2c
index f82f28b..6afa28d 100755
--- a/bin/brightness-i2c
+++ b/bin/brightness-i2c
@@ -2,8 +2,14 @@
 
 OPERATOR="${1}"
 AMOUNT="${2}"
+F="$XDG_RUNTIME_DIR/over/monitors-i2c"
 
-BUSES=(${(s/:/)OVER_ENV_MONITORS_I2C})
+if [[ ! -e "$F" ]]; then
+	exit 1
+fi
+
+MONITORS_I2C=$(cat $XDG_RUNTIME_DIR/over/monitors-i2c)
+BUSES=(${(s/:/)MONITORS_I2C})
 
 for BUS in ${BUSES}
 do
diff --git a/lib/prompt-init b/lib/prompt-init
index 760d539..ae8a5ea 100755
--- a/lib/prompt-init
+++ b/lib/prompt-init
@@ -8,7 +8,8 @@ OVER_PROMPT_TITLE=""
 which ddcutil > /dev/null
 if [[ $? -eq 0 ]]; then
 	local I2C_IDS=($(ddcutil detect --terse | grep "I2C bus" | sed "s/^.*-//"))
-	export OVER_ENV_MONITORS_I2C=${(j|:|)I2C_IDS}
+	mkdir -p $XDG_RUNTIME_DIR/over
+	echo ${(j|:|)I2C_IDS} > $XDG_RUNTIME_DIR/over/monitors-i2c
 fi
 
 if [[ -a "$OVER_PROMPT_CFG" ]]; then