diff --git a/scripts/frank-primary.env b/scripts/frank-primary.env
index ef9e5fd..14586c1 100644
--- a/scripts/frank-primary.env
+++ b/scripts/frank-primary.env
@@ -59,6 +59,11 @@ FRANK_PRIMARY_IMAGE=stilldeadcode/radiance@sha256:4c3f484564bb2872784e46b0a59cbd
 FRANK_PRIMARY_MODEL_DIR=/home/dank/models/rad
 FRANK_PRIMARY_MODEL_FILE=qwen4exp-fp8-native.rad
 FRANK_PRIMARY_STATE_DIR=/home/dank/radiance-state
+# The state dir's tune/ subdirectory holds rad-tune's kernel-selection
+# cache (the engine's selector reads $RADIANCE_HOME/tune/<machine>.tune
+# at boot; $RADIANCE_HOME defaults to /opt/radiance, in the image, so the
+# cache must ride a host mount — serve script mounts it, see the runbook's
+# "Tuning levers").
 # Container identity is the SERVICE name (Frank's call, 2026-10-05): one
 # name across systemctl and podman ps. The runtime changes; the name does
 # not. The legacy list retires every predecessor identity that could hold
diff --git a/scripts/serve-frank-primary.sh b/scripts/serve-frank-primary.sh
index 3190ded..a0bf8a2 100755
--- a/scripts/serve-frank-primary.sh
+++ b/scripts/serve-frank-primary.sh
@@ -101,6 +101,14 @@ mkdir -p "$FRANK_PRIMARY_STATE_DIR/kvcache/frank-primary"
 # left the SSD prefix tier off (measured 2026-10-06 boot ledger). Pre-create
 # the full path on the host so the tier opens on first boot.
 
+mkdir -p "$FRANK_PRIMARY_STATE_DIR/tune"
+# rad-tune's kernel-selection cache (see the runbook's "Tuning levers"):
+# the engine's selector reads $RADIANCE_HOME/tune/<machine>.tune at boot;
+# $RADIANCE_HOME defaults to /opt/radiance, which lives in the image, so
+# the cache must ride a host mount or it dies with the --rm container
+# that wrote it. The dir is pre-created for the same reason as kvcache
+# (the engine's create is not recursive).
+
 if [ ! -e /dev/kfd ] || [ ! -d /dev/dri ]; then
     echo "ERROR: GPU device nodes absent (/dev/kfd, /dev/dri)" >&2
     exit 1
@@ -165,6 +173,7 @@ podman run -d --name "$FRANK_PRIMARY_CONTAINER" \
   --device /dev/kfd --device /dev/dri \
   -v "$FRANK_PRIMARY_MODEL_DIR":/models:ro \
   -v "$FRANK_PRIMARY_STATE_DIR":/data \
+  -v "$FRANK_PRIMARY_STATE_DIR/tune":/opt/radiance/share/radiance/tune \
   -v "$FRANK_PRIMARY_TEMPLATE":/templates/template.jinja:ro \
   "$FRANK_PRIMARY_IMAGE" \
   --model "/models/$FRANK_PRIMARY_MODEL_FILE" \