diff --git a/TODO.AI.md b/TODO.AI.md
new file mode 100644
index 0000000..607f33a
--- /dev/null
+++ b/TODO.AI.md
@@ -0,0 +1,17 @@
+# TODO.AI.md
+
+## Lint cleanup — pre-existing script-lint violations (found incidentally while wiring act_runner cache-server)
+
+Not fixed yet — out of scope for the cache-enablement change; flagged by `script-lint` agent.
+
+- `rootfs/usr/local/bin/start-runners`:
+  - line 24: UUOC — `echo "$SERVER_ADDRESS" | grep -q '://'` should be `[[ "$SERVER_ADDRESS" == *"://"* ]]`
+  - line 24: `grep -q '://'` missing `--` before query
+- `rootfs/usr/local/etc/docker/init.d/zz-act_runner.sh`:
+  - line 4: `##@Version` header present but no matching `VERSION=` assignment in script body
+  - missing `--` before the grep query at lines 124 (x2), 130, 133, 134, 369, 390, 401, 438, 468, 525 (x2), 544 (x2, also should quote the `grep` pattern), 571, 583
+
+## Other observations not yet actioned
+
+- `.gitea/workflows/docker.yaml` uses the same stale/unpinned action pattern (`@v2`-`@v4`, DockerHub-only, `catthehacker/ubuntu:act-latest`) that was removed from the `opengist` repo's duplicate workflow — no `build.yml` counterpart exists here yet.
+- `Dockerfile` sets forbidden OCI labels (`org.opencontainers.image.base.name`, `.schema-version`, duplicate `authors`) — same issue previously found and fixed in `opengist`.
diff --git a/rootfs/tmp/etc/act_runner/cache_server.yaml b/rootfs/tmp/etc/act_runner/cache_server.yaml
index 319af73..6373a26 100644
--- a/rootfs/tmp/etc/act_runner/cache_server.yaml
+++ b/rootfs/tmp/etc/act_runner/cache_server.yaml
@@ -2,7 +2,8 @@ log:
   level: warn
 
 cache:
-  enabled: false
+  enabled: true
   dir: 'REPLACE_RUNNER_CACHE_DIR'
   host: '0.0.0.0'
   port: REPLACE_RUNNER_CACHE_PORT
+  external_secret: 'REPLACE_RUNNER_CACHE_SECRET'
diff --git a/rootfs/tmp/etc/act_runner/default_config.yaml b/rootfs/tmp/etc/act_runner/default_config.yaml
index 366f7ab..265db74 100644
--- a/rootfs/tmp/etc/act_runner/default_config.yaml
+++ b/rootfs/tmp/etc/act_runner/default_config.yaml
@@ -66,4 +66,6 @@ container:
   docker_host: ''
 
 cache:
-  enabled: false
+  enabled: true
+  external_server: 'http://REPLACE_RUNNER_CACHE_HOST:REPLACE_RUNNER_CACHE_PORT/'
+  external_secret: 'REPLACE_RUNNER_CACHE_SECRET'
diff --git a/rootfs/usr/local/bin/start-runners b/rootfs/usr/local/bin/start-runners
index 6484010..6c2ac6c 100755
--- a/rootfs/usr/local/bin/start-runners
+++ b/rootfs/usr/local/bin/start-runners
@@ -47,18 +47,33 @@ __log "Starting $RUNNERS_START act_runner instance(s)"
 __log "Server Address: $SERVER_ADDRESS"
 __log "Runner Name Prefix: ${RUNNER_NAME_PREFIX:-runner}"
 # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+# Shared cache config so runner-N instances use the same cache-server
+# started by zz-act_runner.sh instead of an unshared per-process cache.
+RUNNERS_CACHE_CONFIG=""
+if [ -n "$RUNNER_CACHE_HOST" ] && [ -n "$RUNNER_CACHE_PORT" ] && [ -n "$RUNNER_CACHE_SECRET" ]; then
+	RUNNERS_CACHE_CONFIG="/config/act_runner/runners-cache.yaml"
+	cat <<EOF >"$RUNNERS_CACHE_CONFIG"
+cache:
+  enabled: true
+  external_server: 'http://${RUNNER_CACHE_HOST}:${RUNNER_CACHE_PORT}/'
+  external_secret: '${RUNNER_CACHE_SECRET}'
+EOF
+fi
+# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 # Register a single runner synchronously (no daemon start)
 __register_runner() {
 	local runner_id=$1
 	local runner_name="${RUNNER_NAME_PREFIX:-runner}-${runner_id}"
 	local runner_dir="/config/act_runner/reg/${runner_name}"
+	local config_args=()
 
 	mkdir -p "$runner_dir"
 	[ -d "$runner_dir" ] && cd "$runner_dir" || return 1
+	[ -n "$RUNNERS_CACHE_CONFIG" ] && config_args=(--config "$RUNNERS_CACHE_CONFIG")
 
 	if [ ! -f "$runner_dir/.runner" ]; then
 		__log "Registering runner: $runner_name (ID: $runner_id)"
-		act_runner register --instance "$SERVER_ADDRESS" --token "$SERVER_TOKEN" --name "$runner_name" --labels "$RUNNER_LABELS" --no-interactive
+		act_runner register "${config_args[@]}" --instance "$SERVER_ADDRESS" --token "$SERVER_TOKEN" --name "$runner_name" --labels "$RUNNER_LABELS" --no-interactive
 		if [ $? -ne 0 ]; then
 			__log "ERROR: Failed to register runner $runner_name"
 			return 1
@@ -72,10 +87,12 @@ __start_runner_daemon() {
 	local runner_id=$1
 	local runner_name="${RUNNER_NAME_PREFIX:-runner}-${runner_id}"
 	local runner_dir="/config/act_runner/reg/${runner_name}"
+	local config_args=()
 
 	[ -d "$runner_dir" ] && cd "$runner_dir" || return 1
+	[ -n "$RUNNERS_CACHE_CONFIG" ] && config_args=(--config "$RUNNERS_CACHE_CONFIG")
 	__log "Starting daemon for runner: $runner_name"
-	exec act_runner daemon
+	exec act_runner daemon "${config_args[@]}"
 }
 # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 # Phase 1: register all runners sequentially so IDs are assigned in order
diff --git a/rootfs/usr/local/etc/docker/init.d/zz-act_runner.sh b/rootfs/usr/local/etc/docker/init.d/zz-act_runner.sh
index 0cac728..7cd0e63 100755
--- a/rootfs/usr/local/etc/docker/init.d/zz-act_runner.sh
+++ b/rootfs/usr/local/etc/docker/init.d/zz-act_runner.sh
@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 # shellcheck shell=bash
 # - - - - - - - - - - - - - - - - - - - - - - - - -
-##@Version           :  202606261600-git
+##@Version           :  202608031200-git
 # @@Author           :  Jason Hempstead
 # @@Contact          :  jason@casjaysdev.pro
 # @@License          :  LICENSE.md
@@ -142,6 +142,26 @@ __gen_auth_token() {
 	return $exitCode
 }
 # - - - - - - - - - - - - - - - - - - - - - - - - -
+# shared secret between the runner(s) and the standalone cache-server
+__gen_cache_secret() {
+	local secret token_dir exitCode
+	exitCode=1
+	token_dir="$CONF_DIR/tokens"
+	mkdir -p "$token_dir" >/dev/null 2>&1
+	if [ -n "$RUNNER_CACHE_SECRET" ]; then
+		secret="$RUNNER_CACHE_SECRET"
+	elif [ -s "$token_dir/cache_secret" ]; then
+		secret="$(<"$token_dir/cache_secret")"
+	fi
+	[ -z "$secret" ] && secret="$(__random_password 32)"
+	if [ -n "$secret" ]; then
+		exitCode=0
+		echo "$secret"
+		echo "$secret" >"$token_dir/cache_secret"
+	fi
+	return $exitCode
+}
+# - - - - - - - - - - - - - - - - - - - - - - - - -
 # Script to execute
 START_SCRIPT="/usr/local/etc/docker/exec/$SERVICE_NAME"
 # - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -305,6 +325,7 @@ RUNNER_DAEMON_LOG="${RUNNER_DAEMON_LOG:-$LOG_DIR/daemon.log}"
 RUNNER_CACHE_HOST="${RUNNER_CACHE_HOST:-$IP4_ADDRESS}"
 CACHE_CONFIG_FILE="${CACHE_CONFIG_FILE:-$CONF_DIR/cache_server.yaml}"
 CACHE_LOG_FILE="${CACHE_LOG_FILE:-$LOG_DIR/cache.log}"
+RUNNER_CACHE_SECRET="${RUNNER_CACHE_SECRET:-}"
 # - - - - - - - - - - - - - - - - - - - - - - - - -
 # Additional variables
 
@@ -384,6 +405,7 @@ __run_pre_execute_checks() {
 		[ -d "$DATA_DIR/cache" ] || mkdir -p "$DATA_DIR/cache"
 		[ -d "$CONF_DIR/tokens" ] || mkdir -p "$CONF_DIR/tokens"
 		SYS_AUTH_TOKEN="${SYS_AUTH_TOKEN:-$(__gen_auth_token)}"
+		RUNNER_CACHE_SECRET="${RUNNER_CACHE_SECRET:-$(__gen_cache_secret)}"
 		if [ -f "$RUNNER_CONFIG_DEFAULT" ]; then
 			mkdir -p "$RUNNER_DEFAULT_HOME" "$TMP_DIR/runners/gitea"
 			[ -f "$RUNNER_DEFAULT_HOME/$RUNNER_CONFIG_NAME" ] || copy "$RUNNER_CONFIG_DEFAULT" "$RUNNER_DEFAULT_HOME/$RUNNER_CONFIG_NAME"
@@ -392,6 +414,7 @@ __run_pre_execute_checks() {
 			__replace "REPLACE_RUNNER_HOME" "$RUNNER_DEFAULT_HOME" "$RUNNER_DEFAULT_HOME/$RUNNER_CONFIG_NAME"
 			__replace "REPLACE_RUNNER_CACHE_HOST" "$RUNNER_CACHE_HOST" "$RUNNER_DEFAULT_HOME/$RUNNER_CONFIG_NAME"
 			__replace "REPLACE_RUNNER_CACHE_PORT" "$RUNNER_CACHE_PORT" "$RUNNER_DEFAULT_HOME/$RUNNER_CONFIG_NAME"
+			__replace "REPLACE_RUNNER_CACHE_SECRET" "$RUNNER_CACHE_SECRET" "$RUNNER_DEFAULT_HOME/$RUNNER_CONFIG_NAME"
 			if [ ! -f "$RUNNER_DEFAULT_HOME/runners" ] && [ -n "$SYS_AUTH_TOKEN" ]; then
 				echo "creating gitea runner in $RUNNER_DEFAULT_HOME and registering with http://$INSTANCE_HOSTNAME"
 				act_runner register --config "$RUNNER_DEFAULT_HOME/$RUNNER_CONFIG_NAME" --labels "$RUNNER_LABELS" --name "gitea" --instance "http://$RUNNER_IP_ADDRESS:$GITEA_PORT" --token "$SYS_AUTH_TOKEN" --no-interactive >>"$RUNNER_LOG_FILE" 2>&1 &
@@ -485,6 +508,8 @@ __post_execute() {
 	local postMessageEnd="Finished post commands for $SERVICE_NAME"
 	export RUNNERS_START="${RUNNERS_START:-5}" RUNNER_LABELS RUNNERS_LOG_DIR="$LOG_DIR"
 	export SERVER_ADDRESS="$RUNNER_IP_ADDRESS:$GITEA_PORT" SERVER_TOKEN="${RUNNER_AUTH_TOKEN:-$SYS_AUTH_TOKEN}"
+	export RUNNER_CACHE_HOST RUNNER_CACHE_PORT
+	export RUNNER_CACHE_SECRET="${RUNNER_CACHE_SECRET:-$(__gen_cache_secret)}"
 
 	# wait
 	sleep $waitTime
@@ -512,6 +537,7 @@ __post_execute() {
 			mkdir -p "$DATA_DIR/cache"
 			__replace "REPLACE_RUNNER_CACHE_DIR" "$DATA_DIR/cache" "$CACHE_CONFIG_FILE"
 			__replace "REPLACE_RUNNER_CACHE_PORT" "$RUNNER_CACHE_PORT" "$CACHE_CONFIG_FILE"
+			__replace "REPLACE_RUNNER_CACHE_SECRET" "$RUNNER_CACHE_SECRET" "$CACHE_CONFIG_FILE"
 			act_runner cache-server --config "$CACHE_CONFIG_FILE" 2>>/dev/stderr >>"$CACHE_LOG_FILE" &
 			execPid=$!
 			sleep 5