diff --git a/.agents/skills/multi-agent-mux-delegate-job/multi-agent-mux-delegate-job b/.agents/skills/multi-agent-mux-delegate-job/multi-agent-mux-delegate-job
index 79ed31c..3259f16 100755
--- a/.agents/skills/multi-agent-mux-delegate-job/multi-agent-mux-delegate-job
+++ b/.agents/skills/multi-agent-mux-delegate-job/multi-agent-mux-delegate-job
@@ -228,7 +228,11 @@ EOF
 
     # 3) START THE SUBSCRIBER
     local logf="$REGISTRY_DIR/$JOB_ID.subscriber.out"
-    local sub_extra_args=()
+    # Before the first event the subscriber is bounded by the wall clock only:
+    # delivery (T from the injection, which happens after the subscriber is
+    # up and can take a while itself) is judged by _wait_started, and a failed
+    # injection reaps the subscriber. From the first event on, K x N applies.
+    local sub_extra_args=(--ack-timeout "$TIMEOUT")
     [ -n "$_disp_tok" ] && sub_extra_args+=(--expect-dispatch-token "$_disp_tok")
     _is_remote "$AGENT_SESSION" && sub_extra_args+=(--remote)
     "$PY" "$SCRIPT_DIR/scripts/job_subscriber.py" --registry-dir "$REGISTRY_DIR" \
@@ -401,7 +405,7 @@ EOF
 
       # Start subscriber
       local logf="$REGISTRY_DIR/${JOB_ID}.iter_${iteration}_${display_role}.subscriber.out"
-      local loop_sub_args=(--attempt-id "$attempt")
+      local loop_sub_args=(--attempt-id "$attempt" --ack-timeout "$TIMEOUT")
       [ -n "$_disp_tok" ] && loop_sub_args+=(--expect-dispatch-token "$_disp_tok")
       _is_remote "$current_session" && loop_sub_args+=(--remote)
       "$PY" "$SCRIPT_DIR/scripts/job_subscriber.py" --registry-dir "$REGISTRY_DIR" \
diff --git a/MESSAGING.md b/MESSAGING.md
index f64704e..e81367a 100644
--- a/MESSAGING.md
+++ b/MESSAGING.md
@@ -339,6 +339,7 @@ The subscriber acts as the central execution watchdog:
 * **Dual Timeout Semantics**:
   1. **Wall-Clock Timeout**: Calculated relative to absolute startup time (`wall_deadline = start + wall_timeout`). It acts as a hard budget limit, guarding against an agent hanging indefinitely.
   2. **Activity Idle Timeout**: Measured as the difference between the current monotonic time and the last packet arrival time (`idle_left = idle_timeout - (now - last_event)`). If the agent fails to publish any event (heartbeats and retained state included) for the duration of the idle window - K x N under the Issue #18 contract - the subscriber aborts and exits with code 2.
+* **Idle budget before the first event (Issue #18)**: a standalone subscriber allows `ack_timeout_sec + idle_timeout_sec` before the first accepted event (the injection has to produce `started`). The delegate wrapper passes `--ack-timeout <wall clock>` instead: it judges delivery itself with `_wait_started` (T from the injection, which happens after the subscriber is up) and reaps the subscriber when that fails, so the subscriber's own idle clock only starts with the first event.
 * **Retained state and seq gaps (Issue #18)**: the subscriber also subscribes to `<topic_prefix>/state`; a retained terminal state resolves the job at (re)connect, any state resets the idle clock, and a seq jump on either topic is written to the audit log as `seq_gap`. With `--remote` (or `transport: remote`) accepted `started`/terminal events are mirrored into the local job record.
 
 ---