diff --git a/Cargo.lock b/Cargo.lock
index c97e816..d63c657 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1652,7 +1652,7 @@ checksum = "09edd9e8b54e49e587e4f6295a7d29c3ea94d469cb40ab8ca70b288248a81db2"
 
 [[package]]
 name = "lesavka_client"
-version = "0.16.13"
+version = "0.16.14"
 dependencies = [
  "anyhow",
  "async-stream",
@@ -1686,7 +1686,7 @@ dependencies = [
 
 [[package]]
 name = "lesavka_common"
-version = "0.16.13"
+version = "0.16.14"
 dependencies = [
  "anyhow",
  "base64",
@@ -1698,7 +1698,7 @@ dependencies = [
 
 [[package]]
 name = "lesavka_server"
-version = "0.16.13"
+version = "0.16.14"
 dependencies = [
  "anyhow",
  "base64",
diff --git a/client/Cargo.toml b/client/Cargo.toml
index 0caf2f7..622c9af 100644
--- a/client/Cargo.toml
+++ b/client/Cargo.toml
@@ -4,7 +4,7 @@ path                    = "src/main.rs"
 
 [package]
 name                    = "lesavka_client"
-version                 = "0.16.13"
+version                 = "0.16.14"
 edition                 = "2024"
 
 [dependencies]
diff --git a/common/Cargo.toml b/common/Cargo.toml
index 842121a..d83459e 100644
--- a/common/Cargo.toml
+++ b/common/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name                    = "lesavka_common"
-version                 = "0.16.13"
+version                 = "0.16.14"
 edition                 = "2024"
 build                   = "build.rs"
 
diff --git a/scripts/manual/local_av_stimulus.py b/scripts/manual/local_av_stimulus.py
index ff81229..dfe2a3f 100755
--- a/scripts/manual/local_av_stimulus.py
+++ b/scripts/manual/local_av_stimulus.py
@@ -192,8 +192,10 @@ async function pollCommand() {
 }
 setInterval(pollCommand, 200);
 setInterval(() => postJson('/status', { ready: true, page_message: running ? 'running heartbeat' : 'ready heartbeat' }), 1000);
-postJson('/status', { ready: true, page_message: 'page ready' });
-setStatus('ready\nPoint the real webcam at this window.\nKeep speakers audible to the selected microphone.');
+void postJson('/status', { ready: true, page_message: 'page ready' });
+setStatus(`ready
+Point the real webcam at this window.
+Keep speakers audible to the selected microphone.`);
 </script>
 </body>
 </html>"""
diff --git a/scripts/manual/run_upstream_mirrored_av_sync.sh b/scripts/manual/run_upstream_mirrored_av_sync.sh
index 2c1a4da..b2c5085 100755
--- a/scripts/manual/run_upstream_mirrored_av_sync.sh
+++ b/scripts/manual/run_upstream_mirrored_av_sync.sh
@@ -100,6 +100,41 @@ sys.exit(1)
 PY
 }
 
+wait_for_stimulus_page_ready() {
+  local timeout_seconds=$1
+  local deadline=$(( $(date +%s) + timeout_seconds ))
+  local status_json=""
+  until status_json="$(curl -fsS "http://127.0.0.1:${STIMULUS_PORT}/status" 2>/dev/null)"; do
+    if (( $(date +%s) >= deadline )); then
+      echo "Timed out waiting for local stimulus status endpoint" >&2
+      return 1
+    fi
+    sleep 0.2
+  done
+  while true; do
+    if STATUS_JSON="${status_json}" python3 - <<'PY'
+import json
+import os
+import sys
+
+status = json.loads(os.environ["STATUS_JSON"])
+sys.exit(0 if status.get("ready") and status.get("page_message") != "booting" else 1)
+PY
+    then
+      return 0
+    fi
+    if (( $(date +%s) >= deadline )); then
+      echo "local stimulus page did not become ready before timeout" >&2
+      echo "last stimulus status: ${status_json}" >&2
+      echo "stimulus server log: ${ARTIFACT_DIR}/stimulus-server.log" >&2
+      echo "stimulus browser log: ${ARTIFACT_DIR}/stimulus-browser.log" >&2
+      return 1
+    fi
+    sleep 0.5
+    status_json="$(curl -fsS "http://127.0.0.1:${STIMULUS_PORT}/status" 2>/dev/null || true)"
+  done
+}
+
 start_server_tunnel_if_needed() {
   if [[ "${LESAVKA_SERVER_ADDR}" != "auto" ]]; then
     RESOLVED_LESAVKA_SERVER_ADDR="${LESAVKA_SERVER_ADDR}"
@@ -150,6 +185,7 @@ PREFS
     "http://127.0.0.1:${STIMULUS_PORT}/" \
     >"${ARTIFACT_DIR}/stimulus-browser.log" 2>&1 &
   STIMULUS_BROWSER_PID=$!
+  wait_for_stimulus_page_ready 15
 
   echo "==> position check"
   echo "    Point the real webcam at the stimulus window and keep the selected microphone hearing the tone."
diff --git a/server/Cargo.toml b/server/Cargo.toml
index bce8f7c..6aff42b 100644
--- a/server/Cargo.toml
+++ b/server/Cargo.toml
@@ -10,7 +10,7 @@ bench                   = false
 
 [package]
 name                    = "lesavka_server"
-version                 = "0.16.13"
+version                 = "0.16.14"
 edition                 = "2024"
 autobins                = false
 
diff --git a/testing/tests/client_manual_sync_script_contract.rs b/testing/tests/client_manual_sync_script_contract.rs
index 5a9fbd4..bdcaa45 100644
--- a/testing/tests/client_manual_sync_script_contract.rs
+++ b/testing/tests/client_manual_sync_script_contract.rs
@@ -90,6 +90,7 @@ fn mirrored_sync_script_uses_real_client_capture_path() {
         "BROWSER_SYNC_DRIVER_COMMAND=\"${driver_command}\"",
         "SYNC_ANALYZE_EVENT_WIDTH_CODES=\"${PROBE_EVENT_WIDTH_CODES}\"",
         "run_upstream_browser_av_sync.sh",
+        "wait_for_stimulus_page_ready 15",
         "Point the real webcam at the stimulus window",
     ] {
         assert!(
@@ -114,6 +115,7 @@ fn local_stimulus_matches_sync_analyzer_pulse_contract() {
         "event_width_codes",
         "widthCode",
         "oscillator.frequency.value = 880",
+        "setStatus(`ready",
         "Point the real webcam at this window",
     ] {
         assert!(