diff --git a/scripts/web-probe-sentinel-scheduler.ts b/scripts/web-probe-sentinel-scheduler.ts
index 5e8faea1..7bc38aed 100644
--- a/scripts/web-probe-sentinel-scheduler.ts
+++ b/scripts/web-probe-sentinel-scheduler.ts
@@ -188,9 +188,11 @@ async function triggerSentinel(options: SchedulerOptions, schedule: SentinelSche
     "--timeout-seconds",
     String(schedule.timeoutSeconds),
   ];
+  const hardTimeoutMs = schedulerHardTimeoutMs(schedule);
   const result = await runCommandObserved(command, repoRoot, {
-    timeoutMs: Math.max(60, schedule.timeoutSeconds + 90) * 1000,
+    timeoutMs: hardTimeoutMs,
     heartbeatMs: 30_000,
+    killAfterMs: 3_000,
     maxCaptureChars: 24_000,
     env: { ...process.env, NO_COLOR: "1" },
   });
@@ -215,7 +217,7 @@ async function triggerSentinel(options: SchedulerOptions, schedule: SentinelSche
     latestRunIdAfter: after.latestRunId,
     status,
     stdoutTail: tail(result.stdout, 900),
-    stderrTail: tail(result.stderr, 900),
+    stderrTail: tail(result.timedOut ? `${result.stderr}\nscheduler hard timeout after ${Math.round(hardTimeoutMs / 1000)}s` : result.stderr, 900),
   };
 }
 
@@ -258,6 +260,8 @@ function installSystemd(options: SchedulerOptions): void {
   const servicePath = `/etc/systemd/system/${unit}.service`;
   const timerPath = `/etc/systemd/system/${unit}.timer`;
   const sentinelArg = options.sentinelId === null ? "" : ` --sentinel ${options.sentinelId}`;
+  const timeoutArg = options.timeoutSeconds === null ? "" : ` --timeout-seconds ${options.timeoutSeconds}`;
+  const serviceTimeoutSeconds = systemdServiceTimeoutSeconds(options);
   const service = `[Unit]
 Description=UniDesk web-probe sentinel host cadence scheduler for ${options.node}/${options.lane}
 Wants=network-online.target
@@ -265,12 +269,15 @@ After=network-online.target
 
 [Service]
 Type=oneshot
+TimeoutStartSec=${serviceTimeoutSeconds}s
+TimeoutStopSec=15s
+KillMode=control-group
 Environment=HOME=/root
 Environment=PATH=${SYSTEMD_PATH}
 Environment=NO_PROXY=${SYSTEMD_NO_PROXY}
 Environment=no_proxy=${SYSTEMD_NO_PROXY}
 WorkingDirectory=${repoRoot}
-ExecStart=${BUN_EXECUTABLE} ${join(repoRoot, "scripts", "web-probe-sentinel-scheduler.ts")} run --node ${options.node} --lane ${options.lane}${sentinelArg} --stale-multiplier ${options.staleMultiplier}
+ExecStart=${BUN_EXECUTABLE} ${join(repoRoot, "scripts", "web-probe-sentinel-scheduler.ts")} run --node ${options.node} --lane ${options.lane}${sentinelArg} --stale-multiplier ${options.staleMultiplier}${timeoutArg}
 `;
   const timer = `[Unit]
 Description=Run UniDesk web-probe sentinel host cadence scheduler for ${options.node}/${options.lane}
@@ -301,6 +308,16 @@ WantedBy=timers.target
   if (results.some((result) => result.exitCode !== 0)) process.exitCode = 2;
 }
 
+function schedulerHardTimeoutMs(schedule: SentinelSchedule): number {
+  return Math.max(60, schedule.timeoutSeconds) * 1000;
+}
+
+function systemdServiceTimeoutSeconds(options: SchedulerOptions): number {
+  const schedules = sentinelSchedules(specFor(options), options);
+  const maxTimeout = Math.max(...schedules.map((schedule) => Math.max(60, schedule.timeoutSeconds)));
+  return maxTimeout + Math.max(30, Math.ceil(options.fetchTimeoutMs / 1000) + 15);
+}
+
 function statusSystemd(options: SchedulerOptions): void {
   const unit = systemdUnitName(options);
   const results = [