Add slow_alert_consecutive setting to control slow alert sensitivity

Exposes the consecutive-slow-checks requirement as a configurable setting
instead of hardcoding 3. Saved under key 'slow_alert_consecutive' in the
DB, readable via SLOW_ALERT_CONSECUTIVE env var. UI appears in Settings →
Monitoring alongside the existing Consecutive Failures Threshold field.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/src/SettingsWizard.js

@@ -35,6 +35,7 @@ function SettingsWizard() {
     items_per_page: 20,
     refresh_interval: 5000,
     incident_failure_threshold: 10,
+    slow_alert_consecutive: 3,
   });
 
   const [testResult, setTestResult] = useState(null);
@@ -529,6 +530,18 @@ function SettingsWizard() {
               <small>Number of consecutive failures before triggering an alert (default: 3)</small>
             </div>
 
+            <div className="form-group">
+              <label>Slow Alert Sensitivity</label>
+              <input
+                type="number"
+                value={settings.slow_alert_consecutive || 3}
+                onChange={(e) => setSettings({ ...settings, slow_alert_consecutive: parseInt(e.target.value) })}
+                min="1"
+                max="20"
+              />
+              <small>Consecutive slow checks required before alerting — 1 = any spike, 3 = default, 5+ = only sustained slowness</small>
+            </div>
+
             <div className="form-group">
               <label>Incident Failure Threshold</label>
               <input
@@ -579,6 +592,7 @@ function SettingsWizard() {
               grace_period: settings.grace_period,
               downtime_threshold: settings.downtime_threshold,
               incident_failure_threshold: settings.incident_failure_threshold,
+              slow_alert_consecutive: settings.slow_alert_consecutive,
             })}
             disabled={savingSection === 'Monitoring'}
           >

server/index.js

@@ -147,6 +147,7 @@ function buildSettingsFromDb(dbSettings = {}) {
     ntfy_url: dbSettings.ntfy_url || process.env.NTFY_URL || 'https://ntfy.sh',
     ntfy_topic: dbSettings.ntfy_topic || process.env.NTFY_TOPIC || '',
     incident_failure_threshold: parseInt(dbSettings.incident_failure_threshold || process.env.INCIDENT_FAILURE_THRESHOLD) || 10,
+    slow_alert_consecutive: parseInt(dbSettings.slow_alert_consecutive || process.env.SLOW_ALERT_CONSECUTIVE) || 3,
     webhook_template: dbSettings.webhook_template || process.env.WEBHOOK_TEMPLATE || '',
   };
 }
@@ -773,6 +774,7 @@ app.post('/api/settings', (req, res) => {
     ntfy_url:                { env: 'NTFY_URL',                coerce: v => v || 'https://ntfy.sh' },
     ntfy_topic:              { env: 'NTFY_TOPIC',              coerce: v => v || '' },
     incident_failure_threshold: { env: 'INCIDENT_FAILURE_THRESHOLD', coerce: v => String(v || 10) },
+    slow_alert_consecutive:    { env: 'SLOW_ALERT_CONSECUTIVE',    coerce: v => String(v || 3) },
   };
 
   // Collect only the fields present in this request

server/scheduler.js

@@ -181,8 +181,9 @@ class Scheduler {
           if (result.response_time > effectiveThreshold) {
             const consecutive = (this.slowConsecutiveCount.get(resource.id) || 0) + 1;
             this.slowConsecutiveCount.set(resource.id, consecutive);
-            // Require 3 consecutive slow checks before alerting (avoids single-spike false positives)
+            const slowAlertConsecutiveSetting = db.prepare(`SELECT value FROM settings WHERE key = 'slow_alert_consecutive'`).get();
-            if (consecutive >= 3) {
+            const slowAlertConsecutive = parseInt(slowAlertConsecutiveSetting?.value) || 3;
+            if (consecutive >= slowAlertConsecutive) {
               const lastSlowAlert = this.slowAlertCooldown.get(resource.id) || 0;
               if (now - lastSlowAlert > 60 * 60 * 1000) {
                 this.slowAlertCooldown.set(resource.id, now);