diff --git a/tools/loop-metrics/dist/metrics.js b/tools/loop-metrics/dist/metrics.js
index 2b41b2b4..aa4797d3 100644
--- a/tools/loop-metrics/dist/metrics.js
+++ b/tools/loop-metrics/dist/metrics.js
@@ -48,14 +48,25 @@ export function aggregateMetrics(entries) {
     let totalDurationS = 0;
     let totalActionsTaken = 0;
     let totalEscalations = 0;
+    let runsWithoutEscalation = 0;
     for (const entry of entries) {
         totalTokens += entry.tokens_estimate || 0;
         totalDurationS += entry.duration_s || 0;
         totalActionsTaken += entry.actions_taken || 0;
         totalEscalations += entry.escalations || 0;
+        if (!entry.escalations)
+            runsWithoutEscalation++;
     }
     const totalRuns = entries.length;
-    const successRatePct = totalRuns > 0 ? ((totalRuns - totalEscalations) / totalRuns) * 100 : 0;
+    // totalEscalations is a sum of each run's escalation *count* (a run can
+    // log more than one, e.g. several items escalated in one triage pass) --
+    // subtracting it from totalRuns (a count of runs) conflates events with
+    // runs and can go negative for a real, ordinary run log (this repo's own
+    // loop-run-log.md has entries with escalations: 4 and escalations: 5).
+    // Success rate is "what fraction of runs didn't escalate at all", which
+    // stays correctly bounded to [0, 100] regardless of how many escalations
+    // any single run logged.
+    const successRatePct = totalRuns > 0 ? (runsWithoutEscalation / totalRuns) * 100 : 0;
     const avgDurationS = totalRuns > 0 ? totalDurationS / totalRuns : 0;
     // Simple heuristic: Each successful action is worth +10, each escalation is -5.
     const roiScore = (totalActionsTaken * 10) - (totalEscalations * 5);
diff --git a/tools/loop-metrics/src/metrics.ts b/tools/loop-metrics/src/metrics.ts
index 14afcad5..b4448a53 100644
--- a/tools/loop-metrics/src/metrics.ts
+++ b/tools/loop-metrics/src/metrics.ts
@@ -77,16 +77,26 @@ export function aggregateMetrics(entries: RunEntry[]): MetricsDashboard {
   let totalDurationS = 0;
   let totalActionsTaken = 0;
   let totalEscalations = 0;
+  let runsWithoutEscalation = 0;
 
   for (const entry of entries) {
     totalTokens += entry.tokens_estimate || 0;
     totalDurationS += entry.duration_s || 0;
     totalActionsTaken += entry.actions_taken || 0;
     totalEscalations += entry.escalations || 0;
+    if (!entry.escalations) runsWithoutEscalation++;
   }
 
   const totalRuns = entries.length;
-  const successRatePct = totalRuns > 0 ? ((totalRuns - totalEscalations) / totalRuns) * 100 : 0;
+  // totalEscalations is a sum of each run's escalation *count* (a run can
+  // log more than one, e.g. several items escalated in one triage pass) --
+  // subtracting it from totalRuns (a count of runs) conflates events with
+  // runs and can go negative for a real, ordinary run log (this repo's own
+  // loop-run-log.md has entries with escalations: 4 and escalations: 5).
+  // Success rate is "what fraction of runs didn't escalate at all", which
+  // stays correctly bounded to [0, 100] regardless of how many escalations
+  // any single run logged.
+  const successRatePct = totalRuns > 0 ? (runsWithoutEscalation / totalRuns) * 100 : 0;
   const avgDurationS = totalRuns > 0 ? totalDurationS / totalRuns : 0;
 
   // Simple heuristic: Each successful action is worth +10, each escalation is -5.
diff --git a/tools/loop-metrics/test/metrics.test.mjs b/tools/loop-metrics/test/metrics.test.mjs
index 056d793b..a331dba9 100644
--- a/tools/loop-metrics/test/metrics.test.mjs
+++ b/tools/loop-metrics/test/metrics.test.mjs
@@ -17,6 +17,24 @@ test('loop-metrics filters and aggregates', () => {
   assert.strictEqual(metrics.totalActionsTaken, 3);
   assert.strictEqual(metrics.totalEscalations, 1);
   assert.strictEqual(metrics.roiScore, (3 * 10) - (1 * 5)); // 25
+  assert.strictEqual(metrics.successRatePct, 50); // 1 of 2 runs had no escalation
+});
+
+test('successRatePct stays within [0, 100] when a single run logs more than one escalation', () => {
+  // A run can escalate several items in one pass (this repo's own
+  // loop-run-log.md has real entries with escalations: 4 and 5), so
+  // totalEscalations (a sum of per-run counts) can exceed totalRuns.
+  // successRatePct must still reflect "runs that didn't escalate", not go
+  // negative from subtracting an event count as if it were a run count.
+  const entries = [
+    { run_id: 'a', pattern: 'ci-sweeper', duration_s: 1, items_found: 5, actions_taken: 1, escalations: 5, tokens_estimate: 1000, outcome: 'escalated' },
+    { run_id: 'b', pattern: 'ci-sweeper', duration_s: 1, items_found: 0, actions_taken: 0, escalations: 0, tokens_estimate: 1000, outcome: 'report-only' },
+  ];
+
+  const metrics = aggregateMetrics(entries);
+  assert.strictEqual(metrics.totalEscalations, 5);
+  assert.strictEqual(metrics.successRatePct, 50); // 1 of 2 runs had no escalation
+  assert.ok(metrics.successRatePct >= 0 && metrics.successRatePct <= 100);
 });
 
 test('filterEntries keeps entries with unparseable run_id when a timeframe is set', () => {