@@ -297,8 +297,28 @@ describe("resolveAutoSettlementAt", () => {
     expect(
       ThreadSettlementService.resolveAutoSettlementAt({ ...input, autoSettleAfterDays: null }),
     ).toBeNull();
+  });
+
+  it("anchors an empty thread's inactivity at its creation time", () => {
+    const input = {
+      thread: shell({ createdAt: at(-3 * DAY_MS) }),
+      pullRequest: null,
+      nowMs: NOW_MS,
+      autoSettleAfterDays: 2,
+      autoSettleOnMerge: false,
+    };
+    expect(ThreadSettlementService.resolveAutoSettlementAt(input)).toEqual(at(-3 * DAY_MS));
     expect(
-      ThreadSettlementService.resolveAutoSettlementAt({ ...input, thread: shell() }),
+      ThreadSettlementService.resolveAutoSettlementAt({
+        ...input,
+        thread: shell({ createdAt: at(-DAY_MS) }),
+      }),
+    ).toBeNull();
+    expect(
+      ThreadSettlementService.resolveAutoSettlementAt({
+        ...input,
+        thread: { ...input.thread, lastSnoozeWakeAt: at(-DAY_MS) },
+      }),
     ).toBeNull();
   });
 
 
@@ -231,19 +231,20 @@ export function resolveAutoSettlementAt(input: {
           };
   }
   if (!isAutoSettlementCandidate(thread, input.nowMs)) return null;
-  const activityAtMs = latestMillis([
-    toMillis(thread.latestUserMessageAt),
-    toMillis(thread.latestRunRequestedAt),
-    toMillis(thread.latestRunStartedAt),
-    toMillis(thread.latestRunCompletedAt),
-  ]);
+  const activityAtMs =
+    latestMillis([
+      toMillis(thread.latestUserMessageAt),
+      toMillis(thread.latestRunRequestedAt),
+      toMillis(thread.latestRunStartedAt),
+      toMillis(thread.latestRunCompletedAt),
+    ]) ?? DateTime.toEpochMillis(thread.createdAt);
   if (pullRequest !== null && pullRequestSettles(thread, pullRequest, input.autoSettleOnMerge)) {
-    return activityAtMs === null ? thread.createdAt : DateTime.makeUnsafe(activityAtMs);
+    return DateTime.makeUnsafe(activityAtMs);
   }
   const hasPullRequest =
     pullRequest !== null || thread.linkedPullRequest != null || thread.branchPullRequest != null;
   if (input.autoSettleKeepPullRequests === true && hasPullRequest) return null;
-  if (input.autoSettleAfterDays === null || activityAtMs === null) return null;
+  if (input.autoSettleAfterDays === null) return null;
   const snoozedUntilMs = toMillis(thread.snoozedUntil);
   const timerWakeAtMs =
     snoozedUntilMs !== null && snoozedUntilMs <= input.nowMs ? snoozedUntilMs : null;
 
@@ -148,7 +148,8 @@ Press `Escape` while dragging to cancel.
 
 By default, environments settle inactive threads after three days and settle
 threads whose pull request merged. A closed pull request can also settle an idle
-thread. Work in progress, pending questions or approvals, and live background work
+thread. An empty thread's inactivity counts from when it was created.
+Work in progress, pending questions or approvals, and live background work
 prevent automatic settlement. An open pull request does not prevent inactivity
 settlement unless you turn on **Keep threads with a PR** in **Settings → General**,
 but an old closed or merged pull request does not settle work you