fix(auto-reply): bound session lifecycle expiries

src/auto-reply/reply/commands-session-lifecycle.test.ts

@@ -570,7 +570,7 @@ describe("/session idle and /session max-age", () => {
     expect(result?.reply?.text).toContain("2026-02-20T02:00:00.000Z");
   });
 
-  it("falls back when active idle timeout expiry is Date-invalid", async () => {
+  it("falls back to bind time when idle activity timestamp is out of range", async () => {
     vi.useFakeTimers();
     vi.setSystemTime(new Date("2026-02-20T00:00:00.000Z"));
 
@@ -586,7 +586,26 @@ describe("/session idle and /session max-age", () => {
     );
 
     const result = await handleSessionCommand(createThreadCommandParams("/session idle"), true);
-    expect(result?.reply?.text).toBe("ℹ️ Idle timeout active (2h, next auto-unfocus at n/a).");
+    expect(result?.reply?.text).toContain("Idle timeout active (2h");
+    expect(result?.reply?.text).toContain("2026-02-20T02:00:00.000Z");
+  });
+
+  it("treats overflowed idle timeout metadata as disabled", async () => {
+    hoisted.sessionBindingResolveByConversationMock.mockReturnValue(
+      createThreadBinding({
+        metadata: {
+          boundBy: "user-1",
+          lastActivityAt: Date.now(),
+          idleTimeoutMs: Number.MAX_SAFE_INTEGER,
+          maxAgeMs: 0,
+        },
+      }),
+    );
+
+    const result = await handleSessionCommand(createThreadCommandParams("/session idle"), true);
+    expect(result?.reply?.text).toBe(
+      "ℹ️ Idle timeout is currently disabled for this focused session.",
+    );
   });
 
   it("sets max age for the focused thread-chat session", async () => {

src/auto-reply/reply/commands-session.ts

@@ -27,6 +27,10 @@ import {
 } from "../../infra/restart-sentinel.js";
 import { scheduleGatewaySigusr1Restart, triggerOpenClawRestart } from "../../infra/restart.js";
 import { loadCostUsageSummary, loadSessionCostSummary } from "../../infra/session-cost-usage.js";
+import {
+  asDateTimestampMs,
+  resolveExpiresAtMsFromDurationMs,
+} from "../../shared/number-coercion.js";
 import { formatTokenCount, formatUsd } from "../../utils/usage-format.js";
 import { parseActivationCommand } from "../group-activation.js";
 import { parseSendPolicyCommand } from "../send-policy.js";
@@ -104,13 +108,19 @@ function resolveSessionBindingDurationMs(
 }
 
 function resolveSessionBindingLastActivityAt(binding: SessionBindingRecord): number {
-  const raw = binding.metadata?.lastActivityAt;
-  if (typeof raw !== "number" || !Number.isFinite(raw)) {
+  const raw = asDateTimestampMs(binding.metadata?.lastActivityAt);
+  if (raw === undefined) {
     return binding.boundAt;
   }
   return Math.max(Math.floor(raw), binding.boundAt);
 }
 
+function resolveSessionBindingExpiryAt(baseMs: number, durationMs: number): number | undefined {
+  return durationMs > 0
+    ? resolveExpiresAtMsFromDurationMs(durationMs, { nowMs: baseMs })
+    : undefined;
+}
+
 function resolveSessionBindingBoundBy(binding: SessionBindingRecord): string {
   const raw = binding.metadata?.boundBy;
   return normalizeOptionalString(raw) ?? "";
@@ -177,7 +187,10 @@ function resolveUpdatedBindingExpiry(params: {
         if (idleTimeoutMs <= 0) {
           return undefined;
         }
-        return Math.max(binding.lastActivityAt, binding.boundAt) + idleTimeoutMs;
+        return resolveSessionBindingExpiryAt(
+          Math.max(binding.lastActivityAt, binding.boundAt),
+          idleTimeoutMs,
+        );
       }
 
       const maxAgeMs =
@@ -187,7 +200,7 @@ function resolveUpdatedBindingExpiry(params: {
       if (maxAgeMs <= 0) {
         return undefined;
       }
-      return binding.boundAt + maxAgeMs;
+      return resolveSessionBindingExpiryAt(binding.boundAt, maxAgeMs);
     })
     .filter((expiresAt): expiresAt is number => typeof expiresAt === "number");
 
@@ -537,12 +550,12 @@ export const handleSessionCommand: CommandHandler = async (params, allowTextComm
     "idleTimeoutMs",
     24 * 60 * 60 * 1000,
   );
-  const idleExpiresAt =
-    idleTimeoutMs > 0
-      ? resolveSessionBindingLastActivityAt(activeBinding) + idleTimeoutMs
-      : undefined;
+  const idleExpiresAt = resolveSessionBindingExpiryAt(
+    resolveSessionBindingLastActivityAt(activeBinding),
+    idleTimeoutMs,
+  );
   const maxAgeMs = resolveSessionBindingDurationMs(activeBinding, "maxAgeMs", 0);
-  const maxAgeExpiresAt = maxAgeMs > 0 ? activeBinding.boundAt + maxAgeMs : undefined;
+  const maxAgeExpiresAt = resolveSessionBindingExpiryAt(activeBinding.boundAt, maxAgeMs);
 
   const durationArgRaw = tokens.slice(1).join("");
   if (!durationArgRaw) {