diff --git a/src/infra/outbound/current-conversation-bindings.test.ts b/src/infra/outbound/current-conversation-bindings.test.ts
index 4261faa53603..5119744be81e 100644
--- a/src/infra/outbound/current-conversation-bindings.test.ts
+++ b/src/infra/outbound/current-conversation-bindings.test.ts
@@ -1,7 +1,7 @@
 import fs from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
-import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import { setActivePluginRegistry } from "../../plugins/runtime.js";
 import { createTestRegistry } from "../../test-utils/channel-plugins.js";
 import {
@@ -76,6 +76,7 @@ describe("generic current-conversation bindings", () => {
   });
 
   afterEach(async () => {
+    vi.useRealTimers();
     testing.resetCurrentConversationBindingsForTests({
       deletePersistedFile: true,
     });
@@ -324,6 +325,64 @@ describe("generic current-conversation bindings", () => {
     ).toBeNull();
   });
 
+  it("drops persisted bindings with invalid expiration timestamps", async () => {
+    const filePath = testing.resolveBindingsFilePath();
+    await fs.mkdir(path.dirname(filePath), { recursive: true });
+    await fs.writeFile(
+      filePath,
+      JSON.stringify({
+        version: 1,
+        bindings: [
+          {
+            bindingId: "generic:workspace\u241fdefault\u241f\u241fuser:U123",
+            targetSessionKey: "agent:codex:acp:workspace-dm",
+            targetKind: "session",
+            conversation: {
+              channel: "workspace",
+              accountId: "default",
+              conversationId: "user:U123",
+            },
+            status: "active",
+            boundAt: 1234,
+            expiresAt: 8_640_000_000_000_001,
+          },
+        ],
+      }),
+    );
+
+    expect(
+      resolveGenericCurrentConversationBinding({
+        channel: "workspace",
+        accountId: "default",
+        conversationId: "user:U123",
+      }),
+    ).toBeNull();
+  });
+
+  it("does not bind generic current conversations when ttl expiry overflows", async () => {
+    vi.setSystemTime(new Date(8_640_000_000_000_000));
+
+    await expect(
+      bindGenericCurrentConversation({
+        targetSessionKey: "agent:codex:acp:workspace-dm",
+        targetKind: "session",
+        conversation: {
+          channel: "workspace",
+          accountId: "default",
+          conversationId: "user:U123",
+        },
+        ttlMs: 1,
+      }),
+    ).resolves.toBeNull();
+    expect(
+      resolveGenericCurrentConversationBinding({
+        channel: "workspace",
+        accountId: "default",
+        conversationId: "user:U123",
+      }),
+    ).toBeNull();
+  });
+
   it("persists touched activity across reloads", async () => {
     const bound = await bindGenericCurrentConversation({
       targetSessionKey: "agent:codex:acp:workspace-dm",
diff --git a/src/infra/outbound/current-conversation-bindings.ts b/src/infra/outbound/current-conversation-bindings.ts
index ee65ec276cd0..29292bd178e7 100644
--- a/src/infra/outbound/current-conversation-bindings.ts
+++ b/src/infra/outbound/current-conversation-bindings.ts
@@ -6,6 +6,10 @@ import { resolveStateDir } from "../../config/paths.js";
 import { loadJsonFile } from "../../infra/json-file.js";
 import { saveJsonFile } from "../../plugin-sdk/json-store.js";
 import { getActivePluginChannelRegistryFromState } from "../../plugins/runtime-channel-state.js";
+import {
+  asDateTimestampMs,
+  resolveExpiresAtMsFromDurationMs,
+} from "../../shared/number-coercion.js";
 import { normalizeOptionalLowercaseString } from "../../shared/string-coerce.js";
 import { normalizeConversationRef } from "./session-binding-normalization.js";
 import type {
@@ -46,9 +50,15 @@ function resolveBindingsFilePath(env: NodeJS.ProcessEnv = process.env): string {
 }
 
 function isBindingExpired(record: SessionBindingRecord, now = Date.now()): boolean {
-  return typeof record.expiresAt === "number" && Number.isFinite(record.expiresAt)
-    ? record.expiresAt <= now
-    : false;
+  if (record.expiresAt === undefined) {
+    return false;
+  }
+  const expiresAt = asDateTimestampMs(record.expiresAt);
+  if (expiresAt === undefined) {
+    return true;
+  }
+  const nowMs = asDateTimestampMs(now);
+  return nowMs !== undefined && expiresAt <= nowMs;
 }
 
 function toPersistedFile(): PersistedCurrentConversationBindingsFile {
@@ -159,11 +169,24 @@ export async function bindGenericCurrentConversation(
     return null;
   }
   loadBindingsIntoMemory();
-  const now = Date.now();
+  const rawNow = Date.now();
+  const now = asDateTimestampMs(rawNow);
+  if (now === undefined) {
+    return null;
+  }
   const ttlMs =
     typeof input.ttlMs === "number" && Number.isFinite(input.ttlMs)
       ? Math.max(0, Math.floor(input.ttlMs))
       : undefined;
+  const expiresAt =
+    ttlMs === undefined
+      ? undefined
+      : ttlMs === 0
+        ? now
+        : resolveExpiresAtMsFromDurationMs(ttlMs, { nowMs: rawNow });
+  if (ttlMs !== undefined && expiresAt === undefined) {
+    return null;
+  }
   const key = buildConversationKey(conversation);
   const existing = pruneExpiredBinding(key);
   const record: SessionBindingRecord = {
@@ -173,7 +196,7 @@ export async function bindGenericCurrentConversation(
     conversation,
     status: "active",
     boundAt: now,
-    ...(ttlMs != null ? { expiresAt: now + ttlMs } : {}),
+    ...(expiresAt !== undefined ? { expiresAt } : {}),
     metadata: {
       ...existing?.metadata,
       ...input.metadata,