diff --git a/src/agents/tools/sessions-announce-target.ts b/src/agents/tools/sessions-announce-target.ts
index 401cdc40c61..095bb39c5c9 100644
--- a/src/agents/tools/sessions-announce-target.ts
+++ b/src/agents/tools/sessions-announce-target.ts
@@ -2,6 +2,7 @@ import { getChannelPlugin, normalizeChannelId } from "../../channels/plugins/ind
 import type { CallGatewayOptions } from "../../gateway/call.js";
 import { parseThreadSessionSuffix } from "../../sessions/session-key-utils.js";
 import { normalizeOptionalStringifiedId } from "../../shared/string-coerce.js";
+import { deliveryContextFromSession } from "../../utils/delivery-context.shared.js";
 import type { SessionListRow } from "./sessions-helpers.js";
 import type { AnnounceTarget } from "./sessions-send-helpers.js";
 import { resolveAnnounceTargetFromKey } from "./sessions-send-helpers.js";
@@ -45,30 +46,10 @@ export async function resolveAnnounceTarget(params: {
       sessions.find((entry) => entry?.key === params.sessionKey) ??
       sessions.find((entry) => entry?.key === params.displayKey);
 
-    const deliveryContext =
-      match?.deliveryContext && typeof match.deliveryContext === "object"
-        ? (match.deliveryContext as Record<string, unknown>)
-        : undefined;
-    const origin =
-      match?.origin && typeof match.origin === "object"
-        ? (match.origin as Record<string, unknown>)
-        : undefined;
-    const channel =
-      (typeof deliveryContext?.channel === "string" ? deliveryContext.channel : undefined) ??
-      (typeof match?.lastChannel === "string" ? match.lastChannel : undefined) ??
-      (typeof origin?.provider === "string" ? origin.provider : undefined);
-    const to =
-      (typeof deliveryContext?.to === "string" ? deliveryContext.to : undefined) ??
-      (typeof match?.lastTo === "string" ? match.lastTo : undefined);
-    const accountId =
-      (typeof deliveryContext?.accountId === "string" ? deliveryContext.accountId : undefined) ??
-      (typeof match?.lastAccountId === "string" ? match.lastAccountId : undefined) ??
-      (typeof origin?.accountId === "string" ? origin.accountId : undefined);
-    const threadId = normalizeOptionalStringifiedId(
-      deliveryContext?.threadId ?? match?.lastThreadId ?? origin?.threadId ?? fallbackThreadId,
-    );
-    if (channel && to) {
-      return { channel, to, accountId, threadId };
+    const context = deliveryContextFromSession(match);
+    const threadId = normalizeOptionalStringifiedId(context?.threadId ?? fallbackThreadId);
+    if (context?.channel && context.to) {
+      return { channel: context.channel, to: context.to, accountId: context.accountId, threadId };
     }
   } catch {
     // ignore
diff --git a/src/auto-reply/reply/queue.collect.test.ts b/src/auto-reply/reply/queue.collect.test.ts
index af38525b7cf..6be6bdd5b91 100644
--- a/src/auto-reply/reply/queue.collect.test.ts
+++ b/src/auto-reply/reply/queue.collect.test.ts
@@ -622,6 +622,50 @@ describe("followup queue collect routing", () => {
     expect(calls[0]?.originatingThreadId).toBe("1706000000.000001");
   });
 
+  it("collects messages when numeric and string thread ids share the route key", async () => {
+    const key = `test-collect-thread-normalized-${Date.now()}`;
+    const calls: FollowupRun[] = [];
+    const done = createDeferred<void>();
+    const runFollowup = async (run: FollowupRun) => {
+      calls.push(run);
+      done.resolve();
+    };
+    const settings: QueueSettings = {
+      mode: "collect",
+      debounceMs: 0,
+      cap: 50,
+      dropPolicy: "summarize",
+    };
+
+    enqueueFollowupRun(
+      key,
+      createRun({
+        prompt: "one",
+        originatingChannel: "telegram",
+        originatingTo: "-100123",
+        originatingThreadId: 42.9,
+      }),
+      settings,
+    );
+    enqueueFollowupRun(
+      key,
+      createRun({
+        prompt: "two",
+        originatingChannel: "telegram",
+        originatingTo: "-100123",
+        originatingThreadId: "42",
+      }),
+      settings,
+    );
+
+    scheduleFollowupDrain(key, runFollowup);
+    await done.promise;
+    expect(calls).toHaveLength(1);
+    expect(calls[0]?.prompt).toContain("[Queued messages while agent was busy]");
+    expect(calls[0]?.prompt).toContain("one");
+    expect(calls[0]?.prompt).toContain("two");
+  });
+
   it("does not collect Slack messages when thread ids differ", async () => {
     const key = `test-collect-slack-thread-diff-${Date.now()}`;
     const calls: FollowupRun[] = [];
diff --git a/src/auto-reply/reply/queue/drain.ts b/src/auto-reply/reply/queue/drain.ts
index fcaf5ed2404..31cb3f13acc 100644
--- a/src/auto-reply/reply/queue/drain.ts
+++ b/src/auto-reply/reply/queue/drain.ts
@@ -1,3 +1,4 @@
+import { channelRouteKey, normalizeChannelRouteRef } from "../../../channels/route/ref.js";
 import { defaultRuntime } from "../../../runtime.js";
 import { resolveGlobalMap } from "../../../shared/global-singleton.js";
 import {
@@ -134,11 +135,8 @@ function resolveCrossChannelKey(item: FollowupRun): { cross?: true; key?: string
   if (!isRoutableChannel(channel) || !to) {
     return { cross: true };
   }
-  // Support both number (Telegram topic IDs) and string (Slack thread_ts) thread IDs.
-  const threadKey = threadId != null && threadId !== "" ? String(threadId) : "";
-  return {
-    key: [channel, to, accountId || "", threadKey].join("|"),
-  };
+  const key = channelRouteKey(normalizeChannelRouteRef({ channel, to, accountId, threadId }));
+  return key ? { key } : { cross: true };
 }
 
 export function scheduleFollowupDrain(