diff --git a/src/auto-reply/reply/dispatch-acp-delivery.test.ts b/src/auto-reply/reply/dispatch-acp-delivery.test.ts
index bfca2a4ba27..73c36847ab2 100644
--- a/src/auto-reply/reply/dispatch-acp-delivery.test.ts
+++ b/src/auto-reply/reply/dispatch-acp-delivery.test.ts
@@ -1,4 +1,4 @@
-import { describe, expect, it, vi } from "vitest";
+import { beforeEach, describe, expect, it, vi } from "vitest";
 import { createAcpDispatchDeliveryCoordinator } from "./dispatch-acp-delivery.js";
 import type { ReplyDispatcher } from "./reply-dispatcher.js";
 import { buildTestCtx } from "./test-ctx.js";
@@ -11,10 +11,23 @@ const ttsMocks = vi.hoisted(() => ({
   }),
 }));
 
+const deliveryMocks = vi.hoisted(() => ({
+  routeReply: vi.fn(async (_params: unknown) => ({ ok: true, messageId: "mock-message" })),
+  runMessageAction: vi.fn(async (_params: unknown) => ({ ok: true as const })),
+}));
+
 vi.mock("../../tts/tts.js", () => ({
   maybeApplyTtsToPayload: (params: unknown) => ttsMocks.maybeApplyTtsToPayload(params),
 }));
 
+vi.mock("./route-reply.js", () => ({
+  routeReply: (params: unknown) => deliveryMocks.routeReply(params),
+}));
+
+vi.mock("../../infra/outbound/message-action-runner.js", () => ({
+  runMessageAction: (params: unknown) => deliveryMocks.runMessageAction(params),
+}));
+
 function createDispatcher(): ReplyDispatcher {
   return {
     sendToolResult: vi.fn(() => true),
@@ -43,6 +56,13 @@ function createCoordinator(onReplyStart?: (...args: unknown[]) => Promise<void>)
 }
 
 describe("createAcpDispatchDeliveryCoordinator", () => {
+  beforeEach(() => {
+    deliveryMocks.routeReply.mockClear();
+    deliveryMocks.routeReply.mockResolvedValue({ ok: true, messageId: "mock-message" });
+    deliveryMocks.runMessageAction.mockClear();
+    deliveryMocks.runMessageAction.mockResolvedValue({ ok: true as const });
+  });
+
   it("bypasses TTS when skipTts is requested", async () => {
     const dispatcher = createDispatcher();
     const coordinator = createAcpDispatchDeliveryCoordinator({
@@ -221,4 +241,36 @@ describe("createAcpDispatchDeliveryCoordinator", () => {
     expect(coordinator.getAccumulatedBlockText()).toBe("working on it");
     expect(coordinator.hasDeliveredVisibleText()).toBe(false);
   });
+
+  it("routes ACP replies through the configured default account when AccountId is omitted", async () => {
+    const coordinator = createAcpDispatchDeliveryCoordinator({
+      cfg: createAcpTestConfig({
+        channels: {
+          discord: {
+            defaultAccount: "work",
+          },
+        },
+      }),
+      ctx: buildTestCtx({
+        Provider: "discord",
+        Surface: "discord",
+        SessionKey: "agent:codex-acp:session-1",
+      }),
+      dispatcher: createDispatcher(),
+      inboundAudio: false,
+      shouldRouteToOriginating: true,
+      originatingChannel: "discord",
+      originatingTo: "channel:thread-1",
+    });
+
+    await coordinator.deliver("block", { text: "hello" }, { skipTts: true });
+
+    expect(deliveryMocks.routeReply).toHaveBeenCalledWith(
+      expect.objectContaining({
+        channel: "discord",
+        to: "channel:thread-1",
+        accountId: "work",
+      }),
+    );
+  });
 });
diff --git a/src/auto-reply/reply/dispatch-acp-delivery.ts b/src/auto-reply/reply/dispatch-acp-delivery.ts
index de863975699..877c04f4b43 100644
--- a/src/auto-reply/reply/dispatch-acp-delivery.ts
+++ b/src/auto-reply/reply/dispatch-acp-delivery.ts
@@ -29,6 +29,28 @@ function normalizeDeliveryChannel(value: string | undefined): string | undefined
   return normalized || undefined;
 }
 
+function resolveDeliveryAccountId(params: {
+  cfg: OpenClawConfig;
+  channel: string | undefined;
+  accountId: string | undefined;
+}): string | undefined {
+  const explicit = params.accountId?.trim();
+  if (explicit) {
+    return explicit;
+  }
+  const channelId = normalizeDeliveryChannel(params.channel);
+  if (!channelId) {
+    return undefined;
+  }
+  const channelCfg = (params.cfg.channels as Record<string, { defaultAccount?: unknown } | undefined>)[
+    channelId
+  ];
+  const configuredDefault = channelCfg?.defaultAccount;
+  return typeof configuredDefault === "string" && configuredDefault.trim()
+    ? configuredDefault.trim()
+    : undefined;
+}
+
 function shouldTreatDeliveredTextAsVisible(params: {
   channel: string | undefined;
   kind: ReplyDispatchKind;
@@ -113,6 +135,11 @@ export function createAcpDispatchDeliveryCoordinator(params: {
   };
   const directChannel = normalizeDeliveryChannel(params.ctx.Provider ?? params.ctx.Surface);
   const routedChannel = normalizeDeliveryChannel(params.originatingChannel);
+  const resolvedAccountId = resolveDeliveryAccountId({
+    cfg: params.cfg,
+    channel: routedChannel ?? directChannel,
+    accountId: params.ctx.AccountId,
+  });
 
   const settleDirectVisibleText = async () => {
     if (state.settledDirectVisibleText || state.queuedDirectVisibleTextDeliveries === 0) {
@@ -229,7 +256,7 @@ export function createAcpDispatchDeliveryCoordinator(params: {
         channel: params.originatingChannel,
         to: params.originatingTo,
         sessionKey: params.ctx.SessionKey,
-        accountId: params.ctx.AccountId,
+        accountId: resolvedAccountId,
         threadId: params.ctx.MessageThreadId,
         cfg: params.cfg,
       });
@@ -245,7 +272,7 @@ export function createAcpDispatchDeliveryCoordinator(params: {
       if (kind === "tool" && meta?.toolCallId && result.messageId) {
         state.toolMessageByCallId.set(meta.toolCallId, {
           channel: params.originatingChannel,
-          accountId: params.ctx.AccountId,
+          accountId: resolvedAccountId,
           to: params.originatingTo,
           ...(params.ctx.MessageThreadId != null ? { threadId: params.ctx.MessageThreadId } : {}),
           messageId: result.messageId,