diff --git a/CHANGELOG.md b/CHANGELOG.md
index a887a1d86df..372dba86c8e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,7 +16,7 @@ Docs: https://docs.openclaw.ai
 - Plugins/ClawHub: persist ClawPack digest metadata on ClawHub plugin install and update records so registry refreshes and download verification can reuse stored artifact facts. Thanks @vincentkoc.
 - Plugins/ClawHub: allow official bundled-plugin cutovers to prefer ClawHub installs with npm fallback only when the ClawHub package or version is absent. Thanks @vincentkoc.
 - Plugins/Crestodian: add ClawHub plugin search plus Crestodian plugin list/search/install/uninstall operations, with approval and audit coverage for install and uninstall.
-- Channels/thread bindings: replace split subagent/ACP thread-spawn toggles with `threadBindings.spawnSessions`, default thread-bound spawns on, and let `openclaw doctor --fix` migrate the legacy keys.
+- Channels/thread bindings: replace split subagent/ACP thread-spawn toggles with `threadBindings.spawnSessions`, default thread-bound spawns on, and let `openclaw doctor --fix` migrate the legacy keys. (#75943)
 - Providers/OpenAI: add `extraBody`/`extra_body` passthrough for OpenAI-compatible TTS endpoints, so custom speech servers can receive fields such as `lang` in `/audio/speech` requests. Fixes #39900. Thanks @R3NK0R.
 - Dependencies: refresh workspace dependency pins, including TypeBox 1.1.37, AWS SDK 3.1041.0, Microsoft Teams 2.0.9, and Marked 18.0.3. Thanks @mariozechner, @aws, and @microsoft.
 - Discord/channels: add reusable message-channel access groups plus Discord channel-audience DM authorization, so allowlists can reference `accessGroup:<name>` across channel auth paths. (#75813)
diff --git a/extensions/discord/src/subagent-hooks.test.ts b/extensions/discord/src/subagent-hooks.test.ts
index 2534f49a6a4..02655a1c018 100644
--- a/extensions/discord/src/subagent-hooks.test.ts
+++ b/extensions/discord/src/subagent-hooks.test.ts
@@ -20,23 +20,46 @@ type MockResolvedDiscordAccount = {
   };
 };
 
-const hookMocks = vi.hoisted(() => ({
-  resolveDiscordAccount: vi.fn(
-    (params?: { accountId?: string }): MockResolvedDiscordAccount => ({
-      accountId: params?.accountId?.trim() || "default",
+type MockResolveDiscordAccountParams = {
+  cfg?: {
+    channels?: {
+      discord?: {
+        defaultAccount?: string;
+        accounts?: Record<
+          string,
+          { threadBindings?: MockResolvedDiscordAccount["config"]["threadBindings"] }
+        >;
+      };
+    };
+  };
+  accountId?: string;
+};
+
+const hookMocks = vi.hoisted(() => {
+  const resolveDiscordAccountImpl = (
+    params?: MockResolveDiscordAccountParams,
+  ): MockResolvedDiscordAccount => {
+    const accountId =
+      params?.accountId?.trim() || params?.cfg?.channels?.discord?.defaultAccount || "default";
+    return {
+      accountId,
       config: {
-        threadBindings: {
+        threadBindings: params?.cfg?.channels?.discord?.accounts?.[accountId]?.threadBindings ?? {
           spawnSessions: true,
         },
       },
-    }),
-  ),
-  autoBindSpawnedDiscordSubagent: vi.fn(
-    async (): Promise<{ threadId: string } | null> => ({ threadId: "thread-1" }),
-  ),
-  listThreadBindingsBySessionKey: vi.fn((_params?: unknown): ThreadBindingRecord[] => []),
-  unbindThreadBindingsBySessionKey: vi.fn(() => []),
-}));
+    };
+  };
+  return {
+    resolveDiscordAccountImpl,
+    resolveDiscordAccount: vi.fn(resolveDiscordAccountImpl),
+    autoBindSpawnedDiscordSubagent: vi.fn(
+      async (): Promise<{ threadId: string } | null> => ({ threadId: "thread-1" }),
+    ),
+    listThreadBindingsBySessionKey: vi.fn((_params?: unknown): ThreadBindingRecord[] => []),
+    unbindThreadBindingsBySessionKey: vi.fn(() => []),
+  };
+});
 
 let registerDiscordSubagentHooks: typeof import("../subagent-hooks-api.js").registerDiscordSubagentHooks;
 
@@ -94,7 +117,7 @@ function createSpawnEvent(overrides?: {
   mode?: string;
   requester?: {
     channel?: string;
-    accountId?: string;
+    accountId?: string | undefined;
     to?: string;
     threadId?: string;
   };
@@ -106,7 +129,7 @@ function createSpawnEvent(overrides?: {
   mode: string;
   requester: {
     channel: string;
-    accountId: string;
+    accountId?: string;
     to: string;
     threadId?: string;
   };
@@ -172,14 +195,7 @@ describe("discord subagent hook handlers", () => {
 
   beforeEach(() => {
     hookMocks.resolveDiscordAccount.mockClear();
-    hookMocks.resolveDiscordAccount.mockImplementation((params?: { accountId?: string }) => ({
-      accountId: params?.accountId?.trim() || "default",
-      config: {
-        threadBindings: {
-          spawnSessions: true,
-        },
-      },
-    }));
+    hookMocks.resolveDiscordAccount.mockImplementation(hookMocks.resolveDiscordAccountImpl);
     hookMocks.autoBindSpawnedDiscordSubagent.mockClear();
     hookMocks.listThreadBindingsBySessionKey.mockClear();
     hookMocks.unbindThreadBindingsBySessionKey.mockClear();
@@ -229,6 +245,42 @@ describe("discord subagent hook handlers", () => {
     });
   });
 
+  it("honors defaultAccount policy when requester omits accountId", async () => {
+    await expectSubagentSpawningError({
+      config: {
+        channels: {
+          discord: {
+            defaultAccount: "work",
+            threadBindings: {
+              spawnSessions: true,
+            },
+            accounts: {
+              work: {
+                threadBindings: {
+                  spawnSessions: false,
+                },
+              },
+            },
+          },
+        },
+      },
+      event: createSpawnEvent({
+        requester: {
+          accountId: undefined,
+          channel: "discord",
+          to: "channel:123",
+          threadId: undefined,
+        },
+      }),
+      errorContains: "spawnSessions=true",
+    });
+    expect(hookMocks.resolveDiscordAccount).toHaveBeenCalledWith(
+      expect.objectContaining({
+        accountId: undefined,
+      }),
+    );
+  });
+
   it("returns error when global thread bindings are disabled", async () => {
     await expectSubagentSpawningError({
       config: {
diff --git a/extensions/discord/src/subagent-hooks.ts b/extensions/discord/src/subagent-hooks.ts
index 040bdfacc5a..c99d22b79c7 100644
--- a/extensions/discord/src/subagent-hooks.ts
+++ b/extensions/discord/src/subagent-hooks.ts
@@ -8,6 +8,7 @@ import {
   normalizeOptionalLowercaseString,
   normalizeOptionalStringifiedId,
 } from "openclaw/plugin-sdk/text-runtime";
+import { resolveDiscordAccount } from "./accounts.js";
 import {
   autoBindSpawnedDiscordSubagent,
   listThreadBindingsBySessionKey,
@@ -91,10 +92,14 @@ export async function handleDiscordSubagentSpawning(
   if (channel !== "discord") {
     return undefined;
   }
+  const account = resolveDiscordAccount({
+    cfg: api.config,
+    accountId: event.requester?.accountId,
+  });
   const threadBindingPolicy = resolveThreadBindingSpawnPolicy({
     cfg: api.config,
     channel: "discord",
-    accountId: event.requester?.accountId,
+    accountId: account.accountId,
     kind: "subagent",
   });
   if (!threadBindingPolicy.enabled) {
@@ -121,7 +126,7 @@ export async function handleDiscordSubagentSpawning(
     const agentId = event.agentId?.trim() || "subagent";
     const binding = await autoBindSpawnedDiscordSubagent({
       cfg: api.config,
-      accountId: event.requester?.accountId,
+      accountId: account.accountId,
       channel: event.requester?.channel,
       to: event.requester?.to,
       threadId: event.requester?.threadId,
diff --git a/src/agents/subagent-spawn.context.test.ts b/src/agents/subagent-spawn.context.test.ts
index 713a5abedf6..5d91d64c366 100644
--- a/src/agents/subagent-spawn.context.test.ts
+++ b/src/agents/subagent-spawn.context.test.ts
@@ -179,6 +179,16 @@ describe("sessions_spawn context modes", () => {
       agentId: "main",
       sessionsDir: path.dirname(storePath),
     });
+    expect(callGatewayMock).toHaveBeenCalledWith(
+      expect.objectContaining({
+        method: "sessions.delete",
+        params: expect.objectContaining({
+          key: result.childSessionKey,
+          deleteTranscript: true,
+          emitLifecycleHooks: false,
+        }),
+      }),
+    );
     expect(prepareSubagentSpawn).not.toHaveBeenCalled();
   });
 
diff --git a/src/agents/subagent-spawn.ts b/src/agents/subagent-spawn.ts
index fba5ffe0992..eed7fef2e2d 100644
--- a/src/agents/subagent-spawn.ts
+++ b/src/agents/subagent-spawn.ts
@@ -964,7 +964,7 @@ export async function spawnSubagentDirect(
       try {
         await callSubagentGateway({
           method: "sessions.delete",
-          params: { key: childSessionKey, emitLifecycleHooks: false },
+          params: { key: childSessionKey, deleteTranscript: true, emitLifecycleHooks: false },
           timeoutMs: SUBAGENT_CONTROL_GATEWAY_TIMEOUT_MS,
         });
       } catch {