diff --git a/extensions/slack/src/monitor/slash.test.ts b/extensions/slack/src/monitor/slash.test.ts
index d73392764c30..b94289f51d23 100644
--- a/extensions/slack/src/monitor/slash.test.ts
+++ b/extensions/slack/src/monitor/slash.test.ts
@@ -589,6 +589,7 @@ describe("Slack native command argument menus", () => {
     const commands = new Map<string, (args: unknown) => Promise<void>>();
     const actions = new Map<string | RegExp, (args: unknown) => Promise<void>>();
     const postEphemeral = vi.fn().mockResolvedValue({ ok: true });
+    const runtimeLog = vi.fn();
     const app = {
       client: { chat: { postEphemeral } },
       command: (name: string, handler: (args: unknown) => Promise<void>) => {
@@ -604,7 +605,7 @@ describe("Slack native command argument menus", () => {
     };
     const ctx = {
       cfg: { commands: { native: true, nativeSkills: false } },
-      runtime: {},
+      runtime: { log: runtimeLog },
       botToken: "bot-token",
       botUserId: "bot",
       teamId: "T1",
@@ -637,6 +638,12 @@ describe("Slack native command argument menus", () => {
     // Registration should not throw despite app.options() throwing
     await registerCommands(ctx, account);
     expect(commands.size).toBeGreaterThan(0);
+    expect(runtimeLog).toHaveBeenCalledTimes(1);
+    expect(runtimeLog).toHaveBeenCalledWith(
+      expect.stringContaining(
+        "slack: external arg-menu registration failed; falling back to static slash command menus.",
+      ),
+    );
     expect(
       Array.from(actions.keys()).some(
         (key) => key instanceof RegExp && String(key) === String(/^openclaw_cmdarg/),
diff --git a/extensions/slack/src/monitor/slash.ts b/extensions/slack/src/monitor/slash.ts
index d69ab1846285..d64cce94b6ef 100644
--- a/extensions/slack/src/monitor/slash.ts
+++ b/extensions/slack/src/monitor/slash.ts
@@ -18,7 +18,7 @@ import {
 } from "openclaw/plugin-sdk/native-command-config-runtime";
 import type { ReplyPayload } from "openclaw/plugin-sdk/reply-runtime";
 import type { ResolvedAgentRoute } from "openclaw/plugin-sdk/routing";
-import { danger, logVerbose } from "openclaw/plugin-sdk/runtime-env";
+import { danger, logVerbose, warn } from "openclaw/plugin-sdk/runtime-env";
 import { loadSessionStore, resolveStorePath } from "openclaw/plugin-sdk/session-store-runtime";
 import {
   normalizeLowercaseStringOrEmpty,
@@ -927,6 +927,11 @@ export async function registerSlackMonitorSlashCommands(params: {
     registerArgOptions();
   } catch (err) {
     supportsExternalArgMenus = false;
+    runtime.log?.(
+      warn(
+        "slack: external arg-menu registration failed; falling back to static slash command menus. Enable verbose logs for details.",
+      ),
+    );
     logVerbose(
       `slack: external arg-menu registration failed, falling back to static menus: ${formatErrorMessage(err)}`,
     );