diff --git a/test/generate-openclaw-config-slack-allowlist.test.ts b/test/generate-openclaw-config-slack-allowlist.test.ts
new file mode 100644
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+++ b/test/generate-openclaw-config-slack-allowlist.test.ts
@@ -0,0 +1,76 @@
+// @ts-nocheck
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+//
+// Regression guards for #4869: the generated openclaw.json Slack account must
+// keep its DM and channel allowlists synchronized to SLACK_ALLOWED_USERS, and
+// an unset allowlist must leave every allowlist key absent. The positive
+// users-only and allowed-channels paths are covered in
+// generate-openclaw-config.test.ts (#3729); these guards pin the two halves the
+// issue is named after — the backward-compatibility negative path and the
+// scope-synchronization invariant — without growing that file past its budget.
+
+import { describe, it, expect } from "vitest";
+
+import { buildConfig } from "../scripts/generate-openclaw-config.mts";
+
+/** Minimal env for a valid config-generation run with Slack enabled. */
+function slackEnv(overrides: Record<string, string> = {}): Record<string, string> {
+  return {
+    NEMOCLAW_MODEL: "test-model",
+    NEMOCLAW_PROVIDER_KEY: "test-provider",
+    NEMOCLAW_PRIMARY_MODEL_REF: "test-ref",
+    NEMOCLAW_INFERENCE_BASE_URL: "http://localhost:8080",
+    NEMOCLAW_INFERENCE_API: "openai",
+    NEMOCLAW_AGENT_TIMEOUT: "600",
+    HOME: "/tmp",
+    NEMOCLAW_MESSAGING_CHANNELS_B64: Buffer.from(JSON.stringify(["slack"])).toString("base64"),
+    ...overrides,
+  };
+}
+
+function slackAccount(env: Record<string, string>): any {
+  return buildConfig(env as any).channels.slack.accounts.default;
+}
+
+describe("generate-openclaw-config.mts: Slack allowlist guards (#4869)", () => {
+  // Backward-compatibility negative path: when Slack is enabled but no allowlist
+  // is configured, all four allowlist keys must stay absent. This proves
+  // dmPolicy / allowFrom / groupPolicy / channels are derived only from
+  // SLACK_ALLOWED_USERS and that an unset allowlist never silently broadens
+  // (listen everywhere) or narrows (disable) channel scope.
+  it("keeps all Slack allowlist keys absent when no allowlist is configured", () => {
+    const slack = slackAccount(slackEnv());
+
+    expect(slack.enabled).toBe(true);
+    expect(slack.dmPolicy).toBeUndefined();
+    expect(slack.allowFrom).toBeUndefined();
+    expect(slack.groupPolicy).toBeUndefined();
+    expect(slack.channels).toBeUndefined();
+  });
+
+  // Scope synchronization: #4869 reported channels['*'] coming back empty while
+  // allowFrom was populated. Assert the per-channel wildcard allowlist is fully
+  // populated and that its users are the exact same IDs as the DM allowFrom
+  // list, so the two scopes can never drift out of lockstep.
+  it("keeps Slack DM and channel allowlists synchronized to SLACK_ALLOWED_USERS", () => {
+    const allowedUsers = ["U_DUMMY_ALLOW1", "U_DUMMY_ALLOW2"];
+    const slack = slackAccount(
+      slackEnv({
+        NEMOCLAW_MESSAGING_ALLOWED_IDS_B64: Buffer.from(
+          JSON.stringify({ slack: allowedUsers }),
+        ).toString("base64"),
+      }),
+    );
+
+    expect(slack.dmPolicy).toBe("allowlist");
+    expect(slack.allowFrom).toEqual(allowedUsers);
+    expect(slack.groupPolicy).toBe("allowlist");
+    expect(slack.channels?.["*"]).toEqual({
+      enabled: true,
+      requireMention: true,
+      users: allowedUsers,
+    });
+    expect(slack.channels["*"].users).toEqual(slack.allowFrom);
+  });
+});