diff --git a/src/lib/policies.ts b/src/lib/policies.ts
index d4ae3a861c2..e6702975057 100644
--- a/src/lib/policies.ts
+++ b/src/lib/policies.ts
@@ -95,6 +95,27 @@ function getPresetEndpoints(content: string): string[] {
   return hosts;
 }
 
+/**
+ * Messaging channel presets only open network egress to the provider's API;
+ * the bot token, channel configuration, and in-sandbox bridge are wired up at
+ * `nemoclaw onboard` time, so applying these presets after onboarding without
+ * having enabled the channel opens the firewall but leaves the sandbox
+ * without a running bridge. See #1691.
+ */
+const MESSAGING_PRESET_NAMES = new Set(["telegram", "discord", "slack"]);
+
+function getMessagingPresetWarning(presetName: string): string | null {
+  if (!MESSAGING_PRESET_NAMES.has(presetName)) return null;
+  const label =
+    presetName === "telegram" ? "Telegram" : presetName === "discord" ? "Discord" : "Slack";
+  return [
+    `Note: the '${presetName}' preset only opens network egress to the ${label} API.`,
+    `To actually enable ${label} messaging, re-run 'nemoclaw onboard' and select ${label}`,
+    "in the messaging channels step. The bot token and channel bridge are wired",
+    "up at onboard time and are not added by applying this preset alone.",
+  ].join("\n  ");
+}
+
 /**
  * Extract just the network_policies entries (indented content under
  * the `network_policies:` key) from a preset file, stripping the
@@ -919,6 +940,7 @@ export {
   listPresets,
   loadPreset,
   getPresetEndpoints,
+  getMessagingPresetWarning,
   extractPresetEntries,
   parseCurrentPolicy,
   buildPolicySetCommand,
diff --git a/src/lib/policy-channel-actions.ts b/src/lib/policy-channel-actions.ts
index 490d5429cff..15a6bed6b4e 100644
--- a/src/lib/policy-channel-actions.ts
+++ b/src/lib/policy-channel-actions.ts
@@ -141,6 +141,13 @@ export async function addSandboxPolicy(sandboxName: string, args: string[] = [])
     console.log(`  Endpoints that would be opened: ${endpoints.join(", ")}`);
   }
 
+  const messagingWarning = policies.getMessagingPresetWarning(answer);
+  if (messagingWarning) {
+    console.log("");
+    console.log(`  ${messagingWarning}`);
+    console.log("");
+  }
+
   if (dryRun) {
     console.log("  --dry-run: no changes applied.");
     return;
diff --git a/test/policies.test.ts b/test/policies.test.ts
index a11f76349f6..a80f1f563a6 100644
--- a/test/policies.test.ts
+++ b/test/policies.test.ts
@@ -49,6 +49,7 @@ function runPolicyAdd(
   confirmAnswer: string,
   extraArgs: string[] = [],
   envOverrides: Record<string, string | undefined> = {},
+  presetName: string = "pypi",
 ) {
   const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "nemoclaw-policy-add-"));
   const scriptPath = path.join(tmpDir, "policy-add-check.js");
@@ -57,9 +58,9 @@ const registry = require(${REGISTRY_PATH});
 const policies = require(${POLICIES_PATH});
 const credentials = require(${CREDENTIALS_PATH});
 const calls = [];
-policies.selectFromList = async () => "pypi";
-policies.loadPreset = () => "network_policies:\n  pypi:\n    host: pypi.org\n";
-policies.getPresetEndpoints = () => ["pypi.org"];
+policies.selectFromList = async () => ${JSON.stringify(presetName)};
+policies.loadPreset = () => "network_policies:\n  example:\n    host: example.com\n";
+policies.getPresetEndpoints = () => ["example.com"];
 credentials.prompt = async (message) => {
   calls.push({ type: "prompt", message });
   return ${JSON.stringify(confirmAnswer)};
@@ -82,15 +83,19 @@ Promise.resolve(require(${CLI_PATH}).mainPromise).finally(() => {
 
   fs.writeFileSync(scriptPath, script);
 
-  return spawnSync(process.execPath, [scriptPath], {
-    cwd: REPO_ROOT,
-    encoding: "utf-8",
-    env: {
-      ...process.env,
-      HOME: tmpDir,
-      ...envOverrides,
-    },
-  });
+  try {
+    return spawnSync(process.execPath, [scriptPath], {
+      cwd: REPO_ROOT,
+      encoding: "utf-8",
+      env: {
+        ...process.env,
+        HOME: tmpDir,
+        ...envOverrides,
+      },
+    });
+  } finally {
+    fs.rmSync(tmpDir, { recursive: true, force: true });
+  }
 }
 
 function runSelectFromList(input: string, { applied = [] }: AppliedOptions = {}) {
@@ -250,6 +255,33 @@ describe("policies", () => {
     });
   });
 
+  describe("getMessagingPresetWarning", () => {
+    it("returns a warning for the telegram preset that mentions re-running onboard", () => {
+      const warning = policies.getMessagingPresetWarning("telegram");
+      expect(warning).toBeTruthy();
+      expect(warning).toContain("telegram");
+      expect(warning).toContain("Telegram");
+      expect(warning).toContain("nemoclaw onboard");
+    });
+
+    it("returns a warning for discord and slack", () => {
+      expect(policies.getMessagingPresetWarning("discord")).toContain("Discord");
+      expect(policies.getMessagingPresetWarning("slack")).toContain("Slack");
+    });
+
+    it("returns null for non-messaging presets", () => {
+      expect(policies.getMessagingPresetWarning("npm")).toBeNull();
+      expect(policies.getMessagingPresetWarning("pypi")).toBeNull();
+      expect(policies.getMessagingPresetWarning("github")).toBeNull();
+      expect(policies.getMessagingPresetWarning("brew")).toBeNull();
+    });
+
+    it("returns null for unknown preset names", () => {
+      expect(policies.getMessagingPresetWarning("")).toBeNull();
+      expect(policies.getMessagingPresetWarning("nonexistent")).toBeNull();
+    });
+  });
+
   describe("applyPreset disclosure logging", () => {
     it("logs egress endpoints before applying", () => {
       const logSpy = vi.spyOn(console, "log").mockImplementation(() => {});
@@ -1035,7 +1067,7 @@ selectForRemoval(items, options)
       const calls = JSON.parse(result.stdout.split("__CALLS__")[1].trim()) as PolicyCall[];
       expect(calls.some((call: PolicyCall) => call.type === "prompt")).toBeFalsy();
       expect(calls.some((call: PolicyCall) => call.type === "apply")).toBeFalsy();
-      expect(result.stdout).toMatch(/Endpoints that would be opened: pypi\.org/);
+      expect(result.stdout).toMatch(/Endpoints that would be opened: example\.com/);
       expect(result.stdout).toMatch(/--dry-run: no changes applied\./);
     });
 
@@ -1073,6 +1105,24 @@ selectForRemoval(items, options)
         /Non-interactive mode requires a preset name/,
       );
     });
+
+    it("warns the user that the telegram preset alone does not enable Telegram messaging", () => {
+      const result = runPolicyAdd("y", [], {}, "telegram");
+
+      expect(result.status).toBe(0);
+      expect(result.stdout).toMatch(
+        /Note: the 'telegram' preset only opens network egress to the Telegram API\./,
+      );
+      expect(result.stdout).toMatch(/re-run 'nemoclaw onboard' and select Telegram/);
+    });
+
+    it("does not warn about messaging when a non-messaging preset is selected", () => {
+      const result = runPolicyAdd("y");
+
+      expect(result.status).toBe(0);
+      expect(result.stdout).not.toMatch(/only opens network egress to the/);
+      expect(result.stdout).not.toMatch(/re-run 'nemoclaw onboard' and select/);
+    });
   });
 
   describe("policy-remove confirmation", () => {