fix(heartbeat): skip when HEARTBEAT.md has no tasks and fail closed on delivery (#4111)

tests/cli/test_commands.py

@@ -952,6 +952,29 @@ def test_heartbeat_retains_recent_messages_by_default():
     assert config.gateway.heartbeat.keep_recent_messages == 8
 
 
+@pytest.mark.parametrize(
+    "content, expected",
+    [
+        ("", False),
+        ("# Title\n\n## Active Tasks\n", False),
+        ("<!--\nmulti-line\ncomment\n-->\n", False),  # block comment, not tasks
+        ("<!-- single line -->\n", False),
+        ("## Active Tasks\n\n- water the plants\n", True),
+    ],
+)
+def test_heartbeat_has_active_tasks(content, expected):
+    from nanobot.cli.commands import _heartbeat_has_active_tasks
+
+    assert _heartbeat_has_active_tasks(content) is expected
+
+
+def test_heartbeat_skips_bundled_template():
+    from nanobot.cli.commands import _heartbeat_has_active_tasks
+    from nanobot.utils.helpers import load_bundled_template
+
+    assert _heartbeat_has_active_tasks(load_bundled_template("HEARTBEAT.md")) is False
+
+
 def _write_instance_config(tmp_path: Path) -> Path:
     config_file = tmp_path / "instance" / "config.json"
     config_file.parent.mkdir(parents=True)