diff --git a/bin/dm.py b/bin/dm.py
index 9da54fe..8c978a6 100755
--- a/bin/dm.py
+++ b/bin/dm.py
@@ -202,6 +202,8 @@ LOG_FILE = "/home/super/Projects/NetVM/dm-log.jsonl"
 # Resolved 2026-10-04. Add new entries as sidechats are created.
 SIDCHAT_ALIASES = {
     "646-opm-work": "d410b9ad-f667-465f-a103-43fabc0f69fe",
+    "646 tasks": "1e75a740-d08f-443d-a0f9-793db196e24f",
+    "heartbeat": "1e75a740-d08f-443d-a0f9-793db196e24f",
 }
 
 def resolve_sidechat_target(target):
diff --git a/tests/test_main_nav.py b/tests/test_main_nav.py
new file mode 100644
index 0000000..0217c01
--- /dev/null
+++ b/tests/test_main_nav.py
@@ -0,0 +1,114 @@
+#!/usr/bin/env python3
+"""
+test_main_nav.py — Comprehensive unit and integration test suite for:
+1. Strict Main Chat blocking in CLI (`super dm send`, `super dm wo`)
+2. Explicit override `--allow-main-chat`
+3. Sidechat target resolution & alias mapping
+4. "Reset-at-Begin, Leave-in-Sidechat" navigation logic in dm.py
+5. Harvester sidechat-only thread scope (no Main Chat polling)
+6. Staged file transfer & metadata registry lifecycle
+"""
+import unittest
+import subprocess
+import json
+import os
+import sys
+import tempfile
+from pathlib import Path
+
+REPO_ROOT = Path("/home/super/Projects/NetVM")
+BIN_DIR = REPO_ROOT / "bin"
+SUPER_CLI = BIN_DIR / "super-cli.py"
+DM_PY = BIN_DIR / "dm.py"
+HARVESTER_PY = BIN_DIR / "response-harvester.py"
+
+sys.path.insert(0, str(BIN_DIR))
+
+class TestMainChatPolicyEnforcement(unittest.TestCase):
+    """Test CLI guards blocking unintended Main Chat access."""
+
+    def test_super_dm_send_blocks_main_chat_by_default(self):
+        cmd = [sys.executable, str(SUPER_CLI), "dm", "send", "--to", "646", "--target", "main", "Automated ping"]
+        res = subprocess.run(cmd, capture_output=True, text=True)
+        self.assertNotEqual(res.returncode, 0, "CLI should reject --target main without override")
+        self.assertIn("Targeting Main Chat is blocked by CHAT_POLICY.md", res.stderr)
+        self.assertIn("--allow-main-chat", res.stderr)
+
+    def test_super_dm_wo_blocks_main_chat_by_default(self):
+        cmd = [sys.executable, str(SUPER_CLI), "dm", "wo", "--to", "646", "--target", "main", "--title", "Task", "Task body"]
+        res = subprocess.run(cmd, capture_output=True, text=True)
+        self.assertNotEqual(res.returncode, 0, "CLI should reject work order in Main Chat without override")
+        self.assertIn("Work Orders must target sidechats per CHAT_POLICY.md", res.stderr)
+        self.assertIn("--allow-main-chat", res.stderr)
+
+    def test_super_dm_wo_defaults_to_agent_sidechat(self):
+        # Dry-run test parser defaults: when --target is omitted, should target agent task sidechat
+        cmd = [sys.executable, str(SUPER_CLI), "dm", "wo", "--help"]
+        res = subprocess.run(cmd, capture_output=True, text=True)
+        self.assertEqual(res.returncode, 0)
+        self.assertIn("Target sidechat (default: agent primary task sidechat)", res.stdout)
+
+
+class TestSidechatNavigationLogic(unittest.TestCase):
+    """Test dm.py and sidechat target resolution."""
+
+    def test_resolve_sidechat_target(self):
+        import dm
+        # Well-known mappings
+        self.assertEqual(dm.resolve_sidechat_target("main"), "main")
+        self.assertEqual(dm.resolve_sidechat_target("646 tasks"), "1e75a740-d08f-443d-a0f9-793db196e24f")
+        self.assertEqual(dm.resolve_sidechat_target("heartbeat"), "1e75a740-d08f-443d-a0f9-793db196e24f")
+
+    def test_uuid_regex_detection(self):
+        import dm, re
+        valid_uuid = "1e75a740-d08f-443d-a0f9-793db196e24f"
+        invalid_uuid = "646 tasks"
+        pattern = r"^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$"
+        self.assertTrue(bool(re.match(pattern, valid_uuid, re.I)))
+        self.assertFalse(bool(re.match(pattern, invalid_uuid, re.I)))
+
+
+class TestResponseHarvesterScope(unittest.TestCase):
+    """Verify harvester monitors only sidechats and leaves Main Chat out of periodic cycles."""
+
+    def test_harvester_excludes_main_chat(self):
+        import importlib.util
+        spec = importlib.util.spec_from_file_location("harvester", str(HARVESTER_PY))
+        mod = importlib.util.module_from_spec(spec)
+        spec.loader.exec_module(mod)
+
+        monitored = mod.get_monitored_threads()
+        for agent, threads in monitored.items():
+            thread_ids = [t["id"] for t in threads]
+            self.assertNotIn("main", thread_ids, f"Agent {agent} should not have 'main' in automated harvester scope")
+
+
+class TestPayloadTransfersLifecycle(unittest.TestCase):
+    """Test staging and metadata registry for payload file transfers."""
+
+    def test_files_clean_and_registry_sync(self):
+        with tempfile.NamedTemporaryFile("w", delete=False) as f:
+            f.write("Unit test payload content")
+            tmp_path = f.name
+
+        try:
+            # 1. Clean aged payloads
+            clean_cmd = [sys.executable, str(SUPER_CLI), "dm", "files", "clean", "--older-than", "0"]
+            res = subprocess.run(clean_cmd, capture_output=True, text=True)
+            self.assertEqual(res.returncode, 0)
+            self.assertIn("Cleaned", res.stdout)
+
+            # 2. View files list (JSON output)
+            list_cmd = [sys.executable, str(SUPER_CLI), "dm", "files", "--json"]
+            res = subprocess.run(list_cmd, capture_output=True, text=True)
+            self.assertEqual(res.returncode, 0)
+            data = json.loads(res.stdout)
+            self.assertTrue(data.get("ok"))
+            self.assertEqual(len(data.get("files", [])), 0)
+        finally:
+            if os.path.exists(tmp_path):
+                os.unlink(tmp_path)
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)