diff --git a/bee2bee.egg-info/PKG-INFO b/bee2bee.egg-info/PKG-INFO
index 88cdd09..16d9da8 100644
--- a/bee2bee.egg-info/PKG-INFO
+++ b/bee2bee.egg-info/PKG-INFO
@@ -146,7 +146,7 @@ A modern UI to visualize the network and chat with models.
 
 **Run Locally:**
 ```bash
-cd desktop-app
+cd electron-app
 npm install      # First time only
 npm run dev
 ```
@@ -154,6 +154,7 @@ npm run dev
 - Open the App.
 - It connects to `http://localhost:4002` by default.
 - Go to "Chat" to talk to available providers.
+- See [MANUAL_TESTING.md](MANUAL_TESTING.md) for detailed testing steps.
 
 ---
 
diff --git a/bee2bee.egg-info/SOURCES.txt b/bee2bee.egg-info/SOURCES.txt
index 3b5e27b..6a8c61a 100644
--- a/bee2bee.egg-info/SOURCES.txt
+++ b/bee2bee.egg-info/SOURCES.txt
@@ -17,6 +17,7 @@ bee2bee/p2p_runtime.py
 bee2bee/pieces.py
 bee2bee/protocol.py
 bee2bee/services.py
+bee2bee/stun_client.py
 bee2bee/utils.py
 examples/api_demo.py
 examples/p2p_request_demo.py
diff --git a/bee2bee/node.py b/bee2bee/node.py
index f54f602..df450f2 100644
--- a/bee2bee/node.py
+++ b/bee2bee/node.py
@@ -1,4 +1,18 @@
 from __future__ import annotations
+"""
+⚠️ DEPRECATED: This module uses a legacy coordinator-based architecture.
+
+For new deployments, use `p2p_runtime.py` which provides:
+- True P2P networking (any node can be server/client)
+- NAT traversal with STUN/UPnP
+- Piece-based data transfer
+- Service discovery without central coordinator
+
+This module is kept for backward compatibility with existing deployments
+that use a central coordinator pattern. It will be removed in a future version.
+
+Migration: Replace `node.run_node(url)` with `p2p_runtime.run_p2p_node(bootstrap_link=url)`
+"""
 import asyncio
 import json
 import platform
@@ -6,6 +20,14 @@
 import websockets
 from typing import Dict, Any, Optional
 from rich.console import Console
+import warnings
+
+# Emit deprecation warning when module is imported
+warnings.warn(
+    "bee2bee.node is deprecated. Use bee2bee.p2p_runtime instead.",
+    DeprecationWarning,
+    stacklevel=2
+)
 
 from .protocol import (
     msg,
diff --git a/bee2bee/p2p_runtime.py b/bee2bee/p2p_runtime.py
index f6ebfc8..26a8f04 100644
--- a/bee2bee/p2p_runtime.py
+++ b/bee2bee/p2p_runtime.py
@@ -531,14 +531,106 @@ async def _handle_gen_result(self, ws, data):
             console.log(f"[yellow]Unknown request ID: {rid}[/yellow]")
 
     async def _handle_piece_request(self, ws, data):
-        # ... logic as before ...
-        console.log(f"[debug] Piece request received")
-        pass
+        """Handle a request for piece data by content hash and piece index."""
+        content_hash = data.get("content_hash")
+        piece_index = data.get("piece_index")
+        console.log(f"[debug] Piece request received: hash={content_hash}, idx={piece_index}")
+        
+        if not content_hash or piece_index is None:
+            await self._send(ws, {
+                "type": "piece_data",
+                "content_hash": content_hash,
+                "piece_index": piece_index,
+                "error": "missing_params"
+            })
+            return
+            
+        # Look up piece in local storage
+        piece_info = self.pieces.get(content_hash)
+        if not piece_info:
+            console.log(f"[yellow]Piece not found: {content_hash}[/yellow]")
+            await self._send(ws, {
+                "type": "piece_data",
+                "content_hash": content_hash,
+                "piece_index": piece_index,
+                "error": "not_found"
+            })
+            return
+            
+        pieces_list = piece_info.get("pieces", [])
+        if piece_index < 0 or piece_index >= len(pieces_list):
+            console.log(f"[yellow]Invalid piece index: {piece_index}[/yellow]")
+            await self._send(ws, {
+                "type": "piece_data",
+                "content_hash": content_hash,
+                "piece_index": piece_index,
+                "error": "invalid_index"
+            })
+            return
+            
+        # Send the piece data (base64 encoded for JSON transport)
+        piece_bytes = pieces_list[piece_index]
+        await self._send(ws, {
+            "type": "piece_data",
+            "content_hash": content_hash,
+            "piece_index": piece_index,
+            "data": base64.b64encode(piece_bytes).decode("utf-8"),
+            "hash": piece_info.get("hashes", [])[piece_index] if piece_index < len(piece_info.get("hashes", [])) else None
+        })
+        console.log(f"[green]✅ Sent piece {piece_index} for {content_hash[:16]}...[/green]")
 
     async def _handle_piece_data(self, ws, data):
-        # ... logic as before ...
-        console.log(f"[debug] Piece data received")
-        pass
+        """Handle received piece data - verify and store it."""
+        content_hash = data.get("content_hash")
+        piece_index = data.get("piece_index")
+        piece_data_b64 = data.get("data")
+        expected_hash = data.get("hash")
+        error = data.get("error")
+        
+        console.log(f"[debug] Piece data received: hash={content_hash}, idx={piece_index}")
+        
+        if error:
+            console.log(f"[red]Piece error from peer: {error}[/red]")
+            return
+            
+        if not content_hash or piece_index is None or not piece_data_b64:
+            console.log(f"[red]Invalid piece data message[/red]")
+            return
+            
+        # Decode the piece
+        try:
+            piece_bytes = base64.b64decode(piece_data_b64)
+        except Exception as e:
+            console.log(f"[red]Failed to decode piece data: {e}[/red]")
+            return
+            
+        # Verify hash if provided
+        if expected_hash:
+            from .p2p import sha256_hex_bytes
+            actual_hash = sha256_hex_bytes(piece_bytes)
+            if actual_hash != expected_hash:
+                console.log(f"[red]Piece hash mismatch! Expected {expected_hash[:16]}..., got {actual_hash[:16]}...[/red]")
+                return
+            console.log(f"[debug] Piece hash verified: {actual_hash[:16]}...")
+        
+        # Store the piece
+        async with self._lock:
+            if content_hash not in self.pieces:
+                self.pieces[content_hash] = {"pieces": [], "hashes": [], "complete": False}
+            
+            piece_info = self.pieces[content_hash]
+            
+            # Extend lists if needed
+            while len(piece_info["pieces"]) <= piece_index:
+                piece_info["pieces"].append(None)
+            while len(piece_info["hashes"]) <= piece_index:
+                piece_info["hashes"].append(None)
+            
+            piece_info["pieces"][piece_index] = piece_bytes
+            if expected_hash:
+                piece_info["hashes"][piece_index] = expected_hash
+                
+        console.log(f"[green]✅ Stored piece {piece_index} for {content_hash[:16]}...[/green]")
 
     # --- Public API ---
 
diff --git a/tests/test_nat_optional.py b/tests/test_nat_optional.py
index 95f89f7..7c50f9b 100644
--- a/tests/test_nat_optional.py
+++ b/tests/test_nat_optional.py
@@ -3,12 +3,16 @@
 
 def test_run():
     from bee2bee.nat import try_upnp_map, try_stun
-    ok, ip = try_upnp_map(5555)
-    assert ok in (True, False)
-    assert (ip is None) or isinstance(ip, str)
-
-    async def _s():
+    
+    async def _test():
+        # Test UPnP - returns (success: bool, external_ip: Optional[str])
+        ok, ip = await try_upnp_map(5555)
+        assert isinstance(ok, bool)
+        assert (ip is None) or isinstance(ip, str)
+        
+        # Test STUN - returns (ip, port) tuple or None
         out = await try_stun()
-        assert (out is None) or isinstance(out, str)
-    asyncio.run(_s())
+        assert (out is None) or isinstance(out, tuple)
+    
+    asyncio.run(_test())