diff --git a/.env.example b/.env.example
index f73a32a..246de34 100644
--- a/.env.example
+++ b/.env.example
@@ -16,3 +16,13 @@ ACTIVE_TIMEOUT_SECONDS=300
 
 # Watcher Settings
 DEBOUNCE_SECONDS=2
+
+# Bot mode: 'local' (default, file-based) or 'gateway' (서버 Docker)
+BOT_MODE=local
+# Remote bridge URL (only used when BOT_MODE=remote)
+REMOTE_BRIDGE_URL=
+
+# Gateway API Key (보안)
+# 서버와 Collector에 동일한 키를 설정하세요
+# 생성: python -c "import secrets; print(secrets.token_urlsafe(32))"
+GATEWAY_API_KEY=
diff --git a/bridge.py b/bridge.py
index 055671c..3880f4f 100644
--- a/bridge.py
+++ b/bridge.py
@@ -150,30 +150,107 @@ class LocalTransport(BridgeTransport):
 
 
 class RemoteTransport(BridgeTransport):
-    """HTTP-based transport for remote/multi-PC mode (skeleton).
+    """HTTP-based transport for Collector → Gateway communication.
 
-    Future implementation: polls a remote bridge HTTP server that
-    exposes the same pending/response/commands JSON files via API.
+    Maps BridgeTransport methods to Gateway API endpoints:
+      list_json_files("pending")  → GET /api/pending (returns list)
+      write_json("pending", ...)  → POST /api/pending
+      read_json("response", ...)  → GET /api/response/{rid}
+      write_json("commands", ...) → (not used by Collector, Gateway pushes commands)
+      etc.
     """
 
-    def __init__(self, base_url: str):
+    def __init__(self, base_url: str, api_key: str = ""):
         self.base_url = base_url.rstrip("/")
-        logger.info(f"RemoteTransport: initialized with {self.base_url}")
+        self.api_key = api_key
+        self._headers = {"Content-Type": "application/json"}
+        if api_key:
+            self._headers["Authorization"] = f"Bearer {api_key}"
+        logger.info(f"RemoteTransport: {self.base_url} (auth={'yes' if api_key else 'no'})")
+
+    def _request(self, method: str, path: str, data: dict | None = None) -> dict | None:
+        """Make HTTP request to Gateway API."""
+        import urllib.request
+        import urllib.error
+
+        url = f"{self.base_url}{path}"
+        body = json.dumps(data, ensure_ascii=False).encode("utf-8") if data else None
+        req = urllib.request.Request(url, data=body, headers=self._headers, method=method)
+
+        try:
+            with urllib.request.urlopen(req, timeout=10) as resp:
+                return json.loads(resp.read().decode("utf-8"))
+        except urllib.error.HTTPError as e:
+            logger.warning(f"RemoteTransport: {method} {path} → {e.code} {e.reason}")
+            return None
+        except (urllib.error.URLError, OSError, json.JSONDecodeError) as e:
+            logger.warning(f"RemoteTransport: {method} {path} → {e}")
+            return None
 
     def list_json_files(self, subdir: str) -> list[str]:
-        raise NotImplementedError("RemoteTransport not yet implemented")
+        """List pending requests from Gateway."""
+        if subdir == "pending":
+            result = self._request("GET", "/api/pending")
+            if result and isinstance(result, list):
+                return [f"{r['request_id']}.json" for r in result]
+        elif subdir == "commands":
+            # Commands are polled per-project (handled separately)
+            return []
+        return []
 
     def read_json(self, subdir: str, filename: str) -> dict | None:
-        raise NotImplementedError("RemoteTransport not yet implemented")
+        """Read a JSON file from Gateway."""
+        rid = filename.replace(".json", "")
+        if subdir == "response":
+            return self._request("GET", f"/api/response/{rid}")
+        elif subdir == "pending":
+            # Pending data comes from list, not individual read
+            result = self._request("GET", "/api/pending")
+            if result and isinstance(result, list):
+                for r in result:
+                    if r.get("request_id") == rid:
+                        return r
+        return None
 
     def write_json(self, subdir: str, filename: str, data: dict) -> None:
-        raise NotImplementedError("RemoteTransport not yet implemented")
+        """Write data to Gateway via API."""
+        if subdir == "pending":
+            self._request("POST", "/api/pending", data)
+        elif subdir == "response":
+            rid = data.get("request_id", filename.replace(".json", ""))
+            self._request("POST", f"/api/response/{rid}", data)
+        elif subdir == "commands":
+            # Commands go through write_command in BridgeProtocol
+            self._request("POST", "/api/chat", data)
 
     def delete_file(self, subdir: str, filename: str) -> bool:
-        raise NotImplementedError("RemoteTransport not yet implemented")
+        """Delete not needed for remote — Gateway manages cleanup."""
+        return True
 
     def ensure_dirs(self) -> None:
-        pass  # Remote server manages its own directories
+        """No local dirs needed for remote transport."""
+        pass
+
+    def poll_commands(self, project: str) -> list[dict]:
+        """Poll Gateway for commands (Collector-specific, not in ABC)."""
+        result = self._request("GET", f"/api/commands/{project}")
+        if result and isinstance(result, dict):
+            return result.get("commands", [])
+        return []
+
+    def register_session(self, conversation_id: str, project_name: str) -> None:
+        """Register session → project mapping on Gateway."""
+        self._request("POST", "/api/register", {
+            "conversation_id": conversation_id,
+            "project_name": project_name,
+        })
+
+    def send_chat(self, project_name: str, content: str) -> None:
+        """Push chat snapshot to Gateway for relay to Discord."""
+        self._request("POST", "/api/chat", {
+            "project_name": project_name,
+            "content": content,
+        })
 
 
 # ─── Bridge Protocol (uses Transport) ───
diff --git a/collector.py b/collector.py
new file mode 100644
index 0000000..e485b19
--- /dev/null
+++ b/collector.py
@@ -0,0 +1,127 @@
+"""Collector — local relay between Extension (file-based) and Gateway (HTTP).
+
+The Collector runs on the local PC alongside the AG IDE.
+It bridges the gap between the Extension (which writes to local bridge/ files)
+and the remote Gateway (which manages Discord).
+
+Flow:
+  Extension → bridge/pending/ → Collector → POST Gateway /api/pending
+  Gateway /api/response/{rid} → Collector → bridge/response/ → Extension
+  Gateway /api/commands/{project} → Collector → bridge/commands/ → Extension
+"""
+
+import asyncio
+import json
+import time
+import logging
+from pathlib import Path
+
+from bridge import LocalTransport, RemoteTransport
+from config import Config
+
+logger = logging.getLogger(__name__)
+
+
+class CollectorBridge:
+    """Bridges local file-based bridge with remote Gateway API.
+
+    Periodically:
+    1. Scans local pending/ → forwards new ones to Gateway
+    2. Polls Gateway for responses → writes to local response/
+    3. Polls Gateway for commands → writes to local commands/
+    """
+
+    def __init__(self, local: LocalTransport, remote: RemoteTransport, project_name: str):
+        self.local = local
+        self.remote = remote
+        self.project_name = project_name
+        self._forwarded_pending: set[str] = set()  # already forwarded request IDs
+        self._poll_interval = 3  # seconds
+        self._running = False
+
+    async def start(self):
+        """Start the Collector polling loops."""
+        self._running = True
+        logger.info(f"[COLLECTOR] started for project={self.project_name}")
+        await asyncio.gather(
+            self._forward_pending_loop(),
+            self._poll_responses_loop(),
+            self._poll_commands_loop(),
+        )
+
+    async def stop(self):
+        """Stop the Collector."""
+        self._running = False
+        logger.info("[COLLECTOR] stopped")
+
+    # ─── Forward local pending → Gateway ───
+
+    async def _forward_pending_loop(self):
+        """Scan local pending/ and forward new requests to Gateway."""
+        while self._running:
+            try:
+                for fname in self.local.list_json_files("pending"):
+                    rid = fname.replace(".json", "")
+                    if rid in self._forwarded_pending:
+                        continue
+
+                    data = self.local.read_json("pending", fname)
+                    if data is None or data.get("status") != "pending":
+                        continue
+
+                    # Forward to Gateway
+                    self.remote.write_json("pending", fname, data)
+                    self._forwarded_pending.add(rid)
+                    logger.info(f"[COLLECTOR] → Gateway: pending {rid[:12]}")
+
+                # Clean up stale forwarded tracking (keep last 200)
+                if len(self._forwarded_pending) > 200:
+                    self._forwarded_pending = set(list(self._forwarded_pending)[-100:])
+
+            except Exception as e:
+                logger.error(f"[COLLECTOR] forward_pending error: {e}")
+
+            await asyncio.sleep(self._poll_interval)
+
+    # ─── Poll Gateway responses → local ───
+
+    async def _poll_responses_loop(self):
+        """Poll Gateway for responses and write them locally for Extension."""
+        while self._running:
+            try:
+                # Check each forwarded pending for a response
+                for rid in list(self._forwarded_pending):
+                    data = self.remote.read_json("response", f"{rid}.json")
+                    if data is None or data.get("waiting"):
+                        continue
+
+                    # Write response locally for Extension to pick up
+                    self.local.write_json("response", f"{rid}.json", data)
+                    # Also delete local pending file (Extension expects this)
+                    self.local.delete_file("pending", f"{rid}.json")
+                    self._forwarded_pending.discard(rid)
+                    approved = data.get("approved", "?")
+                    logger.info(f"[COLLECTOR] ← Gateway: response {rid[:12]} approved={approved}")
+
+            except Exception as e:
+                logger.error(f"[COLLECTOR] poll_responses error: {e}")
+
+            await asyncio.sleep(self._poll_interval)
+
+    # ─── Poll Gateway commands → local ───
+
+    async def _poll_commands_loop(self):
+        """Poll Gateway for commands and write them locally for Extension."""
+        while self._running:
+            try:
+                commands = self.remote.poll_commands(self.project_name)
+                for cmd in commands:
+                    cmd_id = cmd.get("id", str(int(time.time() * 1000)))
+                    fname = f"{cmd_id}.json"
+                    self.local.write_json("commands", fname, cmd)
+                    logger.info(f"[COLLECTOR] ← Gateway: command {cmd.get('text', '?')[:30]}")
+
+            except Exception as e:
+                logger.error(f"[COLLECTOR] poll_commands error: {e}")
+
+            await asyncio.sleep(self._poll_interval)
diff --git a/main.py b/main.py
index ddde8eb..5db23bc 100644
--- a/main.py
+++ b/main.py
@@ -51,15 +51,41 @@ async def main():
     # Get the running loop
     loop = asyncio.get_running_loop()
 
-    # Create transport based on BOT_MODE
-    transport = None  # None → LocalTransport (default)
+    # ── Collector mode: no Discord bot, just relay local ↔ Gateway ──
     if Config.BOT_MODE == "remote":
-        from bridge import RemoteTransport
+        from bridge import LocalTransport, RemoteTransport
+        from collector import CollectorBridge
+
         if not Config.REMOTE_BRIDGE_URL:
-            logger.error("REMOTE_BRIDGE_URL is required for remote mode")
+            logger.error("REMOTE_BRIDGE_URL is required for remote (Collector) mode")
             sys.exit(1)
-        transport = RemoteTransport(Config.REMOTE_BRIDGE_URL)
-        logger.info(f"Remote transport: {Config.REMOTE_BRIDGE_URL}")
+
+        bridge_dir = Config.BRAIN_PATH.parent / "bridge"
+        local = LocalTransport(bridge_dir)
+        local.ensure_dirs()
+        remote = RemoteTransport(Config.REMOTE_BRIDGE_URL, api_key=Config.GATEWAY_API_KEY)
+
+        collector = CollectorBridge(local, remote, project_name=Config.PROJECT_NAME)
+        logger.info(f"Collector mode: {Config.REMOTE_BRIDGE_URL}")
+
+        # Optionally start watcher for brain events (local display only)
+        watcher = BrainWatcher(event_queue, loop)
+
+        try:
+            watcher.start()
+            logger.info(f"Watcher started, {len(watcher.known_sessions)} existing sessions")
+            await collector.start()
+        except KeyboardInterrupt:
+            logger.info("Received keyboard interrupt")
+        except Exception as e:
+            logger.error(f"Fatal error: {e}", exc_info=True)
+        finally:
+            await collector.stop()
+            watcher.stop()
+            logger.info("Collector shutdown complete")
+        return
+
+    # ── Local / Gateway mode ──
 
     # Create components
     watcher = None
@@ -67,11 +93,6 @@ async def main():
         watcher = BrainWatcher(event_queue, loop)
     bot = GravityBot(event_queue)
 
-    # Inject transport if specified (otherwise bot uses default LocalTransport)
-    if transport is not None:
-        from bridge import BridgeProtocol
-        bot.bridge = BridgeProtocol(transport)
-
     try:
         # Start watcher (local mode only — gateway receives data via HTTP)
         if watcher: