fix: enable TCP keepalives to detect dead provider connections

run_agent.py

@@ -4366,6 +4366,29 @@ def _create_openai_client(self, client_kwargs: dict, *, reason: str, shared: boo
                 self._client_log_context(),
             )
             return client
+        # Inject TCP keepalives to detect dead connections faster (#10324).
+        # Without keepalives, a provider that drops mid-stream leaves the
+        # socket in CLOSE-WAIT and epoll_wait may never fire, causing the
+        # agent to hang indefinitely.  Keepalive probes detect the dead
+        # peer within ~60s (30s idle + 3×10s probes).
+        if "http_client" not in client_kwargs:
+            try:
+                import httpx as _httpx
+                import socket as _socket
+                _sock_opts = [(_socket.SOL_SOCKET, _socket.SO_KEEPALIVE, 1)]
+                if hasattr(_socket, "TCP_KEEPIDLE"):
+                    # Linux
+                    _sock_opts.append((_socket.IPPROTO_TCP, _socket.TCP_KEEPIDLE, 30))
+                    _sock_opts.append((_socket.IPPROTO_TCP, _socket.TCP_KEEPINTVL, 10))
+                    _sock_opts.append((_socket.IPPROTO_TCP, _socket.TCP_KEEPCNT, 3))
+                elif hasattr(_socket, "TCP_KEEPALIVE"):
+                    # macOS (uses TCP_KEEPALIVE instead of TCP_KEEPIDLE)
+                    _sock_opts.append((_socket.IPPROTO_TCP, _socket.TCP_KEEPALIVE, 30))
+                client_kwargs["http_client"] = _httpx.Client(
+                    transport=_httpx.HTTPTransport(socket_options=_sock_opts),
+                )
+            except Exception:
+                pass  # Fall through to default transport if socket opts fail
         client = OpenAI(**client_kwargs)
         logger.info(
             "OpenAI client created (%s, shared=%s) %s",