fix(gemini): tighten native routing and streaming replay

- only use the native adapter for the canonical Gemini native endpoint
- keep custom and /openai base URLs on the OpenAI-compatible path
- preserve Hermes keepalive transport injection for native Gemini clients
- stabilize streaming tool-call replay across repeated SSE events
- add follow-up tests for base_url precedence, async streaming, and duplicate tool-call chunks

run_agent.py

@@ -4705,6 +4705,30 @@ class AIAgent:
             return bool(getattr(http_client, "is_closed", False))
         return False
 
+    @staticmethod
+    def _build_keepalive_http_client() -> Any:
+        try:
+            import httpx as _httpx
+            import socket as _socket
+
+            _sock_opts = [(_socket.SOL_SOCKET, _socket.SO_KEEPALIVE, 1)]
+            if hasattr(_socket, "TCP_KEEPIDLE"):
+                _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"):
+                _sock_opts.append((_socket.IPPROTO_TCP, _socket.TCP_KEEPALIVE, 30))
+            # When a custom transport is provided, httpx won't auto-read proxy
+            # from env vars (allow_env_proxies = trust_env and transport is None).
+            # Explicitly read proxy settings to ensure HTTP_PROXY/HTTPS_PROXY work.
+            _proxy = _get_proxy_from_env()
+            return _httpx.Client(
+                transport=_httpx.HTTPTransport(socket_options=_sock_opts),
+                proxy=_proxy,
+            )
+        except Exception:
+            return None
+
     def _create_openai_client(self, client_kwargs: dict, *, reason: str, shared: bool) -> Any:
         from agent.auxiliary_client import _validate_base_url, _validate_proxy_env_urls
         # Treat client_kwargs as read-only. Callers pass self._client_kwargs (or shallow
@@ -4746,20 +4770,26 @@ class AIAgent:
             )
             return client
         if self.provider == "gemini":
-            from agent.gemini_native_adapter import GeminiNativeClient
+            from agent.gemini_native_adapter import GeminiNativeClient, is_native_gemini_base_url
 
-            safe_kwargs = {
-                k: v for k, v in client_kwargs.items()
-                if k in {"api_key", "base_url", "default_headers", "timeout"}
-            }
-            client = GeminiNativeClient(**safe_kwargs)
-            logger.info(
-                "Gemini native client created (%s, shared=%s) %s",
-                reason,
-                shared,
-                self._client_log_context(),
-            )
-            return client
+            base_url = str(client_kwargs.get("base_url", "") or "")
+            if is_native_gemini_base_url(base_url):
+                safe_kwargs = {
+                    k: v for k, v in client_kwargs.items()
+                    if k in {"api_key", "base_url", "default_headers", "timeout", "http_client"}
+                }
+                if "http_client" not in safe_kwargs:
+                    keepalive_http = self._build_keepalive_http_client()
+                    if keepalive_http is not None:
+                        safe_kwargs["http_client"] = keepalive_http
+                client = GeminiNativeClient(**safe_kwargs)
+                logger.info(
+                    "Gemini native client created (%s, shared=%s) %s",
+                    reason,
+                    shared,
+                    self._client_log_context(),
+                )
+                return client
         # Inject TCP keepalives so the kernel detects dead provider connections
         # instead of letting them sit silently in CLOSE-WAIT (#10324).  Without
         # this, a peer that drops mid-stream leaves the socket in a state where
@@ -4778,28 +4808,9 @@ class AIAgent:
         # Tests in ``tests/run_agent/test_create_openai_client_reuse.py`` and
         # ``tests/run_agent/test_sequential_chats_live.py`` pin this invariant.
         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))
-                # When a custom transport is provided, httpx won't auto-read proxy
-                # from env vars (allow_env_proxies = trust_env and transport is None).
-                # Explicitly read proxy settings to ensure HTTP_PROXY/HTTPS_PROXY work.
-                _proxy = _get_proxy_from_env()
-                client_kwargs["http_client"] = _httpx.Client(
-                    transport=_httpx.HTTPTransport(socket_options=_sock_opts),
-                    proxy=_proxy,
-                )
-            except Exception:
-                pass  # Fall through to default transport if socket opts fail
+            keepalive_http = self._build_keepalive_http_client()
+            if keepalive_http is not None:
+                client_kwargs["http_client"] = keepalive_http
         client = OpenAI(**client_kwargs)
         logger.info(
             "OpenAI client created (%s, shared=%s) %s",