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

agent/auxiliary_client.py

@@ -815,8 +815,9 @@ def _resolve_api_key_provider() -> Tuple[Optional[OpenAI], Optional[str]]:
                 continue  # skip provider if we don't know a valid aux model
             logger.debug("Auxiliary text client: %s (%s) via pool", pconfig.name, model)
             if provider_id == "gemini":
-                from agent.gemini_native_adapter import GeminiNativeClient
+                from agent.gemini_native_adapter import GeminiNativeClient, is_native_gemini_base_url
 
+                if is_native_gemini_base_url(base_url):
                     return GeminiNativeClient(api_key=api_key, base_url=base_url), model
             extra = {}
             if "api.kimi.com" in base_url.lower():
@@ -840,8 +841,9 @@ def _resolve_api_key_provider() -> Tuple[Optional[OpenAI], Optional[str]]:
             continue  # skip provider if we don't know a valid aux model
         logger.debug("Auxiliary text client: %s (%s)", pconfig.name, model)
         if provider_id == "gemini":
-            from agent.gemini_native_adapter import GeminiNativeClient
+            from agent.gemini_native_adapter import GeminiNativeClient, is_native_gemini_base_url
 
+            if is_native_gemini_base_url(base_url):
                 return GeminiNativeClient(api_key=api_key, base_url=base_url), model
         extra = {}
         if "api.kimi.com" in base_url.lower():
@@ -1703,8 +1705,9 @@ def resolve_provider_client(
         final_model = _normalize_resolved_model(model or default_model, provider)
 
         if provider == "gemini":
-            from agent.gemini_native_adapter import GeminiNativeClient
+            from agent.gemini_native_adapter import GeminiNativeClient, is_native_gemini_base_url
 
+            if is_native_gemini_base_url(base_url):
                 client = GeminiNativeClient(api_key=api_key, base_url=base_url)
                 logger.debug("resolve_provider_client: %s (%s)", provider, final_model)
                 return (_to_async_client(client, final_model) if async_mode

agent/gemini_native_adapter.py

@@ -32,6 +32,16 @@ logger = logging.getLogger(__name__)
 DEFAULT_GEMINI_BASE_URL = "https://generativelanguage.googleapis.com/v1beta"
 
 
+def is_native_gemini_base_url(base_url: str) -> bool:
+    """Return True when the endpoint speaks Gemini's native REST API."""
+    normalized = str(base_url or "").strip().rstrip("/").lower()
+    if not normalized:
+        return False
+    if "generativelanguage.googleapis.com" not in normalized:
+        return False
+    return not normalized.endswith("/openai")
+
+
 class GeminiAPIError(Exception):
     """Error shape compatible with Hermes retry/error classification."""
 
@@ -520,7 +530,7 @@ def translate_stream_event(event: Dict[str, Any], model: str, tool_call_indices:
     parts = ((cand.get("content") or {}).get("parts") or []) if isinstance(cand, dict) else []
     chunks: List[_GeminiStreamChunk] = []
 
-    for part in parts:
+    for part_index, part in enumerate(parts):
         if not isinstance(part, dict):
             continue
         if part.get("thought") is True and isinstance(part.get("text"), str):
@@ -536,14 +546,30 @@ def translate_stream_event(event: Dict[str, Any], model: str, tool_call_indices:
             except (TypeError, ValueError):
                 args_str = "{}"
             thought_signature = part.get("thoughtSignature") if isinstance(part.get("thoughtSignature"), str) else ""
-            call_key = json.dumps({"name": name, "args": args_str, "thought_signature": thought_signature}, sort_keys=True)
+            call_key = json.dumps(
+                {
+                    "part_index": part_index,
+                    "name": name,
+                    "thought_signature": thought_signature,
+                },
+                sort_keys=True,
+            )
             slot = tool_call_indices.get(call_key)
             if slot is None:
                 slot = {
                     "index": len(tool_call_indices),
                     "id": f"call_{uuid.uuid4().hex[:12]}",
+                    "last_arguments": "",
                 }
                 tool_call_indices[call_key] = slot
+            emitted_arguments = args_str
+            last_arguments = str(slot.get("last_arguments") or "")
+            if last_arguments:
+                if args_str == last_arguments:
+                    emitted_arguments = ""
+                elif args_str.startswith(last_arguments):
+                    emitted_arguments = args_str[len(last_arguments):]
+            slot["last_arguments"] = args_str
             chunks.append(
                 _make_stream_chunk(
                     model=model,
@@ -551,7 +577,7 @@ def translate_stream_event(event: Dict[str, Any], model: str, tool_call_indices:
                         "index": slot["index"],
                         "id": slot["id"],
                         "name": name,
-                        "arguments": args_str,
+                        "arguments": emitted_arguments,
                         "extra_content": _tool_call_extra_from_part(part),
                     },
                 )
@@ -672,6 +698,7 @@ class GeminiNativeClient:
         base_url: Optional[str] = None,
         default_headers: Optional[Dict[str, str]] = None,
         timeout: Any = None,
+        http_client: Optional[httpx.Client] = None,
         **_: Any,
     ) -> None:
         self.api_key = api_key
@@ -682,7 +709,9 @@ class GeminiNativeClient:
         self._default_headers = dict(default_headers or {})
         self.chat = _GeminiChatNamespace(self)
         self.is_closed = False
-        self._http = httpx.Client(timeout=timeout or httpx.Timeout(connect=15.0, read=600.0, write=30.0, pool=30.0))
+        self._http = http_client or httpx.Client(
+            timeout=timeout or httpx.Timeout(connect=15.0, read=600.0, write=30.0, pool=30.0)
+        )
 
     def close(self) -> None:
         self.is_closed = True
@@ -707,6 +736,13 @@ class GeminiNativeClient:
         headers.update(self._default_headers)
         return headers
 
+    @staticmethod
+    def _advance_stream_iterator(iterator: Iterator[_GeminiStreamChunk]) -> tuple[bool, Optional[_GeminiStreamChunk]]:
+        try:
+            return False, next(iterator)
+        except StopIteration:
+            return True, None
+
     def _create_chat_completion(
         self,
         *,
@@ -767,7 +803,7 @@ class GeminiNativeClient:
                     if response.status_code != 200:
                         response.read()
                         raise gemini_http_error(response)
-                    tool_call_indices: Dict[str, int] = {}
+                    tool_call_indices: Dict[str, Dict[str, Any]] = {}
                     for event in _iter_sse_events(response):
                         for chunk in translate_stream_event(event, model, tool_call_indices):
                             yield chunk
@@ -790,7 +826,19 @@ class AsyncGeminiNativeClient:
         self.chat = _AsyncGeminiChatNamespace(self)
 
     async def _create_chat_completion(self, **kwargs: Any) -> Any:
-        return await asyncio.to_thread(self._sync.chat.completions.create, **kwargs)
+        stream = bool(kwargs.get("stream"))
+        result = await asyncio.to_thread(self._sync.chat.completions.create, **kwargs)
+        if not stream:
+            return result
+
+        async def _async_stream() -> Any:
+            while True:
+                done, chunk = await asyncio.to_thread(self._sync._advance_stream_iterator, result)
+                if done:
+                    break
+                yield chunk
+
+        return _async_stream()
 
     async def close(self) -> None:
         await asyncio.to_thread(self._sync.close)

plans/gemini-oauth-provider.md

@@ -4,7 +4,7 @@
 Add a first-class `gemini` provider that authenticates via Google OAuth, using the standard Gemini API (not Cloud Code Assist). Users who have a Google AI subscription or Gemini API access can authenticate through the browser without needing to manually copy API keys.
 
 ## Architecture Decision
-- **Path A (chosen):** Standard Gemini API at `generativelanguage.googleapis.com/v1beta/openai/`
+- **Path A (chosen):** Standard Gemini API at `generativelanguage.googleapis.com/v1beta`
 - **NOT Path B:** Cloud Code Assist (`cloudcode-pa.googleapis.com`) — rate-limited free tier, internal API, account ban risk
 - Standard `chat_completions` api_mode via OpenAI SDK — no new api_mode needed
 - Our own OAuth credentials — NOT sharing tokens with Gemini CLI
@@ -32,9 +32,9 @@ Add a first-class `gemini` provider that authenticates via Google OAuth, using t
 - File locking for concurrent access (multiple agent sessions)
 
 ## API Integration
-- Base URL: `https://generativelanguage.googleapis.com/v1beta/openai/`
+- Base URL: `https://generativelanguage.googleapis.com/v1beta`
-- Auth: `Authorization: Bearer <access_token>` (passed as `api_key` to OpenAI SDK)
+- Auth: native Gemini API authentication handled by the provider adapter
-- api_mode: `chat_completions` (standard)
+- api_mode: `chat_completions` (standard facade over native transport)
 - Models: gemini-2.5-pro, gemini-2.5-flash, gemini-2.0-flash, etc.
 
 ## Files to Create/Modify

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
@@ -4746,12 +4770,18 @@ 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
 
+            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"}
+                    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",
@@ -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:
+            keepalive_http = self._build_keepalive_http_client()
-                import httpx as _httpx
+            if keepalive_http is not None:
-                import socket as _socket
+                client_kwargs["http_client"] = keepalive_http
-                _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
         client = OpenAI(**client_kwargs)
         logger.info(
             "OpenAI client created (%s, shared=%s) %s",

tests/agent/test_gemini_native_adapter.py

@@ -186,6 +186,43 @@ def test_native_http_error_keeps_status_and_retry_after():
     assert "quota exhausted" in str(err)
 
 
+def test_native_client_accepts_injected_http_client():
+    from agent.gemini_native_adapter import GeminiNativeClient
+
+    injected = SimpleNamespace(close=lambda: None)
+    client = GeminiNativeClient(api_key="AIza-test", http_client=injected)
+    assert client._http is injected
+
+
+@pytest.mark.asyncio
+async def test_async_native_client_streams_without_requiring_async_iterator_from_sync_client():
+    from agent.gemini_native_adapter import AsyncGeminiNativeClient
+
+    chunk = SimpleNamespace(choices=[SimpleNamespace(delta=SimpleNamespace(content="hi"), finish_reason=None)])
+    sync_stream = iter([chunk])
+
+    def _advance(iterator):
+        try:
+            return False, next(iterator)
+        except StopIteration:
+            return True, None
+
+    sync_client = SimpleNamespace(
+        api_key="AIza-test",
+        base_url="https://generativelanguage.googleapis.com/v1beta",
+        chat=SimpleNamespace(completions=SimpleNamespace(create=lambda **kwargs: sync_stream)),
+        _advance_stream_iterator=_advance,
+        close=lambda: None,
+    )
+
+    async_client = AsyncGeminiNativeClient(sync_client)
+    stream = await async_client.chat.completions.create(stream=True)
+    collected = []
+    async for item in stream:
+        collected.append(item)
+    assert collected == [chunk]
+
+
 def test_stream_event_translation_emits_tool_call_delta_with_stable_index():
     from agent.gemini_native_adapter import translate_stream_event
 
@@ -209,4 +246,30 @@ def test_stream_event_translation_emits_tool_call_delta_with_stable_index():
     assert first[0].choices[0].delta.tool_calls[0].index == 0
     assert second[0].choices[0].delta.tool_calls[0].index == 0
     assert first[0].choices[0].delta.tool_calls[0].id == second[0].choices[0].delta.tool_calls[0].id
+    assert first[0].choices[0].delta.tool_calls[0].function.arguments == '{"q": "abc"}'
+    assert second[0].choices[0].delta.tool_calls[0].function.arguments == ""
     assert first[-1].choices[0].finish_reason == "tool_calls"
+
+
+def test_stream_event_translation_keeps_identical_calls_in_distinct_parts():
+    from agent.gemini_native_adapter import translate_stream_event
+
+    event = {
+        "candidates": [
+            {
+                "content": {
+                    "parts": [
+                        {"functionCall": {"name": "search", "args": {"q": "abc"}}},
+                        {"functionCall": {"name": "search", "args": {"q": "abc"}}},
+                    ]
+                },
+                "finishReason": "STOP",
+            }
+        ]
+    }
+
+    chunks = translate_stream_event(event, model="gemini-2.5-flash", tool_call_indices={})
+    tool_chunks = [chunk for chunk in chunks if chunk.choices[0].delta.tool_calls]
+    assert tool_chunks[0].choices[0].delta.tool_calls[0].index == 0
+    assert tool_chunks[1].choices[0].delta.tool_calls[0].index == 1
+    assert tool_chunks[0].choices[0].delta.tool_calls[0].id != tool_chunks[1].choices[0].delta.tool_calls[0].id

tests/hermes_cli/test_config_validation.py

@@ -13,7 +13,7 @@ class TestCustomProvidersValidation:
         issues = validate_config_structure({
             "custom_providers": {
                 "name": "Generativelanguage.googleapis.com",
-                "base_url": "https://generativelanguage.googleapis.com/v1beta/openai",
+                "base_url": "https://generativelanguage.googleapis.com/v1beta",
                 "api_key": "xxx",
                 "model": "models/gemini-2.5-flash",
                 "rate_limit_delay": 2.0,

tests/hermes_cli/test_gemini_provider.py

@@ -210,8 +210,10 @@ class TestGeminiAgentInit:
     def test_gemini_agent_uses_native_client(self, monkeypatch):
         monkeypatch.setenv("GOOGLE_API_KEY", "AIzaSy_REAL_KEY")
         with patch("agent.gemini_native_adapter.GeminiNativeClient") as mock_client, \
-             patch("run_agent.OpenAI") as mock_openai:
+             patch("run_agent.OpenAI") as mock_openai, \
+             patch("run_agent.ContextCompressor") as mock_compressor:
             mock_client.return_value = MagicMock()
+            mock_compressor.return_value = MagicMock(context_length=1048576, threshold_tokens=524288)
             from run_agent import AIAgent
             AIAgent(
                 model="gemini-2.5-flash",
@@ -222,6 +224,38 @@ class TestGeminiAgentInit:
         assert mock_client.called
         mock_openai.assert_not_called()
 
+    def test_gemini_custom_base_url_keeps_openai_client(self, monkeypatch):
+        monkeypatch.setenv("GOOGLE_API_KEY", "AIzaSy_REAL_KEY")
+        with patch("agent.gemini_native_adapter.GeminiNativeClient") as mock_client, \
+             patch("run_agent.OpenAI") as mock_openai, \
+             patch("run_agent.ContextCompressor") as mock_compressor:
+            mock_openai.return_value = MagicMock()
+            mock_compressor.return_value = MagicMock(context_length=128000, threshold_tokens=64000)
+            from run_agent import AIAgent
+            AIAgent(
+                model="gemini-2.5-flash",
+                provider="gemini",
+                api_key="AIzaSy_REAL_KEY",
+                base_url="https://proxy.example.com/v1",
+            )
+        mock_openai.assert_called_once()
+
+    def test_gemini_openai_compat_base_url_keeps_openai_client(self, monkeypatch):
+        monkeypatch.setenv("GOOGLE_API_KEY", "AIzaSy_REAL_KEY")
+        with patch("agent.gemini_native_adapter.GeminiNativeClient") as mock_client, \
+             patch("run_agent.OpenAI") as mock_openai, \
+             patch("run_agent.ContextCompressor") as mock_compressor:
+            mock_openai.return_value = MagicMock()
+            mock_compressor.return_value = MagicMock(context_length=1048576, threshold_tokens=524288)
+            from run_agent import AIAgent
+            AIAgent(
+                model="gemini-2.5-flash",
+                provider="gemini",
+                api_key="AIzaSy_REAL_KEY",
+                base_url="https://generativelanguage.googleapis.com/v1beta/openai",
+            )
+        mock_openai.assert_called_once()
+
     def test_gemini_resolve_provider_client_uses_native_client(self, monkeypatch):
         """resolve_provider_client('gemini') should build GeminiNativeClient."""
         monkeypatch.setenv("GEMINI_API_KEY", "AIzaSy_TEST_KEY")
@@ -233,6 +267,16 @@ class TestGeminiAgentInit:
         assert mock_client.called
         mock_openai.assert_not_called()
 
+    def test_gemini_resolve_provider_client_keeps_openai_for_non_native_base_url(self, monkeypatch):
+        monkeypatch.setenv("GOOGLE_API_KEY", "AIzaSy_TEST_KEY")
+        monkeypatch.setenv("GEMINI_BASE_URL", "https://proxy.example.com/v1")
+        with patch("agent.gemini_native_adapter.GeminiNativeClient") as mock_client, \
+             patch("agent.auxiliary_client.OpenAI") as mock_openai:
+            mock_openai.return_value = MagicMock()
+            from agent.auxiliary_client import resolve_provider_client
+            resolve_provider_client("gemini")
+        mock_openai.assert_called_once()
+
 
 # ── models.dev Integration ──