fix: downgrade gateway not-routed log to debug, add Bedrock UI note, add sanitizer parity

- Downgrade logger.warning to logger.debug in gateway_overrides for
  not-routed providers and missing API key (Bedrock is the default
  provider in this fork, so these are expected steady states)
- Add Bedrock to the LLMGatewaySection route-toggle description so
  admins know it is not routed through the gateway
- Add SanitizeOpenAIResponsesMiddleware to chat.py for parity with
  server.py and reviewer.py
- Restore the Bedrock region comment in model.py that explains the
  AWS_REGION / AWS_DEFAULT_REGION precedence

Refs #138

agent/chat.py

@@ -33,6 +33,7 @@ from .dashboard.team_settings import get_effective_gateway_enabled, get_team_def
 from .middleware import (
     ExcludeToolsMiddleware,
     SanitizeFireworksMessagesMiddleware,
+    SanitizeOpenAIResponsesMiddleware,
     SanitizeThinkingBlocksMiddleware,
     SanitizeToolInputsMiddleware,
     ToolErrorMiddleware,
@@ -153,6 +154,7 @@ async def get_chat_agent(config: RunnableConfig) -> Pregel:
             ModelCallLimitMiddleware(run_limit=CHAT_MODEL_CALL_LIMIT, exit_behavior="end"),
             ToolErrorMiddleware(),
             ExcludeToolsMiddleware(excluded=_EXCLUDED_TOOLS),
+            SanitizeOpenAIResponsesMiddleware(),
             SanitizeFireworksMessagesMiddleware(),
             SanitizeThinkingBlocksMiddleware(),
         ],

agent/utils/gateway.py

@@ -102,14 +102,14 @@ def gateway_overrides(model_id: str) -> dict[str, object] | None:
     provider = _provider_of(model_id)
     path = _GATEWAY_PROVIDER_PATHS.get(provider)
     if path is None:
-        logger.warning(
+        logger.debug(
             "LangSmith gateway enabled but provider %r is not routed; calling it directly",
             provider,
         )
         return None
     api_key = _langsmith_api_key()
     if not api_key:
-        logger.warning(
+        logger.debug(
             "LangSmith gateway enabled but no LANGSMITH_GATEWAY_API_KEY or "
             "LANGSMITH_API_KEY(_PROD) is set; "
             "calling the provider directly"

agent/utils/model.py

@@ -94,6 +94,9 @@ def make_model(model_id: str, *, use_gateway: bool | None = None, **kwargs: Unpa
         model_kwargs["base_url"] = OPENAI_RESPONSES_WS_BASE_URL
         model_kwargs["use_responses_api"] = True
     elif model_id.startswith("bedrock_converse:"):
+        # Resolve region with the same precedence validate_local_dev_llm_config
+        # accepts (AWS_REGION or AWS_DEFAULT_REGION), so the validated value
+        # is the one actually used.
         model_kwargs.setdefault(
             "region_name",
             os.environ.get("AWS_REGION") or os.environ.get("AWS_DEFAULT_REGION") or "us-east-1",

ui/src/routes/admin.tsx

@@ -595,7 +595,7 @@ function LLMGatewaySection() {
       <div className="divide-y divide-border">
         <SettingsRow
           label="Route through the gateway"
-          description="Inherit uses the LANGSMITH_GATEWAY_ENABLED deployment default. OpenAI, Anthropic, Fireworks, and Google Gemini are routed; other providers call the provider directly."
+          description="Inherit uses the LANGSMITH_GATEWAY_ENABLED deployment default. OpenAI, Anthropic, Fireworks, and Google Gemini are routed through the gateway. Bedrock (AWS) calls the provider directly and is not routed; other providers not listed also call the provider directly."
           control={
             <Select
               value={mode}