feat(auth) normalise the way in which we check whether a user has free/paid access to nous portal so we can expose behaviour and error messages accordingly.

tools/tts_tool.py

@@ -69,7 +69,12 @@ def get_env_value(name, default=None):
     value = _get_env_value(name)
     return default if value is None else value
 from tools.managed_tool_gateway import resolve_managed_tool_gateway
-from tools.tool_backend_helpers import managed_nous_tools_enabled, prefers_gateway, resolve_openai_audio_api_key
+from tools.tool_backend_helpers import (
+    managed_nous_tools_enabled,
+    nous_tool_gateway_unavailable_message,
+    prefers_gateway,
+    resolve_openai_audio_api_key,
+)
 from tools.xai_http import hermes_xai_user_agent
 
 # ---------------------------------------------------------------------------
@@ -2206,8 +2211,13 @@ def _resolve_openai_audio_client_config() -> tuple[str, str]:
     managed_gateway = resolve_managed_tool_gateway("openai-audio")
     if managed_gateway is None:
         message = "Neither VOICE_TOOLS_OPENAI_KEY nor OPENAI_API_KEY is set"
-        if managed_nous_tools_enabled():
-            message += ", and the managed OpenAI audio gateway is unavailable"
+        if managed_nous_tools_enabled() or prefers_gateway("tts"):
+            message += (
+                ". "
+                + nous_tool_gateway_unavailable_message(
+                    "managed OpenAI audio for TTS",
+                )
+            )
         raise ValueError(message)
 
     return managed_gateway.nous_user_token, urljoin(