From 019eaff2251c940dc10af2bfbe197eb7c2f9eb07 Mon Sep 17 00:00:00 2001
From: Xubin Ren <xubinrencs@gmail.com>
Date: Mon, 6 Apr 2026 06:13:43 +0000
Subject: [PATCH] simplify: remove transcription fallback, respect explicit
 config
MIME-Version: 1.0
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Configured provider is the only one used — no silent fallback.

Made-with: Cursor
---
 nanobot/channels/base.py    | 24 ++++++------------------
 nanobot/channels/manager.py |  3 ---
 2 files changed, 6 insertions(+), 21 deletions(-)

diff --git a/nanobot/channels/base.py b/nanobot/channels/base.py
index 27d0b07a8..dd29c0851 100644
--- a/nanobot/channels/base.py
+++ b/nanobot/channels/base.py
@@ -24,7 +24,6 @@ class BaseChannel(ABC):
     display_name: str = "Base"
     transcription_provider: str = "groq"
     transcription_api_key: str = ""
-    _transcription_fallback_key: str = ""
 
     def __init__(self, config: Any, bus: MessageBus):
         """
@@ -39,30 +38,19 @@ class BaseChannel(ABC):
         self._running = False
 
     async def transcribe_audio(self, file_path: str | Path) -> str:
-        """Transcribe an audio file via Whisper. Falls back to the other provider on failure."""
+        """Transcribe an audio file via Whisper (OpenAI or Groq). Returns empty string on failure."""
         if not self.transcription_api_key:
             return ""
-        result = await self._try_transcribe(self.transcription_provider, self.transcription_api_key, file_path)
-        if result:
-            return result
-        fallback = "groq" if self.transcription_provider == "openai" else "openai"
-        if self._transcription_fallback_key:
-            logger.info("{}: trying {} fallback for transcription", self.name, fallback)
-            return await self._try_transcribe(fallback, self._transcription_fallback_key, file_path)
-        return ""
-
-    async def _try_transcribe(self, provider: str, api_key: str, file_path: str | Path) -> str:
-        """Attempt transcription with a single provider. Returns empty string on failure."""
         try:
-            if provider == "openai":
+            if self.transcription_provider == "openai":
                 from nanobot.providers.transcription import OpenAITranscriptionProvider
-                p = OpenAITranscriptionProvider(api_key=api_key)
+                provider = OpenAITranscriptionProvider(api_key=self.transcription_api_key)
             else:
                 from nanobot.providers.transcription import GroqTranscriptionProvider
-                p = GroqTranscriptionProvider(api_key=api_key)
-            return await p.transcribe(file_path)
+                provider = GroqTranscriptionProvider(api_key=self.transcription_api_key)
+            return await provider.transcribe(file_path)
         except Exception as e:
-            logger.warning("{}: {} transcription failed: {}", self.name, provider, e)
+            logger.warning("{}: audio transcription failed: {}", self.name, e)
             return ""
 
     async def login(self, force: bool = False) -> bool:
diff --git a/nanobot/channels/manager.py b/nanobot/channels/manager.py
index d7bb4ef2d..aaec5e335 100644
--- a/nanobot/channels/manager.py
+++ b/nanobot/channels/manager.py
@@ -41,8 +41,6 @@ class ChannelManager:
 
         transcription_provider = self.config.channels.transcription_provider
         transcription_key = self._resolve_transcription_key(transcription_provider)
-        fallback_provider = "groq" if transcription_provider == "openai" else "openai"
-        fallback_key = self._resolve_transcription_key(fallback_provider)
 
         for name, cls in discover_all().items():
             section = getattr(self.config.channels, name, None)
@@ -59,7 +57,6 @@ class ChannelManager:
                 channel = cls(section, self.bus)
                 channel.transcription_provider = transcription_provider
                 channel.transcription_api_key = transcription_key
-                channel._transcription_fallback_key = fallback_key
                 self.channels[name] = channel
                 logger.info("{} channel enabled", cls.display_name)
             except Exception as e: