refactor: unify voice transcription config across all channels

- Move transcriptionProvider to global channels config (not per-channel)
- ChannelManager auto-resolves API key from matching provider config
- BaseChannel gets transcription_provider attribute, no more getattr hack
- Remove redundant transcription fields from WhatsAppConfig
- Update README: document transcriptionProvider, update provider table

Made-with: Cursor

README.md

@@ -900,7 +900,7 @@ IMAP_PASSWORD=your-password-here
 ### Providers
 
 > [!TIP]
-> - **Groq** provides free voice transcription via Whisper. If configured, Telegram voice messages will be automatically transcribed.
+> - **Voice transcription**: Voice messages (Telegram, WhatsApp) are automatically transcribed using Whisper. By default Groq is used (free tier). Set `"transcriptionProvider": "openai"` under `channels` to use OpenAI Whisper instead — the API key is picked from the matching provider config.
 > - **MiniMax Coding Plan**: Exclusive discount links for the nanobot community: [Overseas](https://platform.minimax.io/subscribe/coding-plan?code=9txpdXw04g&source=link) · [Mainland China](https://platform.minimaxi.com/subscribe/token-plan?code=GILTJpMTqZ&source=link)
 > - **MiniMax (Mainland China)**: If your API key is from MiniMax's mainland China platform (minimaxi.com), set `"apiBase": "https://api.minimaxi.com/v1"` in your minimax provider config.
 > - **VolcEngine / BytePlus Coding Plan**: Use dedicated providers `volcengineCodingPlan` or `byteplusCodingPlan` instead of the pay-per-use `volcengine` / `byteplus` providers.
@@ -916,9 +916,9 @@ IMAP_PASSWORD=your-password-here
 | `byteplus` | LLM (VolcEngine international, pay-per-use) | [Coding Plan](https://www.byteplus.com/en/activity/codingplan?utm_campaign=nanobot&utm_content=nanobot&utm_medium=devrel&utm_source=OWO&utm_term=nanobot) · [byteplus.com](https://www.byteplus.com) |
 | `anthropic` | LLM (Claude direct) | [console.anthropic.com](https://console.anthropic.com) |
 | `azure_openai` | LLM (Azure OpenAI) | [portal.azure.com](https://portal.azure.com) |
-| `openai` | LLM (GPT direct) | [platform.openai.com](https://platform.openai.com) |
+| `openai` | LLM + Voice transcription (Whisper) | [platform.openai.com](https://platform.openai.com) |
 | `deepseek` | LLM (DeepSeek direct) | [platform.deepseek.com](https://platform.deepseek.com) |
-| `groq` | LLM + **Voice transcription** (Whisper) | [console.groq.com](https://console.groq.com) |
+| `groq` | LLM + Voice transcription (Whisper, default) | [console.groq.com](https://console.groq.com) |
 | `minimax` | LLM (MiniMax direct) | [platform.minimaxi.com](https://platform.minimaxi.com) |
 | `gemini` | LLM (Gemini direct) | [aistudio.google.com](https://aistudio.google.com) |
 | `aihubmix` | LLM (API gateway, access to all models) | [aihubmix.com](https://aihubmix.com) |
@@ -1233,6 +1233,7 @@ Global settings that apply to all channels. Configure under the `channels` secti
     "sendProgress": true,
     "sendToolHints": false,
     "sendMaxRetries": 3,
+    "transcriptionProvider": "groq",
     "telegram": { ... }
   }
 }
@@ -1243,6 +1244,7 @@ Global settings that apply to all channels. Configure under the `channels` secti
 | `sendProgress` | `true` | Stream agent's text progress to the channel |
 | `sendToolHints` | `false` | Stream tool-call hints (e.g. `read_file("…")`) |
 | `sendMaxRetries` | `3` | Max delivery attempts per outbound message, including the initial send (0-10 configured, minimum 1 actual attempt) |
+| `transcriptionProvider` | `"groq"` | Voice transcription backend: `"groq"` (free tier, default) or `"openai"`. API key is auto-resolved from the matching provider config. |
 
 #### Retry Behavior
 

nanobot/channels/base.py

@@ -22,6 +22,7 @@ class BaseChannel(ABC):
 
     name: str = "base"
     display_name: str = "Base"
+    transcription_provider: str = "groq"
     transcription_api_key: str = ""
 
     def __init__(self, config: Any, bus: MessageBus):
@@ -41,8 +42,7 @@ class BaseChannel(ABC):
         if not self.transcription_api_key:
             return ""
         try:
-            provider_name = getattr(self, "transcription_provider", "groq")
-            if provider_name == "openai":
+            if self.transcription_provider == "openai":
                 from nanobot.providers.transcription import OpenAITranscriptionProvider
                 provider = OpenAITranscriptionProvider(api_key=self.transcription_api_key)
             else:

nanobot/channels/manager.py

@@ -39,7 +39,8 @@ class ChannelManager:
         """Initialize channels discovered via pkgutil scan + entry_points plugins."""
         from nanobot.channels.registry import discover_all
 
-        groq_key = self.config.providers.groq.api_key
+        transcription_provider = self.config.channels.transcription_provider
+        transcription_key = self._resolve_transcription_key(transcription_provider)
 
         for name, cls in discover_all().items():
             section = getattr(self.config.channels, name, None)
@@ -54,7 +55,8 @@ class ChannelManager:
                 continue
             try:
                 channel = cls(section, self.bus)
-                channel.transcription_api_key = groq_key
+                channel.transcription_provider = transcription_provider
+                channel.transcription_api_key = transcription_key
                 self.channels[name] = channel
                 logger.info("{} channel enabled", cls.display_name)
             except Exception as e:
@@ -62,6 +64,12 @@ class ChannelManager:
 
         self._validate_allow_from()
 
+    def _resolve_transcription_key(self, provider: str) -> str:
+        """Pick the API key for the configured transcription provider."""
+        if provider == "openai":
+            return self.config.providers.openai.api_key
+        return self.config.providers.groq.api_key
+
     def _validate_allow_from(self) -> None:
         for name, ch in self.channels.items():
             if getattr(ch.config, "allow_from", None) == []:

nanobot/channels/whatsapp.py

@@ -27,8 +27,6 @@ class WhatsAppConfig(Base):
     bridge_url: str = "ws://localhost:3001"
     bridge_token: str = ""
     allow_from: list[str] = Field(default_factory=list)
-    transcription_provider: str = "openai"  # openai or groq
-    transcription_api_key: str = ""
     group_policy: Literal["open", "mention"] = "open"  # "open" responds to all, "mention" only when @mentioned
 
 
@@ -77,8 +75,6 @@ class WhatsAppChannel(BaseChannel):
         self._ws = None
         self._connected = False
         self._processed_message_ids: OrderedDict[str, None] = OrderedDict()
-        self.transcription_api_key = config.transcription_api_key
-        self.transcription_provider = config.transcription_provider
         self._bridge_token: str | None = None
 
     def _effective_bridge_token(self) -> str:

nanobot/config/schema.py

@@ -28,6 +28,7 @@ class ChannelsConfig(Base):
     send_progress: bool = True  # stream agent's text progress to the channel
     send_tool_hints: bool = False  # stream tool-call hints (e.g. read_file("…"))
     send_max_retries: int = Field(default=3, ge=0, le=10)  # Max delivery attempts (initial send included)
+    transcription_provider: str = "groq"  # Voice transcription backend: "groq" or "openai"
 
 
 class DreamConfig(Base):

tests/channels/test_whatsapp_channel.py

@@ -166,10 +166,9 @@ async def test_group_policy_mention_accepts_mentioned_group_message():
 @pytest.mark.asyncio
 async def test_voice_message_transcription_uses_media_path():
     """Voice messages are transcribed when media path is available."""
-    ch = WhatsAppChannel(
-        {"enabled": True, "transcriptionProvider": "openai", "transcriptionApiKey": "sk-test"},
-        MagicMock(),
-    )
+    ch = WhatsAppChannel({"enabled": True}, MagicMock())
+    ch.transcription_provider = "openai"
+    ch.transcription_api_key = "sk-test"
     ch._handle_message = AsyncMock()
     ch.transcribe_audio = AsyncMock(return_value="Hello world")