refactor: streamline API key retrieval in transcription and TTS tools

- Removed fallback to OPENAI_API_KEY in favor of exclusively using VOICE_TOOLS_OPENAI_KEY for improved clarity and consistency.
- Updated environment variable checks to ensure only VOICE_TOOLS_OPENAI_KEY is considered, enhancing error handling and messaging.

tools/transcription_tools.py

@@ -50,10 +50,7 @@ def transcribe_audio(file_path: str, model: Optional[str] = None) -> dict:
           - "transcript" (str): The transcribed text (empty on failure)
           - "error" (str, optional): Error message if success is False
     """
-    # Use VOICE_TOOLS_OPENAI_KEY to avoid interference with the OpenAI SDK's
+    api_key = os.getenv("VOICE_TOOLS_OPENAI_KEY")
-    # auto-detection of OPENAI_API_KEY (which would break OpenRouter calls).
-    # Falls back to OPENAI_API_KEY for backward compatibility.
-    api_key = os.getenv("VOICE_TOOLS_OPENAI_KEY") or os.getenv("OPENAI_API_KEY")
     if not api_key:
         return {
             "success": False,

tools/tts_tool.py

@@ -210,7 +210,7 @@ def _generate_openai_tts(text: str, output_path: str, tts_config: Dict[str, Any]
     Returns:
         Path to the saved audio file.
     """
-    api_key = os.getenv("VOICE_TOOLS_OPENAI_KEY") or os.getenv("OPENAI_API_KEY", "")
+    api_key = os.getenv("VOICE_TOOLS_OPENAI_KEY", "")
     if not api_key:
         raise ValueError("VOICE_TOOLS_OPENAI_KEY not set. Get one at https://platform.openai.com/api-keys")
 
@@ -392,7 +392,7 @@ def check_tts_requirements() -> bool:
         return True
     if _HAS_ELEVENLABS and os.getenv("ELEVENLABS_API_KEY"):
         return True
-    if _HAS_OPENAI and (os.getenv("VOICE_TOOLS_OPENAI_KEY") or os.getenv("OPENAI_API_KEY")):
+    if _HAS_OPENAI and os.getenv("VOICE_TOOLS_OPENAI_KEY"):
         return True
     return False
 
@@ -409,7 +409,7 @@ if __name__ == "__main__":
     print(f"  ElevenLabs: {'✅ installed' if _HAS_ELEVENLABS else '❌ not installed (pip install elevenlabs)'}")
     print(f"    API Key:  {'✅ set' if os.getenv('ELEVENLABS_API_KEY') else '❌ not set'}")
     print(f"  OpenAI:     {'✅ installed' if _HAS_OPENAI else '❌ not installed'}")
-    print(f"    API Key:  {'✅ set' if (os.getenv('VOICE_TOOLS_OPENAI_KEY') or os.getenv('OPENAI_API_KEY')) else '❌ not set'}")
+    print(f"    API Key:  {'✅ set' if os.getenv('VOICE_TOOLS_OPENAI_KEY') else '❌ not set (VOICE_TOOLS_OPENAI_KEY)'}")
     print(f"  ffmpeg:     {'✅ found' if _has_ffmpeg() else '❌ not found (needed for Telegram Opus)'}")
     print(f"\n  Output dir: {DEFAULT_OUTPUT_DIR}")