Convert text to speech, saved to output/.

Tries Groq's playai-tts first (free tier, no credit card - requires GROQ_API_KEY), falling back to a fully local, keyless model (Kokoro-82M, Apache-2.0) if Groq is unavailable or the key isn't set. The local fallback always produces a .wav file regardless of output_format (Kokoro's native output), and requires the optional local-tts extra (uv sync --extra local-tts) plus the espeak-ng system package for full quality on non-trivial or non-English text.

Args: text: Text to speak. voice: Groq PlayAI voice name (e.g. "Fritz-PlayAI") - ignored by the local fallback, which always uses Kokoro's "af_heart" voice. output_format: "mp3" or "wav". Only honored on the Groq tier.

Transcribe a local audio file to text.

Tries Groq's whisper-large-v3-turbo first (free tier, no credit card - requires GROQ_API_KEY), falling back to a fully local, keyless model (faster-whisper, MIT) if Groq is unavailable or the key isn't set. The local fallback requires the optional local-stt extra (uv sync --extra local-stt) and auto-downloads its model weights on first use.

Args: audio_path: Absolute path to a local audio file (mp3/wav/m4a/flac/ ogg/webm/mp4/mpeg/mpga), max 25MB. language: Optional ISO-639-1 language hint (e.g. "en"). Ignored by the local fallback, which auto-detects language.

List known Groq PlayAI voice names usable with text_to_speech's voice argument. Static list transcribed from Groq's public API docs, not fetched live - like the model names this server wires in, it can drift; check_provider_health confirms the default voice still works, not the full list.

Check whether Groq's hosted TTS/STT endpoints are currently reachable and whether each local fallback's optional dependency is installed - without running a full local model load (kokoro/faster-whisper can take real time and disk space on first use, which would defeat the point of a quick health check).