# Model Backends

- Qwen2.5-VL-7B-Instruct: real frame-conditioned invocations. Only direct or safely repaired structured JSON that passes field validation is accepted.
- CLAP: real audio-tagging scores retained for ProactiveAVInteraction.
- WhisperX small: real segment transcription. Empty no-speech results are explicitly marked `asr_status=no_speech`; timestamps are segment-level.
- OCRScreenGrounding: deterministic generator ground truth, not OCR-model inference.
- Piper `en_US-lessac-medium`: deterministic materialization for the internal speech package. Generated speech is documented as synthetic.