Stub for hosts that can show an MCP App. Chat, Claude, and Gemini pass JSON to tools. They do not attach a microphone. This button asks for the microphone, builds a 16 kHz PCM WAV, and can call score with audio_base64 when the clip is at most 256 KiB.
Codex Desktop and ChatGPT on iOS deny getUserMedia even when ui.permissions.microphone is declared. ChatGPT on desktop Chrome can grant it. MediaRecorder output is usually WebM, which this tutor does not score, so this page writes PCM.
Idle.