Second Brain vs Mercury Voice

Second Brain is a companion voice recorder for the Second Brain macOS app. Capture voice notes on the go and sync them to your Mac for transcription and AI analysis. The app automatically detects speech and silence (Voice Activity Detection), splits recordings into chunks, and transfers them to your Mac over the local network — no cloud involved. Features: - Voice recording with automatic Voice Activity Detection - Background recording — keeps working when the app is minimized - Live Activity — recording progress on Lock Screen and Dynamic Island - Seamless Mac sync via Bonjour (P2P, no cloud) - Geolocation tagging for recordings - Fully offline — all data stays on your device Pair your iPhone with the Second Brain macOS app to unlock transcription, knowledge extraction, and AI-powered search across all your voice notes.

Mercury Voice is a native voice client for Hermes Agent — talk to your self-hosted AI agent hands-free, on your Mac or iPhone. Speak naturally and Mercury Voice listens, transcribes, sends your prompt, and speaks the reply back to you — then re-arms to listen again, so you can keep a real conversation going without touching the screen. FEATURES • Hands-free voice loop — listen, transcribe, submit, speak, repeat • Full-duplex barge-in — interrupt the agent mid-reply just by talking, no button required • Spoken stop words to end a turn without reaching for your device • Live captions of the agent's spoken reply as it streams • Lock-screen Live Activity on iPhone — see session status and mute, stop, or end the conversation without unlocking • Password and native OAuth sign-in for gated servers, or simple token login for local setups • Reconnects automatically and picks up right where a reply left off, even after a dropped connection • One native app, built for both macOS and iOS • Siri Shortcut support so you can start a new session using just your voice YOUR SERVER, YOUR DATA Mercury Voice connects to a Hermes Agent backend that you run yourself. Nothing is sent to a third-party service by this app — you point it at your own server address and sign in with your own credentials. REQUIRES A running Hermes Agent backend (see github.com/NousResearch/hermes-agent). This app does not include or host a backend.