High-school builder open-sources Hearth, a local AI that runs your PC and keeps 9B agents usable

T-90_Soviet · reddit · 2026-07-24

Hearth: an open-source local AI that actually controls your PC

A high-school builder spent about five months of evenings creating Hearth, a local-first AI assistant that can run real apps, files, the browser, and the desktop instead of just chatting about what it would do.

Works with LM Studio, Ollama, llama.cpp, LAN hosts, or cloud keys; it also ships its own llama.cpp server for out-of-the-box use.
Uses the accessibility tree to read real control names, so it clicks UI elements by semantics rather than guessing from pixels.
Supports voice, reminders, document reading for PDF/DOCX/XLSX/EPUB, chunk-summarizing large books, and generating files like PDFs, decks, and spreadsheets.
Can run over Telegram/Discord bots, has a headless JSONL mode, and acts as both an MCP server and client.
The author says the key to making a 9B model work as an agent was keeping tool schemas off the prompt until needed and using auto-compaction for long chats, which helped the session stay useful past turn 30.
Safety-wise, writes are limited to a workspace folder, risky shell actions are pattern-checked, privileged execution is blocked, and the app never phones home.

It also includes a built-in model browser, live settings, one-button move-to-another-drive, and skill import from GitHub repos.

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High-school builder open-sources Hearth, a local AI that runs your PC and keeps 9B agents usable

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