How Hefty Works

Hefty is a personal AI assistant that runs entirely on your computer. It's packaged as a single desktop application - download it, run it, and you're ready to go. No cloud services required.

🖥️ Hefty Desktop App
Core Capabilities
🧠 Reasoning Understands requests
⚡ Actions Controls your computer
📚 Memory Learns from experience
▼
🗄️ Local Storage Your data stays yours
🤖 AI Providers Local or cloud inference

How It All Fits Together

When you send Hefty a message, it goes through several stages. Understanding each one helps you get the most out of Hefty.

Cognition Pipeline

Every message flows through Hefty's cognition pipeline - the brain behind the operation. Hefty recalls relevant knowledge, assembles conversation context, reasons about your request, and decides whether to respond directly or take action. All of this happens in seconds.

Instruments

When Hefty decides to act, it uses instruments - tools that let it run commands, manage files, browse the web, control applications, and more. You see every action in real-time and always know what Hefty is doing on your behalf.

Knowledge

Hefty builds a long-term memory of skills, antipatterns, and entities. Skills capture techniques that worked. Antipatterns capture mistakes to avoid. Entities track people, tools, and projects you work with. This knowledge is recalled automatically when relevant, so Hefty gets better the more you use it.

Conversations

Your interactions are organized into persistent conversations. Hefty maintains context across sessions, generates rolling summaries of older exchanges, and can reference earlier parts of your chat even in long threads.

Initiatives

For larger goals, initiatives let Hefty work through multi-step plans autonomously - with you watching progress and staying in control. You can also set up recurring tasks on a schedule.

Privacy & Data

Everything Hefty knows is stored locally on your machine - by default in ~/.hefty. This includes conversations, learned knowledge, settings, and files Hefty creates. Nothing is sent to external servers unless you explicitly choose a cloud AI provider (OpenAI or Anthropic).

You can back up, move, or delete the data folder at any time. Your data is yours.

Extensibility

Hefty ships with a full set of built-in capabilities, but you can extend it:

  • MCP connections - connect Hefty to external tool servers and their capabilities become available instantly
  • Custom prompts - define specialized AI tasks as reusable instruments
  • API endpoints - point Hefty at any HTTP API and it becomes a callable tool
  • Plugins - install third-party instrument packages

All extensions persist across restarts and can be managed without stopping Hefty.