Twin: An On‑Screen AI Companion That Quietly Remembers Your Day on Mac

A new Mac app called Twin turns an always‑visible desktop buddy into a serious personal memory tool. Instead of living in the cloud, Twin is built as a “local‑first” assistant: it watches what happens on your Mac and stores that activity in DuckDB, a lightweight embedded database running on your machine. You plug in your own API key for the AI model of your choice—Claude, GPT, Gemini, Grok and others—and that model effectively becomes the mind behind the character floating on your screen.

Twin is designed less as a traditional chatbot and more as a companion that remembers what you were doing. It can recap emails and chats you just worked through, remind you about documents you had open earlier in the day, or answer questions like “summarize the spec I was reading this morning.” Because all of this context is stored locally rather than uploaded by default, the app has quickly attracted interest from privacy‑conscious developers and knowledge workers. For now it’s Mac‑only and open source, but its architecture makes it a strong candidate for future ports and community‑driven extensions.