A vault is a folder of notes and files that acts as a working knowledge base, and the point is ownership. It’s just files and folders on your machine or in your synced storage, so the business knowledge has a home that survives when someone leaves or a vendor changes software. Notes are plain markdown text that AI tools read easily, connected to each other through a wikilink.
An office filing cabinet you actually own is the closest comparison. Client folders, project folders, and reference notes all go in it. Unlike a paper cabinet, one note can connect to many others without copying text everywhere, which makes it a working system instead of a static archive.
Why you care
Context compounds in a vault. A raw source comes in, a meeting note gets processed, a decision note preserves why something changed, and over time it becomes a knowledge base both people and agents can read. Point Claude Code or another agent at it and the agent follows the links and picks up context from the system you already maintain. Your context stays yours instead of trapped in a single chat window.