A consultant works with eight clients. Each has its own contracts, tone of voice and history. Conversations must never mix one client's material into another's answers. Which arrangement best fits?

The principle — when a requirement is about what must stay apart, the right tool is the one that draws boundaries, not the one that carries things forward. Continuity and isolation are different goals, and Claude offers a different mechanism for each.

Why the key is correct — Anthropic describes projects as self-contained workspaces with their own chat histories and knowledge bases. Self-contained is the operative property here. Eight projects give eight boundaries: each client's contracts and tone of voice sit in that client's knowledge base, every conversation inside the workspace draws on that material, and nothing from the other seven is present to be drawn on. The consultant gets isolation and convenience at once, and the arrangement scales — a ninth client is a ninth workspace, not a growing risk.

Why the others are wrong — memory is built to carry context between conversations, which is close to the opposite of the requirement; it makes continuity automatic without giving you compartments. A single shared project defeats the purpose entirely, since one knowledge base means every client's documents are available to every answer, and isolation enforced by remembering to name the right client is not a control. Starting fresh each time does prevent mixing, but it makes every conversation begin with re-uploading a client's entire document set, which is exactly the labour a knowledge base exists to remove — the right answer should not cost that.

Remember this — projects draw boundaries; memory crosses them. Choose by which one the task actually needs.

Sources — Anthropic's projects documentation and its chat search and memory article.