Skip to content

Vaultr Journal · Practice

Why local-first is a legal requirement, not a preference 

Confidentiality duties are older than cloud computing. Architecture is how a tool respects them.

8 September 2026 · 6 min read

Back to Journal

A lawyer's duty of confidentiality does not have a carve-out for convenient software. What a client tells counsel is protected; how a firm's tooling handles that material is therefore not an IT preference but a professional obligation. The question every firm should ask of a new AI tool is not "is it good?" but "what does the tool make it possible to disclose?"

Contractual controls versus architectural controls

The standard cloud answer to that question is contractual: terms of service, data-processing addenda, enterprise agreements with training opt-outs. Contracts matter. But a contract is a promise enforced after something has gone wrong, while architecture is a property enforced continuously — the data either crosses a boundary or it does not.

Local-first inference moves the protection from paper to physics. In Vaultr's local mode, matter processing runs in the application process on the firm's own machine: prompts, retrieved passages and outputs do not leave the device, because there is no path by which they could. The exceptions are narrow and explicit — updates and model downloads you start on purpose — and the security brief publishes a test so you can confirm the boundary on your own machine instead of trusting our description of it.

What local-first does not solve

Overselling the boundary would dishonour it. Local-first does not protect a matter from malware running as you on the same device; it does not stop an insider from copying a file to a USB stick; it does not replace disk encryption or device policy. Our threat model page lists these residuals plainly, because a control whose limits are hidden is a control your risk register cannot use.

  • A compromised device compromises everything on it, including Vaultr — device hardening remains yours.
  • Insider risk is a governance problem; the evidence ledger makes actions attributable, which is deterrence and forensics, not prevention.
  • Backups remain whatever your own machine backup captures. Vaultr operates no backup service to lose.
Architecture is a floor, not a guarantee. The floor matters because everything you build on it inherits its height.