Privacy and confidentiality
Legal AI privacy, confidentiality and client data
Legal AI privacy depends on the full data path: matter access, model routing, retention, subprocessors, support access, audit, deletion and whether client data leaves the firm's chosen boundary.
Quick answer
A legal AI privacy review should begin with the client matter, not the marketing claim. Firms need to know who can access the matter, which systems receive its content, how long data and logs persist, whether model providers may retain inputs, and what technical controls enforce the selected deployment boundary.
Reviewed September 2026
Confidentiality
Client obligations are more specific than generic privacy
Law firms may face professional duties, contractual confidentiality, outside-counsel guidelines, ethical walls and client-specific restrictions at the same time. A platform should therefore support matter-level policy rather than assume one data setting fits every engagement.
The practical question is whether the system can demonstrate that one matter's content remains inside the authorized team and approved inference path.
Retention
Zero retention and zero egress are different
Zero retention generally addresses whether a processor stores submitted content after processing. Zero egress addresses whether the content leaves a defined technical boundary at all. A product may satisfy one without satisfying the other.
Sanctum Lex uses deployment-specific language so zero external model egress is claimed only for verified private-perimeter configurations where outbound model routes are denied.
Governance
Privacy controls need an audit trail
Administrators should be able to review the matter boundary, identity policy, approved model routes, retention policy, export state and material agent actions. Privacy becomes more defensible when the organization can show which controls actually applied to the work.
Human review remains separate from privacy: a private answer can still be wrong, so source and authority controls must remain part of the legal workflow.
Frequently asked questions
Can confidential client data be used with legal AI?
Potentially, but only where the firm's professional, contractual, privacy and security requirements are satisfied by the specific deployment and data-handling configuration.
Is zero retention the same as zero egress?
No. Zero retention concerns post-processing storage by a service; zero egress concerns whether data leaves the defined boundary in the first place.
What privacy evidence should a law firm request?
Data-flow diagrams, subprocessors, retention terms, access controls, model routes, encryption, audit logs, deletion processes, support-access policy and any technical evidence supporting private or zero-egress claims.
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