Legal Document Redaction Before Using AI

Begin with the professional decision

Before preparing a legal document for AI, identify the governing jurisdiction, professional rules, engagement terms, protective orders, client instructions, confidentiality agreements, and organisational policy. The same technical workflow can be permitted in one matter and prohibited in another.

ABA Formal Opinion 512 discusses lawyers' duties when using generative AI, including competence, confidentiality, communication, supervision, candour, and fees. Its confidentiality analysis calls for evaluating the information, the tool, its terms and policies, security measures, retention, and the circumstances of the representation.

The opinion does not create a universal rule that client consent is always or never required. The answer depends on the risk and use. Obtain advice from the responsible lawyer or compliance function for the actual matter.

Redaction is broader than court-filing identifiers

Court privacy rules often list identifiers such as Social Security numbers, birth dates, minors' names, and financial account numbers. Those filing rules do not define every fact that must be removed before an AI upload.

A legal file can reveal a client or matter through party roles, chronology, location, transaction value, unusual legal issue, witness description, citation pattern, internal matter number, or quoted correspondence. Names can disappear while the matter remains obvious.

Build a matter-specific inventory that covers direct identifiers, quasi-identifiers, privileged analysis, work product, settlement positions, personal data, trade secrets, sealed content, and material received under restriction.

Prepare the smallest useful extract

Do not begin with the complete case file. Extract only the paragraph, clause, chronology, or synthetic fact pattern needed for the task. Replace live facts with a hypothetical when the AI can answer the legal or drafting question without them.

Use consistent party labels only when relationships matter. Generalise dates, locations, roles, and amounts together. Consider whether the combination can still be linked to public filings, news, internal records, or the recipient's knowledge.

Keep any re-identification key separate under appropriate access controls. If a mapping exists, describe the result as pseudonymised rather than fully anonymous.

Inspect visible and hidden legal content

Use true redaction for visible material and format-specific sanitisation for hidden data. Work on a copy, apply the redaction, close and reopen the output, search again, inspect properties and attachments, and conduct a page-by-page review.

Preserve privilege and confidentiality through governance

A clean-looking document does not answer whether disclosure to the selected AI provider is authorised or whether privilege could be affected. Review the service terms, training policy, retention, administrator access, subpoena or legal-process terms, location, connectors, and contractual protections.

Record the purpose, data classification, transformation, tool and workspace, settings, approver, date, and exact uploaded copy when organisational policy calls for it. Avoid placing confidential values in the audit log itself.

For a high-risk matter, the correct choice may be an approved enterprise environment, an internally controlled model, a synthetic hypothetical, or no AI use. Automation supports the review; it does not make the professional judgment.

Final legal-document checklist

• The responsible lawyer or organisation has approved the use.
• The exact service, workspace, feature, retention, and contract have been reviewed.
• Only the minimum material needed for the task remains.
• Direct and indirect matter identifiers have been assessed together.
• Comments, revisions, properties, attachments, and filenames have been inspected.
• The output was reopened, searched, visually reviewed, and approved by a person.
• The decision and uploaded copy are recorded where required.