Discovered documents and AI: what the Harman obligation means for ChatGPT or Claude.

Documents obtained from the other side by discovery, subpoena or interrogatories come with a condition most firms learned once and rarely think about: they may be used only for the proceeding in which they were produced. The High Court restated it in Hearne v Street, and it is an obligation owed to the court, with contempt as the sanction. That makes summarising discovered material in ChatGPT or Claude a different problem from ordinary AI confidentiality. This page marks every item in a typical discovery review note and shows how the same review happens on Ermos inside the firm.

Documents obtained on discovery

Prepared by the solicitor reviewing the other side’s discovery, for counsel and the partner, before the documents are used in evidence.

An invented review note. Document numbers are illustrative. Hover or tap any highlighted item for the analysis; the full list is below.

What leaves the firm

1. 1
   The proceedings

   Named parties, so every document below is tied to a live matter. Rule 9 confidentiality guide.

2. 2
   The other side’s documents, by number and author

   Three named executives’ internal emails and board papers, produced under compulsion. Under Hearne v Street, a party who obtains documents by compulsory process cannot, without the leave of the court, use them for any purpose other than the proceeding. Legal privilege guide.

3. 3
   An internal email of the opponent

   A quotation from a document the opponent was compelled to produce. Pasting it into an external tool is a use of the document outside the proceeding, which is the use the obligation to the court prohibits. Legal privilege guide.

4. 4
   A restructure paper and its date

   The opponent’s own document, undermining its own case. The most valuable discovered document in the matter, and the one a court would least expect to find on a third party’s servers. Legal privilege guide.

5. 5
   Board papers and an inference about the redactions

   Compelled corporate documents, plus the solicitor’s reading of them. The documents are restricted by the obligation; the reading is privileged. Legal privilege guide.

6. 6
   A remark about the client’s health by a named executive

   A compelled document, about the client’s leave, by a third party. Restricted, sensitive, and about an identified individual. Privacy Act guide.

7. 7
   The solicitor’s assessment and the warning to the client

   Privileged advice on the strength of the case, and the very warning about collateral use that the firm has just failed to follow itself. Legal privilege guide.

8. 8
   The solicitor

   Ties the review to a practitioner personally subject to the obligation, and to the firm. Supervising AI guide.

What happens in Frontier Models (ChatGPT, Claude)

• The whole document is transmitted to the provider’s servers. On personal plans the user cannot choose where it is stored or processed, and for the major providers that has generally meant outside Australia, under that country’s legal process. Some business plans offer storage in Australia, but the provider still receives the content.
• On consumer tiers, prompts can be retained and used to train future models.
• The provider’s staff and systems can reach the content under the provider’s own policies.
• Once sent, the firm no longer controls it. Retention and deletion happen on the provider’s terms.

The same document on Ermos

Part of AI data leakage in law firms. See how this works in practice: Discovery on Ermos.

Common questions