Chain of Custody Governance Log for Perth In-House Counsel: Prove Every AI Touchpoint on Expert Evidence Before It Reaches Court

Your expert witness sent a draft report through last week. It looks tight. But somewhere between the raw data extract, the consultant’s modelling pass, an LLM summary an analyst ran “just to tidy the prose”, and the version sitting on your desk, something happened that nobody fully logged. If opposing counsel asks — at conference, on voir dire, or under cross — who or what generated which paragraph, and on what inputs, you do not currently have an answer you’d be comfortable putting on the record. The Chain of Custody Governance Log is built to close that gap before a matter reaches hearing.

The problem

In-house legal teams in Perth increasingly commission expert evidence — technical, financial, forensic — that passes through multiple hands and multiple tools before it lands in a brief. Where any of those hands or tools include generative AI, the attribution question becomes acute. Who wrote the conclusion? On what data? Was the model output verified? Was it edited? By whom? At what time?

The Australian Solicitors’ Conduct Rules apply to solicitors in Western Australia under the Legal Profession Uniform Law from 1 July 2022. ASCR Rule 19 requires candour to the court, which extends to the integrity of evidence put before it. ASCR Rule 4 (other fundamental ethical duties) requires solicitors to be honest and courteous in all dealings in the course of legal practice and to deliver legal services competently and diligently. An in-house counsel signing off on a brief that includes an expert report whose generation pipeline cannot be reconstructed is exposed on both fronts — and so is the expert.

The threat model here is expert evidence AI attribution failure: a report that cannot, on request, be traced back to its constituent inputs, model runs, human edits, and verification steps. The remedy is not to ban AI from the workflow. It is to keep an immutable log of every touchpoint.

What the Chain of Custody Governance Log does

The Chain of Custody Governance Log is an evidence chain-of-custody record — an immutable, append-only log covering every step from raw data collection through to the version of the expert report tendered in court. Each entry records: actor (human or named model), action (extract, summarise, edit, verify, sign-off), input artefact hash, output artefact hash, timestamp, and any prompts or parameters used where a model was involved.

The log is designed so that, at any point — pre-lodgement, conference, or under cross — you can answer the question “where did this paragraph come from?” with a structured trail rather than a phone call.

How it works

  1. Register the matter and the artefact set. You declare the expert, the scope of the report, and the source data artefacts at the start. Each artefact is hashed.
  2. Log every touchpoint. As the expert, analysts, or your in-house team work on the report, each transformation — human edit, model summary, citation insertion, verification pass — is recorded as a signed entry against the artefact hash.
  3. Record AI use explicitly. Where a generative model is used, the log captures the model name and version, the prompt, the input artefact, the output artefact, and the human reviewer who accepted or rejected the output.
  4. Produce a custody report on demand. Before lodgement, before conference, or in response to a notice to produce, the log generates a structured chain-of-custody report covering every artefact in the matter.
  5. Pair with RuleCheck for citation integrity. Where the report cites authorities, the same artefact can be passed through RuleCheck (the open-source citation verifier at github.com/andrefabre/rulecheck) so the citation verification step is itself recorded as a custody entry.

Why this matters in Perth

Western Australian solicitors have been bound by the Legal Profession Uniform Law and the ASCR since 1 July 2022. In-house counsel in Perth — across resources, energy, infrastructure, and financial services — routinely commission expert reports that travel through interstate consultants, offshore data processors, and increasingly AI-assisted drafting tools. The chain of custody for that work is the in-house team’s problem long before it becomes the court’s. Having a structured, immutable log means that when a Supreme Court of Western Australia matter, an arbitration, or a regulator request asks the attribution question, the answer is already on file.

Sources

Join the waitlist

The Chain of Custody Governance Log is in specification. We are scoping deployment patterns with in-house teams in Perth and other Australian capitals — particularly teams that commission expert evidence in regulated industries. Join the waitlist and we’ll be in touch as access opens.

Join the waitlist for the Chain of Custody Governance Log