Nobody is asking you to log every autocomplete. But billing, supervision and the ability to answer a question two years from now all point at the same one-line note, so you may as well design it once.
Key takeaways
Yes — keep a short, standard note, and keep it short enough that people actually write it. What you are not doing is complying with a logging rule, because there is not one. The Law Society of Alberta’s survey of generative AI rules of engagement for Canadian lawyers records that eleven Canadian courts, nine law societies, two professional liability insurers, one provincial government, the Canadian Judicial Council, the Canadian Bar Association and the College of Patent Agents and Trademark Agents have all issued guidance, that they uniformly emphasise that lawyers are responsible for the truth and accuracy of their work, and that none has attempted to ban its use.
So the file note is not there to satisfy a regulator. It is there because three ordinary obligations quietly require you to be able to reconstruct what happened, and a note written at the time is the cheapest way to be able to.
This is the obligation people miss, and it bites hardest at firms that bill by the hour. The Law Society of Ontario’s Futures Committee white paper on licensees’ use of generative AI, summarised in the Alberta survey linked above, states that if a licensee is billing by the hour they can only charge for the time actually spent on the file even if a generative AI tool has made the task much more efficient, and that whether the cost of the tool can be passed on to a client as a disbursement depends on the specific circumstances.
The Law Society of Manitoba’s guidance, recorded in the same survey, puts the principle the other way round: fee arrangements should not generate an inappropriate windfall arising from the efficiencies created by using an AI tool, and it would not be appropriate to charge hourly fees reflecting the time the work would have taken without it — but it is appropriate to charge for time spent crafting and refining inputs and prompts, and for reviewing, confirming, analysing and editing the output.
That distinction is only defensible if somebody wrote down which was which. A time entry of the form "draft memo — 2.4" tells you nothing. One reading "draft memo — first pass drafted with tool, 1.6 reviewing and rewriting" answers the question before it is asked.
Under rule 6.1-1 of the Law Society of Ontario’s Rules of Professional Conduct, a lawyer must assume complete professional responsibility for their practice and directly supervise non-lawyers to whom tasks and functions are assigned, reviewing that work at frequent intervals. The Law Society of Saskatchewan’s guidelines, as recorded in the Alberta survey, list supervision and delegation among the duties generative AI engages, and state that the outputs of these tools may not always be sufficiently reliable for use in the legal services context without independent vetting by a lawyer.
In a firm of any size, supervision is a paper problem before it is a judgment problem. The supervising lawyer cannot review what they do not know happened. A note naming the reviewer is the mechanism.
If a field takes thought to fill in, it will be left blank. Six dropdowns in the matter management system beat a free-text policy nobody reads. The Alberta Law Society’s note on generative AI and technological competence is a short, practical starting point for what a lawyer is expected to understand about the tool before using it.
A per-file note records what happened. A firm policy decides what is allowed to happen, which is where the real risk control sits. The Law Society of Alberta publishes a model generative AI use policy and explains why a firm needs one — noting that such policies also speak to a lawyer’s obligations to supervise articling students, staff and other personnel. It is adaptable by any professional firm, not only a law firm.
Privacy law points the same way. Principle 1 of Schedule 1 to the Personal Information Protection and Electronic Documents Act makes an organisation responsible for personal information under its control and requires it to designate someone accountable for compliance; clause 4.1.3 extends that responsibility to information transferred to a third party for processing and requires the organisation to use contractual or other means to provide a comparable level of protection while it is being processed. Clause 4.1.4 requires policies and practices to give effect to the principles, including staff training. A vendor list with a named owner satisfies more of that than a stack of file notes ever will.
Keep the note as long as you keep the file. For the firm’s own books, section 230 of the Income Tax Act requires every person carrying on business to keep records and books of account in a form that enables the taxes payable to be determined, and paragraph 230(4)(b) sets a general floor of six years from the end of the last taxation year to which the records relate; subsection 230(4.1) adds that records kept electronically must be retained in an electronically readable format for that period. Treadstone Law’s note on corporate record retention in Ontario is a useful plain-language companion, and professional file retention periods set by your own regulator are usually longer than the tax floor.
A four-partner Ontario firm adds three dropdowns and a reviewer field to its time entry screen. Nothing else changes. Two months later a client queries a bill on a matter where a research memo had been drafted quickly.
The firm can show the entry: first pass drafted with a named tool, 0.4; sources checked and memo rewritten, 2.1; billed 2.1. The conversation ends in one email. Without the entry it ends in a fee assessment, and the firm is arguing about what it did from memory a year later.
The countable measures are the proportion of matters with a completed field and the number of fee queries that close on first reply. Both are in your practice management system already.
Do not paste prompts and outputs into the file by default. On a matter where the input included client information you have just created a second copy of it in a place nobody is thinking about, and on a matter where it did not you have created noise. Log the fact and the reviewer; keep the artefact only where it is the work product itself.
Do not log anything you are not prepared to have read back to you. A note is a record, and records get produced.
Do accountants need this too?
The obligation is differently shaped. A firm performing audits, reviews, other assurance or related services engagements has a system of quality management to maintain, and technological resources are named inside it — that is covered separately in our note on AI and CSQM 1.
Does the client see the log?
Not normally. It is a firm record, not a client communication. Whether and how you tell a client you used a tool is a separate decision with its own test.
Is a tick-box enough?
For most tasks, yes. Reserve a fuller note for work that goes outside the firm under someone’s name — a report, a filing, an opinion — where the question "who checked this" has a real answer and needs to be findable.
What if a staff member used a tool without telling anyone?
That is a policy gap, not a logging gap, and it is the argument for writing the firm policy first. A rule that names which tools are approved, on what information, gives the note something to record.
A 30-minute call is enough to tell you whether AI pays for itself here.
