Draft the letter with a tool if you like. The scope is a lawyer’s decision, and the trust rules are not a drafting question at all.
Key takeaways
Yes to drafting, with a firm template and a lawyer’s review. A retainer letter is a highly repeatable document with a small number of file-specific variables — the client, the matter, the scope, the fee basis, the deposit — and that is precisely the shape of task where document automation has been earning its keep in law firms for years, long before anyone called it AI.
But two things in that letter are not drafting decisions. The scope of the retainer is a professional judgment about what you are and are not taking on. And the money side is governed by rules that are indifferent to how the letter was produced. Getting the second part wrong is a regulatory problem, not a client-service one.
Two provisions do most of the work, and both are worth reading rather than remembering. Under section 7 of the Law Society of Ontario’s By-Law 9, a licensee who receives money in trust for a client must immediately pay it into an account at a bank listed in Schedule I or II to the Bank Act, a credit union or central to which the Credit Unions and Caisses Populaires Act, 2020 applies, or a registered trust corporation, held in the name of the licensee or the firm.
Coming out is narrower. Section 9(1) of the same by-law permits withdrawal from a trust account only for a closed list: money properly required for payment to or on behalf of a client, reimbursement of money properly expended or expenses properly incurred on a client’s behalf, money properly required for or toward payment of fees for services performed for which a billing has been delivered, a direct transfer to another trust account, and money that should not have been in trust and got there by inadvertence.
That third item is the one a retainer letter has to reflect honestly. A deposit does not become your money because the client agreed it was a deposit. It becomes your money when you have done the work and delivered a bill. Section 18 of the same by-law then requires financial records recording all money received and disbursed in connection with professional business. Whatever automation you introduce has to leave those records intact and reconcilable.
Outside Ontario the architecture is similar and the detail is not. In British Columbia the equivalents live in the Law Society Rules and the Code of Professional Conduct for British Columbia, and a firm practising in more than one province needs the local rule, not a generic summary of it. Never let a drafting tool produce trust wording for a province whose rules you have not read.
Rule 3.6-1 of the Rules of Professional Conduct requires that a lawyer not charge or accept any amount for a fee or disbursement unless it is fair and reasonable and has been disclosed in a timely fashion. The retainer letter is the ordinary vehicle for that disclosure, which is why the fee basis, the disbursement practice and the deposit arrangement should be stated in it plainly enough that a client without a legal background understands what will be charged and when.
Scope is the other half. A retainer that does not say what is excluded will be read generously by a client and, later, by everyone else. Where you are deliberately taking on part of a matter rather than all of it, our sister firm’s note on limited scope retainers explains how limited-scope arrangements are framed in Ontario — and that framing has to be a decision, not a paragraph a model produced because it usually appears.
Client identification is a separate obligation that intersects with onboarding rather than with the letter. By-Law 7.1 sets out when a licensee must obtain identification information and when identity must be verified, including that an organisation’s identity must be verified not later than thirty days after first engaging in the relevant activities. If you are automating file opening, that clock is one of the things worth having the system track.
Two distinct jobs, often confused. Document assembly generates the letter from a template and the matter record, which removes retyping and, more importantly, removes the copy-paste error where last month’s client name survives into this month’s letter. Trust accounting is a ledger discipline: Clio’s trust account management pages describe generating trust requests and accepting deposits, keeping separate ledgers for trust and operating accounts, reconciling in the platform, and producing jurisdiction-specific trust reports. Those are two systems doing two things, and the second one is not made safer by the first one being clever.
A generative layer on top can be useful for plain-language explanation — turning the fee section into something a client actually reads — and for consistency checks, such as flagging that the deposit figure in the covering email does not match the letter. It should not be inventing the numbers.
Illustrative. The firm opens perhaps a dozen files a month. Retainer letters are produced by copying the last similar one, which works until it does not: a family matter goes out with a corporate limitation clause, and a deposit is described in the letter as non-refundable in terms nobody would defend.
The rebuild has four steps. The firm writes three template letters — one per practice area — with the fee, disbursement and deposit wording drafted once and approved by both lawyers. The matter-opening form captures the variables, so the letter is assembled rather than retyped. The deposit is described in terms that match what section 9(1) actually permits: held in trust, applied against fees once a bill has been delivered. And a generative assistant is used only to produce the plain-language summary paragraph and to check the letter against the matter record for inconsistencies, with a lawyer reviewing before it is sent.
The gain is fewer errors of the kind that are embarrassing rather than catastrophic, plus an hour or two a week back. The gain that matters more is that the fee and deposit language is now one considered firm position instead of a dozen accidental ones.
Can AI reconcile the trust account?
Reconciliation is a defined accounting process against bank records, run by your practice-management or accounting system, and the person responsible for it is a person. A model summarising a reconciliation report is not a reconciliation.
Can we call the deposit non-refundable in the letter?
Be careful about writing anything into a letter that the trust rules and your professional obligations would not support. Money in trust comes out on the terms section 9(1) allows, and unearned money is accounted for on withdrawal or discharge.
Is a model allowed to see the retainer letter at all?
That is a confidentiality decision, and rule 3.3-1 of the Rules of Professional Conduct requires a lawyer to hold in strict confidence all information concerning the business and affairs of a client acquired in the professional relationship. Which tool, hosted where, retaining what, is the question to answer before the workflow is built.
If what you want is the engagement letter rather than the retainer — the accounting-practice version of the same document — see automated engagement letters for accountants.
A 30-minute call is enough to tell you whether AI pays for itself here.
