Building an assistant from plain instructions and one spreadsheet.
The common question about AI is which jobs it will take. The more useful question for me was narrower. What was taking up the hours that should have gone to client thinking?
I run a small advisory practice. Fifteen to twenty clients, all the advisory work done by me. The model only holds because I stay senior, fast, and out of the busywork. Over the last few weeks I built something that keeps me there. Claude now runs as my executive assistant. The how matters more than the headline, so let me set out what it does and how it was made.
Where the time went
None of it was thinking time. The thinking is the part I am paid for and the part I enjoy. The time went on everything around it.
A monthly cycle for each client that I carried in my head. Accounts to read, a management report to write, a meeting to prepare for, actions to chase and of course questions to respond to. Multiply by twenty and the coordination alone fills days.
The worst of it was the actions. Every Virtual Board meeting ends with things agreed, some mine, some the client’s. They lived in my meeting notes. By the next month some were forgotten, and the ones I had promised to do were the ones that embarrassed me when they surfaced late.
I handed over the coordination around the judgement. The judgement I kept.
What Claude does now
Claude runs three things every day and every month without me.
First, a daily plan. Each morning Claude reads my task list, my calendar, and my inbox, and tells me what the day is for. It gives me two or three priorities, chosen against one test I have used for years: does this move me towards calm, intellectually satisfying, advisory work, or back into busyness. It flags an overloaded day before I walk into it, and it surfaces the emails that needs a reply rather than the forty that do not.
Second, the monthly cycle, written down, which runs the same six stages for every client, counted back from the meeting date. Gather the figures, update the KPIs, write the client management report and commentary, prepare my own pre-meeting brief, hold the meeting, log what was agreed. It used to live in my head. Now it is a documented procedure Claude works through with me, the same way each time, so the management report and commentary reach the client before the meeting rather than during it.
Third, the actions. This is the one that changed the most. Every agreed action now goes into one place, a tab for each client in a single spreadsheet. Mine carry a due date and appear in my daily plan. An action I promised a client and have not done shows up as overdue at the top of the day. The standard I have always set myself, do what I said I would do when I said I would do it, is now held by the system instead of my memory.
A worked example
Take the KPI work, the second of my three advisory pillars. One client runs three separate businesses and wanted a single page that told her whether each was on course. The temptation in that position is to measure everything. We spent a meeting doing the opposite, cutting the list to ten numbers in total, three or four per business: sales at full price, conversion by lead source, gross margin, the cost of the work delivered. The few numbers that, when they move the wrong way, tell her exactly where to look.
That conversation is judgement, and it stayed with me. What Claude does is everything that makes it usable afterwards. It holds the agreed measures, drafts the monthly commentary that explains them, and prepares my brief for the next meeting so the discussion starts where the last one finished. The thinking happens in the room. The preparation and the follow-through happen around it.
How it is made
This is the part worth dwelling on, because it is not what most people picture when they hear AI.
I did not buy a product. I wrote instructions. In Claude these are called skills: plain documents that tell it how I work. One builds the daily plan. One writes the client management report commentary. One prepares the meeting brief. One captures the meeting actions into the spreadsheet. Each is a page of writing in my own words, describing the steps I would otherwise explain to a new assistant on their first morning.
Underneath sits one spreadsheet, my Task Manager, with a tab for tasks and a tab of actions for each client. Claude reads it, writes to it, and leaves the structure intact. Around it, connections to my calendar, my email, and my Zoom meetings, so it works from real information rather than from what I remember.
That is the whole of it. Plain instructions, one spreadsheet, a few connections. Built across an afternoon of conversation and refined by using it. No code. When something was wrong, I said so in ordinary English and it changed. The skill that logs meeting actions now writes each client’s actions to their own tab and builds a new tab the first time I take on a client, because I asked for that after the first version put everyone on one sheet.
The edges
I will be honest about the edges, because anyone copying this should know them.
One connection I wanted, to my document store, did not work, so part of the flow is still manual for now. The meeting records contain confidential client information, so I am deliberate about what it can see and where that material is kept. And nothing is logged or sent without me checking it. Claude prepares. I decide. That line does not move.
How to make it yours
You do not need to be technical, and you do not need to start big. Here is how I would go about it if I were starting again.
Start by writing down one routine you already repeat. The weekly look at your numbers, the monthly review, the list of things you keep meaning to chase. Pick the one that goes wrong most often when you are busy. That is the one worth handing over first.
Then put the information that routine needs in one place Claude can read. For me that is a single spreadsheet. For you it might be a spreadsheet, a shared folder, or your accounts in Xero. One place, kept tidy, so Claude is working from the same source you are.
Next, connect what it needs to see. Your calendar, your email, your meeting recordings. That is what lets it tell you what your day holds instead of asking you.
Now write the instruction. In plain English, describe the routine the way you would explain it to someone joining you on Monday. What to look at, in what order, what good looks like, what to hand back. In Claude that written instruction is called a skill. You save it once and use it again. There is no code, and no setup beyond the writing.
Then run it and correct it. The first version will be roughly right. Tell it what was off, in ordinary words, and it changes. Mine took an afternoon to set up and a week of small corrections to settle.
Two rules I would keep from the start. Decide what it is allowed to see, because some of your information is confidential and belongs only where you choose to put it. And check its work before it goes out. It prepares. You decide.
The test is the one I use for everything. If a task takes time but not judgement, it is a candidate to hand over. If it needs you, keep it.
What stays with me
Strip out the coordination and what is left is the work that needed me in the first place. Reading a set of accounts and seeing the one number that matters. Sitting in a meeting and naming the thing the owner is avoiding. Deciding. That work has not moved.
What has changed is how much of my week reaches it. The preparation is faster. The chasing is automatic. The actions do not fall through. I spend more of my time on the part only I can do, which is the part clients pay for.
The assistant does the work around the judgement. The judgement stays with me.
If you run a practice, or a business, here is the lesson. The system you carry in your head can be written down, and once it is written down, much of it can be handed over. The thinking stays yours. Everything around it is open to question.
Sources and Further Reading
Noel Guilford, ‘How the Strategic Advisory Model Is Built for the AI Era’, Beyond the Return, March 2026.
Noel Guilford, ‘The Practice You Built Is About to Get Faster’, Beyond the Return, April 2026.
Noel Guilford, ‘The Guilford Method™: Five Stages from Clarity to Design’, Beyond the Return, April 2026.
About the Author
Noel Guilford FCA is a chartered accountant and business adviser who works with a small number of deeply engaged business owners through a structured Virtual Board advisory model. He is the founder of Guilford Accounting and writes on practice design, advisory strategy, and the intersection of AI with professional judgement.
To discuss how this approach might work for your business, book a discovery call at calendly.com/noelguilford.
