A custom AI assistant is worth setting up for a job that comes up every week, needs the same company material each time, and has a standard you can describe in a paragraph. A job that fails any of those tests is better served by a general AI assistant and a good brief. Most small businesses have one or two jobs that pass, and many have none yet.
What counts as a custom AI assistant?
A custom AI assistant is a general assistant that has been given standing instructions and a set of your own files, so that it does one job the same way every time. Some products call these projects or custom GPTs. It is not an agent that acts on your systems; that is a separate decision, and the Errand Test in AI agents for small businesses covers it. It is also not software that a developer builds for you.
Why does this question come up now?
Because most small businesses have started with a general assistant and are asking what comes next. In Ireland, the Small Firms Association surveyed 404 small firms of up to 50 employees in the summer of 2026 (fieldwork by Amárach, published 10 August 2026). It found that 92% use generic off-the-shelf tools, 30% use customized AI models (up from 22% in 2025), and 20% build or code their own software (up from 10%). Among firms using customized or strategic AI, 65% reported an immediate boost in efficiency. These are self-reported figures from an industry body, and "customized" is the survey's word.
The depth problem shows up in official figures too. The UK Office for National Statistics reported on 20 July 2026, from its Business Insights and Conditions Survey (wave 159, fieldwork 5 to 28 June 2026, 38,637 responding businesses), that about 35% of businesses with 10 or more employees use at least one AI technology. Among those that do, only 10% say they use it extensively. Only 11% of businesses with 10 or more employees said more than half their workforce has had AI-related training.
In the United States, a Goldman Sachs 10,000 Small Businesses survey run by Babson College and David Binder Research (1,256 owners, 27 January to 4 February 2026, published 17 March 2026) found that 76% of owners use AI, while only 14% are fully integrating it into core operations. Use is wide and depth is thin. A custom assistant is one way to add depth to a single job, so it is worth deciding on purpose.
Which jobs deserve a custom setup?
The Three-Yes Test is three questions an owner asks before setting up a custom AI assistant for any job: Does it come up at least weekly? Does it need the same company material every time? Can you describe in one paragraph what a good result looks like? Three yeses earn a custom setup. Anything less, stay with a general assistant and a good brief.
Each question screens out a different kind of waste. A monthly job does not earn its upkeep, and people forget the setup exists. A job that needs different documents each time works as well with them pasted into a general assistant. A job with no describable standard cannot be judged, so you will never know whether the setup helped.
There is one override. A job that has to read from or write to a system of record, such as your accounts, bookings or customer records, belongs in the specialist-product row below, whatever it scores. A custom assistant works from files you load. It does not keep a live record in step.
Should you use a general assistant, a custom setup, a specialist product or a custom build?
Use the first row until a job passes the test, and move down the table one row at a time. This table is my judgment, not a research finding.
| Approach | Choose it when | What you need in place | The main risk |
|---|---|---|---|
| General assistant with a good brief | The job is occasional, or the material changes each time | A brief that passes the New Hire Test | Every person briefs it differently |
| Custom assistant (standing instructions and your files) | The job passes the Three-Yes Test | A Setup Card, a named owner, a review date | The files go out of date and nobody notices |
| Specialist product for one function | The job must read from or write to a system of record | A person who owns the supplier relationship and the data settings | Your data now sits in one more place |
| Custom build by a developer | A custom assistant has run for a quarter, its card has stopped changing, and the job spans several systems | A written specification, which is the Setup Card, plus an owner | Building before you know what you want |
Moving down the table is never an upgrade in itself. Each row adds something to maintain. The approach that is easiest to maintain and still does the job well is the right one, and for most jobs that is the first row.
What goes on a Setup Card?
A Setup Card is a nine-line page that travels with every custom assistant. Copy the lines below into a shared document, one card per assistant. If you cannot fill a line, the assistant is not ready to share.
Setup Card
Job: one sentence, starting with a verb.
Owner: one named person, and a named second person.
Instructions: paste the standing instructions here, or link to them.
Standing files: list each file, the date it was last checked and who updates it.
Never load: the kinds of material that must not go in.
Good looks like: a paragraph, or one real example, that a stranger could judge against.
Check: who reads the output, and before it goes where.
Stop sign: the situations where a person takes over without using the assistant.
Review date: 30 days from today.
Two lines matter more than they look. The date on each standing file is how you notice that the terms of work changed and the assistant did not. The stop sign is how you keep the thinking with a person, which is the principle I use for all of this: outsource the doing, not the thinking. If you want the briefing habit behind the Instructions line, prompting skills at work explains it.
What does the test look like in a real business?
Take a hypothetical electrical contractor with eighteen employees. The owner asks her team to list the jobs they repeat, then scores each one.
| Job | Weekly? | Same material? | Describable standard? | Verdict |
|---|---|---|---|---|
| Follow-up emails after site visits | Yes | Yes: standard terms of work, past project descriptions | Yes | Custom assistant |
| Summarizing a tender document | No: a few times a year | No: new document each time | Yes | General assistant with a good brief |
| Matching supplier invoices to purchase orders | Yes | Yes | Yes | Override: it reads the accounts, so ask the accounting software supplier what it offers |
She sets up one custom assistant, for the follow-up emails. Her office manager owns it and the operations lead is the second name. The standing files are the terms of work, dated, and five project descriptions that she is happy to have copied. The card's Never load line reads: customer phone numbers, alarm codes and anything from a signed contract. The Check line says the office manager reads every email before it is sent. The Stop sign says complaints and anything about a delay are written by a person.
She does not build a second assistant until the first has survived its review. Passing the test earns a place in the queue, not a setup this month.
What should stay out of a custom assistant?
Anything you would not attach to an email sent to everyone who can open the assistant. Personal data about customers or staff, signed contracts and credentials are the usual candidates for the Never load line. Check what your product does with uploaded files before you load anything sensitive, and ask whoever handles data protection for your business.
Your AI policy should say who may create a custom assistant and who approves it. Without that, you get the shadow AI problem in a new form: assistants nobody else knows about. If you are unsure your files are fit to load, start with is your business data ready for AI.
What I See When I Train Business Teams
The first custom assistant in a business is usually built by the most enthusiastic person, quickly, with whatever files were open that afternoon. It works well for about three weeks. Then the terms of work change, the file does not, and nobody but the builder knows the assistant exists. The fix is rarely more enthusiasm. It is a second name on the card and a review date in two diaries.
One example from my published client work shows the other direction. In April 2023 I spoke about AI in marketing at a business event in Penrith. A year later the marketing team was using AI for content writing, and the managing director asked me back to show teams across the business what was possible. After the September 2024 session the IT Director wrote: "It was a great session and I've heard a lot of good feedback from the attendees." The full case is on my business page. My reading is that one team's habit became something the whole business could discuss, which is when a written card and a plain test start earning their place.
What should you do this week?
- List the five jobs your team repeats most often. Ask the people who do them.
- Run the Three-Yes Test on each job, in ten minutes, and apply the override.
- Choose at most one job. A second custom setup waits until the first has passed its review.
- Fill in the Setup Card with a second person in the room. If that person cannot say what the assistant is for, the card is not finished.
- Put the review date in two diaries. At the review, ask three things: did people use it, did anyone fix its output by hand every time, and are the standing files still current? Then keep, change or drop it, as in AI for businesses with fewer than 10 people.
- Tell the whole team the assistant exists and who owns it. If you want to know whether it helped, measure it against the job, not against logins.
If you want to know where your business stands before you set up anything, take the free Business AI Readiness Scorecard, which takes about five minutes. If your team already has an assistant or two and nobody has shown them how to use them well, that is what my AI training for business teams is built for. And if you are choosing a speaker for an event where most of the room runs a small firm, my business keynotes cover this sequence from first use to settled routine.
Sources and further reading
- Office for National Statistics, Artificial intelligence in UK businesses: 2023 to 2026, released 20 July 2026 (Business Insights and Conditions Survey wave 159, fieldwork 5 to 28 June 2026, UK, 38,637 responding businesses).
- Small Firms Association (Ibec), Small Firms Association sound alarm over "shallow" AI adoption, 10 August 2026 (Ireland, Amárach survey, 404 small firms, summer 2026).
- Goldman Sachs 10,000 Small Businesses Voices, AI Presents a Major Opportunity for Small Businesses, But Support Is Needed to Close the Implementation Gap, 17 March 2026 (United States, 1,256 owners, fieldwork 27 January to 4 February 2026, conducted by Babson College and David Binder Research).
- On this site: Why most small businesses are not getting value from AI, AI agents for small businesses and prompting skills at work.
Dan Fitzpatrick, The AI Educator, is a Forbes contributor, international keynote speaker and bestselling author who has trained more than 150,000 people across 30+ countries. About Dan.
