AI agents14 October 20268 min

AI agents, explained for business owners: what they are, what they cost, where they fail

AI agents explained for business owners: how they differ from chatbots and automations, five real examples with monthly costs, and where they fail.

A sailing school near Cassis was quoted 4,800 € for an AI agent in April 2025, and the owner sent me the quote. The agent in it was a chat bubble linked to her booking calendar.

AI agents are programs given a goal and access to some of your tools, which then work out the steps themselves; the developer Simon Willison, who had collected 211 definitions on Twitter before settling on one in September 2025, puts it as "an LLM agent runs tools in a loop to achieve a goal." For the sailing school the goal would be a child booked into Saturday's beginners' class, with the email, the calendar and the reply left to the agent, and the owner asked whenever it wasn't sure.

A chatbot answers questions but can't book, since it has no access to the calendar, and an automation in Zapier or Make can book but only by repeating the exact steps it was set up with. My studio sets up a first agent from 900 € before tax, a bit over $1,000, and the model then costs 12 to 180 € a month depending on how much it has to read.

AI agents vs chatbots vs automations

In October 2025 I was asked by an estate agency on the Vieux-Port why it was still losing requests with a chatbot and a Make automation in place, so we replayed one of the lost ones, sent by a woman at 7:40 on a Thursday evening, through both and then through an agent.

The chatbot (Crisp) sent her a booking link in under a second, which she never clicked. The automation had processed 140 requests without an error since it was set up and stopped on the 141st without any alert, because she had typed her mobile number into the email field, and it took three weeks and a low contact count in HubSpot before anyone noticed. I still build automations like that one every month, since at 10 or 20 € a month nothing beats them when the data coming in is clean, which is maybe half the time.

For the test, the agent got a goal, a list of tools and four things it must never do. It asked the visitor to confirm her number and then booked a slot in the calendar of Marc, the negotiator, so it did more or less what a person at the agency would have done the next morning, only 13 hours earlier.

Gartner called the habit of selling chatbots as agents "agent washing" in June 2025 and estimated that only about 130 of the thousands of vendors marketing agentic AI were the real thing. My test for a salesperson is to ask which of my programs their product can act in without me, and if the answer is none, it's a chatbot, whatever it costs.

Five examples of AI agents in small businesses

All five are between Marseille and La Ciotat, in the south of France, and have gone live since June 2025. Monthly figures are from the invoices.

A sailing school's inbox near Cassis

The sailing school didn't sign the 4,800 € quote, and has used an agent on its booking inbox since June 2025. In July the school receives 30 to 50 emails a day on a single Gmail address, and about 80% of them ask one of six questions, on dates, prices, minimum age, the mistral, parking and whether children need to be able to swim. Those six it answers alone (with a link to the page on the website); the rest it drafts for the owner.

Set-up cost 900 €, and the model costs between 12 € and 35 € a month depending on the season. A father complained on the second Saturday about receiving a polished reply 40 seconds after a canceled course, and angry messages have been routed to the owner since July 18, 2025.

Viewing requests at the Vieux-Port estate agency

Since November 2025 the agency has kept the agent on its portal requests, which used to wait from a Thursday evening at 7:40 until about 9:10 on Friday, long enough for buyers to write to three other agencies on the quay, and now get an answer in under two minutes with one reminder two days later. For 150 to 200 requests a month the model bill is about 40 €. I wrote up the qualifying rules separately, in a post on lead qualification with an AI agent.

A heating contractor's phone in Aubagne

The contractor missed about fifteen calls a week after 7 pm from November 2024 to February 2025, some of them from people with a broken boiler who then called the next company in the directory, and those calls now go to a voice agent on a Twilio number that takes the address, asks the two questions that tell a leak from a dripping tap and texts real emergencies to the technician on call (you can see a voice agent interface in our portfolio).

Voice costs more, 60 to 180 € a month with the phone line, since a minute of talk is about ten times the data of a written exchange.

Supplier invoices at an accounting firm in La Ciotat

The firm's clients send invoices and receipts to a shared Outlook address. They get sorted by client and month and checked against the bank statements, and at the end of the month each client receives a list of what is missing. Set-up took three weeks instead of the two I had quoted, because the firm's old version of Sage had no usable API, and the model bill is about 48 € a month.

Around 70% of this could be done with a normal n8n workflow (I compare the tools in a post on n8n, Make and Zapier), and the agent is only needed for documents a rule can't handle, like a hardware-store invoice saved as scan0042.pdf.

A carpenter's quotes in Carnoux

The carpenter's quotes used to go out about five days after the site visit, and roughly one in four was never sent. The agent works from a two-minute WhatsApp voice note and his Excel catalog, and the draft is ready the same evening, for around 20 € a month, most of it transcription.

What it costs to set up and run

900 € before tax at my studio and one to three weeks of work, then the model at cost. In September 2026 that was 12 € for the sailing school, down to about ten emails a day by then, and 164 € for the heating contractor with the phone line. The owner of the sailing school phoned to ask whether I had forgotten a zero on hers. I hadn't, though I understand the question, since plenty of offers turn the model into a flat subscription of a few hundred euros.

How many businesses actually run one

I went looking for a number a while back and found two that don't agree. The U.S. Chamber of Commerce says 58% of small businesses were using generative AI in 2025, up from 40% in 2024 and 23% the year before, going by the Lexington Institute's summary of its report. The Census Bureau asks a narrower question, whether a firm used AI in any business function in the past two weeks, and as of May 3, 2026, 19.8% of U.S. firms said yes, with fewer than 20% among firms of four people or fewer. My guess is the Chamber counts everybody who has opened ChatGPT once.

Where AI agents fail

In the same June 2025 release, Gartner predicted that more than 40% of agentic AI projects would be canceled by the end of 2027, citing escalating costs and unclear business value. The problems I have seen at small businesses were smaller, and none of them came from the model.

The carpenter's catalog listed the same door handle three times at three prices, so in the first week his agent produced three different quotes for it. At the estate agency nobody could say how a portal request was handled, since the answer depended on who was asked and on the day of the week, so the first week was spent writing the procedure on one sheet of paper instead of coding.

And the heating contractor's technician was called out one Sunday in December for three dripping taps, because nobody had read the logs that weekend.

Where to start

Pick one process you can count. The heating contractor's count was 31 missed calls in two weeks, and three weeks and 900 € after we automated that one process, with the on-call technician approving at the end, a second two-week count gave 4, all after midnight. If the number had not moved we would have stopped there, and he would have lost 900 € rather than a year.

There's more on choosing that first process in my post on where AI automation pays back first, or you can book a fifteen-minute call with me, in English if you like, even though the booking page is in French.

FAQ

What is an AI agent, in one sentence?

A program given a goal and access to some of your software (Gmail, a calendar, a CRM), which works out the steps itself until the job is done or a person has to decide. A chatbot, by contrast, only answers.

What's the difference between an AI agent and ChatGPT?

ChatGPT is a model in a chat window and can't act in your tools. Connected to the portal and to the negotiator's calendar, as at the Vieux-Port agency, a similar model books the viewing itself.

Can an AI agent work without supervision?

On narrow tasks, yes, such as the sailing school's six recurring questions. On every agent I have built, anything involving money or an unhappy customer goes to a person first, and for a notary in Aubagne, client names and file numbers are never sent to the model at all (it runs in Frankfurt).

How much does an AI agent cost for a small business?

From 900 € before tax at my studio, about $1,000, then the model bill, which for the five businesses above ranges from 12 € to 180 € a month depending mostly on whether the agent reads email or answers the phone.