07Vocal FlowIn production
“they interrupt the class to answer the phone, and say exactly the same thing every time”
me, during a ceramics workshop
A voice that answers, and books the appointment during the call.
The business forwards its calls to a dedicated number. A voice answers at any hour, gives information, books the appointment in the calendar, transfers when it is urgent, then sends the summary by text message. If the voice engine goes down, its understudy takes the call on a second engine.
- From the first file to the first answered call
- 2 days
- What's left of it today
- Answers 24/7, books the appointment during the call
- First real call
- 15 March 2026
Showcase and live demo · designed, coded and shipped, solo
un vrai appel, écoutez-le
Salon Camille0:00
AriaSalon Camille, bonsoir ! Je suis Aria, l'assistante du salon. Qu'est-ce que je peux faire pour vous ?
ClientBonsoir... euh, je voudrais une coupe demain, plutôt en fin de journée si possible ?
AriaBonsoir Monsieur Ferrand, avec plaisir. Demain en fin de journée, je peux vous proposer 17h30 ou 18h15.
Client18h15, parfait.
AriaJe récapitule : une coupe, demain à 18h15, au nom de Monsieur Ferrand. C'est bien ça ?
ClientOui, c'est ça.
AriaC'est réservé. Je vous envoie la confirmation par SMS à l'instant. Je peux faire autre chose pour vous ?
ClientNon, ce sera tout, merci.
AriaMerci à vous, Monsieur Ferrand. À demain, et bonne soirée !
RDV noté · SMS envoyé
- Numéro reconnu
- Agenda consulté
- Rendez-vous créé
- SMS de confirmation envoyé
What the sentence meant
A ceramics workshop. The kilns have broken down, firing the pieces customers left behind is weeks late, and everybody waiting for theirs rings up to find out where it stands. The class I am taking stops at every ring: somebody answers, explains, hangs up, picks up where they left off. The same explanation, word for word, ten times in an evening.
The people teaching the class apologised at every ring, visibly embarrassed. That job is not theirs: it could be lifted off their shoulders and handed to a tool.
What happens when the phone rings
When the phone rings, the voice answers with a greeting, then leads the exchange in real time: it gives information, offers slots, books the appointment, and hands over to a human if it has to. It uses whatever tools you plug into it. The calendar and the transfer are the first two, and nothing stops others being written, for a trade or for a single business: what comes next is a library of tools shared from one client to another, and tuned for each.
- The calendar. The voice checks what is free before offering a time, sums it up, and books only after an explicit yes, under the name given during the call. The slot is confirmed by text message or email and placed in the calendars.
- The transfer. On an explicit request to speak to somebody, or in an emergency, the call is transferred to the owner's number. If nobody can be reached, the voice takes the number and promises a call back.
- The ones you add. A tool is built for a trade, sometimes for a single business, and plugs in again at the next one. That is where the product grows: not in the voice, in what you put into its hands.
- The ending. On a clear goodbye, one sentence of recap, then it hangs up.
It is forbidden from saying “that's booked” or “that's noted” until the calendar has confirmed.
A few seconds after hanging up, a model reads the transcript back and writes a summary in two or three sentences, “for an owner reading between two customers”: what the call was about, how it ended, the intent, the urgency, and up to three things to do. The summary goes out by text message, WhatsApp, email or notification, and can be relayed to another tool. If urgency is high, the message opens with URGENT and leaves without waiting.
Calls of under ten seconds produce nothing: they are almost always a robot. So the voice also sorts cold calling from real enquiries, and some people want nothing else: a filter in front of their line.
SMS · au gérant du salon
Salon Camille : appel reçu Julien Ferrand souhaitait une coupe demain en fin de journée. Rendez-vous fixé demain à 18h15, confirmé pendant l'appel et par SMS. Rien à rappeler. Intent: reservation
Hear who is going to answer
click, they really speak
How these voices are made
The voices, on the technical side
- On the phone: Grok for Aria, Ève and Romain; OpenAI for Marine and Sacha.
- On the website: Cartesia, which is Nathan's voice.
- Six voices on the phone, kept after auditioning 34 of them and running a poll.
- The samples are 8 kHz, the quality of the line, not of a studio.
- Every voice has its understudy on the other engine.
Four of the catalogue voices, rendered by the engine that really answers, at telephone quality.
Web version NathanWarm and steady- AriaBright and playful
- MarineClear and natural
- SachaSoft and reassuring
In real time, and you can cut it off
Since July 2026, a single model listens, thinks and speaks: the previous chain, in three stages, took about two seconds to answer. The silence before its answer is now 0.85 seconds. That is noticeable, and it is not the product's argument: reliability is.
You can cut it off the way you would cut off a person. As soon as the caller speaks, the voice falls silent, and whatever it had not finished saying is taken out of its memory: it does not believe it said something nobody heard.
Set up in plain language
The owner does not set parameters: they describe their business in a few sentences. The product draws a short brief for the voice out of it, fifteen lines at most, because a long brief slows the voice down, then reads it back to them in plain French for approval. That brief slides in between a base nobody edits, the voice, the turn-taking, the tools, the limits, the end of the call, and the raw data: opening hours, address, prices, frequent questions.
Un exemple de configuration
Décrivez en quelques phrases ce que votre assistant doit faire : son objectif principal, son ton, vos règles métier. L'IA traduit votre description en instructions précises, et vous validez le résultat avant qu'il soit actif.
Ex : Je tiens une école de surf. L'assistant doit prendre les réservations de cours, demander le niveau (débutant ou confirmé) avant de proposer un créneau, et être décontracté : on tutoie tout le monde. Si quelqu'un parle de blessure, prendre son numéro pour que je rappelle en urgence.
0 caractères
The confirmation came from the sea
The need was confirmed from a completely different trade. A surf instructor spends hours in the water, with no phone. If they do not answer, the person who wanted to book dials the next number and ends up with a competitor. For them, as for every trade with its hands full, a voice that answers is not a comfort: it is the difference between a customer and a missed call.
The showcase
The showcase has lived at app.antton-brunel.com since 17 July 2026: cream paper, espresso ink, tilted stamps. It gets a voice playing in under ten seconds.
The pricing fits on a receipt: 79 euros a month, 150 minutes included, 99 euros to set up, no commitment. Self-service activation, on the other hand, is still closed: you come in by appointment.
Abonnement mensuel, 150 min incluses79 €
Mise en service, une seule fois99 €
Au-delà des minutes incluses0,25 €/min
What the voice does not do
- It does not hide what it is. Asked outright, it says it is a digital assistant, and carries on.
- It takes no payment, no bank detail, no password, and gives no medical or legal advice: outside its remit, it passes the call on.
- It does not resume a call in progress if its engine dies after fifteen seconds: the caller hears an apology rather than silence. Picking a call back up mid-way has not been judged necessary at this stage.
- It knows nothing about the business that was not written down for it. The opening hours, the address, the prices come from the configuration, word for word.
The result
“Saying exactly the same thing every time” became: a voice that answers at any hour, books the appointment in the calendar during the call, transfers the emergency, and sends the summary by text message. First real call answered on 15 March 2026, two days after the first file. The silence before its answer: 0.85 seconds, measured.