Threll.ai
Conversation design

Everyone hears the first sentence. Here is how to write it.

The opening line is the only part of a voice agent that one hundred percent of callers hear – and it is almost always written last, in five minutes. Eight steps for writing it properly.

6 min read
A woman in her forties stands in an unbuttoned coat by a window of potted plants, a mobile phone to her ear and a bunch of keys in her other hand, while low sunlight lays a warm band across the blue-grey wall behind the desk

Everything else a voice agent says is heard by some people. The answer about opening hours is heard by the people who asked about opening hours. The escalation line is heard by the people who got transferred. The error message is heard by the unlucky.

The opening line is heard by everyone. It is the second of seven links in an ordinary customer call, and the only sentence in the whole setup with one hundred percent coverage – and it is almost always the last one written, by whoever set up the account, in the field that was still empty just before someone wanted to test.

It has to do four things in under ten seconds, and since this summer one of them is a legal requirement. Here is how.

1. Set a budget before you write a word

Ten seconds is roughly 25 to 30 English words at a natural speaking pace. That is the entire budget. Write the number down before you start and hold to it, because everything you add here is paid for by every single caller.

The budget is tight because the caller's patience does not start when the agent answers. She has already found the number, dialled it and listened to it ring. By the time the agent starts talking, she is some way into her own time, not at the start of yours.

One number is worth keeping in mind here, with the caveat that it was commissioned by a company that sells human phone answering. In a OnePoll survey for AnswerConnect of 6,000 consumers in the US, the UK and Canada in May 2026, 31 percent said they would hang up if they were connected to AI – up from 29 percent the year before. An interested party asked the question, but the direction is worth taking seriously: a third of your callers have already decided to dislike what they are hearing before they know what it is. What they are reacting to is rarely the bot itself – but they react in the opening.

2. Say who is answering before you say what is answering

The first words should be the name of the business.

It sounds trivial. It is the most common reason people hang up early, and it is almost always misread as resistance to AI. A caller who has not had it confirmed that she reached the right place spends the next few seconds wondering about that instead of listening.

“Welcome to” is two wasted words. Start with the name. And for a proportion of callers this is not a question of attention at all: they simply cannot catch the name at that pace, and half a second of silence after the greeting costs nothing.

3. Say it is AI – as information, not as an apology

Since 2 August 2026 the European Commission's AI Office and national authorities have been enforcing the AI Act, and the new transparency rules require systems that interact with people to make clear that they are AI and not a human. For a voice agent that means, in practice, saying so audibly, early, and in a language the caller understands. It is the cheapest requirement in the rulebook to meet and the most expensive to ignore.

The craft is in the wording. “I'm a digital assistant” is a sentence. “This call may be processed by automated systems” is a confession, and it is vague enough to be poor compliance as well.

And do not apologise. An apology in the opening invites the objection it is trying to head off – the caller had not thought of it until the agent suggested it.

Want to talk it through with someone who has done this before?

Fifteen minutes on a call. We will tell you honestly whether a voice agent fits your setup – and what has to be settled before it goes live.

Book Meeting (opens in a new window)+47 24 12 66 30

15 minutes · no obligation · pick your own time

4. Offer a way out in the same breath

The escape hatch belongs in the opening line, not three turns into the conversation.

“Just say if you would rather talk to one of us” costs about ten words and removes the strongest reason to hang up: the fear of being stuck. A caller who knows she can reach a person is in no hurry to test it. A caller who does not know tests it immediately – usually by saying “agent” three times, or by hanging up.

The sentence is of course only worth whatever actually happens when someone uses it. Escalation is the part of the setup that is most expensive to do halfway, and a promise in the opening line is a promise you have made to every caller.

5. Ask one open question – then stop talking

Finish with one question. “What can I help you with?” will do.

Not a menu. A setup that asks the caller to choose between billing, orders and other has reintroduced exactly what the agent was bought to remove, just without the keypad. The caller now has to guess which of your categories her problem belongs in, and she guesses wrong more often than you think.

And then the agent has to stop talking. The most common fault in an otherwise good opening line is that it carries on – one more sentence about the call being recorded, one more about opening hours – after the question has been asked. You have asked for an answer and then talked over it.

6. Do not ask for anything you can already look up

If the calling number identifies the customer in your system, the agent should not be asking for a customer number.

Every piece of information you ask for and already have costs two things: seconds, and credibility. The caller knows she rang from the number she is registered with, and an agent that asks anyway reads immediately as a form-filling answering machine. That is an expensive impression to give away in second nine.

7. Write it again in each language – do not translate it

The Norwegian, Danish and Swedish opening lines are not translations of the English one. Word order and rhythm differ, and a sentence translated word for word usually spends a whole extra second getting to the point.

If the agent is set up for more than one language, there is a further requirement. If the call switches language part-way through, the disclosure that this is AI has to be given again in the new language. A disclosure given in a language the recipient does not speak has been said without informing anyone. It is one of six moments that decide a multilingual call, and the only one of them that sits in the opening.

8. Measure the one thing the sentence actually moves

Not satisfaction scores. Not calls answered.

The number is how many callers hang up within the first fifteen seconds. It is the only measure the opening line on its own can move, and it is easy to pull. Measure it for two weeks before you change the sentence, and for two weeks after.

If it falls, the change worked. If it holds steady, the problem was never the opening, and you have saved yourself a round of polishing in the wrong place.

Put together

An opening line that does all four things looks roughly like this:

“Hello, you have reached [company name]. I'm a digital assistant. Just say if you would rather talk to one of us. What can I help you with?”

Twenty-six words. Nine seconds. Name first, disclosure met, a way out offered, one open question – and then silence.

It is not elegant, and it is not supposed to be. It is supposed to be over.

Threll.ai builds voice agents in Norwegian, Swedish and Danish. The opening line is the cheapest part of a setup to change and the only part everyone hears. That is an unusual combination, and most companies leave it unused.

Frequently asked questions

No, and since 2 August 2026 it is not a choice you have. Note also what the figure actually measures: it was commissioned by a company selling human phone answering, and it captures the reaction to being connected to AI with no visible way onward – not the reaction to being told. What the opening can do about that third is offer the way out in the same breath as the disclosure.

Inside the budget, before the open question – not after it. Two obligations and a company name eat around twenty words on their own, so something else has to go: the pleasantry, the “welcome to”, or a shorter phrasing of the way out. Check what your jurisdiction actually requires first, because consent rules for recording differ and some of them ask for more than a notice.

Silence does not mean she did not hear. Give her three or four seconds before the agent says anything, repeat the question once and more briefly, and make the next step a human rather than a third attempt. A third run at the same question is where the caller stops believing there is a way onward.

That is the menu in disguise, just without the keypad. The caller still has to guess which of your categories her problem belongs in, and she guesses wrong more often when the options were read out in passing than when they sit in a menu. Put those three answers where they belong, in the answers, and let the opening end on one question.

It is already in the call log, assembled from two fields: duration under fifteen seconds, and the caller being the party who ended it. Filter those calls and count them per week. It needs no new feature, and two weeks before against two weeks after is enough to see whether the sentence moved anything at all.

Related Articles

Continue reading more articles

See all articles