Ask an AI phone assistant provider where your call data lives and you get one sentence back. Usually a reassuring one. That is almost never the answer, because a phone call passes through at least five hands before it becomes a line in your system — different parties, in different countries, under different contracts.
One sentence cannot cover that. So do not ask for the sentence. Ask for the chain, layer by layer.
Five layers, five different parties
Every AI phone assistant, from anyone, consists of these parts:
- Telephony. Your number sits with a carrier, which records who called when and for how long — even if nothing else is stored.
- Speech to text. Your caller's audio gets transcribed.
- The language model. This decides what the assistant says and asks.
- Text to speech. The voice your caller hears.
- Storage and integrations. Transcript, any recording, appointment, callback request — plus whatever flows on to your calendar, CRM or mailbox.
Layers 2, 3 and 4 often sit with a single supplier. That does not make it a single answer: it means one party sees the content of all your conversations.
Five questions per layer
Put the layers in a column and ask the same five questions at each one:
- Which party is this, by name? "Our platform" is not a party. You want a company name, because that name has to end up in your own record of processing activities.
- Where does the processing happen, and is that contractual? Mind the difference between storage and processing. Data being stored inside the European Economic Area says nothing about where it is processed: many services route on latency or availability, and during a failover it can end up elsewhere.
- What is retained, for how long, and who can reach it? Ask for a period in days, not for "no longer than necessary". And ask who at the provider can open transcripts.
- Is my data used to train or improve a model? This has to be explicitly excluded, including for "quality purposes".
- What if you switch suppliers? Ask whether you hear about it in advance, and how many days. A chain without a notice period can change under your feet.
Above all, do not phrase the region question as "is that possible?", because the answer will always be yes. With suppliers in this chain, a fixed processing region sometimes exists only in the most expensive contract tier, with a separate account and separate keys. The useful question is: which contract is it written into, and which contract do I have?
The data processing agreement is not a formality
As soon as a party processes personal data on your instructions, a data processing agreement is mandatory (Article 28 GDPR). You are the controller; the provider is the processor; everything the provider hires in is a sub-processor. For those sub-processors, you must know who they are and be able to object to a new one. If data goes outside the EEA, you also need a valid basis for that transfer.
In practice three documents have to be on the table before the line goes live: the processing agreement, the list of sub-processors with their locations, and the retention periods. If you cannot get all three, that is your answer. The principles around it — purpose limitation, data minimisation, storage limitation — are in keeping your data in-house.
And do not forget the disclosure duty: since 2 August 2026 a caller has to be told at the start of the call that they are speaking to AI. That is Article 50 of the AI Act, and it sits alongside the GDPR — both apply at once.
The test that exposes everything
Paper is patient. There is one request that shows in a single move whether a provider knows its own chain:
"Here is a phone number. Delete everything you have recorded about it — recording, transcript, appointment, note — including whatever is in the backup, and show me that it is gone."
This is nothing exotic: it is the right to erasure under Article 17 GDPR, which your caller can claim from you. So you have to be able to do it. A provider for whom this becomes an email request and a two-week wait has no grip on its own chain.
What an honest answer sounds like
An honest answer is rarely a pretty one. It sounds roughly like this:
"The speech layer runs with a supplier that processes outside the EEA by default. A fixed processing region only exists in their heaviest contract tier, so we do not promise that. What we do: whatever the assistant records sits on infrastructure under our own management within a minute, and that is where our retention period applies. The processing agreement is written on that."
That is exactly the position I take myself. For the speech layer I promise no fixed processing region — I could not keep that promise. What I do commit to: call data stays under our own management on our own infrastructure, nothing from your conversations trains a model, there is no voice cloning, the AI disclosure is part of the greeting by default, and erasure per phone number is a single action rather than a project.
A provider who answers "in the cloud, completely secure" at every layer promises more than they can keep. That is not a detail: it is your name on the line when your client asks where their data went.
Checklist for the conversation
- Which parties are in the chain, by name and per layer?
- Where is the processing done, and is that region contractually fixed?
- How many days are transcripts and recordings retained?
- Who at the provider can read or listen back to conversations?
- Is training on my data explicitly excluded, including for quality?
- Do I hear in advance when a sub-processor changes?
- Is there a processing agreement before the start?
- Is the AI disclosure standard, and can it be switched off?
- Can everything for one phone number be erased in a single action?
Want to see how this is set up in practice? Look at the AI receptionist or at AI & automation. For the wider comparison between options: AI receptionist, voicemail or call centre.
Please note
This article explains which questions to ask; it is not legal advice. For how the GDPR and the AI Act apply in your situation — certainly with health data or professional confidentiality — consult a specialist lawyer.