Which of your prompts count as personal data under Swiss law?

The revised Swiss Federal Act on Data Protection has applied since 1 September 2023. It contains no rule about artificial intelligence, and it does not need one. It governs the processing of personal data, and a prompt is processing.

That single sentence resolves most of the questions companies ask about AI and Swiss law.

The test is simpler than people expect

Personal data is any information relating to an identified or identifiable natural person. Not just names: a customer number, a vehicle plate, a job title in a small firm, or a description specific enough to point at one individual.

So: pasting a customer complaint into a chatbot is processing personal data. Asking for a rewrite of a performance review is processing personal data, and sensitive data at that. Asking for a synonym is not.

The distinction is not whether the tool is clever. It is whether a person is identifiable in the text.

What follows in practice

• You need a lawful purpose and proportionality. Sending an entire customer file to summarise one paragraph fails on proportionality regardless of consent.
• Disclosure abroad needs a basis. Most large models run outside Switzerland. Adequate-country status, the Swiss-US Data Privacy Framework, or standard contractual clauses — one of them must apply, and your vendor should name which.
• It belongs in your processing register. Many SMEs are exempt from keeping one, but if you keep one, AI tools are processing activities like any other.
• Sensitive data raises the bar. Health, religion, trade-union membership, legal proceedings, biometrics. In an SME, that is mostly HR material. Treat it as off-limits for general chatbots unless you have specifically cleared the path.

The one rule worth giving your team

Forget the legal vocabulary and give them this: before you paste, ask whether you could identify a specific person from the text. If yes, either remove the identifying parts or use the approved tool.

It is not a complete summary of the Act. It is the version people will actually remember on a Tuesday afternoon, and it prevents the great majority of real incidents.