What Claude Agent does — and does not
PaperTax reads your uploaded Swiss tax documents (salary certificates, pillar 3a statements, bank statements, pension and insurance forms) with an AI model operated by Microsoft and extracts the relevant values. Claude Agent (by Anthropic) then uses what was read to generate a field-by-field guide for your canton's official tax application (for example VSTax in Valais, ZHprivateTax in Zurich, or whichever app your canton uses), and answers follow-up questions in chat.
The AI uses the documents and messages you provide, together with tax references and online research. It does not know about income, assets or circumstances you have not shared. A missing document can leave the guide incomplete, and the AI may not notice the gap. It does not submit your return, provide licensed tax advice or legal opinions, or replace a qualified professional.
Limitations and your responsibility
AI models produce incorrect output. Numbers in handwritten or low-quality scans may be misread; the AI's training has a cutoff date and may not reflect the latest cantonal circulars or legislative amendments; edge cases and unusual deductions may be handled incorrectly; and individual tax authority interpretations are not known to the AI.
Swiss tax law puts this responsibility on you and does not let it move. You complete the return truthfully and completely, and you sign it (Art. 124 DBG/LIFD). If it turns out to be wrong, the tax authority comes to you — whatever the source of the figure.
When to consult a professional
If your situation is anything other than a straightforward salaried return, or if you are unsure at any point, consult a certified Swiss tax advisor. When in doubt, ask a human.
The AI providers and data handling
Your uploaded files are read by an AI model that Microsoft Corporation (Redmond, USA) operates on its Azure service. The model was developed by OpenAI; OpenAI does not receive your documents. We reach Microsoft through the AI gateway of our hosting provider Vercel, under a zero-data-retention agreement: Microsoft does not keep your documents after reading them and does not use them to train AI models.
Claude Agent is built by Anthropic, Inc. (San Francisco, USA). When you use PaperTax, what was read from your uploaded tax documents (the extracted values and a text transcription of each document) and your chat messages are transmitted to Anthropic's API in the USA so Claude Agent can build your guide and answer you. Both US transfers are governed by Standard Contractual Clauses.
- Anthropic does not use your documents or conversations to train its AI models — this is guaranteed under our API agreement.
- Anthropic may retain API inputs and outputs temporarily (typically up to 30 days) for safety and abuse monitoring, as described in Anthropic's commercial terms. We do not have a zero-data-retention arrangement with Anthropic.
- Managed Agent transcripts and uploaded file copies are stored until deleted, rather than following that request-retention window. Anthropic’s API retention details
- Anthropic's approach to safety: anthropic.com/safety
The AI generates guidance — it does not make legally binding decisions about you. You review and enter all information yourself, so nFADP Art. 21 automated decision-making provisions do not apply.