AI phone assistant for tax firms: five calls it can take

The 2025 deadline lands on 1 March 2027

The pandemic extension has run out. For tax year 2024, clients represented by a tax firm could still file until 30 April 2026 under Article 97, Section 36(3) of the introductory act to the German Fiscal Code. From tax year 2025 onwards, Section 149(3) of the Fiscal Code applies again: the last day of February in the second following calendar year.

28 February 2027 is a Sunday, so filing happens on 1 March 2027. The workload peak shifts from late April to late February, straight into the weeks already taken up by annual accounts. Miss it and Section 152(2) no. 1 leaves the tax office no discretion: an annual return filed later than 14 months after the year ends triggers a late surcharge, at least 25 euros per started month under subsection 5.

Whether clients phone more often in those weeks is measured by no public survey. Only the date is certain, along with the fact that every February call pulls someone out of a return.

Five requests it may take, two it never answers

The assistant records; it does not reply. telfo describes exactly this role for tax firms: it captures the request, the callback reason, availability and the service area without giving tax advice, flagging anything time critical. That limit comes from professional law, not from the vendor. Section 57(1) of the Tax Advisory Act requires confidentiality over everything learned in practice.

These five requests can be captured in full over the phone without any professional judgement. Each line names the fields the transcript must carry, so nobody has to call back just to understand the question.

• Callback request: name, client number, callback number, time window, topic in one sentence.
• Documents handed in: document type, period, delivery route, date. Never the processing status.
• Portal login fails: application, error message verbatim, login method used. DATEV lists SmartCard, mIDentity stick or SmartLogin as credentials, none of which gets reset over the phone.
• Letter from the tax office: date of the letter, office, tax number, the deadline printed in it. Then flag as urgent.
• New client enquiry: legal form, trade or sector, service wanted, best time to call back.

Two scripted sentences prevent the expensive mistakes

Two questions stay unanswered, always. The first is any question about a figure: back payment, refund, prepayment, surcharge. The second is the processing status, because answering it would mean reading the client file after verifying who is really on the line.

Write both exits out word for word, or the model will improvise. This phrasing works because it hands the caller onwards instead of turning them away:

• Question about a figure: "I am unable to discuss amounts. I will note your question against your tax number, your adviser will call back today or tomorrow. What number reaches you?"
• Status of a return: "I have no view of the status. I am logging a callback, subject: income tax 2025. Does morning or afternoon suit you better?"
• Escalation: anything carrying a deadline inside ten days goes straight to the responsible person as a message, never into the daily list.
• Emergency: audit orders, enforcement notices and account seizures get put through live, not logged.

159 euros a month against 8.4 hours at the front desk

The arithmetic is small enough to check in your head. Take a firm handling 30 calls per working day: across 21 working days that is 630 calls, and at 1.5 minutes each, 945 minutes. The 159 euro telfo plan with 1,500 included minutes covers it, the fonio.ai Solo plan at 99 euros with 1,000 minutes barely does. Both are vendor list prices.

If the assistant catches the five standard requests, say 40 percent of calls, that is 252 conversations. At two minutes each for pickup plus the interruption, 8.4 hours a month stay off the front desk. Divide 159 euros by 8.4 hours and you get 18.93 euros: above that fully loaded hourly rate, the assistant pays for itself.

A managed package changes the answer. Digital Apes charges from 1,490 euros setup plus 449 euros a month on a 12 month term, which is 6,878 euros in year one, 573 euros a month, and a break-even of 68 euros an hour. How to spread such amounts across single transactions is covered in our piece on AI cost per transaction.

Section 62a of the Tax Advisory Act dictates four clauses

Here the contract is the permission, not paperwork. Section 62a of the Tax Advisory Act allows a firm to give service providers access to protected facts, but only on conditions, and Section 203(4) of the Criminal Code makes it an offence to skip binding that provider to secrecy. A phone assistant hears names, tax numbers and requests, so it plainly counts as a contributing party.

Check these four points before signing. All of them come straight from subsections 3 and 4:

• Text form, carrying a secrecy obligation with an explicit warning about criminal consequences.
• A commitment to obtain no more knowledge than the contract requires. That bites on call recordings: keeping them 90 days needs a reason you can state.
• A clause on subcontractors, including the duty to bind them in text form too. Speech model, telephony and hosting are often three separate companies.
• For work performed abroad, evidence of comparable secrecy protection. Subsection 5 adds client consent as soon as the service directly serves one single engagement.

What I would do in your place

Yes, if your phone is genuinely busy. From roughly 25 calls a day, with one person also processing returns, the arithmetic above settles it: 159 euros against 8.4 hours. Start with two request types, callback and document handover, then release the other three after four weeks.

No, if you take fewer than ten calls a day, or if most clients already come through the portal. Setup would then cost more time than it returns. No as well if the vendor will not show you the Section 62a contract. An answering machine records just as well, incidentally; it simply sorts nothing and calls nobody back.

If you are also working out which client data may enter an AI system, use our free tool for redacting before the prompt and the article on redacting customer data before the prompt.

Common questions

May the assistant confirm that someone is a client? No. Even confirming the engagement falls under Section 57(1) sentence 2, because it became known in practice. The assistant asks for the tax number; it never confirms one.

Does the client have to agree? For the general office line, no, that is internal organisation. As soon as the service directly serves one single engagement, Section 62a(5) requires consent.

What about calls from the tax office? Put them through, or call back the same day. Advance filing orders under Section 149(4) of the Fiscal Code carry a four month deadline from notification, and a random selection process may pick anyone.

The next step

Take one week of your call log and sort every entry into one of the five lines above, or into a column marked "impossible". If more than 30 percent land in the five lines, ask the vendor for the draft Section 62a contract plus a written answer on where recordings live and for how long.

You can hear what such an assistant sounds like in our voice demo. For setup, escalation rules and contract review, see our services; the same split inside a law firm, where different professional rules apply, is covered in our piece on AI phone assistants for lawyers.