AI for German tax advisors (Steuerberater): client books, secrecy and the four-eyes release

Relief for the firm, not a replacement

Tax firms are short of time, not of expertise. The point of AI here is to move routine — sorting receipts, pre-coding, chasing documents, watching deadlines — away from qualified staff, so that review, advice and the conversation with the client get the hours. Clients who keep their own books with AI assistance can hand over receipts that are already sorted and pre-coded; the firm still checks, judges and signs.

The software gives no tax advice. It prepares; the firm decides and carries the professional responsibility.

The firm environment

Where the AI works inside the software

• Receipt coding with a reason, a confidence level and a check flag for anything doubtful.
• Mapping accounts to the line items of the HGB balance sheet and income statement.
• Drafting the notes (Anhang) and tax returns as reasoned proposals that staff edit and release.
• A question box on the firm overview that answers only from the firm's own data — for example which clients still have unbooked bank lines.
• Before any filing, the official ERiC validation; a return that fails it is not sent.

Professional secrecy when an AI provider is involved

Steuerberater must practise independently, on their own responsibility, conscientiously and with discretion (§ 57(1) StBerG), and disclosing a client's secret is a criminal offence under § 203(1) No. 3 StGB. § 203(3) sentence 2 StGB permits disclosure to other persons who contribute to the professional work, as far as necessary. § 62a StBerG sets the conditions when a firm uses an external service provider: careful selection; a contract in text form that binds the provider to confidentiality and points out the criminal consequences of a breach; access only as far as the service requires; and, for services performed abroad, protection comparable to Germany's. Where a service directly serves a single client mandate, the client has to consent to the access (§ 62a(5) StBerG).

For the software itself, jahresabschluss.io provides a data processing agreement under Art. 28 GDPR and a confidentiality agreement under § 62a StBerG that the firm accepts in its settings, with hosting in the EU and no AI training on client data. If the firm additionally connects Claude, ChatGPT or another chat AI to a client's books, that provider receives whatever the AI reads — the firm assesses that provider under § 62a StBerG and data protection law itself. This section describes the rules; it is not legal advice.

Claude or ChatGPT on one client's books

Keys and connections are per company, so per client. A review request with read access only; figures are an example:

You:     Fiscal year 2026, as of 30 September. List postings over
         € 1,000 on account 4964 (licences) and show which have no
         receipt reference. Then compare the trial balance with the
         prior year and flag changes above 20 %.

Claude → list_fiscal_years
       → list_journal_entries     account 4964, up to 2026-09-30
       → get_saldenliste          as_of 2026-09-30, both years

Claude:  Seven postings over € 1,000; two have no Belegfeld 1 …

Someone with the Administrator or Preparer role in that client's workspace creates the key under “AI agent & API” and confirms with the second factor. Every key belongs to exactly one company, carries an expiry date at most 366 days ahead and can be revoked at once. Through the claude.ai connector the same logic applies: one approval, one client company, read-only unless “Post” is ticked on the consent page.

Filing stays with the firm

No AI transmits a return on its own. Through the interface, an external agent can run the official ELSTER check and prepare a VAT return; the filing itself happens in the app, through an approval link and with the ELSTER PIN, which never enters a chat. Corrections under § 153 AO, trade tax with apportionment, wage tax and income tax returns and some other filings are not available through the interface at all.

Inside the firm environment the four-eyes rule applies on top: release and filing by two different authorised people, with the release stamp set on the server so that it cannot be overwritten from the interface. A firm in which only one person may file is not locked out.

Bookkeeping offices without a tax advisory licence

Bookkeeping offices, finance consultants and interim CFOs who are not tax advisers get their own account type. Functions reserved for tax advisers — bulk filing, power-of-attorney management, StBVV fees and the § 62a agreement in the settings — are hidden there, and their clients' deadlines follow the general rule of § 149(2) AO rather than the longer one for advised cases.

Getting started

After a firm account is registered, the firm environment is set up together with you in a joint session, so that the first clients, roles and deadlines are right from day one. The intended start is a pilot with a few representative clients while your current firm software keeps running; you decide which processes move first. Conditions for firms are on the firm page.

Not included

• Income tax returns of the partners of a partnership.
• Connections to the power-of-attorney database and the special electronic mailbox for tax advisers (beSt).
• Payroll: the software does not offer it at present.
• Tax or legal advice; professional responsibility stays with the firm.

Frequently asked questions

Is using AI compatible with a Steuerberater's duty of confidentiality?

It can be, if the provider is involved within § 203(3) StGB and § 62a StBerG: carefully selected, bound to confidentiality in a text-form contract and given access only as far as needed — and, for a service that serves one client mandate directly, with that client's consent. The firm assesses each provider; for its own part jahresabschluss.io offers a § 62a agreement and a GDPR processing agreement.

Does the AI file tax returns for our clients?

No. The AI prepares; staff release and file, with the four-eyes rule. External agents can only check and prepare through the interface.

Can a key for one client see another client's books?

No. Each key belongs to exactly one company, and the company comes from the key, not from the request.

Do we have to replace our current firm software?

No. A pilot with a few clients runs alongside your current system; data comes in as Kanzlei Software-format CSV, posting batches or trial balances.

How is a new firm account activated?

After registration we arrange a joint setup session with you and activate the firm environment there, so it fits your clients and roles from the start.

Can bookkeeping offices without a tax advisory licence use it?

Yes, with a separate account type that hides the functions reserved for tax advisers.