SEPA Direct Debit & DATEV Export Skill for MCP Agent

SEPA Direct Debit & DATEV Export

Fee billing is the highest-trust surface of any German membership product. A billing run that reports success but emits a malformed file is a failed run — the failure just surfaces later, at the bank, in someone else's accounting system. This pack supplies the format knowledge needed to say which field is wrong and which rule it violates, rather than "the button did not error".

Everything here is specification-layer knowledge, verified against primary EPC and DATEV sources — what any German-market billing product must emit. What a specific product actually does (its export dialects, its status vocabulary, its configuration) belongs in that product's own domain pack, layered on top of this one.

Module Inventory

Module	Covers	_skill.md
sepa-direct-debit	pain.008 structure and character rules, mandate lifecycle, timing, CORE vs B2B, R-transaction reason codes, IBAN/Creditor-ID validation, bank-statement reconciliation	0.8
datev-extf	EXTF/Buchungsstapel header and record format, silent-non-import rules, SKR03/04/42/49 charts, non-profit tax spheres and KOST1	0.75

The failure taxonomy, fixture matrix and validation heuristics below span both modules — run the whole heuristics list on every export; an XML failure must never suppress the DATEV checks.

Failure Taxonomy

Ordered by how late the failure surfaces. Later is worse: the cost of a defect here is roughly the time until someone notices.

#	Class	Example	Detected by
1	Rejected by schema	Missing MndtId, wrong namespace, NbOfTxs ≠ actual count	XSD validation — free, run it first
2	Rejected by the bank	ChrgBr ≠ SLEV, non-EUR InstdAmt, illegal character in a reference, CtrlSum mismatch	Bank upload — the club sees an error and calls support
3	Accepted, books wrongly	Right amount to the wrong member; EndToEndId not unique; wrong ReqdColltnDt; BtchBookg flipped so the statement shows one lump	Only by reading the file — this is the class this module exists for
4	Correct file, wrong business rule	Pre-notification under 14 days; collecting from a member who resigned; double-billing a family-group payer	Business-rule assertions over the run
5	Surfaces weeks later	MD01 from a dormant mandate; AM05 duplicates; refunds inside the 8-week window	Return file — after the money moved

A QA report is useful in proportion to how high up this list it can push a defect.

Test Fixture Matrix

Synthetic only. Every value below was generated or is a published documentation example; none is a real account. Never copy a value out of a real screen, statement, or export.

Verified-valid IBANs (each passes MOD-97-10, checked locally):

DE50100000000000000001      DE23100000000000000002
DE41500105170123456789      DE62370400440532013001
DE72120300000000202052

Must-be-rejected IBANs (each verified to fail):

Value	Defect
DE00500105170123456789	Check digits zeroed
DE41500105170132456789	Two account digits transposed
DE41500105170123456780	Single digit changed
DE4150010517012345678	21 characters
DE415001051701234567890	23 characters
de41500105170123456789	Lower-case. Note: this one passes MOD-97-10 (uppercase it and the remainder is 1) — it must be rejected on the ISO 13616 upper-case rule, which is why assertion 6 states the case rule separately. A validator that silently upper-cases its input will pass this fixture; that is the defect it is testing for

Verified-valid Gläubiger-IDs: DE13ZZZ00000000123, DE52ZZZ00012345678, DE98ZZZ09999999999. Rejected: DE98ZZZ09999999998 (national identifier mutated).

Member and run cases — each maps to a failure class above:

#	Fixture	Targets
1	Names with ä ö ü ß, capital ẞ, and a non-German diacritic (ą, ł)	Character-set rules — names transliterate, references reject
2	A name long enough to overflow Ustrd / Buchungstext	Truncation
3	First-ever collection sent as RCUR	Must pass — FRST is not mandatory
4	FRST then RCUR on one mandate	Correct transition
5	RCUR after FNAL, and OOFF reused	Must fail
6	Mandate with no collection for 36 months	Dormancy → MD01
7	Mandate amended: new IBAN same bank; new bank; changed MndtId	AmdmntInd + the matching Orgnl* element
8	Minor billed through a guardian (Erziehungsberechtigte)	Debtor is the guardian, member is the child — names must not be swapped
9	Family/group account with one payer and three managed members	One debtor, correct total, no double billing
10	Mid-year fee change and an early-ended fee	Pro-rating and refund handling
11	Two invoice numbers in one Verwendungszweck; a truncated one	CSV reconciliation
12	Rücklastschrift (returned debit) in the uploaded statement	Invoice reopens/holds with the return fee attached — per the product's documented behaviour
13	Year-end run: Belegdatum in December, header fiscal year the next	The DDMM year trap
14	Booking dated outside Datum von–Datum bis	Header/period consistency
15	Run with zero collectable members	NbOfTxs = 0 handling, empty-file behaviour
16	Amount 0,00, -1,00, and one above 999999999.99	InstdAmt inclusive range 0.01..999999999.99 (SEPA rejects 0.00 too, IG 2.98); DATEV rejects 0,00 in Umsatz
17	Two members with identical names and amounts	EndToEndId uniqueness
18	A collection date under 14 days after invoice send	Pre-notification rule
19	A Rechnungsnummer containing a space, a dot, or an umlaut	DATEV Belegfeld 1 charset
20	Bookings across all four tax spheres in one export	KOST1 populated per row (SKR42)
21	A batch at the row boundary — 99,996 / 99,997 / 99,998 postings	DATEV per-file row limit (99,999 rows incl. summary lines)

Validation Heuristics — Run These On An Export

Assertions in order of cost. Each is cheap and independent — run them all and report every failure. Do not stop at the first: the two blocks below cover two different artefacts (1–13 the pain.008 XML, 14–19 the DATEV file), so an XML failure must never suppress the DATEV checks.

#	Check	Rule source
1	Validates against the XSD for the version the organisation is configured to emit — pain.008.001.08 unless the product's export-format selector says otherwise	IG EPC130-08
2	NbOfTxs equals the count of DrctDbtTxInf — at group level and again within every PmtInf	IG 1.4 and IG 2.4
3	CtrlSum equals the sum of InstdAmt — at group level and again within every PmtInf	IG 1.5 and IG 2.5, both mandatory in SEPA
4	Every InstdAmt has Ccy="EUR" and lies in 0.01 .. 999999999.99 inclusive	IG 2.98
5	ChrgBr absent or SLEV	IG 2.68
6	Every IBAN is upper-case (ISO 13616), passes MOD-97-10, and German ones are 22 chars	ISO 13616 + ISO 7064
7	CdtrSchmeId passes the Creditor-Identifier check	Verified locally
8	MndtId and EndToEndId: ≤ 35 chars, allowed charset only, no leading/trailing /, no //	Length: IG 2.102 / 2.84. Charset and the / rules: the IG character-set rule, not an element index — see sepa-direct-debit § The character set
9	EndToEndId unique within the file	Reconciliation
10	SeqTp present, and consistent with that mandate's history	IG 2.14 + rulebook
11	DtOfSgntr present, not in the future, not after ReqdColltnDt	IG 2.103
12	Where AmdmntInd is true, AmdmntInfDtls is present and carries the element matching what changed	IG 2.105 (AmdmntInfDtls), 2.106 (OrgnlMndtId), 2.107 (OrgnlCdtrSchmeId), 2.120 (OrgnlDbtrAcct/SMNDA); and 2.121 OrgnlDbtrAgt absent whenever 2.120 is SMNDA
13	Sachkontenlänge in the header matches the target client's DATEV configuration; no all-zero account number. Personal accounts (Debitor/Kreditor) are legitimately one digit longer than Sachkonten, and short accounts need not be zero-padded — do not flag either	DATEV field spec (see the account-length row above)
14	DATEV: line 1 has 31 fields, line 2 has 125, EXTF not DTVF, field 4 agrees with field 3, filename EXTF_*.csv	DATEV sample + doc 1044208
15	DATEV: every amount uses a decimal comma, no 0,00 in Umsatz; every Belegdatum is 4 digits and inside the header period	DATEV field spec
16	DATEV: Belegfeld 1 contains no space, umlaut, ., ,, ; or :	DATEV field spec
17	DATEV: on an SKR42 client, income and expense rows carry KOST1 (field 37) so the tax sphere is not lost. Establish the client's chart first — on SKR03/SKR04 KOST1 is legitimately optional, and whether the exporter populates it per sphere is a per-product fact	SKR42 sphere model
18	DATEV: file is CP1252 / ISO-8859-1. Treat any UTF-8 as a finding pending confirmation — DATEV's documented Zeichensatz for a Buchungsstapel is ANSI, and the BOM carve-out is not stated in DATEV's own field description	DATEV Zeichensatz rule
19	Run the file through DATEV's free Prüfprogramm DATEV-Format before reporting any structural DATEV defect	DATEV Prüfprogramm

Not checkable on the export — verify out of band. ReqdColltnDt ≥ 14 calendar days after the pre-notification (Rulebook EPC016-06) is a genuine compliance rule, but the pre-notification date is not in the artefact, so it cannot be an assertion over the file (see sepa-direct-debit § Collection Timing & Pre-Notification). Check it against the invoice-send date in the run, and remember the Rulebook allows another timeline if creditor and debtor agreed one — a club's fee bylaws (Beitragsordnung) routinely do.

Use the official validator first. DATEV publishes a free Prüfprogramm DATEV-Format (v2.2.3.0) and a Musterdaten bundle on developer.datev.de, neither requiring a login. Running an export through it costs nothing and settles the structural questions before any manual review — make it the first step of any DATEV ticket.

Authoring Rules

1. Synthetic fixtures only, forever. Every member, mandate, IBAN and account in this pack was generated or is a published documentation example. Never add a value copied from a real screen, statement, or export.
2. Pin the specification edition. Every rule cites its document and version; a rule from the wrong year gives money-path QA false confidence, which is worse than no rule.
3. No product-specific claims. What one vendor's exporter does belongs in that consumer's own domain pack, never here.