Business letter

Use this for a letter that goes on paper or as a PDF attachment: to a customer, a supplier, a landlord, a bank or an authority. A quotation, order confirmation, delivery note or pro forma has its own skill (trade-documents); a memo inside the company is a plain document.

A business letter has a settled page and settled parts. One script owns the page, so your attention goes to what the letter says and to whom. A letter is sent, so hand back the PDF unless the person asks for Word; the Word file has the same page.

How to make one

1. Read what the person gave you: the letter they are answering, their notes, and the company's own details (address, register number, contact).
2. Write a small spec file (JSON) with the facts. Start from the template for the sender's country:

The sender's country picks the page; "layout": "din5008" (or "us", "uk", "no", "be" and so on) overrides it. Put a US, Canadian or Australian recipient's state or province in state and an Irish recipient's county in county; a Spanish recipient's province and the two letters of an Italian recipient's province go in province, an Italian stair, floor or flat in building. A Belgian sender writes Dutch or French: name the language, or the sender's postcode picks it (Wallonia French, Flanders and Brussels Dutch). 3. Build the letter, PDF first:

python3 <skill folder>/scripts/letter_create.py spec.json letter.pdf
python3 <skill folder>/scripts/letter_create.py spec.json letter.docx

4. Read the JSON it prints. When it says company details are missing, say so in your reply.
5. Keep the spec beside the letter and run the pack check; fix what it names: python3 <skill folder>/../_checks/packcheck.py business-letter <your output>

Nothing given is left off

letter_create.py stops before anything is laid out when the spec holds a key it has no field for, or a value of another shape (the body as one string instead of a list of paragraphs), and names the key. spec.fields.json beside this file lists every key. What the letter says goes in body; a particular of the sender that has no field of its own (a licence, a trade body, a second register) goes in sender.further, one line each, printed in the footer under the register details. Never leave a fact out to make the error go away: put it where the message says, or say in your reply what the page does not carry.

The check fails a letter with no body, or with an address a postman cannot deliver to: the addressee, the street and number or a PO box, the town and the postcode all come from the person's files (LETTER-EMPTY, a house rule).

Run the check with --in and the working folder. It then reads the person's own files there and asks, once and never as a fail (NOTES-FLOOR): which e-mail addresses, numbers, dates and amounts the notes hold and the page does not, which of them the page carries changed, and which figures the letter states that the notes do not. Answer the question once: put each on the page as the notes have it, or say in your reply why it does not belong there. Never change one to shorten the list.

Work in the working folder, the folder the person is working in: write the data file there, run the script from there by its full path (<skill folder> is the folder this file is in) and give the output a path there. The builder refuses an output path inside the library's own folder, where the person never looks; hand back the path in the working folder.

Look for company.json in the working folder first: it holds the company's own particulars, written once (name, address, VAT and register numbers, registered office, share capital, bank account). The builder fills from it what the data file leaves out of the sender, stops when the two disagree, and the check fails a page whose sender disagrees with it (COMPANY-FILE). When the folder has none and the person gives their company's particulars, write it once: python3 <skill folder>/../_shared/company.py make company.json name="..." country=.. street="..." postcode=.. city=.. vat_id=.. register_number=..; it says which particulars that country's company law still wants. One the files do not give is declared with unknown=<key>, never made up.

When the sender is a company, its own company law asks its letters and order forms to state its particulars (the register and its number, the registered office, and by country the court, the directors, the share capital), and the check fails a page without one of them (LETTER-COMPANY, citing the article). Take each from the person's files or from company.json. One the files do not give is declared in the sender with "unknown": ["register_number"]: it is printed as nothing, the check then only warns, and your reply says the page is not complete without it. Never make one up.

The parts, in order

Language, dates and closings

language is the language the recipient wrote to you in; leave it out and the sender's country decides. English takes the sender's English-speaking country (else the recipient's), French is Canadian when either side is in Canada. The script writes the date from the spec's year-month-day:

German, Swedish and Danish letters from a German or Swedish sender stay on DIN 5008 with its numeric date; their address is written the way the recipient's post office reads it, like every other letter's (EDINBURGH, then the postcode, then UNITED KINGDOM). A Spanish, Italian or Polish letter writes the sender's town before the date. In French the script turns "straight quotes" into « guillemets ». A letter that runs to a second page keeps clear of the footer, on DIN 5008 as on the window layouts, with the closing and the signature on one page; a Finnish letter numbers its pages in the head, the page count in brackets: 1 (2).

Where it comes from, and what is not checked

• The page: DIN 5008:2020 Form B for Germany, and as house style for Sweden (no SIS or PostNord letter standard was read). Its millimetre values are not proved: DIN 5008 is paid and was not bought. Belgium's NBN Z 01-002, the Dutch NEN 1026, Austria's ÖNORM A 1080, SFS 2487, ISO 269 and DIN 680 are paid standards and were not read; what the letters take from them comes from free descriptions and is named below.
• The address: USPS Publication 28, Canada Post, Australia Post, Royal Mail, Posten, Posti and PostNord addressing guidance and the UPU's country sheets; bpost (MassPost Gids section 1, January 2026), PostNL (Vormgevingsvoorwaarden 2026, bijlagen 1 and 3), Österreichische Post (Richtig adressieren) and An Post (Speed up your post); Correos (the UPU sheet for Spain: the postcode and the locality in capitals, the province on its own line), Poste Italiane (Standard di composizione degli indirizzi, August 2023: three to six lines, the building above the street, CAP, locality and province, the last lines in capitals with no punctuation) and Poczta Polska (Zasady poprawnego adresowania i oznakowania przesyłek listowych: the postcode left of the locality, the locality in capitals, the country's name in Polish abroad). All cited, none copied.
• Dates: Unicode CLDR; the GOV.UK style guide (OGL v3) for 9 October 2026.
• Salutations and closings: the US Navy Correspondence Manual (SECNAV M-5216.5) for the US colon and comma, the Australian Government Style Manual for sincerely and faithfully, the OQLF for the French letter, Taaladvies.net (Taalunie) for the Dutch and the Belgian letter; all cited, none copied. For German the Amtliches Regelwerk der deutschen Rechtschreibung 2024, § 72 (CC BY 4.0). No Belgian authority's rule for the French letter and no Irish one for the English letter was found: they follow the French and the British letter the pack already writes. For Spanish the Real Academia Española (Puntuación de saludos y despedidas en cartas y correos electrónicos; the Diccionario panhispánico de dudas on the comma between place and date): a colon after the salutation, never a comma, and a comma or a full stop after a closing with no verb. rae.es refused a direct fetch on 2026-10-10, so these were read through a search tool's reading of its pages. For Polish the Poradnia Językowa PWN (Interpunkcja zwrotów adresatywnych oraz pożegnalnych, 2021): a comma, or an exclamation mark, after the salutation and no mark after the closing. No Italian authority's rule was found, so the check scripts none for Italian and says so.
• The Finnish page number: Kielitoimiston ohjepankki, Sivunumerointi, which cites SFS 2487 (the page count in brackets after the page number, 4 (7)). Cited, not copied.
• Company details: Directive (EU) 2017/1132 Art. 26, GmbHG 35a (AktG § 80 for an AG; HGB § 37a asks the same of a German sole trader or partnership registered as a Kaufmann: the firm, the legal form, the seat, the register court and number), aktiebolagslagen 28 kap. 5 §; for a UK company the Companies Act 2006 s.82 and SI 2015/17 reg. 25 (the part of the UK it is registered in, its number and its registered office, in register, register_number and registered_office); the Corporations Act 2001 s 153 for an Australian company's ABN or ACN; the Belgian companies code art. 2:20, Handelsregisterwet 2007 art. 27 and BW 2:186, Unternehmensgesetzbuch § 14 and the Irish Companies Act 2014 s.151. Spain: Código de Comercio art. 24 (the registered office, the entry in the Registro Mercantil and the legal form; a company that names its capital names the subscribed and the paid-up capital; share_capital, paid_up_capital). Italy: Codice civile art. 2250 (the seat, the register office and number, the capital as paid up for an S.p.A., S.a.p.a. or S.r.l., a sole shareholder, liquidation; sole_shareholder, in_liquidation) and art. 2497-bis (the company that directs it, directed_by). Poland: Kodeks spółek handlowych art. 206 (sp. z o.o.) and art. 374 (S.A.): the seat and address, the registry court and the KRS number, the NIP, the share capital, an S.A.'s paid-up capital, the group of companies (group). Each was read in the official consolidated text (BOE, Normattiva, ISAP).

The envelope window, country by country

No postal operator publishes the exact position of a window. Each publishes the zone a window or an address must stay in, so every window here is a common maker's window placed inside that zone. Checked on 2026-10-09; skills/_shared/letter.py (WINDOW_SOURCES) carries the same table.

For Spain, Italy and Poland the window is the DIN window mirrored to the right on a DL envelope (90 x 45 mm, 20 mm from the right edge and 15 mm from the bottom): it lies inside all three zones, but no operator's or maker's document gives that position. The address keeps to the part of it that each operator's own clearances leave (Poland 10 mm, Italy 5 mm above and below) and that the country's other usual envelope (115 x 225 mm in Spain, 110 x 230 mm in Italy) still shows; the side margins in Spain and Italy are this pack's own, not published numbers.

The check reads the page (paper, window, the address lines), the parts, the date, the salutation and closing for the variant, a Finnish letter's page numbers, and that every label is in the letter's language. It does not judge the tone or whether the letter says the right thing, and it cannot see the envelope: try one letter in the envelope you use before a mailing.

Official texts

Where each named source is published (read 2026-10-09 to 2026-10-20; DIN 5008, NBN Z 01-002, NEN 1026, ÖNORM A 1080, SFS 2487 and ISO 269 are sold, not published):

• DIN 5008:2020-03, DIN Media: https://www.dinmedia.de/de/norm/din-5008/318422674
• Directive (EU) 2017/1132 Art. 26: https://eur-lex.europa.eu/eli/dir/2017/1132/oj
• Germany: GmbHG § 35a https://www.gesetze-im-internet.de/gmbhg/__35a.html, AktG § 80 https://www.gesetze-im-internet.de/aktg/__80.html, HGB § 37a https://www.gesetze-im-internet.de/hgb/__37a.html
• Sweden: aktiebolagslag (2005:551) 28 kap. 5 §: https://www.riksdagen.se/sv/dokument-och-lagar/dokument/svensk-forfattningssamling/aktiebolagslag-2005551_sfs-2005-551/
• United Kingdom: Companies Act 2006 s.82 https://www.legislation.gov.uk/ukpga/2006/46/section/82 and SI 2015/17 reg. 25 https://www.legislation.gov.uk/uksi/2015/17/regulation/25
• Ireland: Companies Act 2014 s.151 https://www.irishstatutebook.ie/eli/2014/act/38/section/151/enacted/en/html
• Belgium: Wetboek van vennootschappen en verenigingen art. 2:20 https://www.ejustice.just.fgov.be/eli/wet/2019/03/23/2019A40586/justel
• Netherlands: Handelsregisterwet 2007 art. 27 https://wetten.overheid.nl/BWBR0021777 and BW Boek 2 https://wetten.overheid.nl/BWBR0003045/
• Austria: UGB § 14 https://www.ris.bka.gv.at/NormDokument.wxe?Abfrage=Bundesnormen&Gesetzesnummer=10001702&Paragraf=14
• Spain: Código de Comercio art. 24 https://www.boe.es/buscar/act.php?id=BOE-A-1885-6627
• Italy: Codice civile arts. 2250 and 2497-bis https://www.normattiva.it/uri-res/N2Ls?urn:nir:stato:regio.decreto:1942-03-16;262
• Poland: Kodeks spółek handlowych arts. 206 and 374 https://isap.sejm.gov.pl/isap.nsf/DocDetails.xsp?id=WDU20000941037
• Australia: Corporations Act 2001 s 153 https://www.legislation.gov.au/C2004A00818/latest/text
• USPS Publication 28 https://pe.usps.com/text/pub28/28c2_009.htm; GOV.UK style guide https://guidance.publishing.service.gov.uk/writing-to-gov-uk-standards/style-guides/a-to-z-style-guide/; Australian Government Style Manual https://www.stylemanual.gov.au/content-types/emails-and-letters; OQLF https://vitrinelinguistique.oqlf.gouv.qc.ca/23309/la-redaction-et-la-communication/redaction-administrative-et-commerciale/correspondance/lettre/synthese-des-elements-de-la-lettre-administrative; Taaladvies.net https://taaladvies.net/opmaak-van-een-zakelijke-brief-in-nederland-algemeen/; Amtliches Regelwerk 2024 https://www.rechtschreibrat.com/DOX/RfdR_Amtliches-Regelwerk_2024.pdf; Kielitoimiston ohjepankki https://kielitoimistonohjepankki.fi/ohje/sivunumerointi/; Unicode CLDR https://cldr.unicode.org/

Say what passed, not more

Tell the person which checks the letter passed and against which source and version. Never call the letter certified, compliant or approved, and give no legal, tax or accounting advice.