# Envelopes, cards and forms: research notes

Date: 2026-10-25. Scope: paper mailing envelopes (business, window, security, catalog and booklet, invitation and A-series, square), blank cards sold as stationery (index cards, greeting and note cards, postcards), and fill-in business paper (IRS information-return form kits such as 1099 and W-2, computer and manual checks, carbonless receipt, invoice and order books). One register; the splits divide the three families. Left to siblings: padded, bubble, poly and photo mailers (`shipping-boxes`, "Shipping Boxes & Mailers"); cardstock sheets and printable sheet stock (`paper`); address and shipping labels (`labels`); gift tags and gift-card sleeves sold as gift wrap (`gift-bags`); dated planners and calendars (`planners`); educational flash cards (play, "Flash Cards & Reading Toys"). Where a sibling's product overlaps (a 1099 kit that ships with double-window envelopes, a card pack with envelopes), this register covers it as the main product and the bundled part as a facet (`envelopes_included`), not as a second product.

Market: the register is written for US listings (USPS rules, IRS forms, North American envelope numbers). ISO sizes (DL, C5, C4) are kept as values because imported listings carry them, and C5 turns out to be a flat in the US (see Data points).

Quote labels: **verbatim** = the sentence in quotation marks was in text I read myself (pdftotext on a downloaded PDF, or curl plus HTML tag-stripping); **fetched excerpt** = the fetch tool summarised or lightly reworded the page; **search excerpt** = the claim came from a search-engine summary. No search excerpts were used in this run: the session's WebSearch budget was already spent (200 of 200) when this run began, so every source below was reached by direct URL, by following links from a fetched page, or through the Internet Archive. A search-excerpt-only number would not go in category.json in any case.

## Seed

Seed output, verbatim:

```
=== Example entry (from an unrelated category) ===
category: car-tyres
what this shows: a number that is on every listing and still needs a judgement attached, because experts know it only compares within one manufacturer's range.

<example>
{
  "id": "treadwear_grade",
  "label": "Treadwear grade",
  "definition": "A number moulded on the tyre's side, from a US test, that estimates how long the tread lasts relative to a reference tyre set at 100.",
  "why_experts_care": "A 600 should last roughly twice as long as a 300, which is the single biggest driver of cost per mile. The catch experts repeat is that each manufacturer runs its own test, so the number is reliable for comparing tyres within one brand and loose across brands. Softer, grippier tyres sit low on this scale on purpose.",
  "kind": "numeric",
  "unit": "grade",
  "range": { "min": 60, "max": 1000, "typical": "Most everyday tyres sit between 300 and 700." },
  "roles": ["annotation", "sort_key"],
  "novice_answerable": false,
  "source": "listing",
  "listing_field_hint": "Listed as UTQG, usually as three values together, for example 500 A A. Treadwear is the first.",
  "backfill_cost": "low",
  "backfill_note": "If absent from the listing, the manufacturer's spec sheet always has it.",
  "visual": { "chartable": true, "encoding": "position on a horizontal scale, with the grip grade as a second mark so the trade-off shows" },
  "priority": { "narrows_set": 3, "cost_to_answer": 3 },
  "evidence": ["nhtsa_utqg", "tirerack_explainer"]
}
</example>

Judgement that would accompany it:
{
  "claim": "Treadwear grades can be compared across brands as a rough guide but not as a ranking.",
  "confidence": "high",
  "sources_disagree": true,
  "note": "The regulator describes the test as standard. Specialist reviewers say manufacturers calibrate differently. We side with the reviewers because they test the tyres."
}

=== Persona ===
A car mechanic, who thinks in wear, serviceability and what fails first

Ask yourself two things and write the answers under 'Seed' in notes.md:
  1. What is the cards equivalent of the example above?
  2. What would this persona notice first about cards that a typical buyer would not?
Keep what survives the data check. Drop the rest.
```

1. **Equivalent of treadwear: the pound weight.** "24 lb" is on envelope listings (Envelopes.com puts it in the product title) and buyers compare on it, but a pound figure is the weight of 500 sheets of the grade's own basis sheet, and the basis sheet differs by grade (bond 17 x 22 in, cover 20 x 26 in, index 25.5 x 30.5 in; Wikipedia Grammage). So pounds compare within one grade only, the way treadwear compares within one brand. Survived: two sources for the bond basis sheet (Wikipedia Grammage and IRS Pub 1179's "20 pounds (basis 17 x 22-500)"), and the gsm conversion is arithmetic. Kept as the `paper_weight_lb` facet and a judgement. The cover and index basis sheets have one source each, so they stay in these notes and the JSON names only the bond figure.
2. **What the mechanic notices first: the parts that fail in the machine, and the part that expires.** For envelopes the failure point is the sorting machine, not the buyer's hands: clasps, strings, buttons, rigid pieces, square shapes and aspect ratios outside 1.3 to 2.5 all make a letter "nonmachinable" and add a surcharge (USPS DMM 101 and usps.com, both read). For forms the failure point is the IRS scanner and the calendar: home-printed Copy A cannot be scanned and forms are revision-specific to a tax year (IRS Form 1099-NEC notice and Pub 1179). Survived as `postage_class`, `closure`, `copy_a_scannable`, `tax_year` and two judgements. **Dropped:** adhesive shelf life and gum "blocking" in humidity (the mechanic's "what wears out"), because no fetched source carried it and search was unavailable.

## Sources and what each supports

### Regulators: USPS

**USPS Domestic Mail Manual 101, Physical Standards (retail)** https://pe.usps.com/text/dmm300/101.htm (curl, tags stripped)
- verbatim: "Letter-size mail is: Not less than 5 inches long, 3-1/2 inches high, and 0.007-inch thick. ... Not more than 11-1/2 inches long, or more than 6-1/8 inches high, or more than 1/4-inch thick. Not more than 3.5 ounces"
- verbatim: "A letter-size piece is nonmachinable if it has one or more of the following characteristics ... Has an aspect ratio (length divided by height) of less than 1.3 or more than 2.5." ... "Windows in envelopes made of paper do not make mailpieces nonmachinable." ... "Has clasps, strings, buttons, or similar closure devices." ... "Is too rigid" ... "Has a delivery address parallel to the shorter dimension of the mailpiece."
- verbatim: "Flat-size mail is: More than 11-1/2 inches long, or more than 6-1/8 inches high, or more than 1/4 inch thick ... Not more than 15 inches long, or more than 12 inches high, or more than 3/4 inch thick."
- verbatim (6.2.2 Postcard Dimensions): "Not less than 3-1/2 inches high, 5 inches long, and 0.007 inch thick. Not more than 4-1/4 inches high, or more than 6 inches long, or greater than 0.016 inch thick."
- verbatim: "Ineligible cards are subject to letter-size pricing." and "A card that does not meet the applicable standards in 6.2 must not bear the words 'Postcard'".
- Supports: letter and flat boundaries, the aspect-ratio band, clasp and string rule, windows are fine, postcard limits. Confidence high.

**USPS DMM 201, Commercial Letters, Cards, Flats and Parcels** https://pe.usps.com/text/dmm300/201.htm (curl)
- verbatim: "Each stamped card or postcard ... claimed at a card price must be: Not less than 3-1/2 inches high, 5 inches long, and 0.007 inch thick."
- verbatim: "Within an aspect ratio (length divided by height) of 1.3 to 2.5, inclusive" and "Exception: Mailers may use an 11-inch by 8.5-inch sheet to create four identical-size postcards (5.5 inches ÷ 4.25 inches = 1.294 aspect ratio)."
- Supports: second source for the aspect-ratio band and postcard minimums; the four-up postcard exception (relevant because 4.25 x 5.5 is also the A2 card size). Confidence high.

**USPS, Mailing Letters** https://www.usps.com/ship/letters.htm (curl)
- verbatim: "If your envelope can't fit through USPS mail processing machines, or is rigid, lumpy or has clasps, string, or buttons, it's 'nonmachinable' and you'll have to pay $0.49 more to send it. ... You'll also have to pay more if your envelopes are square or vertical (taller than they are wide)."
- verbatim: "Postcards are for short messages that you don't need to put in an envelope." and "(Large or square postcards will cost more.)"
- verbatim: "If you want to send letter-sized papers without folding them, you can use a large envelope (called a 'flat')"
- Supports: square and vertical cost more (second source with DMM 101's aspect ratio and address-orientation rules); clasp surcharge; an unfolded letter page goes in a flat. The $0.49 figure is single-source and changes with every price notice, so it stays here and not in the JSON. Confidence high.

### Regulators: IRS and SSA

**IRS Form 1099-NEC (Rev. December 2026), cover notice** https://www.irs.gov/pub/irs-pdf/f1099nec.pdf (pdftotext)
- verbatim: "Copy A appears in red, similar to the official printed form. However, official printed versions of Copy A are scannable, but self-printed copies of Copy A from this PDF are not. Do not print and file copy A of this PDF; we may impose a penalty for filing information return forms that we can't scan."
- verbatim: "You may download and print Copy B and other copies of this form, which appear in black, to satisfy the requirement to furnish the information to the recipient."
- verbatim: "If you have 10 or more information returns, in the aggregate, to file, you may be required to e-file information returns." and "Note: The order limit for most information returns is 10 due to the e-file requirement."
- verbatim: "we issued an April 2025 revision of Form 1099-NEC ... to use first to report amounts for calendar year 2025. Filers will first file the April 2025 revision with the IRS beginning in January 2026 ... we are developing a December 2026 revision of Form 1099-NEC, to use first to report amounts for calendar year 2026 with the first filings with the IRS beginning in January 2027."
- Supports: Copy A must be the official or conforming red form; black recipient copies can be home-printed; the 10-return e-file line; forms are tied to a reporting year and filed the following January. Confidence high.

**IRS, E-file information returns** https://www.irs.gov/filing/e-file-information-returns (curl)
- verbatim: "E-filing required for 10 or more returns As of tax year 2023, if you have 10 or more information returns, you must file them electronically. This includes Forms W-2, e-filed with the Social Security Administration."
- verbatim: "File for free through the Information Returns Intake System (IRIS) Taxpayer Portal."
- Supports: second source for the 10-return line, from tax year 2023; free e-file route. Confidence high.

**IRS Publication 1179 (Rev. 07-2026), substitute Forms 1096, 1098, 1099, 5498 and W-2G** https://www.irs.gov/pub/irs-pdf/p1179.pdf (pdftotext)
- verbatim: "All print on Copy A of Forms ... 1099-MISC, 1099-NEC ... must be in Flint J-6983 red OCR dropout ink or an exact match. However, the 4-digit form identifying number must be in nonreflective carbon-based black ink in OCR A font."
- verbatim: "Proposed substitutes of Copy A must be exact replicas of the official IRS form with respect to layout and content. Proposed substitutes for Copy A that do not conform to the specifications in this revenue procedure are not acceptable. Further, if you file such forms with the IRS, you may be subject to a penalty"
- verbatim (paper): "20 pounds (basis 17 x 22-500), plus or minus 5% (0.05)"
- Supports: second source for the red-ink Copy A rule and the penalty; private printers may sell conforming red forms; the bond basis sheet is 17 x 22 in. Confidence high.

**IRS Publication 1141 (Rev. 08-2026), substitute Forms W-2 and W-3** https://www.irs.gov/pub/irs-pdf/p1141.pdf (pdftotext)
- verbatim: "SSA-approved black-and-white Forms W-2 (Copy A) and Form W-3 may be generated using a printer by following all guidelines and specifications" and "the preprinted form layout for the red-ink Forms W-2 (Copy A) and Form W-3 must be in Flint J-6983 red OCR dropout ink or an exact match."
- Supports: the W-2 exception: unlike 1099 Copy A, a W-2 Copy A can be printed in black from SSA-approved software. Confidence high.

### Carbonless forms

**NIOSH, Hazard Review: Carbonless Copy Paper (DHHS (NIOSH) Publication 2001-107), via Internet Archive** https://web.archive.org/web/2020id_/https://www.cdc.gov/niosh/docs/2001-107/pdfs/2001-107.pdf (the live cdc.gov URL returned 403 to curl and 404 to the fetch tool; pdftotext on the archived PDF)
- verbatim: "The first sheet in this three-part example is a coated-back (CB) sheet, the second is a coated-front and -back (CFB) sheet, and the third is a coated-front (CF) sheet. The bottom surfaces of the top and the second sheet are coated with a layer of microcapsules that have a diameter of 3 to 6" [µm]
- verbatim: "The weight of the evidence supports the conclusion that exposure to certain types of CCP or its components has, under some conditions, resulted in symptoms of irritation of the skin and of the mucosal membranes of the eyes and upper respiratory tract."
- verbatim: "it is uncertain whether current formulations of CCP represent a significant risk to exposed workers" and "implementing normal precautions and recommendations for maintaining acceptable indoor air quality should be adequate to reduce or eliminate symptoms."
- Supports: how carbonless works (part structure); the health judgement. Confidence high for mechanism, medium for health (the review is from 2000/2001).

**Wikipedia, Carbonless copy paper** https://en.wikipedia.org/wiki/Carbonless_copy_paper (curl)
- verbatim: "When the sheets are written on with pressure (e.g., ball-point pen) or impact (e.g., typewriter, dot-matrix printer ), the pressure causes the micro-capsules to break and release their dye."
- verbatim: "The back of the first sheet is coated with micro-encapsulated dye (referred to as a Coated Back or CB sheet). The lowermost sheet is coated on the top surface with a clay ... (Coated Front, CF). Any intermediate sheets are coated with clay on top and dye on the bottom (Coated Front and Back, CFB)."
- verbatim: "A 2000 review found no irritation or sensitization on contact with carbonless copy paper produced after 1987." and "The average carbonless copy paper contains a high concentration of bisphenol A (BPA)".
- Supports: pressure or impact is needed for the copy (second source with NIOSH's structure); the two sides of the health question. Confidence high for mechanism.

### Envelope sizes, styles and windows

**Envelopes.com, Envelope Size Guide** https://www.envelopes.com/pages/envelope-size-guide (curl; a retailer that also makes its own envelopes, used here as a size chart)
- verbatim: "#10 4 1/8 x 9 1/2 inches The most common size for every day mailing and business needs. Can come plain, or with a variety of windows for return addressing."
- verbatim: "#9 3 7/8 x 8 7/8 inches #9's are common smaller envelopes mostly used as a reply envelope, and often inserted into the #10 or #11 for speedy returns."
- verbatim: "A2 4 3/8 x 5 3/4 inches", "A6 4 3/4 x 6 1/2 inches Their dimensions make them the industry standard for mailing 4" x 6" physical photos", "A7 5 1/4 × 7 1/4 inches ... They comfortably fit standard greeting cards.", "A9 5 3/4 × 8 3/4 inches"
- verbatim: "Gum closure envelopes feature a moisture-activated adhesive strip along the flap that seals securely when dampened" and "Peel and seal envelopes feature a self-adhesive strip protected by a removable liner."
- Supports: North American sizes and their use; closure definitions. Confidence high.

**Wikipedia, Envelope** https://en.wikipedia.org/wiki/Envelope (curl; tables flattened)
- verbatim (table): "A2 (Lady Grey) 4 + 3 ⁄ 8 × 5 + 3 ⁄ 4 ... 1.31 Letter paper folded twice ( 4 + 1 ⁄ 4 × 5 + 1 ⁄ 2 )", "A7 (Besselheim) 5 + 1 ⁄ 4 × 7 + 1 ⁄ 4 ... 1.38", "No. 10 (Business, Commercial) 4 + 1 ⁄ 8 × 9 + 1 ⁄ 2 105 × 241 2.3 No. 9; letter paper folded into thirds", "No. 6 + 3 ⁄ 4 (Personal) 3 + 5 ⁄ 8 × 6 + 1 ⁄ 2 ... Personal check, US currency"
- verbatim: "DL 110 × 220 ... 1 ⁄ 3 A4", "C5 162 × 229 ... A5 (or 1 ⁄ 2 A4)", "C4 229 × 324 ... A4"; "ISO 269 (withdrawn in 2009 without replacement)"
- verbatim: "As of 2009 there is no international standard for window envelopes, but some countries, including Germany and the United Kingdom, have national standards."
- verbatim: "Letters that have a length-to-height aspect ratio of less than 1.3 or more than 2.5 are classified as 'non-machinable' by the USPS and may cost more to mail."
- Supports: second source for every North American size used; ISO sizes; aspect ratios; no universal window standard. Confidence high.

**Envelopes.com, FAQ** https://www.envelopes.com/pages/faq (curl)
- verbatim: "Generally, an envelope should measure 0.25" larger than what is being inserted."
- verbatim: "Booklet envelopes open along the long side, while catalog envelopes open along the short side."
- verbatim: "Simple Seal uses two adhesive surfaces that seal when pressed together. Peel & Seal uses a single adhesive strip protected by a removable liner." and "Traditional gum closures need to be moistened before sealing."
- verbatim: "Security envelopes have an interior pattern that helps keep the contents from showing through."
- verbatim: "every printer is different. Envelope size, paper weight, finish and construction can all affect how an envelope feeds through a printer."
- verbatim: "two papers with the same listed weight can still feel different depending on how they're made."
- Supports: the quarter-inch rule (one source; the size pairs below corroborate it for A-series only); booklet versus catalog; three adhesive closures; security tint. Confidence medium for the quarter-inch rule, high for the definitions.

**Envelopes.com, Clear Window Envelopes** https://www.envelopes.com/pages/clear-window-envelopes (curl)
- verbatim: "Standard #10 window envelopes measure 4 1/8 x 9 1/2 inches and fit letter-size documents folded into thirds."
- verbatim: "Single window envelopes display 1 address area, usually the recipient address. Double window envelopes show both recipient and return address information, making them useful for invoices, checks, payroll, and statements."
- verbatim: "Match the window placement to where the recipient address appears on the folded document. Checking alignment before ordering helps ensure address information remains fully visible through the window."
- Supports: window types; window placement must match the document (with Wikipedia's "no international standard"). Confidence high.

**Envelopes.com, #10 Double Window Envelopes, White with Security Tint 24lb (product page)** https://www.envelopes.com/products/envelopes-white-booklet-10-window-double-4-1-8x9-1-2-white-security-item-ws-3342 (curl; retail listing)
- verbatim: "Top Window-From Left: 10/16, From Right: 5 10/16, From Top: 13/16 From Bottom: 2 7/16 Bottom Window- From Left: 10/16, From Right: 4 15/16, From Top: 2 1/16 From Bottom: 1inch"
- Supports: listing_field_hint for window position (on the product page, not the title); title carries size, window, tint and weight. Confidence high for this listing.

**Envelopes.com, Security Envelopes** https://www.envelopes.com/pages/security-envelopes (curl)
- verbatim: "Security tint is a printed interior pattern that makes enclosed text and numbers harder to see through the envelope." and "Envelopes.com offers #10, #9, #6 3/4, 6 x9 inch, 9 x12 inch, 10 x 13 inch, and W-2/1099 security envelope sizes."
- Supports: security tint is sold across business and large sizes, and in W-2/1099 sizes. Confidence high.

**Envelopes.com, W-2 & 1099 Envelopes (tax shop)** https://www.envelopes.com/pages/tax-shop (curl)
- verbatim: "The correct option depends on the form layout and where recipient and return address information appears, so form and window placement should be checked before ordering."
- Supports: tax-form envelopes are matched to the form layout. Confidence high.

**Envelopes.com, Types of Envelopes (blog)** https://www.envelopes.com/blogs/blogs/different-types-of-envelopes (curl)
- verbatim: "square envelopes add flair for invitations or greeting cards, though they may require extra postage."
- verbatim: "You've got your classic A7s, perfect for 5x7 cards , which are the go-to for weddings and formal invites . Then there are smaller A2s for RSVP cards or thank-you notes"
- Supports: square needs more postage (third source); A7 carries 5 x 7 cards. Confidence high.

**Cards & Pockets, size menu (page itself returned "moved or deleted", the site menu was read)** https://www.cardsandpockets.com/envelope-size-chart (curl)
- verbatim (menu): "(A7) 5 x 7 Flat Card", "(A2) 4.25 x 5.5 Flat Card"
- Supports: second source that card stock is sold under the envelope name it fits (A7 = 5 x 7 in card, A2 = 4.25 x 5.5 in card). Confidence medium (menu text, not an article).

### Paper weight

**Wikipedia, Grammage** https://en.wikipedia.org/wiki/Grammage (curl)
- verbatim (basis sheet table): "Bond, writing, ledger 17 × 22 500", "Cover 20 × 26 500 or 1000", "Index bristol 25 + 1 / 2 × 30 + 1 / 2 500"
- verbatim: "Twenty-pound bond paper is always lighter and thinner than 32-pound bond, no matter what its cut size"
- Supports: pound weights compare only within one grade; the basis sheet sizes. Bond 17 x 22 is confirmed by Pub 1179; cover and index have this one source. Confidence high for the principle.

**Wikipedia, Paper density** https://en.wikipedia.org/wiki/Paper_density (curl)
- verbatim: "The weight in pounds of a ream of basis paper (500 sheets) is used to express the density of any paper produced from it." Supports the definition only. (This page says basis sheets "are usually 17.5 inches by 22.5 inches", which conflicts with the Grammage table and Pub 1179's 17 x 22; I follow Pub 1179 and the Grammage table.)

### Cards

**Wikipedia, Index card** https://en.wikipedia.org/wiki/Index_card (curl)
- verbatim: "The most common size for index card in North America and the UK is 3 by 5 inches ... Other sizes widely available include 4 by 6 inches ..., 5 by 8 inches ... and ISO-size A7 ( 74 by 105 mm ...). Cards are available in blank, ruled and grid styles in a variety of colors."
- Supports: index card sizes and ruling values. Single source; used for the values list only, no threshold.

**Wikipedia, Postcard** https://en.wikipedia.org/wiki/Postcard (curl)
- verbatim: "The United States Postal Service defines a postcard as: rectangular, at least 3 + 1 ⁄ 2 inches ... high × 5 inches ... long × 0.007 inches ... thick and no more than 4 + 1 ⁄ 4 inches ... high × 6 inches ... long × 0.016 inches ... thick."
- Supports: second source for postcard limits.

### Checks

**IRS Pub 1179, sections 2.1.1 and 2.1.5 (re-read after the blind check)** https://www.irs.gov/pub/irs-pdf/p1179.pdf (pdftotext)
- verbatim (2.1.5): "All print on Copy A of Forms 1098, 1098-E, 1098-F, 1098-Q, 1098-T, 1098-VLI, 1099-A, 1099-B, 1099-C, 1099-DA, 1099-DIV, 1099-G, 1099-INT, 1099-K, 1099-LPS, 1099-LS, 1099-MISC, 1099-NEC, 1099-OID, 1099-PATR, 1099-R, 1099-S, 1099-SB, 3921, 5498, and 5498-TA ... must be in Flint J-6983 red OCR dropout ink or an exact match."
- verbatim (2.1.1): "Due to the very low volume of paper Forms 1097-BTC, 1098-C, 1099-CAP, 1099-LTC, 1099-Q, 1099-QA, 1099-SA, 3922, 5498-ESA, 5498-QA, and 5498-SA ... these forms have been converted to fillable online PDFs." ... "Use the official form, found on IRS.gov" ... "All printing must be in high quality nongloss black ink."
- verbatim: "1096 Annual Summary and Transmittal of U.S. Information Returns".
- Supports: the Copy A rule is narrowed to the 2.1.5 list; the fillable exceptions. Confidence high.

**IRS Form 1099-NEC notice, revision rule (re-read)** https://www.irs.gov/pub/irs-pdf/f1099nec.pdf
- verbatim: "For all forms that we do not issue annually (such as Form 1040), the year of the revision date is the first year for which issuers are to use the form to report amounts." The form carries "For calendar year" with a blank, and copies "Copy A", "Copy 1 For State Tax Department", "Copy B", "Copy 2".
- Supports: tax_year restated (a revision stays in use until replaced); part counts. Single source for the revision rule.

**IRS Pub 1141 (re-read)** https://www.irs.gov/pub/irs-pdf/p1141.pdf
- verbatim: "The title of Form W-2 is 'Wage and Tax Statement.'"; "Form W-3, Transmittal of Wage and Tax Statements"; "(Copies B, C, and 2 of Form W-2)", "Copy D (For", "Copy 1", "Copy A—For Social Security Administration".
- Supports: form_number definition; six W-2 copies, matching 6-part kits.

**USPS DMM 101 1.1 and DMM 201 (re-read)**
- verbatim (101 1.1): "For pieces more than 6 inches long or 4-1/4 inches high, the minimum thickness is 0.009. Pieces not meeting the 0.009 thickness are subject to a nonmachinable surcharge under 1.2f."
- verbatim (201): "For pieces more than 4-1/4 inches high or 6 inches long, or both, the minimum thickness is 0.009. Pieces not meeting the 0.009 thickness are nonmachinable letters" and "Cards more than 4-1/4 inches high or 6 inches long, or both, must be a minimum of 0.009 inch thick. (Postcards not meeting the minimum of 0.009 inches thick are nonmachinable letters under 2.1.)"
- Supports: the 0.009 in rule in postage_class. Confidence high.

**Amazon.com search-result titles (curl, 2026-10-25)** https://www.amazon.com/s?k=... (12 queries, listed under Source classes)
- verbatim titles: "1099 NEC Forms 2026, 1099 NEC Laser Forms IRS Approved ... 4 Part Tax Forms Kit, 15 Vendor Kit – Total 23 (63) Forms (Without Envelope)" and the same "(with Envelope)"; "Adams 1099 NEC Forms 2025, 3-Part Kit for 30 Recipients, Includes 30 Envelopes"; "Blue Summit Supplies 1099 NEC 2026 Tax Forms Kit, 25 Pk, 4 Part, Dot Matrix"; "Adams 1099 NEC 3 Up 2021 Continuous Forms, 4 Part Carbonless Forms, for Pin Fed Dot Matrix Printers"; "Blue Summit Supplies W2 2026 Tax Forms Kit, 25 Pk, 6 Part, Envelopes"; "1099 NEC Envelopes 2025 (Not for 2026 Nec.)"; "1099 NEC Copy A Tax Forms 2026 ... Red Scannable Copy A"; "Blue Summit Supplies W2 2026 Copy A Tax Forms, 50 Pk, Red Ink".
- cards: "AUDREE Blank Cards with Envelopes, Watercolor Flower 50 Pack 3.5x5 inches"; "30 PACK Cream Blank Cards and Envelopes 4x6 Inch"; "40 Pack Blank White Cards and Envelopes - 5\" x 7\" ... A7 Envelopes"; "100 Birthday Cards, Happy Birthday Cards Bulk"; "Beautiful Thank You Cards Set of 30 With Envelopes"; "54 All Occasion Greeting Cards with Envelopes Greeting Card Assortment Box"; "Avery Printable Postcards, 4.25\" x 5.5\""; "65lb White Printable Postcards ... Perforated 4 per Sheet"; "Amazon Basics Blank Index Cards ... 3\" x 5\" ... 7.5 pt. Paper Weight"; "250 Count Colored Index Cards 3x5 Inch with Key Ring, 180gsm".
- envelopes: "#10 Envelopes Letter Size Self Seal ... 100% Tinted ... Windowless ... 4-1/8 x 9-1/2 Inches | 24 LB"; "500 Pack #10 Single Window Self-Seal Envelopes, Security Tinted"; "100 Minas Envelope - 9 x 12 Inch Booklet Envelopes ... 28lb Paper, Open Side with Gum Flap Closure"; "300 Pack 9x12 White Catalog Envelopes Peel & Seal ... 120GSM"; "9-x-12-inch Clasp Envelopes ... 28-lb Kraft".
- checks and receipt books: "ABC Computer Voucher Checks Compatible w/Quick Books Check on Top"; "ABC Laser Business Checks, Checks in The Middle"; "ABC Manual Checks for Business 3 on a Page with Stub Voucher"; "DocuGard ... Laser/Inkjet Printer Compatible"; "2 Pack Invoice Books, 2-Part Carbonless Receipt Books"; "2 Pack Receipt Books with Carbon Copies, 3-Part Carbonless".
- Supports: listing reclassification; envelopes_included on tax kits; part counts and dot-matrix kits on tax kits; form_number; occasion; check_position; 3.5 x 5 note cards; gsm and pt weights; both opening styles at 9 x 12. Confidence high for "this is on the title"; these are retail titles, not expert sources.

**Checkomatic, Computer Checks** https://www.checkomatic.com/business-checks/computer-checks/ (curl)
- verbatim: "Computer Check on Top Voucher laser check on top 2 perforated stubs below check", "Computer Check in Middle", "Computer laser check in bottom 2 perforated stubs above check", "3 on a Page Quickbooks Checks"; "A computer check is a pre-printed check sheet designed to be completed by accounting software rather than by hand"; "your accounting software fills those fields in automatically when you run a print job".
- Supports: check_position values; fill_method for checks. That the buyer picks the layout their software prints is our inference from these sentences.

**Compuchecks, home page** https://www.compuchecks.com/ (curl)
- verbatim: "Check on Top", "Check on Bottom", "Personal 3 on a Page", "QuickBooks Voucher Business".
- Supports: second check-layout source.

**Cards & Pockets menu (re-read)**: "3.5 x 5 Flat Card", "3.5x5 (RSVP) Flat Cards". Second source for the 3.5 x 5 card size.

**Wikipedia, Paper size** https://en.wikipedia.org/wiki/Paper_size (curl): "DL 110 × 220", C-series table "229 × 324" (C4) and "162 × 229" (C5). Second page for the ISO envelope sizes.

**Wikipedia, Card stock** https://en.wikipedia.org/wiki/Card_stock (curl): "In the United States, this usually is expressed in thousandths of an inch, often abbreviated thou points (pt. and pts.)". Single source, so the JSON says only that pt is a thickness, with no conversion; the 0.001 in per point and the 7.5 pt versus 0.009 in comparison stay here.

**Wikipedia, Magnetic ink character recognition** https://en.wikipedia.org/wiki/Magnetic_ink_character_recognition (curl)
- verbatim: "MICR characters are printed on documents in one of the two MICR fonts, using magnetizable (commonly known as magnetic) ink or toner , usually containing iron oxide." and "E-13B ... is the standard in Australia, Canada, the United Kingdom, the United States"
- Supports: the MICR vocabulary entry only.

### Could not reach

- Quality Park (envelope maker): connection refused; Internet Archive CDX returned a captcha page.
- Intuit QuickBooks supplies and help pages (check layouts): curl returned no response; the fetch tool returned 404 for a help-article URL.
- Deluxe business checks pages: 404 on the guessed paths; the personal-checks landing page loaded but carries no specs.
- HP and Brother printer guidance on envelopes in laser printers: no reachable URL without search.
- NIOSH live page: 403 (curl) and 404 (fetch); used the Internet Archive copy.
- WebSearch: session budget spent before this run started. Every URL here was typed directly or followed from a fetched page.

Consequence: checks are the thinnest part of the register. Check layout (top, middle or bottom voucher for accounting software), MICR toner and check security features are real expert concerns but I had no fetched source for any of them, so they are not facets. Laser-printer heat and envelope gum is in the same position.

## Data points used for derived metrics

Envelope sizes (inches, height x length) from Envelopes.com size guide and Wikipedia Envelope; aspect ratio computed as length / height; postage class from DMM 101 (letter: 3.5 to 6.125 high, 5 to 11.5 long, 0.25 thick max, aspect 1.3 to 2.5; flat: above any letter maximum, up to 12 x 15 x 0.75).

| Envelope | Size (in) | Aspect ratio | Postage class (empty, flexible, paper closure) | Typical insert | Clearance over insert (in) |
|---|---|---|---|---|---|
| #6 3/4 | 3 5/8 x 6 1/2 | 1.79 | letter | personal check, currency (Wikipedia) | n/a |
| #9 | 3 7/8 x 8 7/8 | 2.29 | letter | reply envelope inside a #10 | n/a |
| #10 | 4 1/8 x 9 1/2 | 2.30 | letter | 8.5 x 11 folded in thirds (3 2/3 x 8 1/2) | 0.46 x 1.0 |
| A2 | 4 3/8 x 5 3/4 | 1.31 | letter (just inside 1.3) | 4.25 x 5.5 card | 0.125 x 0.25 |
| A6 | 4 3/4 x 6 1/2 | 1.37 | letter | 4 x 6 photo | 0.75 x 0.5 |
| A7 | 5 1/4 x 7 1/4 | 1.38 | letter | 5 x 7 card | 0.25 x 0.25 |
| A9 | 5 3/4 x 8 3/4 | 1.52 | letter | 5.5 x 8.5 (letter folded once) | 0.25 x 0.25 |
| 6 x 9 | 6 x 9 | 1.50 | letter (6 is under 6 1/8) | booklets, folded documents | n/a |
| 9 x 12 | 9 x 12 | 1.33 | flat | 8.5 x 11 unfolded | 0.5 x 1.0 |
| 10 x 13 | 10 x 13 | 1.30 | flat | thick packets | n/a |
| square 5 x 5 to 7 x 7 | e.g. 6 1/2 x 6 1/2 | 1.00 | letter plus nonmachinable surcharge | square cards | n/a |
| DL | 4.33 x 8.66 (110 x 220 mm) | 2.00 | letter | A4 folded in thirds | n/a |
| C5 | 6.38 x 9.02 (162 x 229 mm) | 1.41 | flat (6.38 is over 6 1/8) | A5 or A4 folded once | n/a |
| C4 | 9.02 x 12.76 (229 x 324 mm) | 1.41 | flat | A4 unfolded | n/a |

Findings from the table: the quarter-inch rule (Envelopes.com FAQ) holds for A7 and A9 exactly and for A2 on one side; business sizes leave much more room (a #10 has about 1 in of play along the length). A2 is the one common size near the aspect-ratio floor (1.31). C5, a common European card and document envelope, mails as a flat in the US. Clasp and string closures turn any letter-size envelope nonmachinable regardless of size (DMM 101).

Pound to gsm: gsm = lb x 1406 / (basis sheet area in square inches), from 453.6 g per lb spread over 500 sheets (1 sq in = 0.00064516 m²). Bond basis 17 x 22 = 374 sq in, so 20 lb bond is about 75 gsm and 24 lb bond about 90 gsm. Index (777.75 sq in) and cover (520 sq in) would give 110 lb index about 199 gsm and 80 lb cover about 216 gsm; those two use a single-source basis sheet and stay here.

## Against the existing add-on schema

Add-on read: `zamana-expertise/data/schema-parts/supplies/stationery/add-ons/cards.jsonc`, which has one field: `closure` (enum none, gummed_seal, peel_and_seal, self_seal, clasp, string_button, adhesive_strip, not_applicable, unspecified). `stationery-standard.jsonc` is empty ("no shared block has earned a field yet"). `supplies-standard.jsonc` has `high_signal_markdown` and `sizing` (size_stated, pack_count, pieces_included_text, dimensions, capacity, weight, measurements_text). Kinds below use AGENTS.md rule 4 (vertical anchor, quality currency, hard filter, sizing) or "markdown" for the high-signal markdown line. Proposals only; nothing edited.

| Facet in this register | In add-on today | Proposed kind under AGENTS.md | Note |
|---|---|---|---|
| product_family | no | hard filter (enum envelope, card, form) | The leaf bundles three products that share almost no fields; every other field is conditional on this one. Cheap from the title. |
| envelope_size | partly: `sizing.size_stated` and `sizing.dimensions` in supplies-standard | sizing (enum of named sizes plus the existing dimensions) | Buyers buy by the name (#10, A7), and the name decides fit and postage. Can differ per variant, so it belongs inside `sizing`. |
| window | no | hard filter (enum none, single, double) | A fit fact: the document's address block must show through. Window position (inches from left and bottom) is a second-order fit fact; markdown, since only the product page carries it. |
| closure | yes, `closure` | hard filter | Keep. Noise inside the enum: `adhesive_strip` duplicates `peel_and_seal` (both are a liner-covered strip), and `none` and `not_applicable` overlap. Proposed values: gummed, peel_and_seal, press_seal (two-surface "self-seal"), clasp, string_button, not_applicable, unspecified. |
| security_tint | no | hard filter (boolean) | Invisible in photos (it is inside the envelope), stated in the title. Fits rule 1. |
| opening_side | no | markdown | Booklet versus catalog is in titles, and a photo often shows the flap, so it is borderline under rule 1. Not worth a column. |
| postage_class | no | derived at query time | From dimensions, closure and aspect ratio. Not stored (rule 5: fields derivable from kept fields). |
| paper_weight (was paper_weight_lb) | no | markdown | On envelope titles ("24lb"), but buyers rarely filter on it and the grade must travel with it. Not currency we would augment. The `paper` sibling owns weight as currency. |
| card_type | no | hard filter (enum index, greeting_note, postcard) | Splits the cards family; title-level. |
| card_size | partly: `sizing.size_stated` | sizing | Index cards are bought by size (3 x 5, 4 x 6, 5 x 8); note cards by the envelope name. |
| envelopes_included | partly: `sizing.pieces_included_text` | sizing (count of envelopes) | Already expressible in pieces_included_text; a parsed count would let "with envelopes" filter. |
| ruling | no | none (visual) | A photo answers it (rule 1). Kept in the register as an annotation for the assistant, not as a schema field. |
| form_type | no | hard filter (enum tax_information_return, check, carbonless_business_form, other_form) | Splits the forms family. |
| tax_year | no | hard filter (number) | A wrong-year form is the wrong product. On kit titles; must exist on every tax-form row. |
| copy_a_scannable | no | hard filter (boolean) | The IRS rule makes this the single fact that decides whether a 1099 kit can be filed on paper. Invisible in a photo (red versus black prints look alike on screen). |
| part_count | no | sizing (number), since the same receipt book is often sold in 2- and 3-part variants | The thing buyers specify for carbonless books. |
| fill_method | no | markdown | "Laser and inkjet compatible", "for handwriting" sit in bullets; worth a sentence. |

Add-on fields this register considers noise: inside `closure`, the `adhesive_strip` value (duplicates `peel_and_seal`) and the `none` value (no envelope sells without a closure; cards and forms are `not_applicable`). From supplies-standard, `sizing.capacity` (litres, ounces) and `sizing.weight` mean nothing for envelopes or forms; `pack_count` is the useful sizing field.

## Branches

Each branch names the register sentence, or the sentence in these notes, it follows from. Every `when` value is a value of the split facet. The question-to-value rules are stated in each split facet's definition and repeated here.

**Split 1, product_family ("Envelopes, cards, or forms like 1099s and receipt books?")** Answers map one to one onto the values envelopes, cards, forms.

- when `envelopes`: then_ask envelope_size, window, closure; makes_irrelevant card_type, form_type, tax_year, copy_a_scannable, part_count.
  - envelope_size, window, closure: these are the envelope facets; envelope_size definition "The named size of an envelope"; window and closure are defined on envelopes (window definition "A clear opening in the envelope front"; closure definition "How the envelope flap shuts").
  - card_type irrelevant: card_type definition "Which kind of card, within the cards family". form_type irrelevant: form_type definition "Which kind of form, within the forms family". tax_year and copy_a_scannable are defined on IRS information returns ("The calendar year a tax form reports", "Whether the form's Copy A is the red, scannable version"); part_count on carbonless forms ("How many sheets each carbonless set has"). None applies to an envelope.
- when `envelopes` (blind-check revision): makes_irrelevant also lists form_number and check_position, both defined within forms ("Which IRS form a tax kit holds"; "Where the check sits on a sheet of business checks").
- when `cards` (revised after the blind check): then_ask card_type; makes_irrelevant form_type, form_number, tax_year, copy_a_scannable, part_count, check_position.
  - card_type: its definition. envelopes_included moved off this leg onto the greeting-card leg of split 3, because the index-card leg drops it (checker: WEAK).
  - Irrelevant facets: same definition chain as above; form_number and check_position are defined within forms.
- when `forms` (revised after the blind check): then_ask form_type; makes_irrelevant card_type, occasion.
  - form_type: its definition. card_type and occasion are defined on cards ("What a greeting or note card is printed for").
  - envelopes_included is no longer irrelevant here: tax kits are sold with and without envelopes ("1099 NEC Forms 2026 ... 4 Part Tax Forms Kit, 15 Vendor Kit ... (Without Envelope)" and "(with Envelope)"; "Blue Summit Supplies 1099 NEC 2026 Tax Forms Kit, 25 Pk, 4 Part, Envelopes"; Amazon titles, 2026-10-25), and the facet's definition now covers tax-form kits. The leg was UNSUPPORTED in the blind check.
  - Not made irrelevant on this branch: envelope_size and window, because tax forms are mailed in envelopes matched to the form layout (Envelopes.com tax shop, verbatim above). A chain: forms → mailed in a window envelope matched to the form → window still matters.

**Split 2, envelope_size ("A folded letter, a flat page, or a card?")** Rule (envelope_size definition and why_experts_care): folded letter → #10 (DL for A4); flat page → 9 x 12 (C4 for A4); card → the A-series size named for the card (A2 for 4.25 x 5.5, A7 for 5 x 7, A9 for 5.5 x 8.5), or square for a square card.

- when `#10`, `#9`: then_ask window, security_tint.
  - window: "#10 ... Can come plain, or with a variety of windows" (Envelopes.com size guide); "#9 window security envelopes, #9 double window security envelopes" (Envelopes.com security page). Register: window why_experts_care "Windows come on business sizes".
  - security_tint: Envelopes.com security sizes list "#10, #9, #6 3/4, 6 x9 inch, 9 x12 inch, 10 x 13 inch". Register: security_tint why_experts_care.
- when `9 x 12`, `10 x 13`, `C4`: then_ask opening_side, postage_class.
  - opening_side: "Booklet envelopes open along the long side, while catalog envelopes open along the short side" (Envelopes.com FAQ), and the booklet-versus-catalog choice exists for large documents (same page: "For larger documents ... consider a booklet or catalog envelope"). Register: opening_side definition.
  - postage_class: these sizes exceed the letter maximum of 6 1/8 x 11 1/2 in (DMM 101), so they pay flat prices (Data points table). Register: postage_class why_experts_care "9 x 12 and C5 mail as flats".
- when `square`: then_ask postage_class.
  - "You'll also have to pay more if your envelopes are square" (usps.com) and aspect ratio under 1.3 is nonmachinable (DMM 101). Register: postage_class why_experts_care.
- No branch for `A2`: a draft leg sent A2 to postage_class because its aspect ratio (1.31) is the closest common size to the 1.3 floor, but 1.31 is inside the band, and the short-side-address rule (DMM 101) applies to every envelope, not to A2. The leg could not be traced to a rule that changes anything for A2, so it was dropped before delivery. postage_class still names A2 as the size nearest the floor.
- No branch for `A6`, `A7`, `A9`, `#6 3/4`, `6 x 9`, `DL`, `C5`: nothing downstream changes beyond what the size itself sets. C5's flat status is in postage_class but the branch was not added because C5 is rare on US listings.

**Split 3, card_type ("Index cards, greeting or note cards, or postcards?")** Answers map one to one onto the values.

- when `index cards`: then_ask card_size, ruling; makes_irrelevant envelopes_included, occasion.
  - card_size and ruling: index cards are sold "3 by 5 ... 4 by 6 ... 5 by 8" and "in blank, ruled and grid styles" (Wikipedia Index card); Amazon titles "3x5 ... Ruled Index Cards", "Blank Index Cards ... 3\" x 5\"". Register: card_size and ruling definitions.
  - envelopes_included irrelevant: its definition covers greeting, note and postcard packs and tax kits, not index cards. occasion irrelevant: its definition is limited to greeting and note cards.
- when `greeting or note cards` (revised after the blind check): then_ask occasion, card_size, envelopes_included; makes_irrelevant ruling.
  - occasion: Amazon greeting-card titles split on it ("Happy Birthday Cards Bulk", "Thank You Cards Set of 30", "All Occasion Greeting Cards Assortment Box", "Blank Note Cards ... Blank Inside"). Register: occasion definition.
  - card_size replaces envelope_size (checker: WEAK). A pack with envelopes fits by construction (envelopes_included why_experts_care), and the facet that describes the card is card_size; envelope_size's own question ("A folded letter, a flat page, or a card?") is wrong for someone already buying cards. card_size values now include 3.5 x 5 ("AUDREE Blank Cards with Envelopes ... 50 Pack 3.5x5", Amazon; "3.5 x 5 Flat Card", Cards & Pockets menu).
  - envelopes_included: its definition.
  - ruling irrelevant: ruling definition limits it to index cards.
- when `postcards` (revised after the blind check): then_ask card_size, postage_class; makes_irrelevant ruling.
  - card_size: postcards are sold by size ("Avery Printable Postcards, 4\" x 6\"", "4.25\" x 5.5\""; Amazon) and the size decides the card price (next line).
  - postage_class: "Ineligible cards are subject to letter-size pricing" and the 3.5 to 4.25 by 5 to 6 in, 0.007 to 0.016 in limits (DMM 101, DMM 201, Wikipedia Postcard). Register: postage_class why_experts_care.
  - envelopes_included is no longer irrelevant here: some postcard packs ship with envelopes (checker cites "Blank Postcards & Envelopes - 6 x 4 In, 48-pk"; usps.com's "you don't need to put in an envelope" does not say none are sold with one). ruling irrelevant: ruling definition limits it to index cards.

**Split 4, form_type ("Tax forms, checks, or receipt and invoice books?")** Rule: tax forms → tax information returns; checks → checks; receipt and invoice books → carbonless business forms. `other forms` (lease, bill of sale, log books) is reachable only from the listing, not from this question.

- when `tax information returns` (revised after the blind check): then_ask form_number, tax_year, copy_a_scannable, part_count, fill_method, envelopes_included; makes_irrelevant check_position.
  - form_number: kit titles lead with it ("1099 NEC Forms 2026", "1099 MISC Forms 2026", "W2 2026 Tax Forms Kit", "1099 INT 2026 Tax Forms Kit"; Amazon), and Pub 1179 2.1.5 and Pub 1141 name the forms. A "tax forms" query cannot narrow without it (checker fix 3).
  - tax_year: IRS revision notice (f1099nec, verbatim above). copy_a_scannable: f1099nec and Pub 1179. Register: both facets.
  - part_count (was makes_irrelevant, UNSUPPORTED in the blind check): kits are sold by part count ("Adams 1099 NEC Forms 2025, 3-Part Kit", "4 Part Tax Forms Kit", "W2 2026 Tax Forms Kit, 25 Pk, 6 Part"; Amazon), and the forms carry one copy per party (1099-NEC: Copy A, Copy 1 "For State Tax Department", Copy B, Copy 2; W-2: Copies A, B, C, D, 1 and 2, Pub 1141). part_count is redefined as copies per set, separate sheets or carbonless.
  - fill_method: "Adams 1099 NEC 3 Up 2021 Continuous Forms, 4 Part Carbonless Forms, for Pin Fed Dot Matrix Printers" and "Blue Summit Supplies 1099 NEC 2026 Tax Forms Kit, 25 Pk, 4 Part, Dot Matrix" beside laser kits (Amazon); carbonless copies need impact (Wikipedia carbonless).
  - envelopes_included: kits sold "(with Envelope)" and "(Without Envelope)" (Amazon); see split 1.
  - check_position irrelevant: defined on checks.
- when `carbonless business forms`: then_ask part_count, fill_method; makes_irrelevant form_number, tax_year, copy_a_scannable, check_position.
  - part_count: the NIOSH three-part example; "2-Part Carbonless Receipt Books", "3-Part Carbonless" (Amazon). fill_method: copies form only under pen pressure or impact (Wikipedia carbonless; NIOSH microcapsules). Register: fill_method why_experts_care.
  - form_number, tax_year and copy_a_scannable irrelevant: all defined on IRS information returns. check_position: defined on checks.
- when `checks` (revised after the blind check): then_ask check_position, fill_method; makes_irrelevant form_number, tax_year, copy_a_scannable.
  - check_position: "Computer Check on Top Voucher laser check on top 2 perforated stubs below check", "Computer Check in Middle", "Computer laser check in bottom 2 perforated stubs above check", "3 on a Page" (Checkomatic); "Check on Top", "Check on Bottom", "Personal 3 on a Page" (Compuchecks); "ABC Computer Voucher Checks ... Check on Top", "ABC Laser Business Checks, Checks in The Middle", "300 Business Computer Checks, 3 per Page" (Amazon).
  - fill_method: "Laser/Inkjet Printer Compatible" computer checks versus "ABC Manual Checks for Business 3 on a Page" (Amazon); "A computer check is a pre-printed check sheet designed to be completed by accounting software rather than by hand" (Checkomatic).
  - form_number, tax_year and copy_a_scannable irrelevant: defined on IRS information returns. part_count is left open: no source read on duplicate checks either way.

## Numbers in category.json and how many sources stand behind each

| Number | Sources |
|---|---|
| Letter size 3.5 to 6 1/8 in high, 5 to 11 1/2 in long, up to 1/4 in thick | DMM 101; Wikipedia Envelope |
| Aspect ratio 1.3 to 2.5 | DMM 101; DMM 201; Wikipedia Envelope |
| Postcard 3.5 to 4.25 in by 5 to 6 in, 0.007 to 0.016 in | DMM 101; DMM 201 (minimums); Wikipedia Postcard |
| Flat up to 12 x 15 in | DMM 101 only; in JSON only as "above the letter maximum", without the 12 x 15 |
| #10 = 4 1/8 x 9 1/2 in | Envelopes.com size guide; Envelopes.com window page; Wikipedia |
| #9 = 3 7/8 x 8 7/8 in | Envelopes.com size guide; Wikipedia |
| A2 = 4 3/8 x 5 3/4 in, A7 = 5 1/4 x 7 1/4 in, A9 = 5 3/4 x 8 3/4 in, A6 = 4 3/4 x 6 1/2 | Envelopes.com size guide; Wikipedia |
| A7 holds a 5 x 7 card, A2 a 4.25 x 5.5 card | Envelopes.com blog; Cards & Pockets menu; Wikipedia (A2 content) |
| A2 aspect ratio 1.31 | Wikipedia table; arithmetic on the two-source dimensions |
| 10 information returns e-file line, from tax year 2023 | IRS e-file page; f1099nec notice (10 or more) |
| Flint J-6983 red dropout ink for Copy A | Pub 1179; f1099nec ("Copy A appears in red") for the colour; the ink code itself is Pub 1179 only and appears in vocabulary as "a specific red ink", not by code |
| 20 lb bond basis 17 x 22 in | Pub 1179; Wikipedia Grammage |
| 24 lb bond ≈ 90 gsm | arithmetic on the two-source basis sheet |
| Quarter-inch envelope clearance | Envelopes.com FAQ only; corroborated for A7 and A9 by two-source size pairs; stated in JSON as a medium-confidence judgement with the business-size exception |
| Index cards 3 x 5, 4 x 6, 5 x 8 | Wikipedia Index card; Amazon index-card titles ("3x5", "4x6"); 5 x 8 Wikipedia only, used as a value, not a threshold |
| 0.009 in minimum thickness for pieces over 4.25 in high or 6 in long | DMM 101 1.1; DMM 201 1.1.1 and the card-price standard (added after the blind check) |
| Note card 3.5 x 5 in | Amazon titles (AUDREE, "100 Pack Blank Cards ... 3.5 x 5 Inch"); Cards & Pockets menu "3.5 x 5 Flat Card" |
| Note cards 4 x 6 and 5 x 7 in | Amazon titles; Envelopes.com blog ("A7s, perfect for 5x7 cards") for 5 x 7 |
| DL 110 x 220, C5 162 x 229, C4 229 x 324 mm | Wikipedia Envelope; Wikipedia Paper size (two pages of one publisher; inches by arithmetic) |
| #6 3/4 = 3 5/8 x 6 1/2 in | Envelopes.com size guide menu ("#6 3/4 Remittance 3 5/8 x 6 1/2"); Wikipedia Envelope |
| Tax kits 3-, 4- and 6-part | Amazon titles from Adams, Blue Summit, DutyMark, NextDayLabels; the forms' own copy sets (1099-NEC A, 1, B, 2; W-2 A, B, C, D, 1, 2 per Pub 1141) |
| Receipt books 2- and 3-part | Amazon titles; NIOSH three-part example |
| Revision rule (first used in the revision-date year; Dec 2026 1099-NEC for 2026) | f1099nec notice only; marked single-source in judgement 4. Listings consistent ("1099 NEC Envelopes 2025 (Not for 2026 Nec.)") |

## Trimmed detail

- **summary**: "In the US the post office and the IRS write most of the rules that matter." (kept in mechanism).
- **mechanism.plain**: "ISO 269, the international envelope standard, was withdrawn in 2009 without replacement" (Wikipedia; kept here only). "Windows in paper envelopes do not make a letter nonmachinable" (DMM 101; kept in window why_experts_care).
- **window.why_experts_care**: the Envelopes.com double-window example positions (top window 10/16 in from left, 13/16 in from top; bottom window 10/16 in from left, 1 in from bottom) — listing detail, kept in Sources above.
- **copy_a_scannable.why_experts_care**: the IRS order limit "for most information returns is 10 due to the e-file requirement" (f1099nec; kept in the reference's supports).
- **paper_weight_lb.why_experts_care**: the index and cover conversions (110 lb index ≈ 199 gsm, 80 lb cover ≈ 216 gsm), single-source basis sheets; kept in Data points.
- **postage_class.why_experts_care**: the $0.49 nonmachinable surcharge (usps.com, single source, changes with each price notice). The four-up postcard exception (4.25 x 5.5 at 1.294 aspect ratio is allowed, DMM 201).
- **judgement on carbonless health**: Wikipedia's BPA sentence and the 1997 University of Florida ventilation study it cites; kept here.

## Dropped

- Envelope adhesive shelf life and gum blocking in humidity (seed; no fetched source).
- Laser-printer fuser heat sealing gummed envelopes (no reachable printer-maker source).
- Check layout for accounting software (top, middle, bottom voucher), MICR toner, check security features (no reachable source).
- Envelope seam construction (side seam versus diagonal) and window film material (no source read).
- Price per envelope or per form: generic (price over count), fails the generic test.

## Source classes (listing versus researched)

Revised after the blind check: Amazon search-result titles were fetched with curl on 2026-10-25 (12 queries: 1099-NEC forms 2026, 1099 tax forms kit envelopes, 1099 dot matrix continuous, W-2 forms 2026, blank note cards envelopes, greeting cards assortment box, business checks laser, #10 security envelopes, index cards, blank postcards, 9x12 envelopes, carbonless receipt book; about 18 to 25 titles each). window, closure, security_tint, paper_weight, envelopes_included, ruling, tax_year, part_count and fill_method are on those titles and are now `listing`. copy_a_scannable stays `researched` (only some titles say "Red Scannable Copy A" or "Red Ink") and its cost is now medium. opening_side stays `researched`, as the checker did not ask for it, although 9 x 12 titles carry "Booklet ... Open Side" and "Catalog". The paragraph below is the original reasoning, kept for audit.


Retail marketplaces were not fetched in this run (no search, and earlier runs found them blocked). The only retailer pages read were Envelopes.com's. So `source: listing` is kept only for facts a listing cannot omit and still be sellable: envelope_size, card_type, card_size, form_type (and product_family, derived from the title noun). Window, closure, security tint, opening side, paper weight, envelopes included, ruling and part count are on Envelopes.com titles but are marked `researched` with low backfill cost, with the title text named in `listing_field_hint`. tax_year, copy_a_scannable and fill_method are `researched` because they sit in kit descriptions or on the form image.

## Script problems

- `schema.json` restricts `vertical` to formulations, machines, fashion, furnishing, other. The brief says to set `vertical` to `supplies`, which the schema rejects (`validate.py`: "schema vertical: 'supplies' is not one of [...]"). The brief also requires validate, render and viewer to run clean, and the later fix step writes `.ready` only when validation passes. The delivered JSON therefore carries `"vertical": "other"`, the schema's catch-all. `catalog.json` still records this leaf as `supplies` / `stationery`, and `scripts/publish.py` groups entries from the catalog, not from this field. Sibling supplies registers in this folder are split between `supplies` (which fails validation) and `other`. Fix belongs in the skill's schema (add `supplies` to the enum), which this run must not edit.

## Corrections

Author's pre-delivery pass (2026-10-25), before any blind check:

1. Split 2 branch `A2 → postage_class` dropped as untraceable (see Branches).
2. "Reusable" removed from the clasp claims (closure facet, its cold-start question, and the clasp trade-off): no source read says clasps are reused; the sourced fact is only that they make a letter nonmachinable.
3. Card clearance restated as "an eighth to a quarter inch" (the A2 pair is 1/8 in on the short side).
4. Split 1 rationale: "removes about two thirds of the shelf" (an unsourced share) replaced with "removes two of the three families".
5. Eight facets moved from `listing` to `researched`, low backfill (see Source classes).
6. `vertical` set to `other` rather than `supplies` (see Script problems).

Blind check: report in check.md (2026-10-25).

## Corrections after the blind check (2026-10-25)

1. Fix 1: removed `forms → makes_irrelevant envelopes_included`; envelopes_included now covers greeting, note and postcard packs and tax-form kits, `listing`, with Amazon kit titles ("(with Envelope)" / "(Without Envelope)") as evidence.
2. Fix 2: removed `tax information returns → makes_irrelevant part_count`; part_count redefined as copies per set (separate sheets or carbonless), values 2-part to "5-part or more", question "How many copies each: two, three, four or more?"; part_count and fill_method added to the tax leg; fill_method redefined to cover forms and checks, with dot-matrix continuous kits named.
3. Fix 3: new facet `form_number` (1099-NEC, 1099-MISC, 1099-INT, 1099-DIV, 1099-R, 1096, W-2, W-3, other), `listing`, first on the tax leg; new vocabulary entry "Transmittal".
4. Fix 4: tax_year restated from the notice's own rule (a revision not issued annually is first used in its revision-date year and stays in use until replaced; Dec 2026 1099-NEC replaces April 2025 for 2026 payments); judgement 4 now reads "A tax-form kit stays current until the IRS issues a newer revision...", confidence medium, marked single-source; irs_f1099nec supports updated.
5. Fix 5: mechanism, copy_a_scannable and judgement 2 narrowed to the forms in Pub 1179 2.1.5 (1099-NEC, MISC, INT, DIV, R and others), naming the 2.1.1 fillable exceptions (1099-Q, 1099-SA, 1099-LTC); irs_p1179 supports updated.
6. Fix 6: greeting-card leg now asks occasion, card_size, envelopes_included (envelope_size removed); card_size gains "3.5 x 5" (Amazon titles; Cards & Pockets menu) and the question "Which size: 3x5, 4x6, 5x7, or another?"; new facet `occasion` (blank inside, thank you, birthday, all-occasion assortment, other occasion) rather than scoping printed cards out, since Amazon greeting-card results are mostly printed or assorted boxes.
7. Fix 7: envelopes_included removed from the cards-family leg of split 1; it is asked only on the greeting-card and tax legs.
8. Fix 8: postage_class why_experts_care and backfill_note now carry the 0.009 in rule (DMM 101 1.1; DMM 201); the "treat card stock as eligible" default replaced by "mark the surcharge unknown unless thickness is listed"; DMM supports lines added.
9. Fix 9: checks leg now asks check_position (new facet: check on top, in middle, on bottom, 3 per page; Checkomatic, Compuchecks, Amazon) and fill_method. Vocabulary "Voucher check" added. "Could not reach" still holds for MICR toner and security features, which stay out.
10. Fix 10: window, closure, security_tint, paper_weight, envelopes_included, ruling, tax_year, part_count, fill_method moved to `listing`, with an `amazon_titles` reference and listing hints quoting the title words.
11. Fix 11: paper_weight_lb renamed `paper_weight`, kind text, accepts lb, gsm and pt as listed; derived metric bond_gsm renamed `weight_gsm`: listed gsm, else lb x 1406 / 374 only when the grade is bond, else not computed (no default grade assumed, since no source says envelope pound weights are bond); vocabulary "Points (pt)" added (Wikipedia Card stock, one source, so no conversion figure).
12. Fix 12: new numeric facets `envelope_height_in` and `envelope_length_in` (`listing`), with the name-to-inches lookup in envelope_height_in's backfill_note (two sources per size; ISO sizes from Wikipedia Envelope and Paper size); aspect_ratio and insert_clearance_in depend on them, and insert_clearance_in names its insert dimensions (card_size, or 3 2/3 x 8 1/2 for a letter in thirds, Wikipedia Envelope table); the letter-size-box grammar encodes them.
13. Fix 13: scope boundaries written into mechanism.families: printed flash-card sets to `flash-cards`, tear-apart postcard sheets and sheet cardstock to `paper`, thermal receipt rolls to `paper`, check registers to `notebooks`, padded and poly mailers to `shipping-boxes`. The roll and register assignments are our calls; no source decides them.
14. Fix 14: copy_a_scannable question is now "Filing paper forms by mail, or filing online?"; backfill cost raised to medium (a brand-page visit per kit when the title is silent).
15. Fix 15: opening_side's "matters on 6 x 9 and larger sizes" dropped; it now says both styles are sold at 9 x 12 (Amazon "9 x 12 Inch Booklet Envelopes ... Open Side" and "9 x 12 ... Catalog Envelopes"). `postcards → makes_irrelevant envelopes_included` removed and card_size added to the postcard leg.
16. Checker Part A note: the carbonless judgement now says "under some conditions" (NIOSH's words) instead of "in heavy use".
17. Checker Part B note: envelope_size's answer rule now maps a square card to `square`, so the square branch has a question path.
18. Summary updated to "Tax kits are bought by form number and year"; form_type rationale and why_experts_care rewritten, since tax kits and receipt books now share part_count and fill_method; card_type rationale and why_experts_care name occasion and size.

Rejected: none. Not acted on: the checker's note that window position has no value in the facet (not a required fix; position stays a top-N backfill in window's backfill_note).