Scope: Ball Pits (supplies > play > toys > ball_pits) — the enclosure/structure (inflatable, pop-up mesh, foam, frame) AND loose fill balls sold separately or bundled, one register split by product_type.

Seed: (1) ball-pits equivalent of olive oil's harvest_date = small_ball_choking_clearance — almost no listing states ball diameter in mm, it's expensive to check against the 44.4mm federal floor, but it's the one spec that decides whether a pit is legally fit for under-3s. (2) A print-production-manager persona would notice the gap between the marketed "crush-proof" claim and whether the listing gives any test basis for it — same spec-sheet-vs-reality gap as ink coverage claims.

Sources:
[wikipedia_ball_pit] https://en.wikipedia.org/wiki/Ball_pit — ball size ~3in/7.6cm max, hollow plastic, 10mo+ age/suffocation guidance, home vs rental/venue scale — fetched excerpt
[cpsc_small_parts_ban] https://www.cpsc.gov/Business--Manufacturing/Business-Education/Business-Guidance/Small-Parts-for-Toys-and-Childrens-Products — small parts ban 16 CFR 1501, small-ball labeling under 1500.19 — fetched excerpt
[ecfr_1500_2023] govinfo CFR-2023-title16-vol2 part 1500 — small ball = 1.75in/44.4mm, §1500.19 & §1500.20 — fetched excerpt
[ecfr_1500_2022] govinfo CFR-2022-title16-vol2 part 1500 — same 1.75in/44.4mm figure independently at §1500.18(a)(17), second annual edition — fetched excerpt
[ecfr_1307_phthalates] govinfo CFR-2023-title16-vol2 part 1307 — 0.1% phthalate cap, CPSIA 108(a)/(b)(3) — fetched excerpt
[wikipedia_phthalate] https://en.wikipedia.org/wiki/Phthalate — quotes CPSIA 0.1% text verbatim; EU REACH 0.1% — fetched excerpt
[wikipedia_polyethylene] https://en.wikipedia.org/wiki/Polyethylene — non-toxic, density 0.88-0.96, crack/impact resistance — fetched excerpt
[wikipedia_pvc] https://en.wikipedia.org/wiki/Polyvinyl_chloride — needs phthalate plasticizers, DEHP banned 2008, CPSC 1998 voluntary pullback — fetched excerpt
[wikipedia_toy_safety] https://en.wikipedia.org/wiki/Toy_safety — ASTM F963-23 (Oct 2023) mandatory US standard; EN71-1/-2 EU standard — fetched excerpt
[cpsc_cpsia] https://www.cpsc.gov/Regulations-Laws--Standards/Statutes/The-Consumer-Product-Safety-Improvement-Act — CPSIA §108 phthalates, testing/certification — fetched excerpt

Branches: product_type→enclosure_only routes to enclosure_style, justified directly by product_type's own facet rationale (enclosure specs and ball-pack specs share almost nothing) rather than any specific Wikipedia sentence — the home-vs-venue sentence in wikipedia_ball_pit backs size_class, not enclosure_style/structure. product_type→balls_only routes to ball_material (polyethylene/PVC distinction, sourced to the two materials-science Wikipedia pages). setting→commercial_venue routes to flame_retardant_cert + commercial_duty_rating (EN71-2/flammability-inspection reasoning, no consumer-listing source needed since it's venue-side). age_stage→infant_sit_up routes to small_ball_choking_clearance (Wikipedia's suffocation-risk-under-10mo sentence plus the CFR choking floor).

Corrections: trimmed four references[].supports lines over the 20-word cap; added cpsc_small_parts_ban as evidence on small_ball_choking_clearance (validator flagged it as unused).

Noise: "latex balloon" and "marble" definitions in 16 CFR 1500/1501 — same choking-hazard family as small balls but not a ball-pit product, left out. Exact wall height, footprint, and weight-capacity numbers, and exact ball-diameter range/pack-count figures — considered, but retail/brand spec-sheet domains were unreachable this run (DNS failures, 403/429, or JS-only SPA content with no server-rendered specs — tried littletikes.com, fisher-price.com/shop.mattel.com, walmart.com, intexcorp.com, bestwaycorp.com, step2.com, childrensfactory.com, angelescorp.com, softplay.com, and several smaller ball-pit-ball brands that didn't resolve at all), so these stayed qualitative/banded facets (size_class, ball_pack_size) rather than invented numeric ranges. The ~3in ball-size ceiling and the 10-month age guidance are single-sourced to Wikipedia and recorded as judgements rather than asserted as dual-sourced facts. IPEMA/ASTM F1918 (commercial soft-contained-play equipment standard) was checked but yielded no fetchable scope text this run; the commercial-venue safety angle was covered instead through EN71-2/flammability and CPSIA, which did have confirmed fetched text.

Corrections (2026-10-26):
- Named ASTM F1918 (soft contained play equipment standard) and IPEMA in commercial_duty_rating's definition/why_experts_care plus a new vocabulary entry; re-tried ipema.org, astm.org and cpsc.gov directly (all 403/blocked, same as the original run), so this is named from general standards knowledge, not a newly fetched citation — flagged here per the register's disclosure practice.
- Dropped cpsc_cpsia from flame_retardant_cert's evidence (it only supports the phthalate cap, not flammability) and moved it to phthalate_bpa_compliance's evidence, which it actually supports; flame_retardant_cert now cites wikipedia_toy_safety alone (its EN71-2 flammability claim).
- Reclassified age_stage from source: researched to source: listing, matching its own listing_field_hint/backfill_note, which already describe a listing-level field.
- Added a new structure_context facet (standalone_pit / integrated_into_play_structure / therapy_or_educational_use) and two new wikipedia_ball_pit supports lines for it. Could not find a second independent source despite trying Wikipedia's Sensory room, Sensory integration therapy, Jungle gym and Trampoline park articles (none mention ball pits substantively) and IPEMA/astm.org/cpsc.gov (all blocked) — single-sourced to wikipedia_ball_pit, disclosed here as the register does elsewhere for single-sourced claims.
- Corrected the Branches line above: the enclosure_only→enclosure_style leg was wrongly attributed to "Wikipedia's home-vs-venue split sentence," which actually backs size_class, not structure/style; rewritten to cite product_type's own rationale instead.
- Raised commercial_duty_rating's backfill_cost from medium to high to match flame_retardant_cert, since both describe the identical "only on B2B spec sheets, not consumer listings" sourcing difficulty.