Scope: Pet Feeders = devices that store and dispense pet food (automatic/programmable electric feeders, gravity hoppers, aquarium fish feeders); plain static bowls are the sibling `pet-bowls` leaf, not this one.

Seed:
1. Feeders equivalent of harvest_date: `dispensing_mechanism` (impeller/auger vs lid-release) — almost never stated on a listing, found only in spec sheets/teardowns, but decides whether odd-shaped treats jam it and whether wet food is even possible.
2. Industrial designer would notice first: whether the auger/impeller housing is actually sealed against the humid food reservoir, or just has a rubber gasket around the motor shaft — the "quadruple sealed" and "airtight" marketing claims describe the lid, not necessarily the mechanism itself, which is where kibble dust actually jams a motor over time.

Sources:
[petlibro_granary_camera_feeder] https://petlibro.com/products/petlibro-granary-automatic-pet-feeder-with-camera — 5L/20ml/1-10 meals/1-50 portions/2-15mm kibble, AC+3xD battery backup, camera+2-way audio, quadruple sealed — fetched spec table
[petlibro_5g_wifi] https://petlibro.com/products/petlibro-5g-wifi-automatic-pet-feeder — confirms same spec table, adds 2.4/5GHz Wi-Fi, dual-bowl variant exists — fetched spec table
[catit_pixi_smart_feeder] https://www.catit.com/products/catit-pixi-smart-feeder — 2.9L/1.2kg ~2wk, 12 meals/12 portions, 9mm kibble, 2.4GHz only, 58hr battery backup (4xC), impeller auto-reverse, stainless dish, airtight seal — fetched product page
[petsafe_healthy_pet_food_station] https://web.archive.org/web/20100217051651/.../Healthy-Pet-Food-Station-Large.aspx — gravity feeder, 2/4/10 lb S/M/L, BPA-free hopper, stainless bowl, lock-in base, dishwasher safe — fetched Wayback snapshot
[petmate_replendish_feeder] https://www.petmate.com/products/petmate-replendish-pet-feeder-with-microban — gravity feeder, 2/5/10 lb XS/S/M, Microban antimicrobial bowl, transparent reservoir — fetched product page
[surepetcare_microchip_feeder] https://www.surepetcare.com/en-us/pet-feeder/microchip-pet-feeder — microchip/RFID selective lid, wet+dry, 400ml bowl, sealed/fly-free, ~6mo on 4xC batteries, optional Wi-Fi hub — fetched product page
[wikipedia_aquarium_fish_feeder] https://en.wikipedia.org/wiki/Aquarium_fish_feeder — clamp-to-rim, timer-rotated hopper, flake/pellet/freeze-dried, prevents overeating — fetched article
[eheim_autofeeder] https://www.eheim.com/aquaristik/zubehoer/fuettern/autofeeder/eheim-autofeeder — battery standard vs AC+WiFi+app "+" model, ~125ml actively ventilated chamber, mounting bracket — fetched product page (German)
[petlibro_polar_wet_food_feeder] https://petlibro.com/products/polar-wet-food-pet-feeder — Wi-Fi wet-food feeder, thermoelectric-chilled compartment keeps 3 meals fresh 3 days ("no ice packs needed"), cooling pauses before serving, dishwasher-safe stainless bowl — fetched product page

Branches:
feeder_type=automatic_electronic -> routes to connectivity/capacity/meal/kibble/power/camera/mechanism/recognition/food-type/seal/bowl facets — supported by petlibro + catit spec sheets covering exactly these rows.
feeder_type=gravity_non_electronic -> routes to hopper_capacity + hopper_material only — supported by petsafe + petmate, which carry no electronic specs at all.
feeder_type=fish_aquarium -> routes to connectivity/food-type/mounting/ventilation — supported by wikipedia primer + eheim (battery vs AC+app split mirrors the dog/cat split).
connectivity_tier=basic_timer -> makes camera_feature irrelevant: softened claim — no fetched basic-timer (non-Wi-Fi) product was found as positive evidence; this rests on an absence claim (no camera on any fetched product) plus the logical dependency that a live camera feed needs an app/cloud connection a basic timer doesn't have. Treat as a reasoned inference, not a confirmed spec-sheet fact, until a true basic-timer product page is fetched.
connectivity_tier=wifi_app_smart -> then_ask camera_feature: both petlibro smart models offer camera as an add-on tier, confirming it's a real follow-up question only once Wi-Fi/app is already in play.

Noise (spec-sheet rows with no facet):
Model/SKU number — not buyer-relevant.
Net weight of the unit — packaging/shipping detail, not a buying criterion.
Overall unit dimensions (W x H x D) — fit-on-counter concern, too device-specific to generalize as a facet.
Warranty length (Petlibro 24mo) — commerce term, not expertise.
Operating temperature range (Petlibro 0-55°C) — single-brand only, no second source, and rarely a deciding factor indoors.
Cable length (EHEIM ~200cm) — minor installation detail, single-sourced.
"Instant feed" manual-dispense button — near-universal convenience feature, not a differentiator.
Idle/active power draw in watts (Catit) — not something a buyer compares.
Color/finish options — never expertise, per category-expertise rules.
"Pet-Proof Design" (secure lid / stable base against tip-over or pawing, per PetSafe's own "lock-in hopper design to prevent knock-over" bullet and the Silver Paws Pets buying guide's top-6 list) — logged here rather than added as a facet: it overlaps heavily with the build-quality judgement already carried by hopper_material/freshness_sealing, and like the already-excluded unit dimensions it's closer to a build-quality impression than a spec a buyer compares number-to-number across listings.

Corrections:
camera_feature.cold_start_question shortened from a 13-word "Do you want..." preamble to "See and talk to your pet at feeding time?" to pass the 12-word cap and drop the preamble.

Corrections (2026-10-26):
Added facet `wet_food_cooling_method` (none_sealed_bowl_only / ice_pack_or_chilled_compartment) to recover the cooling-mechanism distinction food_type_compatibility's dry_only/dry_and_wet binary was losing; evidence surepetcare_microchip_feeder + new petlibro_polar_wet_food_feeder.
Added facet `dishwasher_safe_parts` (boolean) for the removable-parts cleaning factor the buyer's guide names and PetSafe/Petmate/Petlibro Polar all confirm; applies to both automatic_electronic and gravity_non_electronic branches.
Added facet `anti_jam_feature` (none / app_alert_only / auto_reverse_on_obstruction) covering Catit's confirmed auto-reverse and Petlibro 5G's jam-resistant-vane-plus-app-alert design (added that line to petlibro_5g_wifi's supports).
Relabeled `reservoir_capacity.source` from researched to listing to match hopper_capacity's identical title-level signal.
Softened the connectivity_tier=basic_timer -> camera_feature makes_irrelevant justification above (no basic-timer product could be fetched as positive evidence; left as a reasoned absence/logical-dependency claim).
Added "Reservoir" vocabulary entry so "Hopper" and "Quadruple-sealed" no longer define themselves using an undefined term; added "Thermoelectric cooling" for the new facet.
Logged "Pet-Proof Design" in Noise above (not added as a facet) — see reason there.