Notes from the Saytu team

What we learn building a Live2D character that answers preorder, sizing and authenticity questions on anime storefronts.

Right Match Wrong Image

The product match was right; the card still made it look wrong

A shopper asked for white, and we found a product that really had a white variant. But its main card image was black. We changed the rule so a variant-only match must be stated in the reply or the card stays off the rail.

Build logSeptember 22, 20264 min read

Nine tied rows were enough to make the same question retrieve different sources

Nine tied policy rows produced two different top-threes on consecutive calls. The fix was not a better ranking — it was making the ranking we already had give the same answer twice.

Build logSeptember 21, 20264 min read

Instant Avatar redraws the moving parts instead of rebuilding the whole character

One uploaded drawing stays the source of truth. We redraw the two eyes and the mouth and nothing else, because every unrelated difference between two frames becomes motion.

Live2DSeptember 21, 20264 min read

Pixels, frames, contexts

Three ceilings a character runs into, and none of them say so

A Live2D character is a guest in somebody else's page. The pixel budget, the frame cap that made things worse, and the context limit that breaks the next character rather than the one that leaked.

Live2DSeptember 21, 20264 min read

The model only gets to paint inside three ellipses

One uploaded drawing becomes a face that blinks and speaks. Identity holds because everything outside three marked ellipses is the merchant's own bytes, not because the model was asked nicely.

Build logSeptember 21, 20264 min read

The metafields that crowded out the shop policies

Six policies against two and a half thousand metafields, one shared limit, and a refund policy the assistant never saw. Nothing was broken, and nothing reported it.

Build logSeptember 21, 20263 min read