Dr Ishmael.9685:

https://api.guildwars2.com/v1/item_details.json?item_id=20268

This item, “Boxing Gloves,” has a buff listed in the infix_upgrade with only a skill_id, no description. I’m not sure if this is actually an error, or if it’s intentional, but it’s certainly unexpected.

Normally the buff looks like this:

          "buff":
            {
              "skill_id":"[number]"
              "description":"[string]"
            }

Dr Ishmael.9685:

Found another one: Sonic Tunneling Tool
https://api.guildwars2.com/v1/item_details.json?item_id=42664

Cliff Spradlin.3512:

In these cases, there is no description. The buff being applied is more of an invisible, technical one to enable special features on the item. It’s hard to tell the difference programmatically.. maybe I should exclude buffs with no description?

Dr Ishmael.9685:

On one hand, you could say that if there’s no description, then there’s no use knowing the skill_id. On the other hand, you could say that it’s still worth knowing that there is a buff of some sort on the item. I don’t know which way is best.

In any case, it’s still good to know that this is normal/intentional and not a bug in the API so we can work around/with it.