NPC Trait Disadvantage on all saving throws

[TheShadow]

Is it possible to automate an NPC trait to have disadvantage on all saving throws?

[Zacchaeus]

There's no form of words that you can use in a trait or action that could automatically create such an effect. You can apply the effect from the effect dialog (DISSAV) after placing the NPC on the Combat Tracker and before you roll initiative.

There is an extension (I believe it's called Advanced Effects) which allows you to create an effect on the NPC and that effect is applied automatically when the NPC is placed on the CT.

[MrDDT]

Is it possible to automate an NPC trait to have disadvantage on all saving throws?

As Zacchaeus said is correct, however, there are some other ways to automate this. You can create the effect to be on the NPC's actions so you can easily drag it from there onto the NPC. You can also make a custom effect in that list to make it easy to drag on to the NPC. Creatures (PC or NPC) must be in the CT to have effects applied to them.

There are exts that can help fully automate these things when added to the CT.

Advanced Effects is free and allows you to place effects direction only items or creatures (or features etc) that will apply when the creature is placed in the CT. In the case of items, you would need to also equip the item to apply this, also if it needs attunement that too.
NPCs normally do not come with inventory lists so you would need to use another EXT if you wanted to equip items on them with automated effects.

Equipped Effects is another EXT, does cost money on the FORGE. Which allows for automation of effects much like Advanced Effects, however, it automates it based on name matching. So if you had a trait or item, or feature, etc, that matched the name of that to an effect it would apply that effect to the creature automatically. Example of this is say you had a trait on a creature that was "Power Ego, creature gets advantage on wisdom saves". You would make an effect in the custom effects list that matched the name of the trait "Power Ego" and code it correctly with the effect "Power Ego; ADVSAV: wisdom", then when that creature is added to the CT, it will give them that effect automatically.