Does Cleave work with Assault if played during the Focus step, since Assault applies before the Initial Chain when no Action/Reaction windows exist?

Ruling: Yes, Cleave works with Assault. Assault is a passive ability that applies as long as your unit is the attacker, not a one-time activation that ends.

Nuances:

• Assault is a passive ability similar to Trifarian War Camp, not a trigger that activates once
• "When I attack" triggers apply the first time a unit gets attacker designated in combat
• Assault's bonus continues to apply throughout combat as long as the unit remains the attacker