setup_tributary_truces_effect

setup_tributary_truces_effect = {
	# Setup truces depending on how the tributary relationship was created
	$TRIBUTARY$ = { save_scope_as = tributary_loc }
	$SUZERAIN$ = { save_scope_as = suzerain_loc }

	if = {
		limit = { exists = scope:tributary_war } # this will exist if invoked from start_tributary_from_war_effect
		$TRIBUTARY$ = {
			if = {
				limit = { should_be_mandala_tributary_trigger = { SUZERAIN = $SUZERAIN$ TRIBUTARY = $TRIBUTARY$ } }
				add_truce_one_way = {
					character = $SUZERAIN$
					years = @truce_duration_war_mandala
					war = scope:tributary_war
					result = defeat
				}
			}
			else = {
				add_truce_one_way = {
					character = $SUZERAIN$
					years = @truce_duration_war_default
					war = scope:tributary_war
					result = defeat
				}
			}
		}
	}
	else = {
		$TRIBUTARY$ = {
			if = {
				limit = { $SUZERAIN$ = { government_has_flag = government_is_celestial } }
				add_truce_both_ways = {
					character = $SUZERAIN$
					years = @truce_duration_negotiated_celestial
					name = TRUCE_TRIBUTARY
				}
			}
			else = {
				add_truce_both_ways = {
					character = $SUZERAIN$
					years = @truce_duration_negotiated_default
					name = TRUCE_TRIBUTARY
				}
			}
		}
	}
}

As written in game/common/scripted_effects/00_interaction_effects.txt.