Protect Vassal

is_available = trigger_if = {
	limit = {
		is_ai = yes
	}
	is_at_war = no
}
is_shown = scope:recipient = {
	OR = {
		AND = {
			is_tributary_of = scope:actor
			subject_contract_has_flag = tributary_contract_suzerain_guarantee_override
			scope:actor = {
				has_realm_law = top_liege_not_redirected_to_border_wars_law
			}
		}
		AND = {
			is_vassal_or_below_of = scope:actor
			any_liege_or_above = {
				has_realm_law = top_liege_not_redirected_to_border_wars_law
			}
		}
	}
	is_at_war = yes
	NOR = {
		this = scope:actor
		is_at_war_with = scope:actor
	}
	any_character_war = {
		primary_attacker = {
			NOT = {
				is_vassal_or_below_of = scope:actor
			}
		}
	}
}

As written in game/common/character_interactions/00_alliance.txt.

scope:actor = {
	is_at_war = no
}

As written in game/common/character_interactions/00_alliance.txt.

on_accept = scope:target ?= {
	hidden_effect = {
		set_called_to = scope:actor
	}
	add_defender = scope:actor
	if = {
		limit = {
			OR = {
				scope:actor = {
					any_home_court_hostage = {
						warden ?= {
							is_attacker_in_war = scope:target
						}
					}
				}
				scope:target = {
					any_war_attacker = {
						any_warden_hostage = {
							home_court ?= scope:actor
						}
					}
				}
			}
		}
		custom_tooltip = hostage_execution_warning_tt
	}
	if = {
		limit = {
			is_religious_war = yes
			scope:actor = {
				any_active_accolade = {
					accolade_parameter = acclaimed_knight_piety_from_battle
				}
			}
		}
		scope:actor = {
			add_piety = medium_piety_gain
		}
	}
	if = {
		limit = {
			is_religious_war = yes
			scope:actor = {
				any_active_accolade = {
					accolade_parameter = acclaimed_knight_piety_from_battle_high
				}
			}
		}
		scope:actor = {
			add_piety = major_piety_gain
		}
	}
	scope:actor = {
		stress_and_fulfillment_impact = {
			craven = medium_stress_impact_gain
		}
		add_to_variable_list = {
			name = joined_as_ally
			target = scope:target
		}
	}
}
if = {
	limit = {
		exists = scope:target
		scope:target = {
			primary_defender = scope:recipient
			scope:recipient.house = scope:actor.house
			primary_attacker = {
				house != scope:actor.house
			}
		}
	}
	add_clan_unity_interaction_effect = {
		CHARACTER = scope:actor
		TARGET = scope:recipient
		VALUE = medium_unity_gain
		DESC = clan_unity_join_war.desc
		REVERSE_NON_HOUSE_TARGET = no
	}
}
on_decline = scope:actor = {
	trigger_event = char_interaction.0236
}

As written in game/common/character_interactions/00_alliance.txt.