Death Commands

I define Death Effects as "Doing something when an Entity dies". There are a few wrong ways to achieve this that should be avoided, including:

• Detecting death in the entity file, adding a component, and then trying to detect that component in the animation controller. This is wrong because the entity will be removed from the world before the animation controller has a chance to run.
• Detecting the entity death from an outside source, such as a ticking command block. This method isn't strictly wrong, and in some circumstances, it may even be preferred. However it is costly and easy to break.

Using q.is_alive ​

The best way to create death effects is by using the is_alive query.

Simply create an animation controller with a transition based on is_alive. The final on_entry will run before the entity is removed from the world, allowing you to run your commands.

Here is a sample animation controller:

{
    "format_version": "1.10.0",
    "animation_controllers": {
        "controller.animation.death": {
            "initial_state": "default",
            "states": {
                "default": {
                    "transitions": [
                        {
                            "dead": "!q.is_alive"
                        }
                    ]
                },
                "dead": {
                    "on_entry": ["/say I am dead!"]
                }
            }
        }
    }
}

Use on player entities ​

In the case of player entities, an additional transition must be added to the second animation state in order to ensure the state resets between deaths:

{
    "format_version": "1.10.0",
    "animation_controllers": {
        "controller.animation.death": {
            "initial_state": "default",
            "states": {
                "default": {
                    "transitions": [
                        {
                            "dead": "!q.is_alive"
                        }
                    ]
                },
                "dead": {
                    "on_entry": ["/say I am dead!"],
                    "transitions": [
                        {
                            "default": "q.is_alive"
                        }
                    ]
                }
            }
        }
    }
}

Using minecraft:on_death ​

You can also use the minecraft:on_death component in your entity.json file in the Behavior Pack, which is a fairly easy way to accomplish a command on death.

You first add it to your components and make it run an event on self;

"minecraft:on_death" : {
    "event": "wiki:on_death",
    "target": "self"
}

And then, in your events section you add the event;

"wiki:on_death": {
    "queue_command": {
        "command": [
            "say I have died!"
        ]
    }
}