Parameters and inputs

Parameters

The parameter is text, converted when the input is called. A plain value becomes the first of these that fits: an integer, a float, true or false, three numbers as a Vector3, else a string.

A JSON array like [10, "$activator"] spreads into several arguments. Each value is then converted to the type the method declares. When the method takes a node before any other argument, a text parameter is resolved as a target, so !player or a targetname can be passed straight in.

Placeholders are worked out on the receiving entity, not the one that fired. Inside an array only an element that is exactly the placeholder is replaced.

No parameter

With the parameter left empty, the activator goes into the first argument typed as an object, or untyped and named activator, wherever it sits. That is why take_damage(amount, source) gets it in source. Other values the output carried fill the remaining arguments in order, so changed(value) wired to set_value passes the value on.

This forwards false too: switched(false) wired to a counter's add adds 0. Set an explicit parameter when you want a fixed value.

How an input is found

1. A method of that name, then its PascalCase and camelCase spellings, so a C# AddScore answers to add_score.
2. A property of that name, set to the parameter or the value the output carried. The input speed with parameter 4 changes a door's speed.
3. One of the built-in inputs below.

The entity's own methods come first, which is why disable on a trigger switches the trigger off instead of hiding it. For show and hide only a method in the entity's script counts, Godot's own Node3D.show() is skipped so the built-in version can stop processing too. Anything else prints [GT I/O] <node> has no input '<name>'.