Parameters are provided after the action name.

• send_chat requires message (string, the message you want to send)
• feed requires amount (number, in half food points)
• kill
• damage requires amount (number, in half hearts)
• heal requires amount (number, in half hearts)
• set_time requires time (day/night)
• change_weather requires nothing, but you should provide either rain (true/false) or thunder (true/false)
• burn requires duration (in seconds)
• extinguish
• add_potion_effect requires potion (string, "minecraft:strength"), optionally amplifier and duration (numbers)
• remove_potion_effect requires potion (string, "minecraft:strength")
• set_invulnerable requires invulnerable (true/false)
• set_position requires x, y, z (numbers, can be relative to the current position by using ~)
• cancel
• log requires message (string, whatever you want to log)
• server_command (runs on the server) requires command (string, the command to execute, e.g. "give %%%player.uuid%%% minecraft:diamond")
• command (runs on the client) requires command (string, the command to execute, e.g. "give %%%player.uuid%%% minecraft:diamond")
• explode requires flames (boolean, whether to spawn fire with the explosion), x, y, z (numbers, can be relative to the current position by using ~)
• set_block requires block (string, e.g. "minecraft:stone"), x, y, z (numbers, can be relative to the current position by using ~), and optionally meta (number).
• destroy_block requires x, y, z (numbers, can be relative to the current position by using ~), drop (boolean, whether to drop the block as an item).
• spawn_mob requires mob_type (string, e.g. "minecraft:spider"), x, y, z (numbers, can be relative to the current position by using ~), drop (boolean, whether to drop the block as an item).
• spawn_item requires item (string, e.g. "minecraft:diamond"), x, y, z (numbers, can be relative to the current position by using ~), drop (boolean, whether to drop the block as an item), and optionally nbt (TODO: elaborate on this).