Either specifically during a cooking/crafting process to fix the ‘one burning paper bag let’s me cook or see for crafting for 8 hours’ exploit or as en option to always automatically add available fuel to an adjacent fire to maintain it at a specified level; small, large or raging. Either only for fires in contained tiles or always aka. pyromaniac trait could be dangerous if the char decides to throw a molotov into the fireplace… Optionally.
What items to use as fuel? In what order? How much control should the player have over it eg. a list of priority, a specific tile, only from inventory? How hard is it to add a check for available fire/light after crafting/cooking started? (there are already many ‘something happened, stop doing this y/n?’ prompts, right?
Fuel priority list with menu for control.
Default; firewood, splintered wood, heavy sticks, 2-by-4s, junk(?).
*Built pile of firewood. A special *built tile that can be reloaded with firewood or anything burnable that keeps an adjacent fire going automatically.
Constructed fire-feeders. Either primitive that feed logs into the fire via gravity as they are burned or advanced that drop items stored inside when needed.