I have a more blathery response about what rules are.
Rules do operate in response to some kind of value you supply to them (See 18.8 in the docs for elaboration) but they may do anything you ask them to. There’s no law about a relationship between input and output values. You refer to some kind of input that fires the rule, but you’ll only get specific output that you ask for / program. That may be no output, or tons of output.
But at a broader level, every rule does have an internal result as far as Inform is concerned: success, failure or no outcome. This result will always be set after a rule has fired. There are default paths to each state, but you can also explicitly set the result of any action to any state. Inform might have considered that a rule failed, but you could say (not actual code) ‘actually that rule succeeded’ if it suited your purposes.
The success/failure states have real meaning for Inform in some cases (see the topic about ‘How do I make a scene start?’ for an example) but they won’t’t necessarily correspond to what you consider to be failures, successes or non-outcomes in terms of your game. This is an area where I’m personally not yet aware enough about what the states will do on Inform’s terms, so I don’t cleave to them too heavily.
The biggest real outcome of rules succeeding or failing is that at the moment one of these things happens, the rule stops firing. No further code in the rule is run.
This is where ‘consider’ and ‘abide by’ come in. If Inform is carrying out some code, and you ask it to do one of these things, you can get it to run through a rule like a subroutine, and have that rule’s outcome determine the outcome of the whole action, which can cause the main action to be cut off early, etc.
In terms of - how do I pass a value to a rule? Well, as I say, it’s not really an in+out setup. Rules may run at lots of different times - As a result of an action the player inititaes, as a result of being part of the huge machine of Standard Rules that are run through every turn. Or you may specifically call the rule from another action.
But per se, you don’t have to insert a value into a rule. You don’t even have to make a rulebook. Most rules you make will fall into already-existant rulebooks for actions. All you do generally is set some kind of condition before you go to the applicable rule. You might set a variable, or you might use Inform’s English language techniques (you might set Paul’s fatigue to ‘extreme’ before considering the ‘hunger rule’ - which you made.) In the end, rules are just blobs of code that are placed in order by rulebooks. And they always succeed, fail or produce no outcome, no matter what else you do in them. But I was significantly into my first Inform game before I even started to think about the repercussions of success/failure/no outcome, and that turned out not to be too big a deal.