If you read the drafts of the game system there's something that may not be very clear. How do skills (or, to be more precise, the characteristic/skill combine) map into actions?
Well, in most games with skills or equivalents the map is done this way: You have one skill that has both a procedural value (the number that's used in the decision mechanic) and a description of the way it is intended to use. For instance, you have the skill "jump 13" in a game like Pendragon. You refer to the description of the skill to know when and how to use it; and you know you need to roll 13 or less on 1d20 to succeed. The problem with this type of system is that if you want a variant that does not fit the description of jump you need to create a separate skill; and that creates problems when skills are too close to the point that their usage overlaps.
Another approach is the way things are done in HeroQuest and similar games with freeform stats. In this case you don't have a more or less closed list of well developped abilities. Instead, you are free to create your own. This gives a lot of flexibility, granted, but it also creates a lot of problems of interpretation of what fits an ability or overlap between abilities.
In Ridgeworld I'm following a somewhat different path. I have abilities (the combine between a characteristic and a skill), but I also will have a definite list of pre-defined actions. The latter list includes things like "jump", "climb", "attack", "seduce", etc. Youn can find some samples in the Action draft. This means that types of actions are not skills, there's no one-to-one relationship in such terms that each skill is a type of action.
Remember, in Ridgeworld skills are assembled into backgrounds. Backgrounds correspond to fields of action, professions, etc. They are complexes of knowledge or know-how that are determined within a particular culture. Similar backgrounds in different cultures will have different skills, even if these skills are of the same type. Say, a Kiz fighter and a Tuurg fighter, both have fight skills, but the concrete skills are different. One may know how to fight with the spear, while the other usually uses the mace. The Romleh may use the sword instead.
What happens is that the skill description for a particular culture will detail those differences. Part of it will be the context in which people fight; part of it will be the psychology of fight; part of it the equipement used; etc. And a critical component is to say what type of actions are done with the skill.
This means that a skill may be used for different actions. The agile Illuv may use his fencing skill to attack, but also to jump, roll on the ground, dodge, etc. On the other hand, the massive Tuurg uses his fight skill to attack, parry, charge, etc.
My idea is thus to increase the flexibility at the level of skills descrition, but to keep that flexibility under mechanical control by referring back to a set list of actions that may be performed with different skills.
Does this make sense?