Agency is a metaphysical and philosophical concept concerned with the ability of a person or other agent to act intentionally and to bring about effects through choice or action. Questions about agency examine whether actions originate meaningfully from the agent, how intentions relate to causes, and whether responsibility is possible within deterministic systems. Agency is closely connected with free will, determinism, causation, intention, consciousness, responsibility, and personal identity, making it central to debates about human action and autonomy.