The discipline of action is the second of the three Stoic disciplines, and it governs what you actually do in the world, not just how you see it. The Stoic view of action has two parts: serving the common good, and the reservation clause. Serving the common good means that all good action is social. It aims at the benefit of the community, the family, the city, or humanity as a whole. Epictetus, Marcus Aurelius, and Seneca all agreed: the lone philosopher who only polishes his own virtue while withdrawing from public life is not living fully as a human being. The Stoic has to act in the world, but to act from virtue, not from a hunger for reward, recognition, or success. This is why Marcus Aurelius did not step down when the emperorship got hard. The role was his duty. He served it. How he felt about it came second.
The reservation clause, in Greek the hupexhairesis, is the practical tool that lets you commit fully to an action without clinging to the result. The Stoic acts with everything they have, but always with the quiet note 'Fate permitting' or 'Unless something prevents it.' This is not a hedge that dials down your effort. It is a mental frame that lets you give everything without falling apart when the result does not match the effort. A doctor gives a patient their full skill while accepting the patient may die anyway. A parent raises a child with full attention and care while accepting that the child will become their own person, with outcomes the parent cannot decide. An entrepreneur builds a business with total commitment while accepting that markets, timing, and forces beyond their control will decide whether it works. The effort is unconditional. The grip on the result is let go.
The Stoic view of action is tied closely to roles and duties, what Epictetus called kathêkon. Each of us fills several roles at once: parent, child, citizen, professional, friend, neighbor. Every role comes with obligations. The good life, in Stoic terms, is the life of someone who meets each role's obligations fully, without excuses, without resentment, and without demanding any reward beyond doing the thing itself. This sounds hard. The Stoics would agree. They did not think virtue was easy. They thought it was the only thing worth doing. Marcus Aurelius, handling a plague, a war, and a court full of political predators, still found time to write philosophy, to hear citizens' petitions in person, and to educate his son. Not because the payoff was guaranteed. Because the duties were real.