By far the most important thing is consistency
This is not true. The most important thing is correctness. The code should do what you expect/want it to do. This is followed closely by maintainability. The code should be easy to read and modify. These are the two most important aspects and I believe all other rules or methodologies out there are in service of these two things. Normally the maintainability side of things as correctness is not that hard to achieve with any system of rules out there.
You must resist the urge to make your little corner of the code base nicer than the rest of it.
Uhg. I really don't like these words. I agree with their sentiment, to a degree, but they make it sound like you should not try to improve anything at all. Just leave it as it is and write your new code in the same old crappy way that it always has been. Which is terrible advice. But I get what they are trying to say - you should not jump into a area swinging a wrecking ball around trying to make the code as locally nice as possible at the expense of the rest of the code base and other developmental practices around.
In reality there is a middle ground. You should strive to make your corner of the code base as nice as possible but you should also take into account the rest of the code base and current practices as well. Sometimes having a little bit better local maintainability is not worth the cost of making the code base as a whole less maintainable. Sometimes a big improvement to local maintainability is worth a minor inconvenience to the code base as a whole - especially for fast moving parts of the code base. You don't want something that no one has touched in 10 years to drastically slow down current features you are working on just to keep things consistent.
Yes consistency is important. But things are far more nuanced than that statement alone. You should strive for consistency of a code base - it does after all have a big effect on the maintainability of the code base. But there are times that it hampers maintainability as well. And in those situations always go for maintainability over consistency.
Say for instance some new library or an update to a library introduces a new much better way of working. Your code base is full of the old way though. Should you stick to the old way just to keep up with consistency? If the improvement is good enough then it might be worthwhile. Ideally if you can you would go though and update the whole code base to the new way of working. That way you improve things overall and keep consistency of the code base. But that is not always practical to do. It might be better to decide that the new way is worth switching to for new code, and worth refactoring old code when you are working in that area anyway but not worth the effort of converting the whole code base at once. This makes maintainability of the new code better, at the expense of old less used code.
But the new way might not be a big enough jump in maintainability of new code that it is worth sacrificing the maintainability of the code base as a whole. Every situation like this needs to be discussed with your team and you need to decide on what makes most sense for your project. But the answer is not always that consistency is the most important aspect. Even if it is an important aspect.
The readme for smol has an example for stdout. I assume stdin is the same:
And there is more information about how to use it for reading/writing on the Unblock docs.