I need some rules that one would have to follow if in a secret agency but they seem to be evading me.
Any suggestions?

It must stay secret. Ehem, sorry about that one.

Hahaha, of course that's one rule. I applaud the simplicity.

I guessing the reason you haven't gotten much help is because what's the agency about? If it's a killer for higher business then if you get caught, you get caught, no one's bailing you out.

This strongly depends both on the type of secret agency and the end goal of said agency. Take for instance an intelligence agency that acts apart from any government. We know what they are but what is their goal. They always need and end goal even if the reader doesn't know what it is. For instance the CIA, their end goal is to gather information to make sure American stays on top of the world.

This one, for arguments sake, is to make money. Here we can make three rules right off the top.

1. Discretion (It's a secret after all.)
2. Might Makes Right (In this case, money.)
3. Any information on anyone has value.

Pretty simple and somewhat wild but they fit. Really, you wouldn't actually ever know all of the rules. No one would, because different rules would apply to different agents depending on what their position and rank within the agency was.

Ahhh,
That actually helped me even though it was just an example but I needed a basis of a direction.
I apologize for being vague, I'm new at posting topics so I tried to keep it short and sweet and it came off much more uninviting.
The agency is more of a secret collaboration of demons and humans working together to fend off rogue demons/humans and keep the peace in a world that doesn't even acknowledge that demons exist.
My main character breaks these rules and gets exiled.
I have a rough template for the rules but I don't think they sound badass enough.
Like,
Don't tell
Don't ever go without your partner
You never have a steady partnership forever
And don't let anyone see you

I like the first and last one but the other two seem as though they can be subcategory rules like you've explained, apply sometimes to different agents differently. I need strong core rules for the agency that if broken can cause problems.
Is that better information?

Don't tell.
Don't be seen.
Don't be heard.
Don't get involved.

Core rules.

Though in this event, most, if not all, of the members that appear will be partnered with someone. So another rule.

Don't get to close to your partner. (Secret speak for don't fall in love.)

There are a lot of other little things you could do but those five really cover the major points. The "don't get involved rule" is more of a thing about keeping out of things that aren't directly connected to work.

You could also add a sixth rule.

Don't let anyone who sees you live.

I hope that helps.

Phenomenal!
That's spot on.
I think all of those are exactly the direction I'm going in.
Thank you!

It was really bothering me, now I can continue writing.
Back to my good ol' paper and pen!