ERJ 170/175 Flight Attendant reported a close call inadvertent escape slide deployment when gate agent returned to provide paperwork and Flight Attendant disarmed and opened aircraft door.

Narrative

I was working a flight from ZZZ1-ZZZ. Towards the end of boarding we were waiting for one passenger and a few others were giving me a hard time about bags; etc so I was more distracted then usual. This being said after that last passenger boarded; the ground crew gave me a thumbs up and said you are good to go now! Since I was distracted; I went ahead; played boarding complete; and shut and armed the doors. Well a few moments later (before shutting flight deck door); the gate agent came knocking; and showing me the papers she didn't give me. I without hesitation disarmed the 1L door to ensure that the slide wouldn't deploy if the gate agent were to open the door to give me papers. We opened; gave papers; exchanged a few words; then I closed and rearmed the doors and double checked the 1R door as well; closed FD door; Cabin Secure to Taxi. Upon further realization; I believe there is a procedure for if you were to need to reopen the 1L door after the door operating procedures have been completed. I am unsure but I will be looking in the Flight Attendant Manual (FAM) after submitting this report.