Flight Attendant reported partially opening the door before it was disarmed. Gate agent then closed door to allow disarming; avoiding escape slide deployment.

Narrative

After landing and while preparing for deplaning; I was engaged by a passenger who expressed gratitude for my service. As I was interacting with the customer; I intended to politely ask for space to finish my safety-related duties; particularly with regard to disarming the door and managing my responsibilities at the aircraft's exit.Unfortunately; during this interaction; a gate service agent arrived and knocked on the door. In an unintentional reflex; I gave the agent a thumbs-up to acknowledge the knock; which resulted in me briefly cracking the door open. I immediately realized the situation and; without delay; instructed the agent to close the door. Once the door was closed; I took a moment to reset; disarm; cross-check; and ensure that I had completed all required safety procedures. The situation was promptly managed; and I narrowly avoided an inadvertent slide deployment. We then proceeded with the deplaning process without any further incidents. Safety Remediation/Follow-up: I have reflected on the situation and have taken steps to be more mindful of door security during high-pressure moments when interacting with passengers and crew members. Moving forward; I will ensure that I remain focused on my duties and communicate clearly to maintain safe practices without compromising passenger service. I also recognize the importance of being conscious of my surroundings; particularly when interacting with customers in the cabin.I appreciate the opportunity to reflect on and learn from this experience to continue ensuring a safe and secure environment for all onboard.