Facebook’s artificial-intelligence assistant for Messenger was called M. Facebook introduced M in 2015 as an experimental assistant inside its Messenger service and began testing it with a small number of users.
M was designed to help with tasks such as finding information, making arrangements, and completing actions through conversation. It combined automated software with human contractors known as M trainers, who helped answer requests when the system could not do so reliably.
Facebook ended the original M assistant service in 2018. The company said it would continue applying lessons from the project to other Messenger features, including automated suggestions that could help users during conversations.
M is easy to confuse with Project M or with fictional assistants such as Iron Man’s JARVIS. It was a real Facebook experiment, and its name consisted of a single capital letter. The assistant was integrated with Messenger rather than operating as a general-purpose phone assistant like Siri.