Automatic modification of message signatures using contextual data

In automatically modifying message signatures, a system extract message content from the message text from a sender to a recipient. Using at least the message content, the system determines: a relationship context capturing a nature of the relationship between the sender and the recipient, a temporal context capturing temporal features of the message content, a historical context capturing a nature of electronic interactions between the sender and the recipient over time, and a tone category capturing a primary tone and strength of the primary tone of the message content. The system selects a signature template associated with contextual data that includes the relationship, temporal, and historical contexts and the tone category. The signature template includes a set of sections where a signature is modified by inserting section values associated with the contextual data into the set of sections. The modified signature is inserted into the message text.