Disclosed are various approaches for validating a relevance or an accuracy associated with an item being attached to a message or inserted inline with the text of the message or other type of document. An addition of the item (e.g., attachment, hyperlink, embedded image, etc.) to the message being generated by a sender can be detected. Message keywords associated with the message content and item keywords associated with the item content can be identified following an analysis of the message content and item content. The message keywords and item keywords can be compared to determine a likelihood of a mismatch between the item and the message. Upon determining a potential mismatch and prior to the message being sent to a recipient, a notification identifying the likelihood of the mismatch is presented to the sender.