# Message attributes Additional metadata can be added to any type of message as attributes alongside the actual message. When sending via a transport (eg: SQS, RabbitMQ) the message is sent in a message envelope. [Commands](/guide/messages/commands.md) and [events](/guide/messages/events.md) are serialized into the message body, whilst attributes are added to the message header. Attributes are designed to hold data that is related to technical concerns of routing the message, or auditing/logging information such as details around the originator. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://bus.node-ts.com/guide/message-attributes.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.