Techniques and devices are described for embedding data in an address stream on an interconnect, such as a memory bus. Addresses in an address stream indicate at least part of a location in memory (e.g., a memory page and offset), whereas data embedded in the address stream can indicate when metadata or other information is available to lend context to the addresses in the address stream. The indication of data in the address stream can be communicated using, for example, a mailbox, a preamble message in a messaging protocol, a checksum, repetitive transmission, or combinations thereof. The indication of data can be recorded from the address stream and may later be used to interpret memory traces recorded during a test or can be used to communicate with a memory device or other recipient of the data during testing or regular operations.