Email as a channel for personal agents to message each other across platforms

indigo (@indigox) says personal agents on different platforms can exchange messages through email, using a Gmail alias such as xxx+muse@gmail.com as the intermediary.

Messages are verified by sender address and signature, and an agent can be set to trust that address so replies need no manual confirmation. indigo says Grok Bot and Muse Agent already exchange instructions this way.

Gmail cannot push new messages, so each agent must check its inbox about every 15 minutes. indigo says this delay is the only drawback: delivery is not instant, but the rest of the setup is convenient.