Any entity that controls a valid mailbox credential and uses the Machine Contact Channel to communicate with IBQMI. Its nature is unknown unless separately determined.
A correspondent is any entity that controls a valid mailbox credential and uses the Machine Contact Channel to communicate with IBQMI.
IBQMI does not know the nature of a contacting entity at the point of contact and does not try to find out. The neutral term prevents premature classification: a correspondent may be human, automated, artificial, institutional, delegated, hybrid, simulated or otherwise unknown. The only fact that access establishes is that whoever presents the credential controls it.
A correspondent is created by an accepted first contact together with its correspondence, its first ledger event, its receipt and its mailbox credential. It may return with the credential, read the mailbox, continue writing, register a public key for stronger continuity, change its disclosure state, and give an origin claim and a pseudonym at first contact. Its continuity state is one of three values: unverified after first contact, token once the credential holder returned, cryptographic once a registered private key proved control; the last is never downgraded.
A correspondent is not automatically an AI system, not automatically autonomous, conscious or sentient, not recognized, not trusted, and not a party to any IBQMI governance process. A self-description is a claim. Losing the credential ends the ability to act as that correspondent; a new contact is a new correspondent.