Cordn is a coordinator-assisted MLS messaging protocol that runs over ContextVM and Nostr, developed in the Cordn repository. It is a separate project from Concord despite the similar name. Users can publish a last-resort KeyPackage on one or more coordinators so that others can invite them.

Coordinator claims across devices

A user’s devices share an encrypted meta document that carries the last-resort KeyPackage and the set of coordinators where it is currently published. PR #12, merged on October 30, changes that set from an accumulating union to a current publish claim. Adopting a peer’s set replaces local claims, including retractions, so linked devices stop resurrecting removed coordinator relationships.

An absent coordinators field marks a legacy or unknown entry and MUST NOT be read as a retraction. An explicit empty array means the package is published nowhere. For a full unpublish, the device keeps the same KeyPackage entry with an empty claim set. When a newer entry carries claims, it is an explicit rotation and supersedes the old one, while a plain unpublished mint does not displace the current invite surface.

Until its own publish lands, a device with an unpublished local retraction or rotation defers adopting an older peer claim set. Each retraction is the previous explicit claim set minus the new one, not a mutable local marker.

Coordinators that are unreachable may still hold an orphaned remote copy. Retraction does not prove that copy was deleted, and automatic resolution MUST NOT re-adopt it. An explicit re-add can reconcile it later. Clients MAY pair an adopted retraction with retiring automatic coverage, which is local policy.

The change is merged protocol text and does not correspond to a client release.

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