flying-jib/agent/ADRs/0009-invite-capability-format-fj1.md

ADR-0009: Invite capability format fj1.

• Status: Accepted
• Date: 2026-07-30

Context

Users need a single copy-pasteable secret to join private worlds, similar to peardock pd1. invites, without accounts or central invite servers.

Decision

Invite envelope:

fj1.<encoded-payload>

Payload (logical) includes protocol version, type (private-world | mesh), worldKey, shared cap, optional name/mcVersion/expires.

Phase 2 encoding: JSON → z32 (debug-friendly). May migrate to compact-encoding later (Q13).

Bearer capability model: possession grants join attempt; host enforces proof and may rotate keys.

Consequences

Positive

• Offline-friendly, self-contained
• Familiar UX (paste string / QR later)

Negative / tradeoffs

• Leak = unauthorized join until rotation
• Long strings if JSON grows

Follow-ups

• Phase 2 mint/parse library
• Phase 5 TTL/revoke/roles