Registry and Catalog

This section is the protocol-level reference for how Matrix actors find each other. The authority surfaces are system.runtimes (physical process inventory), system.registry (logical mount claims), and system.devices (linked-Device inventory); the read projection is system.catalog plus gateway projections like /api/apps.

Source: WORKSTREAMS/core-and-packaging/MATRIX-AUTHORITY-MODEL.md § "Authority / projection table". Authority surfaces accept writes; projection surfaces are read-only and MUST be derivable from authorities.

Page	What it covers
Registry vs catalog	The authority/projection rule, the four-actor split, and what each owns.
Mount claims	Detailed system.registry claim shape, ops, and lifecycle (registry.register/heartbeat/resolve/unregister).
Singleton claims	Mounts where exactly one provider per authority root is allowed.
Instance claims	Multiple-provider claims for non-singleton mounts.
Consumer groups	Subscribers that share work across providers.
Discovery projections	system.catalog, /api/apps, system.devices — what they project and how.

Quick mental model

Writes
   ↓
┌──────────────────┐  ┌──────────────────┐  ┌──────────────────┐  ┌──────────────────┐
│ system.runtimes  │  │ system.registry  │  │ system.devices   │  │ system.auth      │
│ (processes)      │  │ (logical mounts) │  │ (linked Devices) │  │ (Spaces/links)   │
└────────┬─────────┘  └────────┬─────────┘  └────────┬─────────┘  └────────┬─────────┘
         │                     │                     │                     │
         └──────────┬──────────┘                     │                     │
                    ↓                                 │                     │
       ┌──────────────────────┐                       │                     │
       │ system.catalog       │ (read projection)     │                     │
       │ /api/apps            │                       │                     │
       │ /api/identity/runtime-summary               ←┘                     │
       └──────────────────────┘                                             │
                    ↑                                                       │
                    └───────────────────────────────────────────────────────┘
                              Reads (no writes)

See also

• Mounts — the logical mount concept.
• Mount claims (addressing) — the shape of a claim record.
• MATRIX-AUTHORITY-MODEL.md — the full authoritative table.
• MATRIX-DISCOVERY-METADATA-SPEC.md — vocabulary and the catalog separation.