- the Gateway itself, and
- user-visible clients connected to the Gateway (mac app, WebChat, nodes, etc.)
Presence fields (what shows up)
Presence entries are structured objects with fields like:instanceId(optional but strongly recommended): stable client identity (usuallyconnect.client.instanceId)host: human-friendly host nameip: best-effort IP addressversion: client version stringdeviceFamily/modelIdentifier: hardware hintsmode:ui,webchat,cli,backend,node,probe,testlastInputSeconds: seconds since last user input, if knownreason: free-form client-supplied string; the Gateway itself only emitsself,connect, anddisconnectdeviceId,roles,scopes: device identity and role/scope hints from the connect handshakets: last update timestamp (ms since epoch)
Producers (where presence comes from)
Presence entries are produced by multiple sources and merged.1) Gateway self entry
The Gateway always seeds a “self” entry at startup so UIs show the gateway host even before any clients connect.2) WebSocket connect
Every WS client begins with aconnect request. On successful handshake the
Gateway upserts a presence entry for that connection.
Why ephemeral control-plane connections do not show up
CLI commands, backend RPC clients, and probes often connect briefly. To avoid retaining that churn for the full presence TTL, clients incli, backend,
or probe mode are not turned into presence entries. Test-mode clients
stay tracked because test suites use them as stand-ins for real clients.
3) system-event beacons
Clients can send richer periodic beacons via the system-event method. The mac
app uses this to report host name, IP, and lastInputSeconds.
4) Node connects (role: node)
When a node connects over the Gateway WebSocket withrole: node, the Gateway
upserts a presence entry for that node (same flow as other WS clients).
Merge + dedupe rules (why instanceId matters)
Presence entries are stored in a single in-memory map, keyed case-insensitively
by the first available of, in order: a paired device id, connect.client.instanceId,
or the per-connection id as a last resort.
Ephemeral control-plane clients are excluded from tracking entirely (see
above), so their connection ids never become keys. For every other client, the
connection id fallback means a client that reconnects without a stable
instanceId shows up as a duplicate row.
TTL and bounded size
Presence is intentionally ephemeral:- TTL: entries older than 5 minutes are pruned
- Max entries: 200 (oldest dropped first)
Remote/tunnel caveat (loopback IPs)
When a client connects over an SSH tunnel / local port forward, the Gateway may see the remote address as127.0.0.1. To avoid recording that tunnel
address as the client’s IP, connect handling omits ip entirely for
detected-local (loopback) clients rather than writing the loopback address
into the entry.
Consumers
Control UI Devices page
The Devices page joinssystem-presence with durable pairing and node
records. It pins the Gateway self beacon first and uses matching device or
instance ids for live platform, version, model, and input-recency metadata.
macOS Instances tab
The macOS app renders the output ofsystem-presence and applies a small status
indicator (Active/Idle/Stale) based on the age of the last update.
Debugging tips
- To see the raw list, call
system-presenceagainst the Gateway. - If you see duplicates:
- confirm clients send a stable
client.instanceIdin the handshake - confirm periodic beacons use the same
instanceId - check whether the connection-derived entry is missing
instanceId(duplicates are expected)
- confirm clients send a stable
Related
Active computer presence
How physical Mac input selects an active node and routes connection alerts.
Typing indicators
When typing indicators are sent and how to tune them.
Streaming and chunking
Outbound streaming, chunking, and per-channel formatting.
Gateway architecture
Gateway components and the WebSocket protocol that drives presence updates.
Gateway protocol
The wire protocol for
connect, system-event, and system-presence.