Silo

ctx.agents beta ​

Host-computed coding-agent activity and resume-identity observability — a live, read-only view of what each Agent Session is doing, plus an honest resume hint when a session's backend dies uncleanly. The companion to ctx.processes (foreground process facts); this surface is for agent activity and resume identity. Detection is sealed in the host — there is no registerAgent / detector API.

An Agent Session is either a Terminal session (an agent drawing its own TUI in a PTY; Silo infers activity from OSC/output) or a Chat session (an Agent Client Protocol child that reports activity directly). ctx.agents reports the same AgentInfo shape for both — see AgentSessionKind. Use reveal(id) to bring a session into view (its terminal tab or its transcript panel) without branching on which kind it is.

ts
ctx.agents: AgentsService

Example ​

Notify when a session dies with a resume command ​

ts
export const extension: Extension = {
  id: "my.agent-resume-toast",
  activate(ctx) {
    const sub = ctx.agents.subscribe((agents) => {
      const dead = agents.find((a) => a.activity === "dead" && a.resumeCommand);
      if (dead) ctx.ui.notify("info", dead.resumeCommand!);
    });
    ctx.subscriptions.push(sub);
  },
};

Acknowledge finished runs when the user looks at the session ​

needsAttention is separate from activity === "idle". The host never auto-clears attention on focus — that is a per-consumer policy. Use subscribeActive, which reports whichever Agent Session the user is looking at, terminal tab or Chat transcript alike:

ts
ctx.subscriptions.push(
  ctx.agents.subscribeActive((agentSessionId) => {
    if (agentSessionId) ctx.agents.acknowledge(agentSessionId);
  }),
);

Badge a session's tab, whichever kind it is ​

bindActivity / bindIcon take an Agent Session id, so one provider paints a terminal tab and a Chat transcript tab identically. The host resolves which tab a session is showing on — a terminal tab, or a DockPanelKind panel that declared api.setAgentSession(id).

provide runs synchronously for every visible tab during render, so keep it a lookup:

ts
const agents = new Map<string, AgentInfo>();
ctx.subscriptions.push(
  ctx.agents.subscribe(
    (state) => {
      agents.clear();
      for (const a of state) agents.set(a.id, a);
      // Something outside the snapshot (a setting, the theme) can also change
      // what a provider returns — say so explicitly.
      ctx.agents.invalidateAdornments();
    },
    { allWorkspaces: true },
  ),
);

ctx.subscriptions.push(
  ctx.agents.bindActivity({
    id: "my-ext.agent-badge",
    provide(agentSessionId) {
      const info = agents.get(agentSessionId);
      if (info?.activity !== "working") return null;
      return { activity: "working", tooltip: "Agent working" };
    },
  }),
);

Return null for "no adornment". With bindIcon, be careful that a component which renders nothing produces null rather than a truthy element descriptor, or the host reserves tab space for an icon that never appears.

Read the agent catalog (icons + display names) ​

ctx.agents.catalog() returns every coding agent Silo knows about as read-only CatalogAgentSummary records. The list is memoized and deeply frozen — safe to call inside a tab-render callback like ctx.agents.bindIcon. Render an agent's brand mark with the SDK's AgentIconGlyph:

tsx
import { AgentIconGlyph } from "@silo-code/sdk";

const icon = ctx.agents.catalog().find((a) => a.id === "claude")?.icon;

// `mode`: "none" | "color" (brand hex) | "monotone" (inherits currentColor)
<AgentIconGlyph icon={icon} mode="color" colorScheme="dark" />;

AgentIconGlyph returns null when mode is "none" or icon is absent, so gate any tab chrome on the return value rather than rendering it blind.

Detection stays sealed (ADR 0028) — catalog() is read-only, with no way to register into the list.

End a session, either kind ​

close(id) closes a Terminal session's terminal tab or a Chat session's transcript panel — reaping the agent either way — with no branch on kind:

ts
ctx.agents.close(info.id);

Start an agent ​

This surface observes agents that are already running. To start one, use ctx.agents.profiles — the user's own named launch recipes, which can also carry an opening prompt.

What you get ​

FieldMeaning
idStable Agent Session id — the key reveal / resume / acknowledge / close take. Equals terminalId for a Terminal session.
titleThe session's display label, host-computed for either kind: the agent's own words (an OSC title, or a Chat session_info_update) with status markers stripped, else the user's name, else a fallback. Render this rather than deriving your own.
kindterminal | chat — see AgentSessionKind. Same fields for both.
terminalIdThe backing terminal record id — present for a Terminal session, absent for a Chat session.
activitynone | working | idle | error | dead
needsAttentionSticky "finished while you weren't looking" — cleared only by acknowledge
sessionId / resumeCommandExact resume when a Settings → Agents hook (or native session file) resolved an id; otherwise an honest session-id-less note. Silo never infers an id from cwd/recency.
canResumeWhether resume(id) will do something. A Terminal session's is true only with an exact sessionId, and resume() is still a no-op for it — run resumeCommand. A Chat session's is true when the agent advertises session/resume or session/load.
chatResumeStatekind: "chat" only — where the session stands in Chat session resurrection: live | resuming | resumed | journal-only | unavailable. See ChatResumeState.
agentId / agentNameCatalog key + display name once a known agent leader is detected

See also ​