feat: add sessions_spawn sub-agent tool

src/agents/tools/sessions-announce-target.ts

@@ -0,0 +1,36 @@
+import { callGateway } from "../../gateway/call.js";
+import type { AnnounceTarget } from "./sessions-send-helpers.js";
+import { resolveAnnounceTargetFromKey } from "./sessions-send-helpers.js";
+
+export async function resolveAnnounceTarget(params: {
+  sessionKey: string;
+  displayKey: string;
+}): Promise<AnnounceTarget | null> {
+  const parsed = resolveAnnounceTargetFromKey(params.sessionKey);
+  if (parsed) return parsed;
+  const parsedDisplay = resolveAnnounceTargetFromKey(params.displayKey);
+  if (parsedDisplay) return parsedDisplay;
+
+  try {
+    const list = (await callGateway({
+      method: "sessions.list",
+      params: {
+        includeGlobal: true,
+        includeUnknown: true,
+        limit: 200,
+      },
+    })) as { sessions?: Array<Record<string, unknown>> };
+    const sessions = Array.isArray(list?.sessions) ? list.sessions : [];
+    const match =
+      sessions.find((entry) => entry?.key === params.sessionKey) ??
+      sessions.find((entry) => entry?.key === params.displayKey);
+    const channel =
+      typeof match?.lastChannel === "string" ? match.lastChannel : undefined;
+    const to = typeof match?.lastTo === "string" ? match.lastTo : undefined;
+    if (channel && to) return { channel, to };
+  } catch {
+    // ignore
+  }
+
+  return null;
+}