fix(backends,conversations,telegram,ui): a background subagent reports back as its own turn

ui/src/lib/panel/activity.svelte.ts

@@ -27,6 +27,9 @@ export interface Turn {
   itemOrigin: string | null;
   nodes: Record<string, ToolNode>;
   origin: string;
+  // A tool call came between two pieces of text; the next piece starts a
+  // paragraph, as the final message will show it.
+  paused: boolean;
   resultSubtype: string | null;
   roots: string[];
   says: string[];
@@ -51,6 +54,20 @@ function str(value: unknown): string | null {
   return typeof value === "string" ? value : null;
 }
 
+export function joinText(head: string, tail: string, paused: boolean): string {
+  if (paused && head.trim() && !head.endsWith("\n")) {
+    return `${head.trimEnd()}\n\n${tail.trimStart()}`;
+  }
+  return head + tail;
+}
+
+export function isLive(turn: Turn): boolean {
+  return (
+    turn.status === "running" ||
+    Object.values(turn.nodes).some((node) => node.status === "running")
+  );
+}
+
 function stopStatus(turn: Turn, stop: string | null): TurnStatus {
   if (stop === "end_turn") {
     return turn.status === "error" ? "error" : "done";
@@ -65,6 +82,9 @@ export class ActivityModel {
   turns = $state<Turn[]>([]);
   question = $state<PendingQuestion | null>(null);
 
+  // A subagent still working after its turn ended: nothing on this page
+  // knows the turn, so its tool calls hang under the launching Agent node
+  // of a turn named after that node.
   private readonly handlers: Record<string, (c: Cursor) => void> = {
     "conversation.created": (c) => this.onConversation(c),
     "conversation.updated": (c) => this.onConversation(c),
@@ -89,6 +109,12 @@ export class ActivityModel {
     return this.turns.find((turn) => turn.status === "running") ?? null;
   }
 
+  // A turn is live while it runs or while a subagent it launched still
+  // works: the CLI reports subagent tool calls after the turn's own end.
+  get live(): Turn[] {
+    return this.turns.filter((turn) => isLive(turn));
+  }
+
   setConversation(info: ConversationInfo): void {
     this.conversation = info;
     this.question = info.question;
@@ -151,6 +177,42 @@ export class ActivityModel {
     turn.startedAt = ts;
     turn.itemOrigin = str(event.item_origin);
     turn.userText = str(event.text) ?? turn.userText;
+    if (turn.origin === "task") {
+      this.settleAgents(ts);
+    }
+  }
+
+  // The report is in: whatever Agent node still runs has finished.
+  private settleAgents(ts: string): void {
+    for (const turn of this.turns) {
+      if (turn.origin === "agent" && turn.status === "running") {
+        turn.status = "done";
+        turn.endedAt = ts;
+      }
+      for (const node of Object.values(turn.nodes)) {
+        const agent = SUBAGENT_TOOLS.has(node.name) || node.name === "?";
+        if (node.status === "running" && node.parent === null && agent) {
+          node.status = "done";
+          node.endedAt = ts;
+        }
+      }
+    }
+  }
+
+  // Subagent traffic belongs to the turn that launched the subagent, whatever
+  // turn the gateway was in when it arrived.
+  private turnFor(turnId: string, ts: string, parent: string | null): Turn {
+    if (parent) {
+      const owner = this.turns.find((turn) => parent in turn.nodes);
+      if (owner) {
+        return owner;
+      }
+      const current = this.turns.find((turn) => turn.id === turnId);
+      if (current?.status !== "running") {
+        return this.ensureTurn(`agent:${parent}`, ts, "agent");
+      }
+    }
+    return this.ensureTurn(turnId, ts, null);
   }
 
   private onStream({ event, ts, turnId, parent }: Cursor): void {
@@ -158,7 +220,7 @@ export class ActivityModel {
     if (!(turnId && raw && typeof raw === "object")) {
       return;
     }
-    const turn = this.ensureTurn(turnId, ts, null);
+    const turn = this.turnFor(turnId, ts, parent);
     const sdk = raw as Record<string, unknown>;
     if (sdk.type === "content_block_start") {
       const block = sdk.content_block as Record<string, unknown> | undefined;
@@ -172,7 +234,8 @@ export class ActivityModel {
     if (sdk.type === "content_block_delta" && parent === null) {
       const delta = sdk.delta as Record<string, unknown> | undefined;
       if (delta?.type === "text_delta" && typeof delta.text === "string") {
-        turn.text += delta.text;
+        turn.text = joinText(turn.text, delta.text, turn.paused);
+        turn.paused = false;
       }
     }
   }
@@ -181,7 +244,10 @@ export class ActivityModel {
     if (!(turnId && typeof event.tool_use_id === "string")) {
       return;
     }
-    const turn = this.ensureTurn(turnId, ts, null);
+    const turn = this.turnFor(turnId, ts, parent);
+    if (parent === null) {
+      turn.paused = true;
+    }
     const node = this.ensureNode(
       turn,
       event.tool_use_id,
@@ -196,7 +262,7 @@ export class ActivityModel {
     if (!(turnId && typeof event.tool_use_id === "string")) {
       return;
     }
-    const turn = this.ensureTurn(turnId, ts, null);
+    const turn = this.turnFor(turnId, ts, parent);
     const node = this.ensureNode(turn, event.tool_use_id, "?", parent, ts);
     node.status = event.is_error ? "error" : "done";
     node.endedAt = ts;
@@ -266,11 +332,13 @@ export class ActivityModel {
     };
   }
 
+  // The turn's own tool calls die with it; a subagent's keep going until
+  // their own results arrive.
   private closeTurn(turn: Turn, status: TurnStatus, ts: string): void {
     turn.status = status;
     turn.endedAt = ts;
     for (const node of Object.values(turn.nodes)) {
-      if (node.status === "running") {
+      if (node.status === "running" && node.parent === null) {
         node.status = "aborted";
         node.endedAt = ts;
       }
@@ -291,6 +359,7 @@ export class ActivityModel {
       itemOrigin: null,
       nodes: {},
       origin: origin ?? "?",
+      paused: false,
       resultSubtype: null,
       roots: [],
       says: [],
@@ -394,3 +463,11 @@ export function summarizeInput(name: string, input: unknown): string {
 export function toolLabel(name: string): string {
   return name.startsWith("mcp__") ? name.slice(5).replace("__", " · ") : name;
 }
+
+// How a turn was started, as a word for the header.
+export const ORIGIN_LABELS: Record<string, string> = {
+  agent: "subagent at work",
+  inject: "inject",
+  task: "subagent report",
+  user: "user",
+};