fix: count busy descendants in the agents-view subagents indicator

packages/coding-agent/.changes/res-1253-busy-descendant-indicator.md

@@ -0,0 +1 @@
+- Fixed the agents view undercounting running subagents: the "N subagents running" indicator now counts busy descendants at any depth, stays visible on collapsed groups, and idle sessions with busy subagents sort above plain idle sessions.

packages/coding-agent/src/modes/agents-view/agents-view-mode.ts

@@ -2528,7 +2528,9 @@ export class AgentsViewMode implements Component, Focusable {
 		if (row.kind === "subagent-summary") {
 			const indent = "  ".repeat(row.depth);
 			const hint = row.hasSpawnCode ? theme.fg("dim", ` · ${keyText("app.agents.program")} show program`) : "";
-			const label = `${theme.fg("dim", `${row.expanded ? "▾" : "▸"} ${row.title}`)}${hint}`;
+			// Busy descendants must be legible on a collapsed group, not dimmed away.
+			const titleColor = row.runningSubagentCount > 0 ? ("success" as const) : ("dim" as const);
+			const label = `${theme.fg(titleColor, `${row.expanded ? "▾" : "▸"} ${row.title}`)}${hint}`;
 			const line = padLine(truncateToWidth(`${indent}${label}`, width, ""), width);
 			return selected ? `${SELECTED_ROW_MARKER}${line}` : line;
 		}

packages/coding-agent/src/modes/agents-view/agents-view-state.ts

@@ -698,13 +698,25 @@ export function buildAgentsViewRows(
 		}
 		nestedRows.add(row);
 		parentByChild.set(row, parent);
-		if (row.section === "running") {
-			parent.runningSubagentCount += 1;
-		}
 		const siblings = childrenByParent.get(parent) ?? [];
 		siblings.push(row);
 		childrenByParent.set(parent, siblings);
 	}
+	// The parent's own hasRunningRlmChildren snapshot goes stale between its
+	// flushes; the live descendant rows are the truth the indicator shows. The
+	// tally runs before heartbeat propagation so it counts intrinsically busy
+	// rows only, never promotion-inflated ancestors.
+	const tallyRunningDescendants = (row: MutableAgentsViewRow): number => {
+		let count = 0;
+		for (const child of childrenByParent.get(row) ?? []) {
+			count += (child.section === "running" ? 1 : 0) + tallyRunningDescendants(child);
+		}
+		row.runningSubagentCount = count;
+		return count;
+	};
+	for (const row of baseRows) {
+		if (!nestedRows.has(row)) tallyRunningDescendants(row);
+	}
 	propagateHeartbeatStateToAncestors(baseRows, parentByChild);
 
 	const roots = baseRows.filter((row) => !nestedRows.has(row));
@@ -876,6 +888,10 @@ function compareAgentsViewRows(a: AgentsViewRow, b: AgentsViewRow): number {
 		return sectionDiff;
 	}
 	if (a.section !== "running") {
+		const busyDescendantsDiff = Number(b.runningSubagentCount > 0) - Number(a.runningSubagentCount > 0);
+		if (busyDescendantsDiff !== 0) {
+			return busyDescendantsDiff;
+		}
 		const activityDiff = getTimestamp(b.summary.lastActivityAt) - getTimestamp(a.summary.lastActivityAt);
 		if (activityDiff !== 0) {
 			return activityDiff;

packages/coding-agent/test/agents-view-mode.test.ts

@@ -19,7 +19,7 @@ import {
 } from "../src/modes/agents-view/agents-view-state.js";
 import type { SessionSummary } from "../src/modes/daemon/daemon-session-list.js";
 import type { InteractiveModeUiServices } from "../src/modes/interactive/interactive-mode-services.js";
-import { stopThemeWatcher } from "../src/modes/interactive/theme/theme.js";
+import { stopThemeWatcher, theme } from "../src/modes/interactive/theme/theme.js";
 
 const modeMocks = vi.hoisted(() => ({
 	interactiveRun: vi.fn<() => Promise<never>>(),
@@ -685,6 +685,38 @@ describe("AgentsViewMode", () => {
 			stopThemeWatcher();
 		}
 	});
+
+	it("renders a collapsed group's busy-subagent badge legibly instead of dimmed", () => {
+		const parent = summary({ id: "parent", activeSessionId: "parent", sessionId: "parent-session" });
+		const busyChild = summary({
+			id: "busy-child",
+			activeSessionId: "busy-child",
+			sessionId: "busy-child-session",
+			sessionFile: "/tmp/busy-child.jsonl",
+			runtimeKind: "subagent",
+			parentActiveSessionId: "parent",
+			activity: "working",
+			isSessionActive: true,
+			isStreaming: true,
+		});
+		const idleChild = { ...busyChild, activity: "idle" as const, isSessionActive: false, isStreaming: false };
+		const view = new AgentsViewMode({ config: {}, uiServices: createUiServices() }, {});
+
+		try {
+			const busyRows = buildAgentsViewRows([parent, busyChild]);
+			const busySummaryRow = busyRows.find((row) => row.kind === "subagent-summary");
+			expect(busySummaryRow).toMatchObject({ section: "idle", title: "1 subagent running" });
+			Reflect.set(view, "rows", busyRows);
+			expect(invoke("renderRow", view, busySummaryRow, 160)).toContain(theme.fg("success", "▸ 1 subagent running"));
+
+			const idleRows = buildAgentsViewRows([parent, idleChild]);
+			const idleSummaryRow = idleRows.find((row) => row.kind === "subagent-summary");
+			Reflect.set(view, "rows", idleRows);
+			expect(invoke("renderRow", view, idleSummaryRow, 160)).toContain(theme.fg("dim", "▸ 1 subagent"));
+		} finally {
+			stopThemeWatcher();
+		}
+	});
 });
 
 function createUiServices(): InteractiveModeUiServices {

packages/coding-agent/test/agents-view-state.test.ts

@@ -391,6 +391,159 @@ describe("agents view state", () => {
 		});
 	});
 
+	test("shows a busy settled child on its collapsed idle parent without promoting it", () => {
+		const summaries = [
+			makeSummary({
+				id: "parent-active",
+				activeSessionId: "parent-active",
+				sessionId: "parent-session",
+				sessionName: "Parent",
+				activity: "idle",
+				taskState: "completed",
+				messageCount: 2,
+			}),
+			makeSummary({
+				id: "busy-child",
+				activeSessionId: "busy-child",
+				sessionId: "busy-child-session",
+				sessionName: "Busy child",
+				runtimeKind: "subagent",
+				parentActiveSessionId: "parent-active",
+				activity: "working",
+				isSessionActive: true,
+				isStreaming: true,
+			}),
+		];
+
+		const collapsed = buildAgentsViewRows(summaries);
+		expect(collapsed[0]).toMatchObject({ kind: "agent", section: "idle", runningSubagentCount: 1 });
+		expect(collapsed[1]).toMatchObject({ kind: "subagent-summary", section: "idle", title: "1 subagent running" });
+	});
+
+	test("counts a busy grandchild on every idle ancestor without promoting them", () => {
+		const summaries = [
+			makeSummary({
+				id: "parent-active",
+				activeSessionId: "parent-active",
+				sessionId: "parent-session",
+				sessionName: "Parent",
+				activity: "idle",
+				taskState: "completed",
+				messageCount: 2,
+			}),
+			makeSummary({
+				id: "child-active",
+				activeSessionId: "child-active",
+				sessionId: "child-session",
+				sessionName: "Child",
+				runtimeKind: "subagent",
+				parentActiveSessionId: "parent-active",
+				activity: "idle",
+				taskState: "completed",
+			}),
+			makeSummary({
+				id: "grandchild-active",
+				activeSessionId: "grandchild-active",
+				sessionId: "grandchild-session",
+				sessionName: "Grandchild",
+				runtimeKind: "subagent",
+				parentActiveSessionId: "child-active",
+				activity: "working",
+				isSessionActive: true,
+				isStreaming: true,
+			}),
+		];
+
+		const collapsed = buildAgentsViewRows(summaries);
+		expect(collapsed[0]).toMatchObject({ kind: "agent", section: "idle", runningSubagentCount: 1 });
+		expect(collapsed[1]).toMatchObject({ kind: "subagent-summary", section: "idle", title: "1 subagent running" });
+
+		const expanded = buildAgentsViewRows(summaries, new Set([collapsed[0]?.identity ?? ""]));
+		const childRow = expanded.find((row) => row.title === "Child");
+		expect(childRow).toMatchObject({ kind: "subagent", section: "idle", runningSubagentCount: 1 });
+	});
+
+	test("counts a heartbeat-active grandchild once, not its promotion-inflated ancestors", () => {
+		const summaries = [
+			makeSummary({
+				id: "parent-active",
+				activeSessionId: "parent-active",
+				sessionId: "parent-session",
+				sessionName: "Parent",
+				activity: "idle",
+				taskState: "completed",
+				messageCount: 2,
+			}),
+			makeSummary({
+				id: "child-active",
+				activeSessionId: "child-active",
+				sessionId: "child-session",
+				sessionName: "Child",
+				runtimeKind: "subagent",
+				parentActiveSessionId: "parent-active",
+				activity: "idle",
+				taskState: "completed",
+			}),
+			makeSummary({
+				id: "grandchild-active",
+				activeSessionId: "grandchild-active",
+				sessionId: "grandchild-session",
+				sessionName: "Heartbeat grandchild",
+				runtimeKind: "subagent",
+				parentActiveSessionId: "child-active",
+				hasActiveHeartbeat: true,
+				activity: "idle",
+			}),
+		];
+
+		const collapsed = buildAgentsViewRows(summaries);
+		expect(collapsed[0]?.runningSubagentCount).toBe(1);
+		expect(collapsed[1]).toMatchObject({ kind: "subagent-summary", title: "1 subagent running" });
+		const expanded = buildAgentsViewRows(summaries, new Set([collapsed[0]?.identity ?? ""]));
+		expect(expanded.find((row) => row.title === "Child")?.runningSubagentCount).toBe(1);
+	});
+
+	test("ranks idle rows with busy descendants above plain idle rows", () => {
+		const rows = buildAgentsViewRows([
+			makeSummary({
+				id: "plain-idle",
+				activeSessionId: "plain-idle",
+				sessionId: "plain-session",
+				sessionName: "Plain idle",
+				activity: "idle",
+				taskState: "completed",
+				messageCount: 2,
+				lastActivityAt: "2026-09-02T00:00:00Z",
+			}),
+			makeSummary({
+				id: "parent-active",
+				activeSessionId: "parent-active",
+				sessionId: "parent-session",
+				sessionName: "Busy-subtree parent",
+				activity: "idle",
+				taskState: "completed",
+				messageCount: 2,
+				lastActivityAt: "2026-08-01T00:00:00Z",
+			}),
+			makeSummary({
+				id: "busy-child",
+				activeSessionId: "busy-child",
+				sessionId: "busy-child-session",
+				sessionName: "Busy child",
+				runtimeKind: "subagent",
+				parentActiveSessionId: "parent-active",
+				activity: "working",
+				isSessionActive: true,
+				isStreaming: true,
+			}),
+		]);
+
+		expect(rows.filter((row) => row.kind === "agent").map((row) => [row.title, row.section])).toEqual([
+			["Busy-subtree parent", "idle"],
+			["Plain idle", "idle"],
+		]);
+	});
+
 	test("counts every idle heartbeating subagent as running", () => {
 		const heartbeatChildren = Array.from({ length: 10 }, (_, index) =>
 			makeSummary({
@@ -577,7 +730,7 @@ describe("agents view state", () => {
 		const oneLevel = buildAgentsViewRows(summaries, new Set([rootIdentity]));
 		expect(oneLevel.map((row) => [row.title, row.kind])).toEqual([
 			["Root", "agent"],
-			["1 subagent running", "subagent-summary"],
+			["2 subagents running", "subagent-summary"],
 			["Child", "subagent"],
 			["1 subagent running", "subagent-summary"],
 		]);
@@ -586,7 +739,7 @@ describe("agents view state", () => {
 		const twoLevel = buildAgentsViewRows(summaries, new Set([rootIdentity, childIdentity]));
 		expect(twoLevel.map((row) => [row.title, row.kind, row.depth])).toEqual([
 			["Root", "agent", 0],
-			["1 subagent running", "subagent-summary", 1],
+			["2 subagents running", "subagent-summary", 1],
 			["Child", "subagent", 1],
 			["1 subagent running", "subagent-summary", 2],
 			["Grandchild", "subagent", 2],