feat: split session and subagent cost under the context meter

2026-08-24 15:53:16 +01:00
parent ce870b7134
commit 87509a2395
15 changed files with 68 additions and 7 deletions
@@ -194,8 +194,13 @@ export const WorkStatusPrimaryGroup: React.FC<Props> = ({ sessionId, directory,
  // Rollup total: own cost plus every descendant subagent's cost, recursively
  // (see useSubagentCostRollup). Shown here instead of session.cost alone, so
  // spend that ran in a spawned subagent doesn't hide from the reader.
-  const { totalCost } = useSubagentCostRollup(sessionId);
+  const { totalCost, ownCost, subagentCost, subagentCount } = useSubagentCostRollup(sessionId);
  const cost = totalCost !== null && totalCost > 0 ? totalCost : null;
+  // The total answers "what has this cost"; the split answers "why is it more
+  // than the session I am looking at". Only worth a line once subagents exist —
+  // without them the total *is* the session's own cost and the row would
+  // restate the number directly above it.
+  const showCostBreakdown = cost !== null && subagentCount > 0 && subagentCost > 0;
  const hasSession = showSession && (usagePercent !== null || cost !== null || Boolean(goalRow));
  const hasRepository = showRepository && Boolean(branch || changed || prSummary || attentionLabel);

@@ -224,6 +229,17 @@ export const WorkStatusPrimaryGroup: React.FC<Props> = ({ sessionId, directory,
                )}
              />
              <WorkStatusMeter percent={usagePercent} color={meterColor} />
+              {/* Caption, not a row: it explains the figure above it rather
+                  than reporting a reading of its own, so it carries no icon
+                  and no label column. */}
+              {showCostBreakdown ? (
+                <p className="mx-1 mb-1 truncate text-[11px] leading-4 text-muted-foreground tabular-nums">
+                  {t('chat.workStatus.cost.breakdown', {
+                    session: formatCost(ownCost),
+                    subagents: formatCost(subagentCost),
+                  })}
+                </p>
+              ) : null}
            </>
          ) : null}
          {/* Below the context readout: the goal is a standing instruction,
@@ -20,6 +20,20 @@ describe('computeRollup', () => {
    expect(result.subagentCount).toBe(3);
  });

+  test('splits the total into the session own cost and the subagent share', () => {
+    const result = computeRollup(sessions, 'root');
+    expect(result.ownCost).toBe(1);
+    expect(result.subagentCost).toBe(10);
+    expect(result.ownCost + result.subagentCost).toBe(result.totalCost);
+  });
+
+  test('reports a zero subagent share for a session with no children', () => {
+    const result = computeRollup(sessions, 'a1');
+    expect(result.ownCost).toBe(5);
+    expect(result.subagentCost).toBe(0);
+    expect(result.totalCost).toBe(5);
+  });
+
  test('maps each direct child to its own subtree cost', () => {
    const result = computeRollup(sessions, 'root');
    expect(result.perChildCost.get('a')).toBe(7);
@@ -5,11 +5,21 @@ import { buildChildrenIndex, computeSubtreeCost } from './subagentCost';

 export type SubagentCostRollup = {
  totalCost: number | null;
+  /** The root session's own spend, excluding every subagent. */
+  ownCost: number;
+  /** Everything the subagents cost between them: `totalCost - ownCost`. */
+  subagentCost: number;
  subagentCount: number;
  perChildCost: Map<string, number>;
 };

-const EMPTY_ROLLUP: SubagentCostRollup = { totalCost: null, subagentCount: 0, perChildCost: new Map() };
+const EMPTY_ROLLUP: SubagentCostRollup = {
+  totalCost: null,
+  ownCost: 0,
+  subagentCost: 0,
+  subagentCount: 0,
+  perChildCost: new Map(),
+};

 function countDescendants(id: string, childrenByParent: Map<string, Session[]>, visited: Set<string>): number {
  if (visited.has(id)) return 0;
@@ -34,13 +44,20 @@ export function computeRollup(liveSessions: Session[], sessionId: string | null)
  const totalCost = computeSubtreeCost(sessionId, sessionsById, childrenByParent);

  const perChildCost = new Map<string, number>();
+  let subagentCost = 0;
  for (const child of childrenByParent.get(sessionId) ?? []) {
-    perChildCost.set(child.id, computeSubtreeCost(child.id, sessionsById, childrenByParent));
+    const childSubtree = computeSubtreeCost(child.id, sessionsById, childrenByParent);
+    perChildCost.set(child.id, childSubtree);
+    subagentCost += childSubtree;
  }

+  // Derived by subtraction rather than read back off the session, so the split
+  // always adds up to the total the panel shows even if a cycle guard trimmed
+  // part of the walk.
+  const ownCost = totalCost - subagentCost;
  const subagentCount = countDescendants(sessionId, childrenByParent, new Set());

-  return { totalCost, subagentCount, perChildCost };
+  return { totalCost, ownCost, subagentCost, subagentCount, perChildCost };
 }

 /**
@@ -5,7 +5,8 @@ import { SessionDialogs } from '@/components/session/SessionDialogs';
 import { ChatView } from '@/components/views/ChatView';
 import { useSessionUIStore } from '@/sync/session-ui-store';
 import { useViewportStore } from '@/sync/viewport-store';
-import { useSessions, useDirectorySync, useSession, useSessionMessages, useSessionMessagesResolved } from '@/sync/sync-context';
+import { useSessions, useDirectorySync, useSessionMessages, useSessionMessagesResolved } from '@/sync/sync-context';
+import { useSubagentCostRollup } from '@/components/chat/work-status/useSubagentCostRollup';
 import { useConfigStore } from '@/stores/useConfigStore';
 import { resolveGlobalSessionDirectory, useGlobalSessionsStore } from '@/stores/useGlobalSessionsStore';
 import { contextTokensFromBreakdown } from '@/stores/utils/tokenUtils';
@@ -666,7 +667,9 @@ const VSCodeHeader: React.FC<VSCodeHeaderProps> = ({ title, showBack, onBack, on
  const providers = useConfigStore((state) => state.providers);
  const currentSessionId = useSessionUIStore((state) => state.currentSessionId);
  const activeProjectId = useProjectsStore((state) => state.activeProjectId);
-  const currentSession = useSession(currentSessionId ?? '');
+  // Same rollup the work-status panel reports, so the header and the panel
+  // never disagree about what this session has cost.
+  const { totalCost: sessionTotalCost } = useSubagentCostRollup(currentSessionId ?? null);
  const currentSessionMessages = useSessionMessages(currentSessionId ?? '');
  const currentSessionMessagesResolved = useSessionMessagesResolved(currentSessionId ?? '');
  const quotaResults = useQuotaStore((state) => state.results);
@@ -1023,7 +1026,7 @@ const VSCodeHeader: React.FC<VSCodeHeaderProps> = ({ title, showBack, onBack, on
          percentage={stableContextUsage.percentage}
          contextLimit={stableContextUsage.contextLimit}
          outputLimit={stableContextUsage.outputLimit ?? 0}
-          cost={(currentSession?.cost ?? 0) > 0 ? currentSession?.cost : null}
+          cost={(sessionTotalCost ?? 0) > 0 ? sessionTotalCost : null}
          className="h-9 shrink-0 pl-1 pr-1 typography-ui-label"
          valueClassName="font-semibold leading-none"
          hideIcon
@@ -3096,6 +3096,7 @@ export const dict = {
  'updateDialog.changelog.title': 'Neuigkeiten',
  'chat.workStatus.ariaLabel': 'Arbeitsstatus',
  'chat.workStatus.context.label': 'Kontext',
+  'chat.workStatus.cost.breakdown': 'Sitzung {session} · Unteragenten {subagents}',
  'chat.workStatus.git.changedFileSingle': '{count} Datei geändert',
  'chat.workStatus.git.changedFilePlural': '{count} Dateien geändert',
  'chat.workStatus.pr.untitled': 'Pull Request ohne Titel',
@@ -3098,6 +3098,7 @@ export const dict = {
  'quota.window.premiumInteractions': 'Premium interactions',
  'chat.workStatus.ariaLabel': 'Work status',
  'chat.workStatus.context.label': 'Context',
+  'chat.workStatus.cost.breakdown': 'Session {session} · Subagents {subagents}',
  'chat.workStatus.git.changedFileSingle': '{count} file changed',
  'chat.workStatus.git.changedFilePlural': '{count} files changed',
  'chat.workStatus.pr.untitled': 'Untitled pull request',
@@ -3099,6 +3099,7 @@ export const dict: Record<I18nKey, string> = {
  "quota.window.premiumInteractions": "Premium interactions",
  'chat.workStatus.ariaLabel': 'Estado del trabajo',
  'chat.workStatus.context.label': 'Contexto',
+  'chat.workStatus.cost.breakdown': "Sesión {session} · Subagentes {subagents}",
  'chat.workStatus.git.changedFileSingle': '{count} archivo modificado',
  'chat.workStatus.git.changedFilePlural': '{count} archivos modificados',
  'chat.workStatus.pr.untitled': 'Pull request sin título',
@@ -3096,6 +3096,7 @@ export const dict = {
  'vscodeLayout.actions.cancel': 'Annuler',
  'chat.workStatus.ariaLabel': 'État du travail',
  'chat.workStatus.context.label': 'Contexte',
+  'chat.workStatus.cost.breakdown': 'Session {session} · Sous-agents {subagents}',
  'chat.workStatus.git.changedFileSingle': '{count} fichier modifié',
  'chat.workStatus.git.changedFilePlural': '{count} fichiers modifiés',
  'chat.workStatus.pr.untitled': 'Pull request sans titre',
@@ -3098,6 +3098,7 @@ export const dict: Record<I18nKey, string> = {

  'chat.workStatus.ariaLabel': '作業状況',
  'chat.workStatus.context.label': 'コンテキスト',
+  'chat.workStatus.cost.breakdown': 'セッション {session} · サブエージェント {subagents}',
  'chat.workStatus.git.changedFileSingle': '{count} 件のファイルを変更',
  'chat.workStatus.git.changedFilePlural': '{count} 件のファイルを変更',
  'chat.workStatus.pr.untitled': 'タイトルなしのプルリクエスト',
@@ -3098,6 +3098,7 @@ export const dict: Record<I18nKey, string> = {
  'quota.window.premiumInteractions': 'Premium interactions',
  'chat.workStatus.ariaLabel': '작업 상태',
  'chat.workStatus.context.label': '컨텍스트',
+  'chat.workStatus.cost.breakdown': '세션 {session} · 서브 에이전트 {subagents}',
  'chat.workStatus.git.changedFileSingle': '파일 {count}개 변경됨',
  'chat.workStatus.git.changedFilePlural': '파일 {count}개 변경됨',
  'chat.workStatus.pr.untitled': '제목 없는 풀 리퀘스트',
@@ -3115,6 +3115,7 @@ export const dict: Record<I18nKey, string> = {
  'quota.window.premiumInteractions': 'Premium interactions',
  'chat.workStatus.ariaLabel': 'Stan pracy',
  'chat.workStatus.context.label': 'Kontekst',
+  'chat.workStatus.cost.breakdown': 'Sesja {session} · Podagenci {subagents}',
  'chat.workStatus.git.changedFileSingle': 'Zmieniono {count} plik',
  'chat.workStatus.git.changedFilePlural': 'Zmieniono {count} plików',
  'chat.workStatus.pr.untitled': 'Pull request bez tytułu',
@@ -3099,6 +3099,7 @@ export const dict: Record<I18nKey, string> = {
  "quota.window.premiumInteractions": "Premium interactions",
  'chat.workStatus.ariaLabel': 'Status do trabalho',
  'chat.workStatus.context.label': 'Contexto',
+  'chat.workStatus.cost.breakdown': "Sessão {session} · Subagentes {subagents}",
  'chat.workStatus.git.changedFileSingle': '{count} arquivo alterado',
  'chat.workStatus.git.changedFilePlural': '{count} arquivos alterados',
  'chat.workStatus.pr.untitled': 'Pull request sem título',
@@ -3099,6 +3099,7 @@ export const dict: Record<I18nKey, string> = {
  "quota.window.premiumInteractions": "Premium interactions",
  'chat.workStatus.ariaLabel': 'Стан роботи',
  'chat.workStatus.context.label': 'Контекст',
+  'chat.workStatus.cost.breakdown': "Сеанс {session} · Субагенти {subagents}",
  'chat.workStatus.git.changedFileSingle': 'Змінено {count} файл',
  'chat.workStatus.git.changedFilePlural': 'Змінено {count} файлів',
  'chat.workStatus.pr.untitled': 'Pull request без назви',
@@ -3099,6 +3099,7 @@ export const dict: Record<I18nKey, string> = {
  'quota.window.premiumInteractions': 'Premium interactions',
  'chat.workStatus.ariaLabel': '工作状态',
  'chat.workStatus.context.label': '上下文',
+  'chat.workStatus.cost.breakdown': '会话 {session} · 子智能体 {subagents}',
  'chat.workStatus.git.changedFileSingle': '已更改 {count} 个文件',
  'chat.workStatus.git.changedFilePlural': '已更改 {count} 个文件',
  'chat.workStatus.pr.untitled': '未命名的拉取请求',
@@ -3098,6 +3098,7 @@ export const dict: Record<I18nKey, string> = {
  'quota.window.premiumInteractions': 'Premium interactions',
  'chat.workStatus.ariaLabel': '工作狀態',
  'chat.workStatus.context.label': '上下文',
+  'chat.workStatus.cost.breakdown': '工作階段 {session} · 子 Agent {subagents}',
  'chat.workStatus.git.changedFileSingle': '已變更 {count} 個檔案',
  'chat.workStatus.git.changedFilePlural': '已變更 {count} 個檔案',
  'chat.workStatus.pr.untitled': '未命名的提取請求',