fix: scope turn-activity panel metrics to per-agent events in sequential workflows

In sequential workflows, multiple collapsible turn-activity panels shared
the same SessionRunRecord and displayed identical aggregate metrics (tool
calls, approvals, etc.) instead of per-agent counts.

Root cause: ChatPane grouped thinking messages correctly per agent, but
passed the full unfiltered run object to every TurnActivityPanel, so
summarizeActivity() counted all events from the entire run for each panel.

Changes:
- Extract filterEventsByAgent() and summarizeActivity() to
  runTimelineFormatting.ts as pure, testable helpers
- Add agentNames (derived from thinking message authors) and isLastRunPanel
  to the DisplayItem turn-activity variant in ChatPane
- TurnActivityPanel now filters run.events through filterEventsByAgent()
  so each panel only counts events belonging to its agents
- Git summary / discard actions only render on the last panel of a run
- Per-agent timing derived from scoped events instead of run-level start

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/renderer/components/ChatPane.tsx

@@ -46,7 +46,16 @@ import {
 
 type DisplayItem =
   | { type: 'message'; message: ChatMessageRecord }
-  | { type: 'turn-activity'; thinkingMessages: ChatMessageRecord[]; run?: SessionRunRecord; turnStartedAt?: string };
+  | {
+    type: 'turn-activity';
+    thinkingMessages: ChatMessageRecord[];
+    run?: SessionRunRecord;
+    turnStartedAt?: string;
+    /** Agent names in this turn group, derived from thinking message authors. Used to scope run events. */
+    agentNames?: ReadonlySet<string>;
+    /** True when this is the last turn-activity panel that shares a given run (controls git summary / discard). */
+    isLastRunPanel?: boolean;
+  };
 
 interface ChatPaneProps {
   project: ProjectRecord;
@@ -147,6 +156,15 @@ export function ChatPane({
     // can detect orphaned runs that need their own panel.
     const consumedRunIds = new Set<string>();
 
+    /** Collect unique author names from a batch of thinking messages. */
+    function collectAgentNames(msgs: ChatMessageRecord[]): Set<string> | undefined {
+      const names = new Set<string>();
+      for (const m of msgs) {
+        if (m.authorName) names.add(m.authorName);
+      }
+      return names.size > 0 ? names : undefined;
+    }
+
     for (let i = 0; i < messages.length; i++) {
       const message = messages[i];
       const isLast = i === messages.length - 1;
@@ -176,7 +194,13 @@ export function ChatPane({
       if (pendingThinking.length > 0) {
         const run = lastUserMessageId ? runsByTrigger.get(lastUserMessageId) : undefined;
         if (run) consumedRunIds.add(run.id);
-        items.push({ type: 'turn-activity', thinkingMessages: pendingThinking, run, turnStartedAt: run?.startedAt });
+        items.push({
+          type: 'turn-activity',
+          thinkingMessages: pendingThinking,
+          run,
+          turnStartedAt: run?.startedAt,
+          agentNames: collectAgentNames(pendingThinking),
+        });
         pendingThinking = [];
       }
       items.push({ type: 'message', message });
@@ -188,7 +212,13 @@ export function ChatPane({
     if (pendingThinking.length > 0) {
       const run = lastUserMessageId ? runsByTrigger.get(lastUserMessageId) : undefined;
       if (run) consumedRunIds.add(run.id);
-      items.push({ type: 'turn-activity', thinkingMessages: pendingThinking, run, turnStartedAt: run?.startedAt });
+      items.push({
+        type: 'turn-activity',
+        thinkingMessages: pendingThinking,
+        run,
+        turnStartedAt: run?.startedAt,
+        agentNames: collectAgentNames(pendingThinking),
+      });
     }
 
     // If the session is busy but no turn-activity was emitted for the
@@ -201,6 +231,22 @@ export function ChatPane({
       }
     }
 
+    // Tag the last turn-activity panel for each run so only it shows
+    // run-level metadata (git summary, discard button, etc.).
+    const lastPanelIndexByRunId = new Map<string, number>();
+    for (let i = 0; i < items.length; i++) {
+      const item = items[i];
+      if (item.type === 'turn-activity' && item.run) {
+        lastPanelIndexByRunId.set(item.run.id, i);
+      }
+    }
+    for (let i = 0; i < items.length; i++) {
+      const item = items[i];
+      if (item.type === 'turn-activity' && item.run) {
+        item.isLastRunPanel = lastPanelIndexByRunId.get(item.run.id) === i;
+      }
+    }
+
     return items;
   }, [session.messages, session.runs, session.status]);
 
@@ -547,6 +593,8 @@ export function ChatPane({
                         isActive={isTurnActive(item, itemIndex)}
                         turnStartedAt={item.turnStartedAt}
                         sessionId={session.id}
+                        agentNames={item.agentNames}
+                        isLastRunPanel={item.isLastRunPanel}
                         onDiscard={onDiscardRunChanges}
                         onOpenCommitComposer={onOpenCommitComposer}
                       />

src/renderer/components/chat/TurnActivityPanel.tsx

@@ -16,7 +16,7 @@ import {
 import { useElapsedTimer } from '@renderer/hooks/useElapsedTimer';
 import { FileChangePreview } from '@renderer/components/chat/FileChangePreview';
 import { RunChangeSummaryCard } from '@renderer/components/chat/RunChangeSummaryCard';
-import { formatEventLabel, truncateContent } from '@renderer/lib/runTimelineFormatting';
+import { formatEventLabel, truncateContent, filterEventsByAgent, summarizeActivity, type ActivitySummary } from '@renderer/lib/runTimelineFormatting';
 import type { ChatMessageRecord } from '@shared/domain/session';
 import type { ProjectGitFileReference } from '@shared/domain/project';
 import type { RunTimelineEventRecord, SessionRunRecord } from '@shared/domain/runTimeline';
@@ -40,6 +40,10 @@ export interface TurnActivityPanelProps {
   isActive: boolean;
   turnStartedAt?: string;
   sessionId: string;
+  /** Agent names in this turn group — used to scope run events in multi-agent runs. */
+  agentNames?: ReadonlySet<string>;
+  /** True when this panel is the last one sharing a given run (controls git summary / discard). */
+  isLastRunPanel?: boolean;
   onDiscard?: (sessionId: string, runId: string, files?: ProjectGitFileReference[]) => Promise<unknown>;
   onOpenCommitComposer?: () => void;
 }
@@ -78,36 +82,6 @@ function buildActivityStream(
   return items;
 }
 
-interface ActivitySummary {
-  thinkingSteps: number;
-  toolCalls: number;
-  handoffs: number;
-  approvals: number;
-  hasError: boolean;
-}
-
-function summarizeActivity(
-  thinkingMessages: ChatMessageRecord[],
-  run?: SessionRunRecord,
-): ActivitySummary {
-  const thinkingSteps = thinkingMessages.filter((m) => m.content).length;
-  let toolCalls = 0;
-  let handoffs = 0;
-  let approvals = 0;
-  let hasError = false;
-
-  if (run) {
-    for (const e of run.events) {
-      if (e.kind === 'tool-call') toolCalls++;
-      else if (e.kind === 'handoff') handoffs++;
-      else if (e.kind === 'approval') approvals++;
-      else if (e.kind === 'run-failed') hasError = true;
-    }
-  }
-
-  return { thinkingSteps, toolCalls, handoffs, approvals, hasError };
-}
-
 function formatSummaryParts(summary: ActivitySummary): string[] {
   const parts: string[] = [];
   if (summary.toolCalls > 0) {
@@ -267,6 +241,8 @@ export function TurnActivityPanel({
   isActive,
   turnStartedAt,
   sessionId,
+  agentNames,
+  isLastRunPanel,
   onDiscard,
   onOpenCommitComposer,
 }: TurnActivityPanelProps) {
@@ -286,19 +262,43 @@ export function TurnActivityPanel({
 
   const toggle = useCallback(() => setExpanded((prev) => !prev), []);
 
+  // When the run is shared across multiple panels (multi-agent sequential),
+  // scope events to only those belonging to this panel's agents.
+  const scopedEvents = useMemo(
+    () => filterEventsByAgent(run?.events ?? [], agentNames),
+    [run?.events, agentNames],
+  );
+
+  // Derive per-agent timing from the scoped events when agent names are set
+  // (multi-agent run). For single-agent runs, use the run-level start time.
+  const effectiveTurnStartedAt = useMemo(() => {
+    if (!agentNames || agentNames.size === 0 || scopedEvents.length === 0) {
+      return turnStartedAt;
+    }
+    // Use the earliest scoped event as the start time for this agent's panel.
+    let earliest = turnStartedAt;
+    for (const e of scopedEvents) {
+      if (!earliest || e.occurredAt < earliest) {
+        earliest = e.occurredAt;
+        break; // events are already in insertion order (chronological)
+      }
+    }
+    return earliest;
+  }, [agentNames, scopedEvents, turnStartedAt]);
+
   const elapsed = useElapsedTimer(
-    thinkingMessages.length > 0 || run ? turnStartedAt : undefined,
+    thinkingMessages.length > 0 || run ? effectiveTurnStartedAt : undefined,
     isActive,
   );
 
   const summary = useMemo(
-    () => summarizeActivity(thinkingMessages, run),
-    [thinkingMessages, run],
+    () => summarizeActivity(thinkingMessages, scopedEvents),
+    [thinkingMessages, scopedEvents],
   );
 
   const activityStream = useMemo(
-    () => buildActivityStream(thinkingMessages, run?.events ?? []),
-    [thinkingMessages, run?.events],
+    () => buildActivityStream(thinkingMessages, scopedEvents),
+    [thinkingMessages, scopedEvents],
   );
 
   // Nothing to show — no thinking messages, no run, and not active
@@ -312,7 +312,8 @@ export function TurnActivityPanel({
   const isFailed = runStatus === 'error';
   const isCancelled = runStatus === 'cancelled';
   const isTerminated = isCompleted || isFailed || isCancelled;
-  const showGitSummary = run && isTerminated && run.postRunGitSummary && onDiscard;
+  // Only show git summary and discard on the last panel for a given run
+  const showGitSummary = run && isTerminated && run.postRunGitSummary && onDiscard && (isLastRunPanel !== false);
 
   // Build the summary label
   let summaryLabel: string;

src/renderer/lib/runTimelineFormatting.ts

@@ -168,3 +168,68 @@ export function truncateContent(content: string | undefined, maxLength = 80): st
 export function findLatestRun(runs: readonly SessionRunRecord[]): SessionRunRecord | undefined {
   return runs.length > 0 ? runs[0] : undefined;
 }
+
+/* ── Agent-scoped event filtering ──────────────────────────── */
+
+/** Run-level events that are not scoped to any specific agent. */
+const RUN_LEVEL_EVENT_KINDS = new Set<RunTimelineEventKind>([
+  'run-started',
+  'run-completed',
+  'run-cancelled',
+  'run-failed',
+]);
+
+/**
+ * Filter run events to only those belonging to the given agents.
+ * When `agentNames` is undefined or empty (single-agent run), all events pass through.
+ * Run-level events (start/complete/fail) are excluded from agent-scoped panels
+ * because they represent the entire run, not a specific agent's work.
+ */
+export function filterEventsByAgent(
+  events: readonly RunTimelineEventRecord[],
+  agentNames: ReadonlySet<string> | undefined,
+): RunTimelineEventRecord[] {
+  if (!agentNames || agentNames.size === 0) return events.slice();
+
+  return events.filter((e) => {
+    if (RUN_LEVEL_EVENT_KINDS.has(e.kind)) return false;
+    if (e.kind === 'handoff') {
+      return (e.sourceAgentName != null && agentNames.has(e.sourceAgentName))
+        || (e.targetAgentName != null && agentNames.has(e.targetAgentName));
+    }
+    if (e.agentName) return agentNames.has(e.agentName);
+    return false;
+  });
+}
+
+/** Counts of different activity types within a set of run timeline events. */
+export interface ActivitySummary {
+  thinkingSteps: number;
+  toolCalls: number;
+  handoffs: number;
+  approvals: number;
+  hasError: boolean;
+}
+
+/**
+ * Summarize activity from thinking messages and (already-filtered) run events.
+ */
+export function summarizeActivity(
+  thinkingMessages: ReadonlyArray<{ content: string }>,
+  events: readonly RunTimelineEventRecord[],
+): ActivitySummary {
+  const thinkingSteps = thinkingMessages.filter((m) => m.content).length;
+  let toolCalls = 0;
+  let handoffs = 0;
+  let approvals = 0;
+  let hasError = false;
+
+  for (const e of events) {
+    if (e.kind === 'tool-call') toolCalls++;
+    else if (e.kind === 'handoff') handoffs++;
+    else if (e.kind === 'approval') approvals++;
+    else if (e.kind === 'run-failed') hasError = true;
+  }
+
+  return { thinkingSteps, toolCalls, handoffs, approvals, hasError };
+}