refactor(graph): simplify comment particle rendering with dedicated bubble function

- Replaced inline drawing logic for task comments with a new `drawCommentBubble` function to enhance readability and maintainability.
- The new function encapsulates the drawing of a speech-bubble icon, including the rounded rectangle body, tail, and inner dots to suggest text.

packages/agent-graph/src/canvas/draw-particles.ts

@@ -156,16 +156,7 @@ function drawParticleCore(
   ctx.drawImage(sprite, pos.x - glowR, pos.y - glowR);
 
   if (kind === 'task_comment') {
-    ctx.strokeStyle = color;
-    ctx.lineWidth = 1.8;
-    ctx.beginPath();
-    ctx.arc(pos.x, pos.y, size * 1.1, 0, Math.PI * 2);
-    ctx.stroke();
-
-    ctx.fillStyle = '#ffffff';
-    ctx.beginPath();
-    ctx.arc(pos.x, pos.y, size * 0.35, 0, Math.PI * 2);
-    ctx.fill();
+    drawCommentBubble(ctx, pos.x, pos.y, size, color);
     return;
   }
 
@@ -181,3 +172,48 @@ function drawParticleCore(
   ctx.arc(pos.x, pos.y, size * PARTICLE_DRAW.coreHighlightScale, 0, Math.PI * 2);
   ctx.fill();
 }
+
+/**
+ * Draw a speech-bubble icon for comment particles.
+ * Rounded rect body + small triangular tail at bottom-left.
+ */
+function drawCommentBubble(
+  ctx: CanvasRenderingContext2D,
+  cx: number,
+  cy: number,
+  size: number,
+  color: string,
+): void {
+  const w = size * 2.4;
+  const h = size * 1.8;
+  const r = size * 0.4; // corner radius
+  const x = cx - w / 2;
+  const y = cy - h / 2;
+
+  // Bubble body
+  ctx.fillStyle = color;
+  ctx.beginPath();
+  ctx.roundRect(x, y, w, h, r);
+  ctx.fill();
+
+  // Tail (small triangle at bottom-left)
+  const tailX = x + w * 0.25;
+  const tailY = y + h;
+  ctx.beginPath();
+  ctx.moveTo(tailX, tailY - 1);
+  ctx.lineTo(tailX - size * 0.4, tailY + size * 0.5);
+  ctx.lineTo(tailX + size * 0.4, tailY - 1);
+  ctx.closePath();
+  ctx.fill();
+
+  // Inner dots (three small dots to suggest text)
+  ctx.fillStyle = '#ffffff';
+  const dotR = size * 0.18;
+  const dotY = cy - size * 0.05;
+  const gap = size * 0.5;
+  for (let i = -1; i <= 1; i++) {
+    ctx.beginPath();
+    ctx.arc(cx + i * gap, dotY, dotR, 0, Math.PI * 2);
+    ctx.fill();
+  }
+}

src/main/services/team/ChangeExtractorService.ts

@@ -371,6 +371,7 @@ export class ChangeExtractorService {
         return derived.length > 0 ? derived : undefined;
       })();
       return {
+        createdAt: typeof parsed.createdAt === 'string' ? parsed.createdAt : undefined,
         owner: typeof parsed.owner === 'string' ? parsed.owner : undefined,
         status: typeof parsed.status === 'string' ? parsed.status : undefined,
         intervals: derivedIntervals,
@@ -725,6 +726,7 @@ export class ChangeExtractorService {
     }
 
     const descriptor = buildTaskChangePresenceDescriptor({
+      createdAt: taskMeta.createdAt,
       owner: effectiveOptions.owner ?? taskMeta.owner,
       status: effectiveOptions.status ?? taskMeta.status,
       intervals: effectiveOptions.intervals ?? taskMeta.intervals,

src/main/services/team/TeamDataService.ts

@@ -234,6 +234,7 @@ export class TeamDataService {
 
     for (const task of tasks) {
       const descriptor = buildTaskChangePresenceDescriptor({
+        createdAt: task.createdAt,
         owner: task.owner,
         status: task.status,
         intervals: task.workIntervals,

src/main/services/team/taskChangePresenceUtils.ts

@@ -2,6 +2,7 @@ import {
   getTaskChangeStateBucket,
   type TaskChangeStateBucket,
 } from '@shared/utils/taskChangeState';
+import { deriveTaskSince } from '@shared/utils/taskChangeSince';
 import { createHash } from 'crypto';
 
 export interface TaskChangePresenceInterval {
@@ -13,6 +14,7 @@ export interface TaskChangePresenceDescriptorInput {
   owner?: string;
   status?: string;
   intervals?: TaskChangePresenceInterval[];
+  createdAt?: string;
   since?: string;
   reviewState?: 'review' | 'needsFix' | 'approved' | 'none';
   historyEvents?: unknown[];
@@ -102,6 +104,15 @@ export function computeTaskChangePresenceProjectFingerprint(
 export function buildTaskChangePresenceDescriptor(
   input: TaskChangePresenceDescriptorInput
 ): TaskChangePresenceDescriptor {
+  const effectiveSince =
+    typeof input.since === 'string'
+      ? input.since
+      : deriveTaskSince({
+          createdAt: input.createdAt,
+          workIntervals: input.intervals,
+          historyEvents: input.historyEvents as { timestamp?: string | null }[] | undefined,
+        });
+
   const effectiveIntervals =
     Array.isArray(input.intervals) && input.intervals.length > 0
       ? input.intervals.map((interval) => ({
@@ -124,7 +135,7 @@ export function buildTaskChangePresenceDescriptor(
     owner: typeof input.owner === 'string' ? input.owner.trim() : '',
     status: typeof input.status === 'string' ? input.status.trim() : '',
     intervals: effectiveIntervals,
-    since: typeof input.since === 'string' ? input.since : '',
+    since: effectiveSince ?? '',
   };
 
   return {

src/main/services/team/taskChangeWorkerTypes.ts

@@ -1,6 +1,7 @@
 import type { TaskChangeSetV2 } from '@shared/types';
 
 export interface TaskChangeTaskMeta {
+  createdAt?: string;
   owner?: string;
   status?: string;
   intervals?: { startedAt: string; completedAt?: string }[];

src/renderer/features/agent-graph/adapters/TeamGraphAdapter.ts

@@ -494,6 +494,9 @@ export class TeamGraphAdapter {
       if (this.#seenMessageIds.has(msgKey)) continue;
       this.#seenMessageIds.add(msgKey);
 
+      // Skip comment notifications — #buildCommentParticles handles them with real text
+      if (msg.summary?.startsWith('Comment on ')) continue;
+
       const edgeId = TeamGraphAdapter.#resolveMessageEdge(msg, teamName, leadId, leadName, edges);
       if (!edgeId) continue;
 

src/renderer/utils/taskChangeRequest.ts

@@ -3,12 +3,11 @@ import {
   isTaskChangeSummaryCacheable,
   type TaskChangeStateBucket,
 } from '@shared/utils/taskChangeState';
+import { deriveTaskSince as deriveSharedTaskSince } from '@shared/utils/taskChangeSince';
 
 import type { ReviewAPI } from '@shared/types/api';
 import type { TeamTaskWithKanban } from '@shared/types/team';
 
-const TASK_SINCE_GRACE_MS = 2 * 60 * 1000;
-
 export type TaskChangeRequestOptions = NonNullable<Parameters<ReviewAPI['getTaskChanges']>[2]>;
 
 export interface TaskChangeContext {
@@ -31,27 +30,7 @@ type TaskChangeTaskLike = Pick<
 >;
 
 export function deriveTaskSince(task: TaskChangeTaskLike | null): string | undefined {
-  if (!task) return undefined;
-
-  const sources: string[] = [];
-  if (task.createdAt) sources.push(task.createdAt);
-  if (Array.isArray(task.workIntervals)) {
-    for (const interval of task.workIntervals) {
-      if (interval.startedAt) sources.push(interval.startedAt);
-    }
-  }
-  if (Array.isArray(task.historyEvents)) {
-    for (const event of task.historyEvents) {
-      if (event.timestamp) sources.push(event.timestamp);
-    }
-  }
-  if (sources.length === 0) return undefined;
-
-  const [first, ...rest] = sources;
-  const earliest = rest.reduce((a, b) => (a < b ? a : b), first);
-  const date = new Date(earliest);
-  date.setTime(date.getTime() - TASK_SINCE_GRACE_MS);
-  return date.toISOString();
+  return deriveSharedTaskSince(task);
 }
 
 export function buildTaskChangeRequestOptions(

src/shared/utils/taskChangeSince.ts

@@ -0,0 +1,51 @@
+const TASK_SINCE_GRACE_MS = 2 * 60 * 1000;
+
+type TaskChangeIntervalLike = {
+  startedAt?: string | null;
+};
+
+type TaskChangeHistoryEventLike = {
+  timestamp?: string | null;
+};
+
+export interface TaskChangeSinceLike<
+  TInterval extends TaskChangeIntervalLike = TaskChangeIntervalLike,
+  THistoryEvent extends TaskChangeHistoryEventLike = TaskChangeHistoryEventLike,
+> {
+  createdAt?: string | null;
+  workIntervals?: TInterval[] | null;
+  historyEvents?: THistoryEvent[] | null;
+}
+
+export function deriveTaskSince<
+  TInterval extends TaskChangeIntervalLike,
+  THistoryEvent extends TaskChangeHistoryEventLike,
+>(task: TaskChangeSinceLike<TInterval, THistoryEvent> | null | undefined): string | undefined {
+  if (!task) return undefined;
+
+  const sources: string[] = [];
+  if (typeof task.createdAt === 'string' && task.createdAt.length > 0) {
+    sources.push(task.createdAt);
+  }
+  if (Array.isArray(task.workIntervals)) {
+    for (const interval of task.workIntervals) {
+      if (typeof interval?.startedAt === 'string' && interval.startedAt.length > 0) {
+        sources.push(interval.startedAt);
+      }
+    }
+  }
+  if (Array.isArray(task.historyEvents)) {
+    for (const event of task.historyEvents) {
+      if (typeof event?.timestamp === 'string' && event.timestamp.length > 0) {
+        sources.push(event.timestamp);
+      }
+    }
+  }
+  if (sources.length === 0) return undefined;
+
+  const [first, ...rest] = sources;
+  const earliest = rest.reduce((a, b) => (a < b ? a : b), first);
+  const date = new Date(earliest);
+  date.setTime(date.getTime() - TASK_SINCE_GRACE_MS);
+  return date.toISOString();
+}

test/main/services/team/TeamDataService.test.ts

@@ -1867,6 +1867,94 @@ describe('TeamDataService', () => {
     expect(mismatched.tasks[0]?.changePresence).toBe('unknown');
   });
 
+  it('preserves cached changePresence when persisted entry was recorded with derived since', async () => {
+    const task: TeamTask = {
+      id: 'task-1',
+      subject: 'Review API',
+      status: 'completed',
+      owner: 'alice',
+      createdAt: '2026-03-01T10:05:00.000Z',
+      workIntervals: [{ startedAt: '2026-03-01T10:10:00.000Z' }],
+      historyEvents: [
+        {
+          id: 'evt-1',
+          type: 'status_changed',
+          from: 'pending',
+          to: 'in_progress',
+          timestamp: '2026-03-01T10:00:00.000Z',
+        },
+      ],
+    };
+
+    const persistedDescriptor = buildTaskChangePresenceDescriptor({
+      createdAt: task.createdAt,
+      owner: task.owner,
+      status: task.status,
+      intervals: task.workIntervals,
+      since: '2026-03-01T09:58:00.000Z',
+      historyEvents: task.historyEvents,
+      reviewState: 'none',
+    });
+
+    const service = new TeamDataService(
+      {
+        listTeams: vi.fn(),
+        getConfig: vi.fn(async () => ({ name: 'My team', members: [], projectPath: '/repo' })),
+      } as never,
+      {
+        getTasks: vi.fn(async () => [task]),
+      } as never,
+      {
+        listInboxNames: vi.fn(async () => []),
+        getMessages: vi.fn(async () => []),
+      } as never,
+      {} as never,
+      {} as never,
+      {
+        resolveMembers: vi.fn(() => []),
+      } as never,
+      {
+        getState: vi.fn(async () => ({ teamName: 'my-team', reviewers: [], tasks: {} })),
+      } as never
+    );
+
+    service.setTaskChangePresenceServices(
+      {
+        load: vi.fn(async () => ({
+          version: 1,
+          teamName: 'my-team',
+          projectFingerprint: 'project-fingerprint',
+          logSourceGeneration: 'log-generation',
+          writtenAt: '2026-03-01T12:00:00.000Z',
+          entries: {
+            'task-1': {
+              taskId: 'task-1',
+              taskSignature: persistedDescriptor.taskSignature,
+              presence: 'has_changes',
+              writtenAt: '2026-03-01T12:00:00.000Z',
+              logSourceGeneration: 'log-generation',
+            },
+          },
+        })),
+        upsertEntry: vi.fn(async () => undefined),
+      } as never,
+      {
+        getSnapshot: vi.fn(() => ({
+          projectFingerprint: 'project-fingerprint',
+          logSourceGeneration: 'log-generation',
+        })),
+        ensureTracking: vi.fn(async () => ({
+          projectFingerprint: 'project-fingerprint',
+          logSourceGeneration: 'log-generation',
+        })),
+      } as never
+    );
+
+    const data = await service.getTeamData('my-team');
+
+    expect(data.tasks[0]?.changePresence).toBe('has_changes');
+  });
+
   it('returns lightweight task change presence without loading full team data', async () => {
     const task: TeamTask = {
       id: 'task-1',