trunk-merge/pr-3671/35a106b6-808f-4162-ba67-55975397117a

apps/code/src/renderer/desktop-contributions.ts

@@ -13,6 +13,7 @@ import { agentUiModule } from "@posthog/ui/features/agent/agent.module";
 import { authUiModule } from "@posthog/ui/features/auth/auth.module";
 import { billingUiModule } from "@posthog/ui/features/billing/billing.module";
 import { browserTabsUiModule } from "@posthog/ui/features/browser-tabs/browser-tabs.module";
+import { taskActivityUiModule } from "@posthog/ui/features/canvas/task-activity/taskActivity.module";
 import { cloneUiModule } from "@posthog/ui/features/clone/clone.module";
 import { connectivityUiModule } from "@posthog/ui/features/connectivity/connectivity.module";
 import { discordPresenceUiModule } from "@posthog/ui/features/discord-presence/discordPresence.module";
@@ -36,6 +37,7 @@ export function registerDesktopContributions(): void {
     authUiModule,
     autoresearchCoreModule,
     billingUiModule,
+    taskActivityUiModule,
     taskThreadCoreModule,
     browserTabsUiModule,
     cloneUiModule,

apps/web/src/web-container.ts

@@ -190,6 +190,7 @@ import {
   BROWSER_TABS_CLIENT,
   type BrowserTabsClient,
 } from "@posthog/ui/features/browser-tabs/browserTabsClient";
+import { taskActivityUiModule } from "@posthog/ui/features/canvas/task-activity/taskActivity.module";
 import {
   REVIEW_HOST,
   type ReviewHost,
@@ -779,6 +780,7 @@ container.bind(REVIEW_HOST).toConstantValue(webReviewHost);
 // (notificationsUiModule) is resolved by SessionService on task events and by
 // the settings test harness; it needs these three providers.
 container.load(notificationsUiModule);
+container.load(taskActivityUiModule);
 container.bind(NOTIFICATIONS_SERVICE).toConstantValue(webNotifications);
 container
   .bind(NOTIFICATION_SETTINGS_PROVIDER)

packages/api-client/src/posthog-client.ts

@@ -86,6 +86,9 @@ import type {
   SuggestedReviewersArtefact,
   SuggestedReviewerWriteEntry,
   Task,
+  TaskActivityMarkReadResult,
+  TaskActivityPage,
+  TaskActivityReadMarker,
   TaskChannel,
   TaskMention,
   TaskRun,
@@ -2506,6 +2509,53 @@ export class PostHogAPIClient {
     return (await response.json()) as TaskMention[];
   }
 
+  // Tasks the current user is involved in (created, mentioned, or messaged),
+  // one row per task, newest activity first.
+  async getTaskActivity(options?: {
+    before?: string;
+    beforeId?: string;
+  }): Promise<TaskActivityPage> {
+    const teamId = await this.getTeamId();
+    const urlPath = `/api/projects/${teamId}/task_activity/`;
+    const url = new URL(`${this.api.baseUrl}${urlPath}`);
+    if (options?.before && options.beforeId) {
+      url.searchParams.set("before", options.before);
+      url.searchParams.set("before_id", options.beforeId);
+    }
+    const response = await this.api.fetcher.fetch({
+      method: "get",
+      url,
+      path: urlPath,
+    });
+    if (!response.ok) {
+      throw new Error(`Failed to fetch task activity: ${response.statusText}`);
+    }
+    return (await response.json()) as TaskActivityPage;
+  }
+
+  // Read state is per task, so callers name the tasks the user has seen rather than
+  // clearing the whole feed.
+  async markTaskActivityRead(
+    activities: TaskActivityReadMarker[],
+  ): Promise<TaskActivityMarkReadResult> {
+    const teamId = await this.getTeamId();
+    const urlPath = `/api/projects/${teamId}/task_activity/mark_read/`;
+    const response = await this.api.fetcher.fetch({
+      method: "post",
+      url: new URL(`${this.api.baseUrl}${urlPath}`),
+      path: urlPath,
+      overrides: {
+        body: JSON.stringify({ activities }),
+      },
+    });
+    if (!response.ok) {
+      throw new Error(
+        `Failed to mark task activity read: ${response.statusText}`,
+      );
+    }
+    return (await response.json()) as TaskActivityMarkReadResult;
+  }
+
   async getTaskThreadMessages(taskId: string): Promise<TaskThreadMessage[]> {
     const teamId = await this.getTeamId();
     const urlPath = `/api/projects/${teamId}/tasks/${taskId}/thread_messages/`;

packages/core/src/canvas/taskActivity.test.ts

@@ -0,0 +1,68 @@
+import type { TaskActivity, UserBasic } from "@posthog/shared/domain-types";
+import { describe, expect, it } from "vitest";
+import { toTaskActivityItems } from "./taskActivity";
+
+const ann: UserBasic = {
+  id: 2,
+  uuid: "ann-uuid",
+  email: "ann@posthog.com",
+  first_name: "Ann",
+};
+
+function activity(overrides: Partial<TaskActivity> = {}): TaskActivity {
+  return {
+    id: "activity-1",
+    task_id: "t1",
+    task_title: "Task t1",
+    channel_id: "c1",
+    channel_name: "general",
+    activity_at: "2026-07-01T10:00:00Z",
+    activity_kind: "mention",
+    snippet: "ping @[Me](me@posthog.com)",
+    latest_author: ann,
+    latest_message_id: "m1",
+    is_unread: true,
+    ...overrides,
+  };
+}
+
+describe("toTaskActivityItems", () => {
+  it("maps the authoritative activity and unread state", () => {
+    expect(toTaskActivityItems([activity()])).toEqual([
+      {
+        id: "activity-1",
+        taskId: "t1",
+        taskTitle: "Task t1",
+        channelId: "c1",
+        channelName: "general",
+        activityAt: "2026-07-01T10:00:00Z",
+        activityKind: "mention",
+        snippet: "ping @[Me](me@posthog.com)",
+        author: ann,
+        messageId: "m1",
+        isUnread: true,
+      },
+    ]);
+  });
+
+  it("labels untitled tasks and tolerates missing optional values", () => {
+    const [item] = toTaskActivityItems([
+      activity({
+        task_title: "",
+        channel_id: null,
+        channel_name: null,
+        latest_author: null,
+        latest_message_id: null,
+        activity_kind: "created",
+        snippet: "",
+      }),
+    ]);
+    expect(item).toMatchObject({
+      taskTitle: "Untitled task",
+      channelId: null,
+      channelName: null,
+      author: null,
+      messageId: null,
+    });
+  });
+});

packages/core/src/canvas/taskActivity.ts

@@ -0,0 +1,48 @@
+import type {
+  TaskActivity,
+  TaskActivityKind,
+  UserBasic,
+} from "@posthog/shared/domain-types";
+
+/**
+ * The Activity feed — tasks the current user is involved in (created, mentioned
+ * in, or messaged in) — as served by the backend task-activity index
+ * (`getTaskActivity`). One row per task, newest activity first; the client only
+ * maps DTOs to items.
+ */
+
+export interface TaskActivityItem {
+  id: string;
+  taskId: string;
+  taskTitle: string;
+  /** Backend channel (tasks product Channel UUID); null for channel-less tasks. */
+  channelId: string | null;
+  /** Backend channel name, for the "#channel" label. */
+  channelName: string | null;
+  activityAt: string;
+  activityKind: TaskActivityKind;
+  /** Content of the message tied to the latest activity; empty for created rows. */
+  snippet: string;
+  author: UserBasic | null;
+  messageId: string | null;
+  isUnread: boolean;
+}
+
+/** Map activity DTOs (already newest-first from the backend) to feed items. */
+export function toTaskActivityItems(
+  activity: readonly TaskActivity[],
+): TaskActivityItem[] {
+  return activity.map((row) => ({
+    id: row.id,
+    taskId: row.task_id,
+    taskTitle: row.task_title || "Untitled task",
+    channelId: row.channel_id ?? null,
+    channelName: row.channel_name ?? null,
+    activityAt: row.activity_at,
+    activityKind: row.activity_kind,
+    snippet: row.snippet,
+    author: row.latest_author ?? null,
+    messageId: row.latest_message_id ?? null,
+    isUnread: row.is_unread,
+  }));
+}

packages/core/src/sessions/sessionService.ts

@@ -6830,6 +6830,37 @@ export class SessionService {
     return () => {};
   }
 
+  public async watchCreatedCloudTask(task: Task): Promise<void> {
+    const run = task.latest_run;
+    if (run?.environment !== "cloud") return;
+
+    const authStatus = await this.getAuthCredentialsStatus();
+    if (authStatus.kind !== "ready") return;
+
+    this.updateSessionTaskTitle(
+      task.id,
+      task.title || task.description || "Cloud Task",
+    );
+    this.watchCloudTask(
+      task.id,
+      run.id,
+      authStatus.auth.apiHost,
+      authStatus.auth.projectId,
+      undefined,
+      run.log_url,
+      typeof run.state?.initial_permission_mode === "string"
+        ? run.state.initial_permission_mode
+        : undefined,
+      run.runtime_adapter === "codex" ? "codex" : "claude",
+      run.model ?? undefined,
+      task.description ?? undefined,
+      undefined,
+      run.status,
+      run.reasoning_effort ?? undefined,
+      run.state,
+    );
+  }
+
   private logReconcileSkipOnce(
     taskId: string,
     reason: string,

packages/core/src/task-detail/taskCreationSaga.test.ts

@@ -47,6 +47,7 @@ const host = mockHost as unknown as ITaskCreationHost;
 const sessionService = {
   connectToTask: vi.fn(),
   disconnectFromTask: vi.fn(),
+  watchCreatedCloudTask: vi.fn(),
   rememberInitialCloudPrompt: vi.fn(),
   markTaskCreationInFlight: vi.fn(),
 } as unknown as SessionService;
@@ -186,6 +187,9 @@ describe("TaskCreationSaga", () => {
       pendingUserArtifactIds: undefined,
     });
     expect(sendRunCommandMock).not.toHaveBeenCalled();
+    expect(sessionService.watchCreatedCloudTask).toHaveBeenCalledWith(
+      startedTask,
+    );
     expect(onTaskReady).toHaveBeenCalledTimes(1);
     expect(onTaskReady.mock.calls[0][0].task.latest_run?.branch).toBe(
       "release/remembered-branch",
@@ -633,6 +637,9 @@ describe("TaskCreationSaga", () => {
     // Warm-activated at create time: no fresh run is created or started.
     expect(createTaskRunMock).not.toHaveBeenCalled();
     expect(startTaskRunMock).not.toHaveBeenCalled();
+    expect(sessionService.watchCreatedCloudTask).toHaveBeenCalledWith(
+      warmActivatedTask,
+    );
   });
 
   it("suppresses warm reuse when attachments exist but no warm lease is known", async () => {

packages/core/src/task-detail/taskCreationSaga.ts

@@ -319,8 +319,11 @@ export class TaskCreationSaga extends Saga<
       );
     }
 
-    if (!hasProvisioning && !shouldStartCloudRun && this.deps.onTaskReady) {
-      this.deps.onTaskReady({ task, workspace });
+    if (!hasProvisioning && !shouldStartCloudRun) {
+      if (!taskId && workspaceMode === "cloud") {
+        await this.deps.sessionService.watchCreatedCloudTask(task);
+      }
+      this.deps.onTaskReady?.({ task, workspace });
     }
 
     if (hasProvisioning) {
@@ -469,8 +472,9 @@ export class TaskCreationSaga extends Saga<
         },
       });
 
-      if (!hasProvisioning && this.deps.onTaskReady) {
-        this.deps.onTaskReady({ task, workspace });
+      if (!hasProvisioning) {
+        await this.deps.sessionService.watchCreatedCloudTask(task);
+        this.deps.onTaskReady?.({ task, workspace });
       }
     }
 

packages/shared/src/domain-types.ts

@@ -139,6 +139,51 @@ export interface TaskMention {
   created_at: string;
 }
 
+/** Which signal produced an activity row; mirrors the backend `activity_kind`. */
+export type TaskActivityKind =
+  | "awaiting_input"
+  | "completed"
+  | "message"
+  | "mention"
+  | "created";
+
+/**
+ * One task the current user is involved in, from the backend task-activity feed
+ * (`/task_activity/`). One row per task, newest activity first. Mirrors
+ * `TaskActivityDTO`.
+ */
+export interface TaskActivity {
+  id: string;
+  task_id: string;
+  task_title: string;
+  channel_id?: string | null;
+  channel_name?: string | null;
+  activity_at: string;
+  activity_kind: TaskActivityKind;
+  snippet: string;
+  latest_author?: UserBasic | null;
+  latest_message_id?: string | null;
+  is_unread: boolean;
+}
+
+export interface TaskActivityPage {
+  results: TaskActivity[];
+  /** Unread tasks across the whole feed, not just this page. Backs the sidebar badge. */
+  unread_count: number;
+  next_before?: string | null;
+  next_before_id?: string | null;
+}
+
+export interface TaskActivityReadMarker {
+  task_id: string;
+  seen_before: string;
+}
+
+export interface TaskActivityMarkReadResult {
+  marked_read: number;
+  unread_count: number;
+}
+
 export type TaskRunStatus =
   | "not_started"
   | "queued"