feat(team): add task stall monitor shadow rollout

2026-04-19 21:17:09 +03:00 · 2026-04-19 21:17:09 +03:00 · a8cca65658
commit a8cca65658
parent cd52660f88
28 changed files with 3217 additions and 42 deletions
--- a/src/main/index.ts
+++ b/src/main/index.ts
@ -111,6 +111,7 @@ import {
 } from './utils/safeWebContentsSend';
 import { syncTelemetryFlag } from './sentry';
 import {
+  ActiveTeamRegistry,
  BoardTaskActivityDetailService,
  BoardTaskActivityRecordSource,
  BoardTaskActivityService,
@ -130,6 +131,11 @@ import {
  TaskBoundaryParser,
  TeamDataService,
  TeamLogSourceTracker,
+  TeamTaskStallJournal,
+  TeamTaskStallMonitor,
+  TeamTaskStallNotifier,
+  TeamTaskStallPolicy,
+  TeamTaskStallSnapshotSource,
  TeammateToolTracker,
  TeamMemberLogsFinder,
  TeamProvisioningService,
@ -415,6 +421,7 @@ let cliInstallerService: CliInstallerService;
 let ptyTerminalService: PtyTerminalService;
 let httpServer: HttpServer;
 let schedulerService: SchedulerService;
+let teamTaskStallMonitor: TeamTaskStallMonitor | null = null;
 let skillsWatcherService: SkillsWatcherService | null = null;
 let teamBackupService: TeamBackupService | null = null;
 let branchStatusService: BranchStatusService | null = null;
@ -848,6 +855,13 @@ async function initializeServices(): Promise<void> {

  const taskChangePresenceRepository = new JsonTaskChangePresenceRepository();
  const teamLogSourceTracker = new TeamLogSourceTracker(teamMemberLogsFinder);
+  teamTaskStallMonitor = new TeamTaskStallMonitor(
+    new ActiveTeamRegistry(teamDataService, teamLogSourceTracker),
+    new TeamTaskStallSnapshotSource(),
+    new TeamTaskStallPolicy(),
+    new TeamTaskStallJournal(),
+    new TeamTaskStallNotifier(teamDataService)
+  );
  let teammateToolTracker: TeammateToolTracker | null = null;
  branchStatusService = new BranchStatusService((event) => {
    safeSendToRenderer(mainWindow, TEAM_PROJECT_BRANCH_CHANGE, event);
@ -930,6 +944,7 @@ async function initializeServices(): Promise<void> {
  // Allow TeamProvisioningService to trigger team refresh events (e.g. live lead replies).
  const teamChangeEmitter = (event: TeamChangeEvent): void => {
    forwardTeamChange(event);
+    teamTaskStallMonitor?.noteTeamChange(event);
    if (event.type === 'lead-activity' && event.detail === 'offline') {
      teammateToolTracker?.handleTeamOffline(event.teamName);
    }
@ -939,6 +954,7 @@ async function initializeServices(): Promise<void> {
  teamLogSourceTracker.onLogSourceChange((teamName) => {
    teammateToolTracker?.handleLogSourceChange(teamName);
  });
+  teamTaskStallMonitor.start();

  // Allow SchedulerService to push schedule events to renderer
  schedulerService.setChangeEmitter((event) => {
@ -1142,6 +1158,10 @@ function shutdownServices(): void {
  if (teamDataService) {
    teamDataService.stopProcessHealthPolling();
  }
+  if (teamTaskStallMonitor) {
+    void teamTaskStallMonitor.stop();
+    teamTaskStallMonitor = null;
+  }
  branchStatusService?.dispose();
  branchStatusService = null;

--- a/src/main/services/team/TeamDataService.ts
+++ b/src/main/services/team/TeamDataService.ts
@ -511,6 +511,27 @@ export class TeamDataService {
    return this.configReader.listTeams();
  }

+  async listAliveProcessTeams(): Promise<string[]> {
+    const teams = await this.listTeams();
+    const alive: string[] = [];
+
+    for (const team of teams) {
+      if (team.deletedAt) {
+        continue;
+      }
+      try {
+        const processes = await this.readProcesses(team.teamName);
+        if (processes.some((process) => !process.stoppedAt)) {
+          alive.push(team.teamName);
+        }
+      } catch {
+        // best-effort per team
+      }
+    }
+
+    return alive.sort((left, right) => left.localeCompare(right));
+  }
+
  async getAllTasks(): Promise<GlobalTask[]> {
    const rawTasks = await this.taskReader.getAllTasks();
    const teams = await this.configReader.listTeams();
@ -1741,6 +1762,23 @@ export class TeamDataService {
    return result;
  }

+  async sendSystemNotificationToLead(args: {
+    teamName: string;
+    summary: string;
+    text: string;
+    taskRefs?: TaskRef[];
+  }): Promise<SendMessageResult> {
+    const leadName = await this.resolveLeadName(args.teamName);
+    return this.sendMessage(args.teamName, {
+      member: leadName,
+      from: 'system',
+      summary: args.summary,
+      text: args.text,
+      ...(args.taskRefs && args.taskRefs.length > 0 ? { taskRefs: args.taskRefs } : {}),
+      source: TASK_COMMENT_NOTIFICATION_SOURCE,
+    });
+  }
+
  private resolveLeadNameFromConfig(config: TeamConfig | null): string {
    if (!config) return 'team-lead';
    const lead = config.members?.find((m) => m.role?.toLowerCase().includes('lead'));
--- a/src/main/services/team/TeamLogSourceTracker.ts
+++ b/src/main/services/team/TeamLogSourceTracker.ts
@ -22,7 +22,11 @@ interface TeamLogSourceSnapshot {
  logSourceGeneration: string | null;
 }

-export type TeamLogSourceTrackingConsumer = 'change_presence' | 'tool_activity' | 'task_log_stream';
+export type TeamLogSourceTrackingConsumer =
+  | 'change_presence'
+  | 'tool_activity'
+  | 'task_log_stream'
+  | 'stall_monitor';

 interface TrackingState {
  watcher: FSWatcher | null;
--- a/src/main/services/team/index.ts
+++ b/src/main/services/team/index.ts
@ -39,3 +39,12 @@ export { TeamSentMessagesStore } from './TeamSentMessagesStore';
 export { TeamTaskReader } from './TeamTaskReader';
 export { TeamTaskWriter } from './TeamTaskWriter';
 export { countLineChanges } from './UnifiedLineCounter';
+export { ActiveTeamRegistry } from './stallMonitor/ActiveTeamRegistry';
+export { BoardTaskActivityBatchIndexer } from './stallMonitor/BoardTaskActivityBatchIndexer';
+export { TeamTaskLogFreshnessReader } from './stallMonitor/TeamTaskLogFreshnessReader';
+export { TeamTaskStallExactRowReader } from './stallMonitor/TeamTaskStallExactRowReader';
+export { TeamTaskStallJournal } from './stallMonitor/TeamTaskStallJournal';
+export { TeamTaskStallMonitor } from './stallMonitor/TeamTaskStallMonitor';
+export { TeamTaskStallNotifier } from './stallMonitor/TeamTaskStallNotifier';
+export { TeamTaskStallPolicy } from './stallMonitor/TeamTaskStallPolicy';
+export { TeamTaskStallSnapshotSource } from './stallMonitor/TeamTaskStallSnapshotSource';
--- a/src/main/services/team/stallMonitor/ActiveTeamRegistry.ts
+++ b/src/main/services/team/stallMonitor/ActiveTeamRegistry.ts
@ -0,0 +1,101 @@
+import type { TeamLogSourceTracker } from '../TeamLogSourceTracker';
+import type { TeamChangeEvent } from '@shared/types';
+
+interface TeamAliveProcessesReader {
+  listAliveProcessTeams(): Promise<string[]>;
+}
+
+interface TeamLogSourceTrackingHandle {
+  enableTracking(
+    teamName: string,
+    consumer: 'stall_monitor'
+  ): Promise<{ projectFingerprint: string | null; logSourceGeneration: string | null }>;
+  disableTracking(
+    teamName: string,
+    consumer: 'stall_monitor'
+  ): Promise<{ projectFingerprint: string | null; logSourceGeneration: string | null }>;
+}
+
+export class ActiveTeamRegistry {
+  private readonly activeTeams = new Set<string>();
+  private reconcileTimer: ReturnType<typeof setInterval> | null = null;
+
+  constructor(
+    private readonly teamDataService: TeamAliveProcessesReader,
+    private readonly teamLogSourceTracker: Pick<
+      TeamLogSourceTracker,
+      'enableTracking' | 'disableTracking'
+    > &
+      TeamLogSourceTrackingHandle,
+    private readonly reconcileIntervalMs: number = 5 * 60_000
+  ) {}
+
+  noteTeamChange(event: TeamChangeEvent): void {
+    if (
+      event.type === 'member-spawn' ||
+      (event.type === 'lead-activity' && event.detail !== 'offline')
+    ) {
+      if (!this.activeTeams.has(event.teamName)) {
+        this.activeTeams.add(event.teamName);
+        void this.teamLogSourceTracker.enableTracking(event.teamName, 'stall_monitor');
+      }
+      return;
+    }
+
+    if (event.type === 'task-log-change' || event.type === 'log-source-change') {
+      if (!this.activeTeams.has(event.teamName)) {
+        return;
+      }
+    }
+  }
+
+  async listActiveTeams(): Promise<string[]> {
+    return [...this.activeTeams].sort((left, right) => left.localeCompare(right));
+  }
+
+  start(): void {
+    if (this.reconcileTimer) {
+      return;
+    }
+    void this.reconcile();
+    this.reconcileTimer = setInterval(() => {
+      void this.reconcile();
+    }, this.reconcileIntervalMs);
+  }
+
+  async stop(): Promise<void> {
+    if (this.reconcileTimer) {
+      clearInterval(this.reconcileTimer);
+      this.reconcileTimer = null;
+    }
+
+    const teamNames = [...this.activeTeams];
+    this.activeTeams.clear();
+    await Promise.all(
+      teamNames.map((teamName) =>
+        this.teamLogSourceTracker.disableTracking(teamName, 'stall_monitor')
+      )
+    );
+  }
+
+  async reconcile(): Promise<void> {
+    const aliveTeams = await this.teamDataService.listAliveProcessTeams();
+    const aliveSet = new Set(aliveTeams);
+
+    for (const teamName of aliveTeams) {
+      if (this.activeTeams.has(teamName)) {
+        continue;
+      }
+      this.activeTeams.add(teamName);
+      await this.teamLogSourceTracker.enableTracking(teamName, 'stall_monitor');
+    }
+
+    for (const teamName of [...this.activeTeams]) {
+      if (aliveSet.has(teamName)) {
+        continue;
+      }
+      this.activeTeams.delete(teamName);
+      await this.teamLogSourceTracker.disableTracking(teamName, 'stall_monitor');
+    }
+  }
+}
--- a/src/main/services/team/stallMonitor/BoardTaskActivityBatchIndexer.ts
+++ b/src/main/services/team/stallMonitor/BoardTaskActivityBatchIndexer.ts
@ -0,0 +1,30 @@
+import { BoardTaskActivityRecordBuilder } from '../taskLogs/activity/BoardTaskActivityRecordBuilder';
+
+import type { BoardTaskActivityRecord } from '../taskLogs/activity/BoardTaskActivityRecord';
+import type { RawTaskActivityMessage } from '../taskLogs/activity/BoardTaskActivityTranscriptReader';
+import type { TeamTask } from '@shared/types';
+
+export class BoardTaskActivityBatchIndexer {
+  constructor(
+    private readonly recordBuilder: Pick<
+      BoardTaskActivityRecordBuilder,
+      'buildForTasks'
+    > = new BoardTaskActivityRecordBuilder()
+  ) {}
+
+  buildIndex(args: {
+    teamName: string;
+    tasks: TeamTask[];
+    messages: RawTaskActivityMessage[];
+  }): Map<string, BoardTaskActivityRecord[]> {
+    if (args.tasks.length === 0 || args.messages.length === 0) {
+      return new Map();
+    }
+
+    return this.recordBuilder.buildForTasks({
+      teamName: args.teamName,
+      tasks: args.tasks,
+      messages: args.messages,
+    });
+  }
+}
--- a/src/main/services/team/stallMonitor/TeamTaskLogFreshnessReader.ts
+++ b/src/main/services/team/stallMonitor/TeamTaskLogFreshnessReader.ts
@ -0,0 +1,124 @@
+import * as fs from 'fs/promises';
+import * as path from 'path';
+
+import { BoardTaskActivityParseCache } from '../taskLogs/activity/BoardTaskActivityParseCache';
+
+import type { TaskLogFreshnessSignal } from './TeamTaskStallTypes';
+
+const BOARD_TASK_LOG_FRESHNESS_DIRNAME = '.board-task-log-freshness';
+const BOARD_TASK_LOG_FRESHNESS_FILE_SUFFIX = '.json';
+
+interface ParsedFreshnessSignal {
+  taskId: string;
+  updatedAt: string;
+  transcriptFileBasename?: string;
+}
+
+function encodeTaskId(taskId: string): string {
+  return encodeURIComponent(taskId);
+}
+
+function isValidTimestamp(value: unknown): value is string {
+  return typeof value === 'string' && value.trim().length > 0 && Number.isFinite(Date.parse(value));
+}
+
+export class TeamTaskLogFreshnessReader {
+  private readonly cache = new BoardTaskActivityParseCache<ParsedFreshnessSignal | false>();
+
+  async readSignals(
+    projectDir: string,
+    taskIds: string[]
+  ): Promise<Map<string, TaskLogFreshnessSignal>> {
+    const uniqueTaskIds = [...new Set(taskIds)].filter((taskId) => taskId.trim().length > 0).sort();
+    const signalFilePaths = uniqueTaskIds.map((taskId) =>
+      path.join(
+        projectDir,
+        BOARD_TASK_LOG_FRESHNESS_DIRNAME,
+        `${encodeTaskId(taskId)}${BOARD_TASK_LOG_FRESHNESS_FILE_SUFFIX}`
+      )
+    );
+    this.cache.retainOnly(new Set(signalFilePaths));
+
+    const rows = await Promise.all(
+      uniqueTaskIds.map(async (taskId, index) => {
+        const filePath = signalFilePaths[index];
+        const parsed = await this.readSignal(filePath);
+        if (!parsed || parsed.taskId !== taskId) {
+          return null;
+        }
+        return [
+          taskId,
+          {
+            taskId,
+            updatedAt: parsed.updatedAt,
+            filePath,
+            ...(parsed.transcriptFileBasename
+              ? { transcriptFileBasename: parsed.transcriptFileBasename }
+              : {}),
+          } satisfies TaskLogFreshnessSignal,
+        ] as const;
+      })
+    );
+
+    return new Map(rows.filter((row): row is NonNullable<typeof row> => row !== null));
+  }
+
+  private async readSignal(filePath: string): Promise<ParsedFreshnessSignal | false> {
+    try {
+      const stat = await fs.stat(filePath);
+      if (!stat.isFile()) {
+        this.cache.clearForPath(filePath);
+        return false;
+      }
+
+      const cached = this.cache.getIfFresh(filePath, stat.mtimeMs, stat.size);
+      if (cached !== null) {
+        return cached;
+      }
+
+      const inFlight = this.cache.getInFlight(filePath);
+      if (inFlight) {
+        return inFlight;
+      }
+
+      const promise = this.parseSignal(filePath);
+      this.cache.setInFlight(filePath, promise);
+      try {
+        const parsed = await promise;
+        this.cache.set(filePath, stat.mtimeMs, stat.size, parsed);
+        return parsed;
+      } finally {
+        this.cache.clearInFlight(filePath);
+      }
+    } catch {
+      this.cache.clearForPath(filePath);
+      return false;
+    }
+  }
+
+  private async parseSignal(filePath: string): Promise<ParsedFreshnessSignal | false> {
+    const raw = await fs.readFile(filePath, 'utf8');
+    const parsed = JSON.parse(raw) as unknown;
+    if (!parsed || typeof parsed !== 'object') {
+      return false;
+    }
+
+    const record = parsed as Record<string, unknown>;
+    const taskId =
+      typeof record.taskId === 'string' && record.taskId.trim().length > 0
+        ? record.taskId.trim()
+        : null;
+    const updatedAt = isValidTimestamp(record.updatedAt) ? record.updatedAt : null;
+    if (!taskId || !updatedAt) {
+      return false;
+    }
+
+    return {
+      taskId,
+      updatedAt,
+      ...(typeof record.transcriptFile === 'string' && record.transcriptFile.trim().length > 0
+        ? { transcriptFileBasename: path.basename(record.transcriptFile.trim()) }
+        : {}),
+    };
+  }
+}
--- a/src/main/services/team/stallMonitor/TeamTaskStallExactRowReader.ts
+++ b/src/main/services/team/stallMonitor/TeamTaskStallExactRowReader.ts
@ -0,0 +1,127 @@
+import { yieldToEventLoop } from '@main/utils/asyncYield';
+import { parseJsonlLine } from '@main/utils/jsonl';
+import { createLogger } from '@shared/utils/logger';
+import { createReadStream } from 'fs';
+import * as fs from 'fs/promises';
+import * as readline from 'readline';
+
+import { BoardTaskActivityParseCache } from '../taskLogs/activity/BoardTaskActivityParseCache';
+
+import type { TeamTaskStallExactRow } from './TeamTaskStallTypes';
+
+const logger = createLogger('Service:TeamTaskStallExactRowReader');
+
+function asRecord(value: unknown): Record<string, unknown> | null {
+  return value && typeof value === 'object' ? (value as Record<string, unknown>) : null;
+}
+
+function hasStrictTimestamp(record: Record<string, unknown>): boolean {
+  return typeof record.timestamp === 'string' && Number.isFinite(Date.parse(record.timestamp));
+}
+
+function parseSystemSubtype(record: Record<string, unknown>): 'turn_duration' | 'init' | undefined {
+  return record.subtype === 'turn_duration' || record.subtype === 'init'
+    ? record.subtype
+    : undefined;
+}
+
+export class TeamTaskStallExactRowReader {
+  private readonly cache = new BoardTaskActivityParseCache<TeamTaskStallExactRow[]>();
+
+  async parseFiles(filePaths: string[]): Promise<Map<string, TeamTaskStallExactRow[]>> {
+    const uniquePaths = [...new Set(filePaths)].sort();
+    this.cache.retainOnly(new Set(uniquePaths));
+
+    const rows = await Promise.all(
+      uniquePaths.map(async (filePath) => [filePath, await this.parseFile(filePath)] as const)
+    );
+    return new Map(rows);
+  }
+
+  private async parseFile(filePath: string): Promise<TeamTaskStallExactRow[]> {
+    try {
+      const stat = await fs.stat(filePath);
+      const cached = this.cache.getIfFresh(filePath, stat.mtimeMs, stat.size);
+      if (cached !== null) {
+        return cached;
+      }
+
+      const inFlight = this.cache.getInFlight(filePath);
+      if (inFlight) {
+        return inFlight;
+      }
+
+      const promise = this.readFile(filePath);
+      this.cache.setInFlight(filePath, promise);
+      try {
+        const parsed = await promise;
+        this.cache.set(filePath, stat.mtimeMs, stat.size, parsed);
+        return parsed;
+      } finally {
+        this.cache.clearInFlight(filePath);
+      }
+    } catch (error) {
+      logger.debug(`Skipping unreadable stall exact-log transcript ${filePath}: ${String(error)}`);
+      this.cache.clearForPath(filePath);
+      return [];
+    }
+  }
+
+  private async readFile(filePath: string): Promise<TeamTaskStallExactRow[]> {
+    const rows: TeamTaskStallExactRow[] = [];
+    const stream = createReadStream(filePath, { encoding: 'utf8' });
+    const rl = readline.createInterface({
+      input: stream,
+      crlfDelay: Infinity,
+    });
+
+    let lineCount = 0;
+    let sourceOrder = 0;
+
+    for await (const line of rl) {
+      if (!line.trim()) {
+        continue;
+      }
+      lineCount += 1;
+
+      try {
+        const raw = JSON.parse(line) as unknown;
+        const record = asRecord(raw);
+        if (!record || !hasStrictTimestamp(record)) {
+          continue;
+        }
+
+        const parsed = parseJsonlLine(line);
+        if (!parsed) {
+          continue;
+        }
+
+        sourceOrder += 1;
+        const systemSubtype = parseSystemSubtype(record);
+        rows.push({
+          filePath,
+          sourceOrder,
+          messageUuid: parsed.uuid,
+          timestamp: record.timestamp as string,
+          parsedMessage: parsed,
+          ...(parsed.requestId ? { requestId: parsed.requestId } : {}),
+          ...(parsed.sourceToolUseID ? { sourceToolUseId: parsed.sourceToolUseID } : {}),
+          ...(parsed.sourceToolAssistantUUID
+            ? { sourceToolAssistantUuid: parsed.sourceToolAssistantUUID }
+            : {}),
+          ...(systemSubtype ? { systemSubtype } : {}),
+          toolUseIds: parsed.toolCalls.map((toolCall) => toolCall.id),
+          toolResultIds: parsed.toolResults.map((toolResult) => toolResult.toolUseId),
+        });
+      } catch (error) {
+        logger.debug(`Skipping malformed stall exact-log line in ${filePath}: ${String(error)}`);
+      }
+
+      if (lineCount % 250 === 0) {
+        await yieldToEventLoop();
+      }
+    }
+
+    return rows;
+  }
+}
--- a/src/main/services/team/stallMonitor/TeamTaskStallJournal.ts
+++ b/src/main/services/team/stallMonitor/TeamTaskStallJournal.ts
@ -0,0 +1,145 @@
+import { getTeamsBasePath } from '@main/utils/pathDecoder';
+import * as fs from 'fs';
+import * as path from 'path';
+
+import { atomicWriteAsync } from '../atomicWrite';
+import { withFileLock } from '../fileLock';
+
+import type {
+  TaskStallEvaluation,
+  TaskStallJournalEntry,
+  TaskStallJournalState,
+} from './TeamTaskStallTypes';
+
+function isValidState(value: unknown): value is TaskStallJournalState {
+  return value === 'suspected' || value === 'alert_ready' || value === 'alerted';
+}
+
+export class TeamTaskStallJournal {
+  private getFilePath(teamName: string): string {
+    return path.join(getTeamsBasePath(), teamName, 'stall-monitor-journal.json');
+  }
+
+  async reconcileScan(args: {
+    teamName: string;
+    evaluations: TaskStallEvaluation[];
+    activeTaskIds: string[];
+    now: string;
+  }): Promise<TaskStallEvaluation[]> {
+    const filePath = this.getFilePath(args.teamName);
+    let readyEvaluations: TaskStallEvaluation[] = [];
+
+    await withFileLock(filePath, async () => {
+      const entries = await this.readUnlocked(filePath);
+      const candidateByEpoch = new Map(
+        args.evaluations
+          .filter(
+            (
+              evaluation
+            ): evaluation is TaskStallEvaluation &
+              Required<Pick<TaskStallEvaluation, 'taskId' | 'branch' | 'signal' | 'epochKey'>> =>
+              evaluation.status === 'alert' &&
+              typeof evaluation.taskId === 'string' &&
+              typeof evaluation.branch === 'string' &&
+              typeof evaluation.signal === 'string' &&
+              typeof evaluation.epochKey === 'string'
+          )
+          .map((evaluation) => [evaluation.epochKey, evaluation] as const)
+      );
+
+      const activeTaskIdSet = new Set(args.activeTaskIds);
+      for (let i = entries.length - 1; i >= 0; i -= 1) {
+        const entry = entries[i];
+        if (!activeTaskIdSet.has(entry.taskId) || !candidateByEpoch.has(entry.epochKey)) {
+          entries.splice(i, 1);
+        }
+      }
+
+      for (const [epochKey, evaluation] of candidateByEpoch) {
+        const existing = entries.find((entry) => entry.epochKey === epochKey);
+        if (!existing) {
+          entries.push({
+            epochKey,
+            teamName: args.teamName,
+            taskId: evaluation.taskId,
+            branch: evaluation.branch,
+            signal: evaluation.signal,
+            state: 'suspected',
+            consecutiveScans: 1,
+            createdAt: args.now,
+            updatedAt: args.now,
+          });
+          continue;
+        }
+
+        existing.updatedAt = args.now;
+        if (existing.state === 'alerted') {
+          continue;
+        }
+
+        existing.consecutiveScans += 1;
+        if (existing.consecutiveScans >= 2) {
+          existing.state = 'alert_ready';
+          readyEvaluations.push(evaluation);
+        }
+      }
+
+      await atomicWriteAsync(filePath, JSON.stringify(entries, null, 2));
+    });
+
+    return readyEvaluations;
+  }
+
+  async markAlerted(teamName: string, epochKey: string, now: string): Promise<void> {
+    const filePath = this.getFilePath(teamName);
+    await withFileLock(filePath, async () => {
+      const entries = await this.readUnlocked(filePath);
+      const target = entries.find((entry) => entry.epochKey === epochKey);
+      if (!target) {
+        return;
+      }
+      target.state = 'alerted';
+      target.updatedAt = now;
+      target.alertedAt = now;
+      await atomicWriteAsync(filePath, JSON.stringify(entries, null, 2));
+    });
+  }
+
+  private async readUnlocked(filePath: string): Promise<TaskStallJournalEntry[]> {
+    try {
+      const raw = await fs.promises.readFile(filePath, 'utf8');
+      const parsed = JSON.parse(raw) as unknown;
+      if (!Array.isArray(parsed)) {
+        return [];
+      }
+
+      return parsed
+        .filter(
+          (item): item is TaskStallJournalEntry =>
+            item != null &&
+            typeof item === 'object' &&
+            typeof (item as TaskStallJournalEntry).epochKey === 'string' &&
+            typeof (item as TaskStallJournalEntry).teamName === 'string' &&
+            typeof (item as TaskStallJournalEntry).taskId === 'string' &&
+            ((item as TaskStallJournalEntry).branch === 'work' ||
+              (item as TaskStallJournalEntry).branch === 'review') &&
+            ((item as TaskStallJournalEntry).signal === 'turn_ended_after_touch' ||
+              (item as TaskStallJournalEntry).signal === 'mid_turn_after_touch' ||
+              (item as TaskStallJournalEntry).signal === 'touch_then_other_turns') &&
+            isValidState((item as TaskStallJournalEntry).state) &&
+            typeof (item as TaskStallJournalEntry).consecutiveScans === 'number' &&
+            typeof (item as TaskStallJournalEntry).createdAt === 'string' &&
+            typeof (item as TaskStallJournalEntry).updatedAt === 'string'
+        )
+        .map((entry) => ({
+          ...entry,
+          ...(entry.alertedAt ? { alertedAt: entry.alertedAt } : {}),
+        }));
+    } catch (error) {
+      if ((error as NodeJS.ErrnoException).code === 'ENOENT') {
+        return [];
+      }
+      throw error;
+    }
+  }
+}
--- a/src/main/services/team/stallMonitor/TeamTaskStallMonitor.ts
+++ b/src/main/services/team/stallMonitor/TeamTaskStallMonitor.ts
@ -0,0 +1,246 @@
+import { createLogger } from '@shared/utils/logger';
+import { getTaskDisplayId } from '@shared/utils/taskIdentity';
+
+import { ActiveTeamRegistry } from './ActiveTeamRegistry';
+import {
+  getTeamTaskStallActivationGraceMs,
+  getTeamTaskStallScanIntervalMs,
+  getTeamTaskStallStartupGraceMs,
+  isTeamTaskStallAlertsEnabled,
+  isTeamTaskStallMonitorEnabled,
+} from './featureGates';
+
+import type { TeamTaskStallSnapshotSource } from './TeamTaskStallSnapshotSource';
+import type { TeamTaskStallPolicy } from './TeamTaskStallPolicy';
+import type { TeamTaskStallJournal } from './TeamTaskStallJournal';
+import type { TeamTaskStallNotifier } from './TeamTaskStallNotifier';
+import type { TaskStallAlert, TaskStallEvaluation } from './TeamTaskStallTypes';
+import type { TeamChangeEvent } from '@shared/types';
+
+const logger = createLogger('Service:TeamTaskStallMonitor');
+
+interface TeamObservationState {
+  firstSeenAtMs: number;
+  lastActivationAtMs: number;
+}
+
+export class TeamTaskStallMonitor {
+  private scanTimer: ReturnType<typeof setTimeout> | null = null;
+  private nudgeTimer: ReturnType<typeof setTimeout> | null = null;
+  private scanInFlight = false;
+  private started = false;
+  private readonly observationByTeam = new Map<string, TeamObservationState>();
+
+  constructor(
+    private readonly registry: ActiveTeamRegistry,
+    private readonly snapshotSource: TeamTaskStallSnapshotSource,
+    private readonly policy: TeamTaskStallPolicy,
+    private readonly journal: TeamTaskStallJournal,
+    private readonly notifier: TeamTaskStallNotifier
+  ) {}
+
+  start(): void {
+    if (!isTeamTaskStallMonitorEnabled()) {
+      logger.debug('Task stall monitor disabled by feature gate');
+      return;
+    }
+    if (this.started) {
+      return;
+    }
+    this.started = true;
+    this.registry.start();
+    this.scheduleNextScan(2_000);
+  }
+
+  async stop(): Promise<void> {
+    this.started = false;
+    if (this.scanTimer) {
+      clearTimeout(this.scanTimer);
+      this.scanTimer = null;
+    }
+    if (this.nudgeTimer) {
+      clearTimeout(this.nudgeTimer);
+      this.nudgeTimer = null;
+    }
+    await this.registry.stop();
+  }
+
+  noteTeamChange(event: TeamChangeEvent): void {
+    this.registry.noteTeamChange(event);
+    if (!isTeamTaskStallMonitorEnabled()) {
+      return;
+    }
+
+    if (
+      event.type === 'member-spawn' ||
+      (event.type === 'lead-activity' && event.detail !== 'offline')
+    ) {
+      const now = Date.now();
+      const existing = this.observationByTeam.get(event.teamName);
+      this.observationByTeam.set(event.teamName, {
+        firstSeenAtMs: existing?.firstSeenAtMs ?? now,
+        lastActivationAtMs: now,
+      });
+      this.scheduleNudgedScan();
+      return;
+    }
+
+    if (event.type === 'task-log-change' || event.type === 'log-source-change') {
+      this.scheduleNudgedScan();
+    }
+  }
+
+  private scheduleNextScan(delayMs: number): void {
+    if (!this.started) {
+      return;
+    }
+    if (this.scanTimer) {
+      clearTimeout(this.scanTimer);
+    }
+    this.scanTimer = setTimeout(() => {
+      this.scanTimer = null;
+      void this.runScan();
+    }, delayMs);
+  }
+
+  private scheduleNudgedScan(): void {
+    if (!this.started || this.nudgeTimer) {
+      return;
+    }
+    this.nudgeTimer = setTimeout(() => {
+      this.nudgeTimer = null;
+      void this.runScan();
+    }, 5_000);
+  }
+
+  private async runScan(): Promise<void> {
+    if (!this.started || this.scanInFlight) {
+      return;
+    }
+    this.scanInFlight = true;
+    try {
+      const activeTeams = await this.registry.listActiveTeams();
+      const activeSet = new Set(activeTeams);
+      for (const teamName of [...this.observationByTeam.keys()]) {
+        if (!activeSet.has(teamName)) {
+          this.observationByTeam.delete(teamName);
+        }
+      }
+
+      const now = new Date();
+      for (const teamName of activeTeams) {
+        const observation = this.getOrCreateObservation(teamName, now.getTime());
+        const startupAgeMs = now.getTime() - observation.firstSeenAtMs;
+        if (startupAgeMs < getTeamTaskStallStartupGraceMs()) {
+          continue;
+        }
+
+        const activationAgeMs = now.getTime() - observation.lastActivationAtMs;
+        if (activationAgeMs < getTeamTaskStallActivationGraceMs()) {
+          continue;
+        }
+
+        await this.scanTeam(teamName, now);
+      }
+    } catch (error) {
+      logger.warn(`Task stall monitor scan failed: ${String(error)}`);
+    } finally {
+      this.scanInFlight = false;
+      this.scheduleNextScan(getTeamTaskStallScanIntervalMs());
+    }
+  }
+
+  private getOrCreateObservation(teamName: string, nowMs: number): TeamObservationState {
+    const existing = this.observationByTeam.get(teamName);
+    if (existing) {
+      return existing;
+    }
+    const created = {
+      firstSeenAtMs: nowMs,
+      lastActivationAtMs: nowMs,
+    };
+    this.observationByTeam.set(teamName, created);
+    return created;
+  }
+
+  private async scanTeam(teamName: string, now: Date): Promise<void> {
+    const snapshot = await this.snapshotSource.getSnapshot(teamName);
+    if (!snapshot) {
+      return;
+    }
+
+    const evaluations: TaskStallEvaluation[] = [];
+    for (const task of snapshot.inProgressTasks) {
+      evaluations.push(this.policy.evaluateWork({ now, task, snapshot }));
+    }
+    for (const task of snapshot.reviewOpenTasks) {
+      evaluations.push(this.policy.evaluateReview({ now, task, snapshot }));
+    }
+
+    const activeTaskIds = [
+      ...new Set([...snapshot.inProgressTasks, ...snapshot.reviewOpenTasks].map((task) => task.id)),
+    ];
+    const readyEvaluations = await this.journal.reconcileScan({
+      teamName,
+      evaluations,
+      activeTaskIds,
+      now: now.toISOString(),
+    });
+
+    const alerts = readyEvaluations
+      .map((evaluation) => this.buildAlert(snapshot, evaluation))
+      .filter((alert): alert is TaskStallAlert => alert !== null);
+
+    if (alerts.length === 0) {
+      return;
+    }
+
+    if (!isTeamTaskStallAlertsEnabled()) {
+      logger.debug(`Task stall monitor shadow-ready alerts for ${teamName}: ${alerts.length}`);
+      return;
+    }
+
+    await this.notifier.notifyLead(teamName, alerts);
+    await Promise.all(
+      alerts.map((alert) => this.journal.markAlerted(teamName, alert.epochKey, now.toISOString()))
+    );
+  }
+
+  private buildAlert(
+    snapshot: Awaited<ReturnType<TeamTaskStallSnapshotSource['getSnapshot']>>,
+    evaluation: TaskStallEvaluation
+  ): TaskStallAlert | null {
+    if (
+      !snapshot ||
+      evaluation.status !== 'alert' ||
+      !evaluation.taskId ||
+      !evaluation.branch ||
+      !evaluation.signal ||
+      !evaluation.epochKey
+    ) {
+      return null;
+    }
+
+    const task = snapshot.allTasksById.get(evaluation.taskId);
+    if (!task) {
+      return null;
+    }
+
+    const displayId = getTaskDisplayId(task);
+    return {
+      teamName: snapshot.teamName,
+      taskId: task.id,
+      displayId,
+      subject: task.subject,
+      branch: evaluation.branch,
+      signal: evaluation.signal,
+      reason: evaluation.reason,
+      epochKey: evaluation.epochKey,
+      taskRef: {
+        taskId: task.id,
+        displayId,
+        teamName: snapshot.teamName,
+      },
+    };
+  }
+}
--- a/src/main/services/team/stallMonitor/TeamTaskStallNotifier.ts
+++ b/src/main/services/team/stallMonitor/TeamTaskStallNotifier.ts
@ -0,0 +1,32 @@
+import { formatTaskDisplayLabel } from '@shared/utils/taskIdentity';
+
+import type { TaskStallAlert } from './TeamTaskStallTypes';
+import type { TeamDataService } from '../TeamDataService';
+
+function buildLeadAlertText(alerts: TaskStallAlert[]): string {
+  return alerts
+    .map(
+      (alert) =>
+        `- ${formatTaskDisplayLabel({ id: alert.taskId, displayId: alert.displayId })} [${alert.branch}] ${alert.subject} - ${alert.reason}`
+    )
+    .join('\n');
+}
+
+export class TeamTaskStallNotifier {
+  constructor(
+    private readonly teamDataService: Pick<TeamDataService, 'sendSystemNotificationToLead'>
+  ) {}
+
+  async notifyLead(teamName: string, alerts: TaskStallAlert[]): Promise<void> {
+    if (alerts.length === 0) {
+      return;
+    }
+
+    await this.teamDataService.sendSystemNotificationToLead({
+      teamName,
+      summary: 'Potential stalled tasks detected',
+      text: buildLeadAlertText(alerts),
+      taskRefs: alerts.map((alert) => alert.taskRef),
+    });
+  }
+}
--- a/src/main/services/team/stallMonitor/TeamTaskStallPolicy.ts
+++ b/src/main/services/team/stallMonitor/TeamTaskStallPolicy.ts
@ -0,0 +1,508 @@
+import type {
+  ReviewTaskContext,
+  TaskStallBranch,
+  TaskStallEvaluation,
+  TaskStallSignal,
+  TeamTaskStallExactRow,
+  TeamTaskStallSnapshot,
+  WorkTaskContext,
+} from './TeamTaskStallTypes';
+import type { BoardTaskActivityRecord } from '../taskLogs/activity/BoardTaskActivityRecord';
+import type { TeamTask, TaskWorkInterval, TaskHistoryEvent } from '@shared/types';
+
+const WORK_TOUCH_TOOLS = new Set(['task_start', 'task_add_comment', 'task_set_status']);
+const REVIEW_TOUCH_TOOLS = new Set(['review_start', 'task_add_comment']);
+
+const ONE_MINUTE_MS = 60_000;
+const WORK_THRESHOLDS_MS: Record<TaskStallSignal, number> = {
+  turn_ended_after_touch: 8 * ONE_MINUTE_MS,
+  touch_then_other_turns: 10 * ONE_MINUTE_MS,
+  mid_turn_after_touch: 20 * ONE_MINUTE_MS,
+};
+const REVIEW_THRESHOLDS_MS: Record<TaskStallSignal, number> = {
+  turn_ended_after_touch: 10 * ONE_MINUTE_MS,
+  touch_then_other_turns: 10 * ONE_MINUTE_MS,
+  mid_turn_after_touch: 25 * ONE_MINUTE_MS,
+};
+
+function skip(
+  taskId: string,
+  reason: string,
+  skipReason: TaskStallEvaluation['skipReason']
+): TaskStallEvaluation {
+  return {
+    status: 'skip',
+    taskId,
+    reason,
+    skipReason,
+  };
+}
+
+function isAfterOrEqual(timestamp: string, lowerBound: string): boolean {
+  return Date.parse(timestamp) >= Date.parse(lowerBound);
+}
+
+function getOpenWorkInterval(task: TeamTask): TaskWorkInterval | null {
+  const intervals = task.workIntervals ?? [];
+  for (let i = intervals.length - 1; i >= 0; i -= 1) {
+    const interval = intervals[i];
+    if (!interval.completedAt) {
+      return interval;
+    }
+  }
+  return null;
+}
+
+function getOpenReviewWindowStart(task: TeamTask): string | null {
+  if (task.reviewState !== 'review' || !task.historyEvents?.length) {
+    return null;
+  }
+
+  for (let i = task.historyEvents.length - 1; i >= 0; i -= 1) {
+    const event = task.historyEvents[i];
+    if (event.type === 'review_started') {
+      return event.timestamp;
+    }
+    if (
+      event.type === 'review_approved' ||
+      event.type === 'review_changes_requested' ||
+      (event.type === 'status_changed' && event.to === 'in_progress')
+    ) {
+      return null;
+    }
+  }
+  return null;
+}
+
+function hasReviewStartedByReviewer(
+  historyEvents: TaskHistoryEvent[] | undefined,
+  reviewer: string,
+  windowStartedAt: string
+): boolean {
+  if (!historyEvents?.length) {
+    return false;
+  }
+
+  return historyEvents.some(
+    (event) =>
+      event.type === 'review_started' &&
+      event.actor === reviewer &&
+      isAfterOrEqual(event.timestamp, windowStartedAt)
+  );
+}
+
+function isStrongReviewTouch(
+  record: BoardTaskActivityRecord,
+  reviewer: string,
+  hasExplicitStartedReview: boolean,
+  windowStartedAt: string
+): boolean {
+  if (
+    record.actor.memberName !== reviewer ||
+    !record.action?.canonicalToolName ||
+    !REVIEW_TOUCH_TOOLS.has(record.action.canonicalToolName) ||
+    !isAfterOrEqual(record.timestamp, windowStartedAt)
+  ) {
+    return false;
+  }
+
+  if (record.action.canonicalToolName === 'review_start') {
+    return true;
+  }
+
+  if (
+    record.actorContext.relation === 'same_task' &&
+    record.actorContext.activePhase === 'review'
+  ) {
+    return true;
+  }
+
+  return hasExplicitStartedReview;
+}
+
+function findLastMeaningfulWorkTouch(
+  records: BoardTaskActivityRecord[],
+  owner: string,
+  intervalStartedAt: string
+): BoardTaskActivityRecord | null {
+  return (
+    [...records]
+      .filter((record) => record.actor.memberName === owner)
+      .filter((record) => isAfterOrEqual(record.timestamp, intervalStartedAt))
+      .filter((record) => WORK_TOUCH_TOOLS.has(record.action?.canonicalToolName ?? ''))
+      .at(-1) ?? null
+  );
+}
+
+function findLastMeaningfulReviewTouch(
+  records: BoardTaskActivityRecord[],
+  reviewer: string,
+  windowStartedAt: string,
+  hasExplicitStartedReview: boolean
+): BoardTaskActivityRecord | null {
+  return (
+    [...records]
+      .filter((record) =>
+        isStrongReviewTouch(record, reviewer, hasExplicitStartedReview, windowStartedAt)
+      )
+      .at(-1) ?? null
+  );
+}
+
+function anchorEvidenceRank(row: TeamTaskStallExactRow, toolUseId: string | undefined): number {
+  if (!toolUseId || row.parsedMessage.type !== 'assistant') {
+    return 0;
+  }
+  if (row.toolUseIds.includes(toolUseId)) {
+    return 2;
+  }
+  if (row.sourceToolUseId === toolUseId || row.toolResultIds.includes(toolUseId)) {
+    return 1;
+  }
+  return 0;
+}
+
+function deduplicateAssistantRowsByRequestId(
+  rows: TeamTaskStallExactRow[],
+  toolUseId: string | undefined
+): TeamTaskStallExactRow[] {
+  const preferredIndexByRequestId = new Map<string, number>();
+  for (let i = 0; i < rows.length; i += 1) {
+    const row = rows[i];
+    if (row.parsedMessage.type !== 'assistant' || !row.requestId) {
+      continue;
+    }
+    const existingIndex = preferredIndexByRequestId.get(row.requestId);
+    if (existingIndex === undefined) {
+      preferredIndexByRequestId.set(row.requestId, i);
+      continue;
+    }
+    const existingRank = anchorEvidenceRank(rows[existingIndex], toolUseId);
+    const nextRank = anchorEvidenceRank(row, toolUseId);
+    if (nextRank > existingRank || (nextRank === existingRank && i > existingIndex)) {
+      preferredIndexByRequestId.set(row.requestId, i);
+    }
+  }
+
+  if (preferredIndexByRequestId.size === 0) {
+    return rows;
+  }
+
+  return rows.filter((row, index) => {
+    if (row.parsedMessage.type !== 'assistant' || !row.requestId) {
+      return true;
+    }
+    return preferredIndexByRequestId.get(row.requestId) === index;
+  });
+}
+
+function findAnchorRowIndex(
+  rows: TeamTaskStallExactRow[],
+  messageUuid: string,
+  toolUseId?: string
+): number {
+  const candidates = rows
+    .map((row, index) => ({ row, index }))
+    .filter(({ row }) => row.messageUuid === messageUuid);
+  if (candidates.length === 0) {
+    return -1;
+  }
+
+  if (toolUseId) {
+    const explicitToolUse = candidates.filter(({ row }) => row.toolUseIds.includes(toolUseId));
+    if (explicitToolUse.length > 0) {
+      return explicitToolUse.at(-1)!.index;
+    }
+
+    const linkedRows = candidates.filter(
+      ({ row }) => row.sourceToolUseId === toolUseId || row.toolResultIds.includes(toolUseId)
+    );
+    if (linkedRows.length > 0) {
+      return linkedRows.at(-1)!.index;
+    }
+  }
+
+  return candidates.at(-1)!.index;
+}
+
+function classifyPostTouchState(args: {
+  rows: TeamTaskStallExactRow[];
+  anchorMessageUuid: string;
+  anchorToolUseId?: string;
+}): TaskStallSignal | 'ambiguous' {
+  const normalizedRows = deduplicateAssistantRowsByRequestId(args.rows, args.anchorToolUseId);
+  const anchorIndex = findAnchorRowIndex(
+    normalizedRows,
+    args.anchorMessageUuid,
+    args.anchorToolUseId
+  );
+  if (anchorIndex < 0) {
+    return 'ambiguous';
+  }
+
+  let sawTurnEnd = false;
+  let sawLaterRows = false;
+
+  for (let i = anchorIndex + 1; i < normalizedRows.length; i += 1) {
+    const row = normalizedRows[i];
+    if (row.systemSubtype === 'turn_duration') {
+      sawTurnEnd = true;
+      continue;
+    }
+
+    sawLaterRows = true;
+    if (sawTurnEnd) {
+      return 'touch_then_other_turns';
+    }
+  }
+
+  if (sawTurnEnd) {
+    return 'turn_ended_after_touch';
+  }
+  if (sawLaterRows) {
+    return 'mid_turn_after_touch';
+  }
+  return 'mid_turn_after_touch';
+}
+
+function buildEpochKey(
+  task: TeamTask,
+  branch: TaskStallBranch,
+  signal: TaskStallSignal,
+  touch: BoardTaskActivityRecord
+): string {
+  return [
+    task.id,
+    branch,
+    signal,
+    touch.timestamp,
+    touch.source.filePath,
+    touch.source.messageUuid,
+    touch.source.toolUseId ?? 'ambient',
+  ].join(':');
+}
+
+function buildAlertEvaluation(args: {
+  task: TeamTask;
+  branch: TaskStallBranch;
+  signal: TaskStallSignal;
+  touch: BoardTaskActivityRecord;
+  reason: string;
+}): TaskStallEvaluation {
+  return {
+    status: 'alert',
+    taskId: args.task.id,
+    branch: args.branch,
+    signal: args.signal,
+    epochKey: buildEpochKey(args.task, args.branch, args.signal, args.touch),
+    reason: args.reason,
+  };
+}
+
+export class TeamTaskStallPolicy {
+  evaluateWork(args: {
+    now: Date;
+    task: TeamTask;
+    snapshot: TeamTaskStallSnapshot;
+  }): TaskStallEvaluation {
+    const { task, snapshot } = args;
+
+    if (!snapshot.activityReadsEnabled) {
+      return skip(task.id, 'Task activity reads are disabled', 'activity_reads_disabled');
+    }
+    if (!snapshot.exactReadsEnabled) {
+      return skip(task.id, 'Exact log reads are disabled', 'exact_reads_disabled');
+    }
+    if (task.status !== 'in_progress') {
+      return skip(task.id, 'Task is not in progress', 'task_not_in_progress');
+    }
+    if (!task.owner) {
+      return skip(task.id, 'Task has no owner', 'owner_missing');
+    }
+    if (task.owner === snapshot.leadName) {
+      return skip(task.id, 'Task owner is the lead', 'owner_is_lead');
+    }
+    if (task.reviewState === 'review') {
+      return skip(task.id, 'Task is currently under review', 'review_active');
+    }
+    if (task.blockedBy?.length) {
+      return skip(task.id, 'Task is blocked', 'task_blocked');
+    }
+    if (task.needsClarification) {
+      return skip(task.id, 'Task is waiting for clarification', 'needs_clarification');
+    }
+
+    const openWorkInterval = getOpenWorkInterval(task);
+    if (!openWorkInterval?.startedAt) {
+      return skip(task.id, 'Task has no open work interval', 'no_open_work_interval');
+    }
+
+    const records = snapshot.recordsByTaskId.get(task.id) ?? [];
+    if (records.length === 0 && !snapshot.freshnessByTaskId.has(task.id)) {
+      return skip(
+        task.id,
+        'Task run is not instrumented enough for stall evaluation',
+        'non_instrumented_run'
+      );
+    }
+
+    const workContext: WorkTaskContext | null = (() => {
+      const touch = findLastMeaningfulWorkTouch(records, task.owner!, openWorkInterval.startedAt);
+      if (!touch) {
+        return null;
+      }
+      return {
+        owner: task.owner!,
+        intervalStartedAt: openWorkInterval.startedAt,
+        lastMeaningfulTouch: touch,
+        lastMeaningfulTouchAt: touch.timestamp,
+      };
+    })();
+
+    if (!workContext) {
+      return skip(
+        task.id,
+        'No positive work touch found in current work interval',
+        'no_positive_touch'
+      );
+    }
+
+    const exactRows = snapshot.exactRowsByFilePath.get(
+      workContext.lastMeaningfulTouch.source.filePath
+    );
+    if (!exactRows?.length) {
+      return skip(task.id, 'Post-touch exact rows are unavailable', 'ambiguous_state');
+    }
+
+    const signal = classifyPostTouchState({
+      rows: exactRows,
+      anchorMessageUuid: workContext.lastMeaningfulTouch.source.messageUuid,
+      anchorToolUseId: workContext.lastMeaningfulTouch.source.toolUseId,
+    });
+    if (signal === 'ambiguous') {
+      return skip(task.id, 'Post-touch state is ambiguous', 'ambiguous_state');
+    }
+
+    const elapsedMs = args.now.getTime() - Date.parse(workContext.lastMeaningfulTouchAt);
+    const thresholdMs = WORK_THRESHOLDS_MS[signal];
+    if (elapsedMs < thresholdMs) {
+      return skip(
+        task.id,
+        'Work touch is still below the configured stall threshold',
+        'below_threshold'
+      );
+    }
+
+    return buildAlertEvaluation({
+      task,
+      branch: 'work',
+      signal,
+      touch: workContext.lastMeaningfulTouch,
+      reason: `Potential work stall after ${signal.replaceAll('_', ' ')}.`,
+    });
+  }
+
+  evaluateReview(args: {
+    now: Date;
+    task: TeamTask;
+    snapshot: TeamTaskStallSnapshot;
+  }): TaskStallEvaluation {
+    const { task, snapshot } = args;
+
+    if (!snapshot.activityReadsEnabled) {
+      return skip(task.id, 'Task activity reads are disabled', 'activity_reads_disabled');
+    }
+    if (!snapshot.exactReadsEnabled) {
+      return skip(task.id, 'Exact log reads are disabled', 'exact_reads_disabled');
+    }
+    if (task.reviewState !== 'review') {
+      return skip(task.id, 'Task is not in an open review window', 'review_terminal');
+    }
+    if (task.needsClarification) {
+      return skip(task.id, 'Task is waiting for clarification', 'needs_clarification');
+    }
+
+    const reviewWindowStartedAt = getOpenReviewWindowStart(task);
+    if (!reviewWindowStartedAt) {
+      return skip(task.id, 'Task has no open review window', 'no_open_review_window');
+    }
+
+    const resolvedReviewer = snapshot.resolvedReviewersByTaskId.get(task.id) ?? {
+      reviewer: null,
+      source: 'none',
+    };
+    if (!resolvedReviewer.reviewer) {
+      return skip(task.id, 'Reviewer could not be resolved safely', 'reviewer_unresolved');
+    }
+
+    const records = snapshot.recordsByTaskId.get(task.id) ?? [];
+    if (records.length === 0 && !snapshot.freshnessByTaskId.has(task.id)) {
+      return skip(
+        task.id,
+        'Review run is not instrumented enough for stall evaluation',
+        'non_instrumented_run'
+      );
+    }
+
+    const explicitReviewStarted = hasReviewStartedByReviewer(
+      task.historyEvents,
+      resolvedReviewer.reviewer,
+      reviewWindowStartedAt
+    );
+    const reviewContext: ReviewTaskContext | null = (() => {
+      const touch = findLastMeaningfulReviewTouch(
+        records,
+        resolvedReviewer.reviewer!,
+        reviewWindowStartedAt,
+        explicitReviewStarted
+      );
+      if (!touch) {
+        return null;
+      }
+      return {
+        resolvedReviewer,
+        reviewWindowStartedAt,
+        lastMeaningfulTouch: touch,
+        lastMeaningfulTouchAt: touch.timestamp,
+      };
+    })();
+
+    if (!reviewContext) {
+      return skip(task.id, 'No explicit started-review evidence was found', 'no_positive_touch');
+    }
+
+    const exactRows = snapshot.exactRowsByFilePath.get(
+      reviewContext.lastMeaningfulTouch.source.filePath
+    );
+    if (!exactRows?.length) {
+      return skip(task.id, 'Post-review exact rows are unavailable', 'ambiguous_state');
+    }
+
+    const signal = classifyPostTouchState({
+      rows: exactRows,
+      anchorMessageUuid: reviewContext.lastMeaningfulTouch.source.messageUuid,
+      anchorToolUseId: reviewContext.lastMeaningfulTouch.source.toolUseId,
+    });
+    if (signal === 'ambiguous') {
+      return skip(task.id, 'Post-review state is ambiguous', 'ambiguous_state');
+    }
+
+    const elapsedMs = args.now.getTime() - Date.parse(reviewContext.lastMeaningfulTouchAt);
+    const thresholdMs = REVIEW_THRESHOLDS_MS[signal];
+    if (elapsedMs < thresholdMs) {
+      return skip(
+        task.id,
+        'Review touch is still below the configured stall threshold',
+        'below_threshold'
+      );
+    }
+
+    return buildAlertEvaluation({
+      task,
+      branch: 'review',
+      signal,
+      touch: reviewContext.lastMeaningfulTouch,
+      reason: `Potential started-review stall after ${signal.replaceAll('_', ' ')}.`,
+    });
+  }
+}
--- a/src/main/services/team/stallMonitor/TeamTaskStallSnapshotSource.ts
+++ b/src/main/services/team/stallMonitor/TeamTaskStallSnapshotSource.ts
@ -0,0 +1,119 @@
+import { TeamTaskReader } from '../TeamTaskReader';
+import { TeamKanbanManager } from '../TeamKanbanManager';
+import { TeamTranscriptSourceLocator } from '../taskLogs/discovery/TeamTranscriptSourceLocator';
+import { BoardTaskActivityTranscriptReader } from '../taskLogs/activity/BoardTaskActivityTranscriptReader';
+import { isBoardTaskActivityReadEnabled } from '../taskLogs/activity/featureGates';
+import { isBoardTaskExactLogsReadEnabled } from '../taskLogs/exact/featureGates';
+
+import { BoardTaskActivityBatchIndexer } from './BoardTaskActivityBatchIndexer';
+import { TeamTaskLogFreshnessReader } from './TeamTaskLogFreshnessReader';
+import { TeamTaskStallExactRowReader } from './TeamTaskStallExactRowReader';
+import { buildResolvedReviewerIndex } from './reviewerResolution';
+
+import type { BoardTaskActivityRecord } from '../taskLogs/activity/BoardTaskActivityRecord';
+import type { TeamTaskStallSnapshot } from './TeamTaskStallTypes';
+import type { TeamConfig, TeamTask } from '@shared/types';
+
+function resolveLeadNameFromConfig(config: TeamConfig): string {
+  const lead = config.members?.find((member) => member.role?.toLowerCase().includes('lead'));
+  return lead?.name ?? config.members?.[0]?.name ?? 'team-lead';
+}
+
+export class TeamTaskStallSnapshotSource {
+  constructor(
+    private readonly transcriptSourceLocator: TeamTranscriptSourceLocator = new TeamTranscriptSourceLocator(),
+    private readonly taskReader: TeamTaskReader = new TeamTaskReader(),
+    private readonly kanbanManager: TeamKanbanManager = new TeamKanbanManager(),
+    private readonly transcriptReader: BoardTaskActivityTranscriptReader = new BoardTaskActivityTranscriptReader(),
+    private readonly activityBatchIndexer: BoardTaskActivityBatchIndexer = new BoardTaskActivityBatchIndexer(),
+    private readonly freshnessReader: TeamTaskLogFreshnessReader = new TeamTaskLogFreshnessReader(),
+    private readonly exactRowReader: TeamTaskStallExactRowReader = new TeamTaskStallExactRowReader()
+  ) {}
+
+  async getSnapshot(teamName: string): Promise<TeamTaskStallSnapshot | null> {
+    const transcriptContext = await this.transcriptSourceLocator.getContext(teamName);
+    if (!transcriptContext) {
+      return null;
+    }
+
+    const [activeTasks, deletedTasks, kanbanState] = await Promise.all([
+      this.taskReader.getTasks(teamName),
+      this.taskReader.getDeletedTasks(teamName),
+      this.kanbanManager.getState(teamName),
+    ]);
+    const allTasks = [...activeTasks, ...deletedTasks];
+    const allTasksById = new Map(allTasks.map((task) => [task.id, task] as const));
+    const inProgressTasks = activeTasks.filter(
+      (task) => task.status === 'in_progress' && task.reviewState !== 'review'
+    );
+    const reviewOpenTasks = activeTasks.filter((task) => task.reviewState === 'review');
+    const resolvedReviewersByTaskId = buildResolvedReviewerIndex(activeTasks, kanbanState);
+    const activityReadsEnabled = isBoardTaskActivityReadEnabled();
+    const exactReadsEnabled = isBoardTaskExactLogsReadEnabled();
+
+    let recordsByTaskId = new Map<string, BoardTaskActivityRecord[]>();
+    if (
+      activityReadsEnabled &&
+      allTasks.length > 0 &&
+      transcriptContext.transcriptFiles.length > 0
+    ) {
+      const messages = await this.transcriptReader.readFiles(transcriptContext.transcriptFiles);
+      recordsByTaskId = this.activityBatchIndexer.buildIndex({
+        teamName,
+        tasks: allTasks,
+        messages,
+      });
+    }
+
+    const relevantMonitorTasks = [...inProgressTasks, ...reviewOpenTasks];
+    const relevantExactFiles = this.collectRelevantExactFiles(
+      relevantMonitorTasks,
+      recordsByTaskId
+    );
+    const [freshnessByTaskId, exactRowsByFilePath] = await Promise.all([
+      this.freshnessReader.readSignals(
+        transcriptContext.projectDir,
+        relevantMonitorTasks.map((task) => task.id)
+      ),
+      exactReadsEnabled
+        ? this.exactRowReader.parseFiles(relevantExactFiles)
+        : Promise.resolve(new Map()),
+    ]);
+
+    return {
+      teamName,
+      scannedAt: new Date().toISOString(),
+      projectDir: transcriptContext.projectDir,
+      projectId: transcriptContext.projectId,
+      leadName: resolveLeadNameFromConfig(transcriptContext.config),
+      transcriptFiles: transcriptContext.transcriptFiles,
+      activityReadsEnabled,
+      exactReadsEnabled,
+      activeTasks,
+      deletedTasks,
+      allTasksById,
+      inProgressTasks,
+      reviewOpenTasks,
+      resolvedReviewersByTaskId,
+      recordsByTaskId,
+      freshnessByTaskId,
+      exactRowsByFilePath,
+    };
+  }
+
+  private collectRelevantExactFiles(
+    inProgressTasks: TeamTask[],
+    recordsByTaskId: Map<string, BoardTaskActivityRecord[]>
+  ): string[] {
+    const filePaths = new Set<string>();
+
+    for (const task of inProgressTasks) {
+      const records = recordsByTaskId.get(task.id) ?? [];
+      for (const record of records) {
+        filePaths.add(record.source.filePath);
+      }
+    }
+
+    return [...filePaths].sort((left, right) => left.localeCompare(right));
+  }
+}
--- a/src/main/services/team/stallMonitor/TeamTaskStallTypes.ts
+++ b/src/main/services/team/stallMonitor/TeamTaskStallTypes.ts
@ -0,0 +1,139 @@
+import type { BoardTaskActivityRecord } from '../taskLogs/activity/BoardTaskActivityRecord';
+import type { ParsedMessage } from '@main/types';
+import type { TeamTask } from '@shared/types';
+
+export type TaskStallBranch = 'work' | 'review';
+
+export type TaskStallSignal =
+  | 'turn_ended_after_touch'
+  | 'mid_turn_after_touch'
+  | 'touch_then_other_turns';
+
+export type TaskStallEvaluationStatus = 'skip' | 'suspected' | 'alert';
+
+export type TaskStallSkipReason =
+  | 'task_not_in_progress'
+  | 'owner_missing'
+  | 'owner_is_lead'
+  | 'task_blocked'
+  | 'needs_clarification'
+  | 'review_active'
+  | 'review_terminal'
+  | 'reviewer_unresolved'
+  | 'non_instrumented_run'
+  | 'activity_reads_disabled'
+  | 'exact_reads_disabled'
+  | 'no_positive_touch'
+  | 'no_open_work_interval'
+  | 'no_open_review_window'
+  | 'ambiguous_state'
+  | 'below_threshold'
+  | 'first_scan_only';
+
+export type ResolvedReviewerSource =
+  | 'kanban_state'
+  | 'history_review_approved_actor'
+  | 'history_review_started_actor'
+  | 'history_review_requested_reviewer'
+  | 'none';
+
+export interface ResolvedReviewer {
+  reviewer: string | null;
+  source: ResolvedReviewerSource;
+}
+
+export interface TaskStallEvaluation {
+  status: TaskStallEvaluationStatus;
+  taskId?: string;
+  branch?: TaskStallBranch;
+  signal?: TaskStallSignal;
+  epochKey?: string;
+  reason: string;
+  skipReason?: TaskStallSkipReason;
+}
+
+export interface TaskLogFreshnessSignal {
+  taskId: string;
+  updatedAt: string;
+  filePath: string;
+  transcriptFileBasename?: string;
+}
+
+export interface TeamTaskStallExactRow {
+  filePath: string;
+  sourceOrder: number;
+  messageUuid: string;
+  timestamp: string;
+  parsedMessage: ParsedMessage;
+  requestId?: string;
+  sourceToolUseId?: string;
+  sourceToolAssistantUuid?: string;
+  systemSubtype?: 'turn_duration' | 'init';
+  toolUseIds: string[];
+  toolResultIds: string[];
+}
+
+export interface TeamTaskStallSnapshot {
+  teamName: string;
+  scannedAt: string;
+  projectDir: string;
+  projectId: string;
+  leadName: string;
+  transcriptFiles: string[];
+  activityReadsEnabled: boolean;
+  exactReadsEnabled: boolean;
+  activeTasks: TeamTask[];
+  deletedTasks: TeamTask[];
+  allTasksById: Map<string, TeamTask>;
+  inProgressTasks: TeamTask[];
+  reviewOpenTasks: TeamTask[];
+  resolvedReviewersByTaskId: Map<string, ResolvedReviewer>;
+  recordsByTaskId: Map<string, BoardTaskActivityRecord[]>;
+  freshnessByTaskId: Map<string, TaskLogFreshnessSignal>;
+  exactRowsByFilePath: Map<string, TeamTaskStallExactRow[]>;
+}
+
+export interface WorkTaskContext {
+  owner: string;
+  intervalStartedAt: string;
+  lastMeaningfulTouch: BoardTaskActivityRecord;
+  lastMeaningfulTouchAt: string;
+}
+
+export interface ReviewTaskContext {
+  resolvedReviewer: ResolvedReviewer;
+  reviewWindowStartedAt: string;
+  lastMeaningfulTouch: BoardTaskActivityRecord;
+  lastMeaningfulTouchAt: string;
+}
+
+export interface TaskStallAlert {
+  teamName: string;
+  taskId: string;
+  displayId: string;
+  subject: string;
+  branch: TaskStallBranch;
+  signal: TaskStallSignal;
+  reason: string;
+  epochKey: string;
+  taskRef: {
+    taskId: string;
+    displayId: string;
+    teamName: string;
+  };
+}
+
+export type TaskStallJournalState = 'suspected' | 'alert_ready' | 'alerted';
+
+export interface TaskStallJournalEntry {
+  epochKey: string;
+  teamName: string;
+  taskId: string;
+  branch: TaskStallBranch;
+  signal: TaskStallSignal;
+  state: TaskStallJournalState;
+  consecutiveScans: number;
+  createdAt: string;
+  updatedAt: string;
+  alertedAt?: string;
+}
--- a/src/main/services/team/stallMonitor/featureGates.ts
+++ b/src/main/services/team/stallMonitor/featureGates.ts
@ -0,0 +1,42 @@
+function readEnabledFlag(value: string | undefined, defaultValue: boolean): boolean {
+  if (value == null) {
+    return defaultValue;
+  }
+
+  const normalized = value.trim().toLowerCase();
+  if (normalized === '0' || normalized === 'false' || normalized === 'off' || normalized === 'no') {
+    return false;
+  }
+  if (normalized === '1' || normalized === 'true' || normalized === 'on' || normalized === 'yes') {
+    return true;
+  }
+  return defaultValue;
+}
+
+function readInt(value: string | undefined, defaultValue: number): number {
+  if (value == null) {
+    return defaultValue;
+  }
+  const parsed = Number.parseInt(value.trim(), 10);
+  return Number.isFinite(parsed) && parsed > 0 ? parsed : defaultValue;
+}
+
+export function isTeamTaskStallMonitorEnabled(): boolean {
+  return readEnabledFlag(process.env.CLAUDE_TEAM_TASK_STALL_MONITOR_ENABLED, false);
+}
+
+export function isTeamTaskStallAlertsEnabled(): boolean {
+  return readEnabledFlag(process.env.CLAUDE_TEAM_TASK_STALL_ALERTS_ENABLED, false);
+}
+
+export function getTeamTaskStallScanIntervalMs(): number {
+  return readInt(process.env.CLAUDE_TEAM_TASK_STALL_SCAN_INTERVAL_MS, 60_000);
+}
+
+export function getTeamTaskStallStartupGraceMs(): number {
+  return readInt(process.env.CLAUDE_TEAM_TASK_STALL_STARTUP_GRACE_MS, 180_000);
+}
+
+export function getTeamTaskStallActivationGraceMs(): number {
+  return readInt(process.env.CLAUDE_TEAM_TASK_STALL_ACTIVATION_GRACE_MS, 120_000);
+}
--- a/src/main/services/team/stallMonitor/reviewerResolution.ts
+++ b/src/main/services/team/stallMonitor/reviewerResolution.ts
@ -0,0 +1,47 @@
+import { TeamKanbanManager } from '../TeamKanbanManager';
+
+import type { ResolvedReviewer } from './TeamTaskStallTypes';
+import type { TeamTask } from '@shared/types';
+
+export function resolveReviewerFromHistory(task: TeamTask): ResolvedReviewer {
+  if (!task.historyEvents?.length) {
+    return { reviewer: null, source: 'none' };
+  }
+
+  for (let i = task.historyEvents.length - 1; i >= 0; i -= 1) {
+    const event = task.historyEvents[i];
+    if (event.type === 'review_approved' && event.actor) {
+      return { reviewer: event.actor, source: 'history_review_approved_actor' };
+    }
+    if (event.type === 'review_started' && event.actor) {
+      return { reviewer: event.actor, source: 'history_review_started_actor' };
+    }
+    if (event.type === 'review_requested' && event.reviewer) {
+      return { reviewer: event.reviewer, source: 'history_review_requested_reviewer' };
+    }
+  }
+
+  return { reviewer: null, source: 'none' };
+}
+
+export function buildResolvedReviewerIndex(
+  tasks: TeamTask[],
+  kanbanState: Awaited<ReturnType<TeamKanbanManager['getState']>>
+): Map<string, ResolvedReviewer> {
+  const resolved = new Map<string, ResolvedReviewer>();
+
+  for (const task of tasks) {
+    const kanbanReviewer = kanbanState.tasks[task.id]?.reviewer;
+    if (typeof kanbanReviewer === 'string' && kanbanReviewer.trim().length > 0) {
+      resolved.set(task.id, {
+        reviewer: kanbanReviewer.trim(),
+        source: 'kanban_state',
+      });
+      continue;
+    }
+
+    resolved.set(task.id, resolveReviewerFromHistory(task));
+  }
+
+  return resolved;
+}
--- a/src/main/services/team/taskLogs/activity/BoardTaskActivityRecordBuilder.ts
+++ b/src/main/services/team/taskLogs/activity/BoardTaskActivityRecordBuilder.ts
@ -312,6 +312,21 @@ function compareRecords(left: BoardTaskActivityRecord, right: BoardTaskActivityR
  return left.id.localeCompare(right.id);
 }

+function resolveCandidateTaskIds(locator: BoardTaskLocator, lookup: TaskLookup): string[] {
+  const canonicalTask =
+    (locator.canonicalId && lookup.byId.get(locator.canonicalId)) ||
+    (locator.refKind === 'canonical' ? lookup.byId.get(locator.ref) : undefined) ||
+    (locator.refKind === 'unknown' && looksLikeCanonicalTaskId(locator.ref)
+      ? lookup.byId.get(locator.ref)
+      : undefined);
+  if (canonicalTask) {
+    return [canonicalTask.id];
+  }
+
+  const displayCandidates = lookup.byDisplayId.get(normalizeDisplayRef(locator.ref)) ?? [];
+  return [...new Set(displayCandidates.map((task) => task.id))];
+}
+
 export class BoardTaskActivityRecordBuilder {
  buildForTask(args: {
    teamName: string;
@ -319,64 +334,98 @@ export class BoardTaskActivityRecordBuilder {
    tasks: TeamTask[];
    messages: RawTaskActivityMessage[];
  }): BoardTaskActivityRecord[] {
+    return (
+      this.buildForTasks({
+        teamName: args.teamName,
+        tasks: args.tasks,
+        messages: args.messages,
+      }).get(args.targetTask.id) ?? []
+    );
+  }
+
+  buildForTasks(args: {
+    teamName: string;
+    tasks: TeamTask[];
+    messages: RawTaskActivityMessage[];
+  }): Map<string, BoardTaskActivityRecord[]> {
    const lookup = buildTaskLookup(args.tasks);
-    const records: BoardTaskActivityRecord[] = [];
-    const seenIds = new Set<string>();
+    const recordsByTaskId = new Map<string, BoardTaskActivityRecord[]>();
+    const seenIdsByTaskId = new Map<string, Set<string>>();

    for (const message of args.messages) {
      const actionMap = buildActionMap(message.boardTaskToolActions);

      for (const link of message.boardTaskLinks) {
        const resolvedTask = resolveLocatorToTaskRef(args.teamName, link.task, lookup);
-        if (
-          resolvedTask.taskRef?.taskId !== args.targetTask.id &&
-          !locatorCouldMatchTask(link.task, args.targetTask, lookup)
-        ) {
+        const candidateTaskIds = resolveCandidateTaskIds(link.task, lookup);
+        if (candidateTaskIds.length === 0) {
          continue;
        }
-
        const action =
          link.linkKind === 'execution' || !link.toolUseId
            ? undefined
            : actionMap.get(link.toolUseId);
-        const peerTask = resolvePeerTask(
-          args.teamName,
-          link,
-          message.boardTaskLinks,
-          args.targetTask,
-          lookup
-        );
-        const record: BoardTaskActivityRecord = {
-          id: [
-            message.uuid,
-            link.toolUseId ?? 'ambient',
-            link.task.ref,
-            link.targetRole,
-            link.linkKind,
-          ].join(':'),
-          timestamp: message.timestamp,
-          task: resolvedTask,
-          linkKind: link.linkKind,
-          targetRole: link.targetRole,
-          actor: resolveActivityActor(message),
-          actorContext: buildActorContext(args.teamName, link.actorContext, lookup),
-          ...(action ? { action: buildAction({ action, link, peerTask }) } : {}),
-          source: {
-            messageUuid: message.uuid,
-            filePath: message.filePath,
-            ...(link.toolUseId ? { toolUseId: link.toolUseId } : {}),
-            sourceOrder: message.sourceOrder,
-          },
-        };

-        if (seenIds.has(record.id)) {
-          continue;
+        for (const taskId of candidateTaskIds) {
+          const targetTask = lookup.byId.get(taskId);
+          if (!targetTask) {
+            continue;
+          }
+          if (
+            resolvedTask.taskRef?.taskId !== targetTask.id &&
+            !locatorCouldMatchTask(link.task, targetTask, lookup)
+          ) {
+            continue;
+          }
+
+          const peerTask = resolvePeerTask(
+            args.teamName,
+            link,
+            message.boardTaskLinks,
+            targetTask,
+            lookup
+          );
+          const record: BoardTaskActivityRecord = {
+            id: [
+              message.uuid,
+              link.toolUseId ?? 'ambient',
+              link.task.ref,
+              link.targetRole,
+              link.linkKind,
+            ].join(':'),
+            timestamp: message.timestamp,
+            task: resolvedTask,
+            linkKind: link.linkKind,
+            targetRole: link.targetRole,
+            actor: resolveActivityActor(message),
+            actorContext: buildActorContext(args.teamName, link.actorContext, lookup),
+            ...(action ? { action: buildAction({ action, link, peerTask }) } : {}),
+            source: {
+              messageUuid: message.uuid,
+              filePath: message.filePath,
+              ...(link.toolUseId ? { toolUseId: link.toolUseId } : {}),
+              sourceOrder: message.sourceOrder,
+            },
+          };
+
+          const seenIds = seenIdsByTaskId.get(taskId) ?? new Set<string>();
+          if (seenIds.has(record.id)) {
+            continue;
+          }
+          seenIds.add(record.id);
+          seenIdsByTaskId.set(taskId, seenIds);
+
+          const taskRecords = recordsByTaskId.get(taskId) ?? [];
+          taskRecords.push(record);
+          recordsByTaskId.set(taskId, taskRecords);
        }
-        seenIds.add(record.id);
-        records.push(record);
      }
    }

-    return records.sort(compareRecords);
+    for (const [taskId, records] of recordsByTaskId) {
+      recordsByTaskId.set(taskId, records.sort(compareRecords));
+    }
+
+    return recordsByTaskId;
  }
 }
--- a/test/main/services/team/TeamDataService.stallMonitor.test.ts
+++ b/test/main/services/team/TeamDataService.stallMonitor.test.ts
@ -0,0 +1,133 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { TeamDataService } from '../../../../src/main/services/team/TeamDataService';
+
+import type { SendMessageResult, TaskRef, TeamSummary } from '../../../../src/shared/types';
+
+function createService(configReaderOverrides: Record<string, unknown> = {}): TeamDataService {
+  return new TeamDataService(
+    {
+      getConfig: vi.fn(async () => null),
+      listTeams: vi.fn(async () => []),
+      ...configReaderOverrides,
+    } as never,
+    { getTasks: vi.fn(async () => []) } 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: 'demo', reviewers: [], tasks: {} })) } as never,
+    {} as never,
+    { getMembers: vi.fn(async () => []), writeMembers: vi.fn(async () => {}) } as never,
+    { readMessages: vi.fn(async () => []) } as never
+  );
+}
+
+describe('TeamDataService stall-monitor helpers', () => {
+  it('lists alive process teams using non-stopped processes and ignores per-team read errors', async () => {
+    const teams: TeamSummary[] = [
+      {
+        teamName: 'beta',
+        displayName: 'beta',
+        description: '',
+        memberCount: 0,
+        taskCount: 0,
+        lastActivity: null,
+      },
+      {
+        teamName: 'alpha',
+        displayName: 'alpha',
+        description: '',
+        memberCount: 0,
+        taskCount: 0,
+        lastActivity: null,
+      },
+      {
+        teamName: 'gamma',
+        displayName: 'gamma',
+        description: '',
+        memberCount: 0,
+        taskCount: 0,
+        lastActivity: null,
+      },
+      {
+        teamName: 'deleted',
+        displayName: 'deleted',
+        description: '',
+        memberCount: 0,
+        taskCount: 0,
+        lastActivity: null,
+        deletedAt: '2026-04-19T12:09:00.000Z',
+      },
+    ];
+
+    const service = createService({
+      listTeams: vi.fn(async () => teams),
+    });
+
+    const readProcesses = vi.fn(async (teamName: string) => {
+      if (teamName === 'alpha') {
+        return [{ id: '1', label: 'alpha', pid: 101, registeredAt: '2026-04-19T12:00:00.000Z' }];
+      }
+      if (teamName === 'beta') {
+        return [
+          {
+            id: '2',
+            label: 'beta',
+            pid: 202,
+            registeredAt: '2026-04-19T12:00:00.000Z',
+            stoppedAt: '2026-04-19T12:05:00.000Z',
+          },
+        ];
+      }
+      if (teamName === 'deleted') {
+        return [{ id: '9', label: 'deleted', pid: 909, registeredAt: '2026-04-19T12:00:00.000Z' }];
+      }
+      throw new Error('boom');
+    });
+
+    (service as unknown as { readProcesses: typeof readProcesses }).readProcesses = readProcesses;
+
+    await expect(service.listAliveProcessTeams()).resolves.toEqual(['alpha']);
+    expect(readProcesses).not.toHaveBeenCalledWith('deleted');
+  });
+
+  it('routes system notifications to the resolved lead via sendMessage', async () => {
+    const leadTaskRef: TaskRef = {
+      taskId: 'task-1',
+      displayId: '1',
+      teamName: 'demo',
+    };
+
+    const service = createService({
+      getConfig: vi.fn(async () => ({
+        name: 'demo',
+        members: [{ name: 'lead', role: 'Team Lead' }],
+      })),
+    });
+
+    const expectedResult = { messageId: 'msg-1' } as SendMessageResult;
+    const sendMessageSpy = vi.spyOn(service, 'sendMessage').mockResolvedValue(expectedResult);
+
+    await expect(
+      service.sendSystemNotificationToLead({
+        teamName: 'demo',
+        summary: 'Potential stalled tasks detected',
+        text: 'Task #1 looks stalled.',
+        taskRefs: [leadTaskRef],
+      })
+    ).resolves.toBe(expectedResult);
+
+    expect(sendMessageSpy).toHaveBeenCalledWith(
+      'demo',
+      expect.objectContaining({
+        member: 'lead',
+        from: 'system',
+        summary: 'Potential stalled tasks detected',
+        text: 'Task #1 looks stalled.',
+        taskRefs: [leadTaskRef],
+        source: 'system_notification',
+      })
+    );
+  });
+});
--- a/test/main/services/team/TeamLogSourceTracker.test.ts
+++ b/test/main/services/team/TeamLogSourceTracker.test.ts
@ -116,4 +116,38 @@ describe('TeamLogSourceTracker', () => {
    await tracker.disableTracking('demo', 'task_log_stream');
    await tracker.disableTracking('demo', 'tool_activity');
  });
+
+  it('supports stall_monitor as an independent tracking consumer', async () => {
+    tempDir = await mkdtemp(path.join(tmpdir(), 'team-log-source-tracker-stall-monitor-'));
+
+    const logsFinder = {
+      getLogSourceWatchContext: vi.fn(async () => ({
+        projectDir: tempDir!,
+        sessionIds: [],
+      })),
+    } as unknown as TeamMemberLogsFinder;
+
+    const tracker = new TeamLogSourceTracker(logsFinder);
+    const emitter = vi.fn<(event: TeamChangeEvent) => void>();
+    tracker.setEmitter(emitter);
+
+    await tracker.enableTracking('demo', 'stall_monitor');
+    emitter.mockClear();
+    await new Promise((resolve) => setTimeout(resolve, 100));
+
+    const taskId = '323e4567-e89b-12d3-a456-426614174999';
+    const signalDir = path.join(tempDir, '.board-task-log-freshness');
+    await mkdir(signalDir, { recursive: true });
+    await writeFile(path.join(signalDir, `${encodeURIComponent(taskId)}.json`), '{"ok":true}');
+
+    await vi.waitFor(() => {
+      expect(emitter).toHaveBeenCalledWith({
+        type: 'task-log-change',
+        teamName: 'demo',
+        taskId,
+      });
+    });
+
+    await tracker.disableTracking('demo', 'stall_monitor');
+  });
 });
--- a/test/main/services/team/stallMonitor/ActiveTeamRegistry.test.ts
+++ b/test/main/services/team/stallMonitor/ActiveTeamRegistry.test.ts
@ -0,0 +1,127 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { ActiveTeamRegistry } from '../../../../../src/main/services/team/stallMonitor/ActiveTeamRegistry';
+
+describe('ActiveTeamRegistry', () => {
+  it('activates a team on lead-activity and enables stall-monitor tracking', async () => {
+    const tracker = {
+      enableTracking: vi.fn(async () => ({ projectFingerprint: null, logSourceGeneration: null })),
+      disableTracking: vi.fn(async () => ({ projectFingerprint: null, logSourceGeneration: null })),
+    };
+    const registry = new ActiveTeamRegistry(
+      { listAliveProcessTeams: vi.fn(async () => []) },
+      tracker as never
+    );
+
+    registry.noteTeamChange({
+      type: 'lead-activity',
+      teamName: 'demo',
+      detail: 'active',
+    });
+
+    await vi.waitFor(() => {
+      expect(tracker.enableTracking).toHaveBeenCalledWith('demo', 'stall_monitor');
+    });
+    await expect(registry.listActiveTeams()).resolves.toEqual(['demo']);
+  });
+
+  it('does not re-enable tracking for repeated activation events on the same team', async () => {
+    const tracker = {
+      enableTracking: vi.fn(async () => ({ projectFingerprint: null, logSourceGeneration: null })),
+      disableTracking: vi.fn(async () => ({ projectFingerprint: null, logSourceGeneration: null })),
+    };
+    const registry = new ActiveTeamRegistry(
+      { listAliveProcessTeams: vi.fn(async () => []) },
+      tracker as never
+    );
+
+    registry.noteTeamChange({
+      type: 'lead-activity',
+      teamName: 'demo',
+      detail: 'active',
+    });
+    registry.noteTeamChange({
+      type: 'member-spawn',
+      teamName: 'demo',
+      detail: 'alice',
+    });
+
+    await vi.waitFor(() => {
+      expect(tracker.enableTracking).toHaveBeenCalledTimes(1);
+    });
+    await expect(registry.listActiveTeams()).resolves.toEqual(['demo']);
+  });
+
+  it('does not cold-activate a team from task-log-change alone', async () => {
+    const tracker = {
+      enableTracking: vi.fn(async () => ({ projectFingerprint: null, logSourceGeneration: null })),
+      disableTracking: vi.fn(async () => ({ projectFingerprint: null, logSourceGeneration: null })),
+    };
+    const registry = new ActiveTeamRegistry(
+      { listAliveProcessTeams: vi.fn(async () => []) },
+      tracker as never
+    );
+
+    registry.noteTeamChange({
+      type: 'task-log-change',
+      teamName: 'cold-team',
+      taskId: 'task-1',
+    });
+
+    expect(tracker.enableTracking).not.toHaveBeenCalled();
+    await expect(registry.listActiveTeams()).resolves.toEqual([]);
+  });
+
+  it('reconciles alive teams through TeamDataService helper and tracker consumer', async () => {
+    const tracker = {
+      enableTracking: vi.fn(async () => ({ projectFingerprint: null, logSourceGeneration: null })),
+      disableTracking: vi.fn(async () => ({ projectFingerprint: null, logSourceGeneration: null })),
+    };
+    const registry = new ActiveTeamRegistry(
+      { listAliveProcessTeams: vi.fn(async () => ['beta']) },
+      tracker as never
+    );
+
+    registry.noteTeamChange({
+      type: 'member-spawn',
+      teamName: 'alpha',
+      detail: 'alice',
+    });
+    await vi.waitFor(() => {
+      expect(tracker.enableTracking).toHaveBeenCalledWith('alpha', 'stall_monitor');
+    });
+
+    tracker.enableTracking.mockClear();
+    await registry.reconcile();
+
+    expect(tracker.enableTracking).toHaveBeenCalledWith('beta', 'stall_monitor');
+    expect(tracker.disableTracking).toHaveBeenCalledWith('alpha', 'stall_monitor');
+    await expect(registry.listActiveTeams()).resolves.toEqual(['beta']);
+  });
+
+  it('does not re-enable tracking for teams that are already active during reconcile', async () => {
+    const tracker = {
+      enableTracking: vi.fn(async () => ({ projectFingerprint: null, logSourceGeneration: null })),
+      disableTracking: vi.fn(async () => ({ projectFingerprint: null, logSourceGeneration: null })),
+    };
+    const registry = new ActiveTeamRegistry(
+      { listAliveProcessTeams: vi.fn(async () => ['demo']) },
+      tracker as never
+    );
+
+    registry.noteTeamChange({
+      type: 'lead-activity',
+      teamName: 'demo',
+      detail: 'active',
+    });
+    await vi.waitFor(() => {
+      expect(tracker.enableTracking).toHaveBeenCalledTimes(1);
+    });
+
+    tracker.enableTracking.mockClear();
+    await registry.reconcile();
+
+    expect(tracker.enableTracking).not.toHaveBeenCalled();
+    await expect(registry.listActiveTeams()).resolves.toEqual(['demo']);
+  });
+});
--- a/test/main/services/team/stallMonitor/BoardTaskActivityBatchIndexer.test.ts
+++ b/test/main/services/team/stallMonitor/BoardTaskActivityBatchIndexer.test.ts
@ -0,0 +1,118 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { BoardTaskActivityBatchIndexer } from '../../../../../src/main/services/team/stallMonitor/BoardTaskActivityBatchIndexer';
+import { BoardTaskActivityRecordBuilder } from '../../../../../src/main/services/team/taskLogs/activity/BoardTaskActivityRecordBuilder';
+
+import type { RawTaskActivityMessage } from '../../../../../src/main/services/team/taskLogs/activity/BoardTaskActivityTranscriptReader';
+import type { TeamTask } from '../../../../../src/shared/types';
+
+describe('BoardTaskActivityBatchIndexer', () => {
+  it('delegates one batched build through buildForTasks', () => {
+    const built = new Map([['task-a', [{ id: 'r1' }]]]);
+    const builder = {
+      buildForTasks: vi.fn(() => built),
+    };
+
+    const indexer = new BoardTaskActivityBatchIndexer(builder as never);
+    const result = indexer.buildIndex({
+      teamName: 'demo',
+      tasks: [{ id: 'task-a', subject: 'A', status: 'in_progress' } as TeamTask],
+      messages: [{ uuid: 'm1' } as RawTaskActivityMessage],
+    });
+
+    expect(result).toBe(built);
+    expect(builder.buildForTasks).toHaveBeenCalledTimes(1);
+  });
+
+  it('keeps buildForTask behavior consistent with batched build', () => {
+    const builder = new BoardTaskActivityRecordBuilder();
+    const taskA: TeamTask = {
+      id: 'task-a',
+      displayId: 'abcd1234',
+      subject: 'Task A',
+      status: 'in_progress',
+    };
+    const taskB: TeamTask = {
+      id: 'task-b',
+      displayId: 'deadbeef',
+      subject: 'Task B',
+      status: 'pending',
+    };
+    const messages: RawTaskActivityMessage[] = [
+      {
+        filePath: '/tmp/session.jsonl',
+        uuid: 'msg-1',
+        timestamp: '2026-04-19T12:00:00.000Z',
+        sessionId: 'session-a',
+        agentName: 'alice',
+        isSidechain: true,
+        sourceOrder: 1,
+        boardTaskLinks: [
+          {
+            schemaVersion: 1,
+            toolUseId: 'tool-1',
+            task: {
+              ref: 'task-a',
+              refKind: 'canonical',
+              canonicalId: 'task-a',
+            },
+            targetRole: 'subject',
+            linkKind: 'board_action',
+            actorContext: {
+              relation: 'same_task',
+            },
+          },
+          {
+            schemaVersion: 1,
+            toolUseId: 'tool-2',
+            task: {
+              ref: 'task-b',
+              refKind: 'canonical',
+              canonicalId: 'task-b',
+            },
+            targetRole: 'subject',
+            linkKind: 'board_action',
+            actorContext: {
+              relation: 'same_task',
+            },
+          },
+        ],
+        boardTaskToolActions: [
+          {
+            schemaVersion: 1,
+            toolUseId: 'tool-1',
+            canonicalToolName: 'task_start',
+          },
+          {
+            schemaVersion: 1,
+            toolUseId: 'tool-2',
+            canonicalToolName: 'task_add_comment',
+          },
+        ],
+      },
+    ];
+
+    const recordsByTaskId = builder.buildForTasks({
+      teamName: 'demo',
+      tasks: [taskA, taskB],
+      messages,
+    });
+
+    expect(recordsByTaskId.get('task-a')).toEqual(
+      builder.buildForTask({
+        teamName: 'demo',
+        targetTask: taskA,
+        tasks: [taskA, taskB],
+        messages,
+      })
+    );
+    expect(recordsByTaskId.get('task-b')).toEqual(
+      builder.buildForTask({
+        teamName: 'demo',
+        targetTask: taskB,
+        tasks: [taskA, taskB],
+        messages,
+      })
+    );
+  });
+});
--- a/test/main/services/team/stallMonitor/TeamTaskLogFreshnessReader.test.ts
+++ b/test/main/services/team/stallMonitor/TeamTaskLogFreshnessReader.test.ts
@ -0,0 +1,57 @@
+import * as fs from 'fs/promises';
+import * as os from 'os';
+import * as path from 'path';
+import { afterEach, describe, expect, it } from 'vitest';
+
+import { TeamTaskLogFreshnessReader } from '../../../../../src/main/services/team/stallMonitor/TeamTaskLogFreshnessReader';
+
+const tempDirs: string[] = [];
+
+afterEach(async () => {
+  await Promise.all(
+    tempDirs.splice(0).map(async (dirPath) => {
+      await fs.rm(dirPath, { recursive: true, force: true });
+    })
+  );
+});
+
+describe('TeamTaskLogFreshnessReader', () => {
+  it('reads valid freshness signals and normalizes transcript basename', async () => {
+    const projectDir = await fs.mkdtemp(path.join(os.tmpdir(), 'stall-freshness-'));
+    tempDirs.push(projectDir);
+    const signalDir = path.join(projectDir, '.board-task-log-freshness');
+    await fs.mkdir(signalDir, { recursive: true });
+
+    await fs.writeFile(
+      path.join(signalDir, `${encodeURIComponent('task-a')}.json`),
+      JSON.stringify({
+        taskId: 'task-a',
+        updatedAt: '2026-04-19T12:00:00.000Z',
+        transcriptFile: '/tmp/nested/session-a.jsonl',
+      }),
+      'utf8'
+    );
+    await fs.writeFile(
+      path.join(signalDir, `${encodeURIComponent('task-b')}.json`),
+      JSON.stringify({
+        taskId: 'task-b',
+        updatedAt: 'not-a-date',
+      }),
+      'utf8'
+    );
+
+    const signals = await new TeamTaskLogFreshnessReader().readSignals(projectDir, [
+      'task-a',
+      'task-b',
+      'task-missing',
+    ]);
+
+    expect([...signals.keys()]).toEqual(['task-a']);
+    expect(signals.get('task-a')).toEqual({
+      taskId: 'task-a',
+      updatedAt: '2026-04-19T12:00:00.000Z',
+      filePath: path.join(signalDir, `${encodeURIComponent('task-a')}.json`),
+      transcriptFileBasename: 'session-a.jsonl',
+    });
+  });
+});
--- a/test/main/services/team/stallMonitor/TeamTaskStallExactRowReader.test.ts
+++ b/test/main/services/team/stallMonitor/TeamTaskStallExactRowReader.test.ts
@ -0,0 +1,149 @@
+import { afterEach, describe, expect, it } from 'vitest';
+import * as fs from 'fs/promises';
+import * as os from 'os';
+import * as path from 'path';
+
+import { TeamTaskStallExactRowReader } from '../../../../../src/main/services/team/stallMonitor/TeamTaskStallExactRowReader';
+
+const tempDirs: string[] = [];
+
+afterEach(async () => {
+  await Promise.all(
+    tempDirs.splice(0).map(async (dirPath) => {
+      await fs.rm(dirPath, { recursive: true, force: true });
+    })
+  );
+});
+
+function createAssistantEntry(args: {
+  uuid: string;
+  timestamp: string;
+  content: unknown[];
+  requestId?: string;
+}): Record<string, unknown> {
+  return {
+    type: 'assistant',
+    uuid: args.uuid,
+    timestamp: args.timestamp,
+    sessionId: 'session-a',
+    teamName: 'demo',
+    agentName: 'alice',
+    isSidechain: true,
+    ...(args.requestId ? { requestId: args.requestId } : {}),
+    message: {
+      id: `${args.uuid}-msg`,
+      role: 'assistant',
+      model: 'claude-test',
+      type: 'message',
+      stop_reason: 'tool_use',
+      stop_sequence: null,
+      usage: {
+        input_tokens: 0,
+        output_tokens: 0,
+      },
+      content: args.content,
+    },
+  };
+}
+
+function createUserEntry(args: {
+  uuid: string;
+  timestamp: string;
+  content: unknown[];
+  sourceToolUseID?: string;
+}): Record<string, unknown> {
+  return {
+    type: 'user',
+    uuid: args.uuid,
+    timestamp: args.timestamp,
+    sessionId: 'session-a',
+    teamName: 'demo',
+    agentName: 'alice',
+    isSidechain: true,
+    ...(args.sourceToolUseID ? { sourceToolUseID: args.sourceToolUseID } : {}),
+    message: {
+      role: 'user',
+      content: args.content,
+    },
+  };
+}
+
+describe('TeamTaskStallExactRowReader', () => {
+  it('keeps strict rows with subtype and tool ids', async () => {
+    const tempDir = await fs.mkdtemp(path.join(os.tmpdir(), 'stall-exact-rows-'));
+    tempDirs.push(tempDir);
+
+    const filePath = path.join(tempDir, 'session.jsonl');
+    await fs.writeFile(
+      filePath,
+      [
+        JSON.stringify({
+          type: 'system',
+          uuid: 'sys-init',
+          timestamp: '2026-04-19T12:00:00.000Z',
+          sessionId: 'session-a',
+          teamName: 'demo',
+          agentName: 'alice',
+          isSidechain: true,
+          isMeta: true,
+          subtype: 'turn_duration',
+          durationMs: 1234,
+        }),
+        JSON.stringify(
+          createAssistantEntry({
+            uuid: 'asst-1',
+            timestamp: '2026-04-19T12:01:00.000Z',
+            requestId: 'req-1',
+            content: [
+              {
+                type: 'tool_use',
+                id: 'tool-1',
+                name: 'task_start',
+                input: { taskId: 'task-a' },
+              },
+            ],
+          })
+        ),
+        JSON.stringify(
+          createUserEntry({
+            uuid: 'user-1',
+            timestamp: '2026-04-19T12:01:01.000Z',
+            sourceToolUseID: 'tool-1',
+            content: [{ type: 'tool_result', tool_use_id: 'tool-1', content: 'ok' }],
+          })
+        ),
+        JSON.stringify({
+          uuid: 'bad-ts',
+          type: 'assistant',
+          timestamp: 'not-a-date',
+          message: { role: 'assistant', content: 'bad row' },
+        }),
+      ].join('\n'),
+      'utf8'
+    );
+
+    const parsed = await new TeamTaskStallExactRowReader().parseFiles([filePath]);
+    const rows = parsed.get(filePath) ?? [];
+
+    expect(rows).toHaveLength(3);
+    expect(rows.map((row) => row.messageUuid)).toEqual(['sys-init', 'asst-1', 'user-1']);
+    expect(rows[0]).toMatchObject({
+      systemSubtype: 'turn_duration',
+      sourceOrder: 1,
+      toolUseIds: [],
+      toolResultIds: [],
+    });
+    expect(rows[1]).toMatchObject({
+      requestId: 'req-1',
+      toolUseIds: ['tool-1'],
+      toolResultIds: [],
+      sourceOrder: 2,
+    });
+    expect(rows[2]).toMatchObject({
+      sourceToolUseId: 'tool-1',
+      toolUseIds: [],
+      toolResultIds: ['tool-1'],
+      sourceOrder: 3,
+    });
+  });
+});
--- a/test/main/services/team/stallMonitor/TeamTaskStallJournal.test.ts
+++ b/test/main/services/team/stallMonitor/TeamTaskStallJournal.test.ts
@ -0,0 +1,51 @@
+import * as os from 'os';
+import * as path from 'path';
+import { afterEach, describe, expect, it } from 'vitest';
+import * as fs from 'fs/promises';
+
+import { TeamTaskStallJournal } from '../../../../../src/main/services/team/stallMonitor/TeamTaskStallJournal';
+import { setClaudeBasePathOverride } from '../../../../../src/main/utils/pathDecoder';
+
+describe('TeamTaskStallJournal', () => {
+  let tmpDir: string | null = null;
+
+  afterEach(async () => {
+    setClaudeBasePathOverride(null);
+    if (tmpDir) {
+      await fs.rm(tmpDir, { recursive: true, force: true });
+      tmpDir = null;
+    }
+  });
+
+  it('requires two scans before returning an alert-ready candidate', async () => {
+    tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'stall-journal-'));
+    setClaudeBasePathOverride(tmpDir);
+    await fs.mkdir(path.join(tmpDir, 'teams', 'demo'), { recursive: true });
+
+    const journal = new TeamTaskStallJournal();
+    const evaluation = {
+      status: 'alert',
+      taskId: 'task-a',
+      branch: 'work',
+      signal: 'turn_ended_after_touch',
+      epochKey: 'task-a:epoch-1',
+      reason: 'Potential work stall',
+    } as const;
+
+    const firstReady = await journal.reconcileScan({
+      teamName: 'demo',
+      evaluations: [evaluation],
+      activeTaskIds: ['task-a'],
+      now: '2026-04-19T12:10:00.000Z',
+    });
+    const secondReady = await journal.reconcileScan({
+      teamName: 'demo',
+      evaluations: [evaluation],
+      activeTaskIds: ['task-a'],
+      now: '2026-04-19T12:11:00.000Z',
+    });
+
+    expect(firstReady).toEqual([]);
+    expect(secondReady).toEqual([evaluation]);
+  });
+});
--- a/test/main/services/team/stallMonitor/TeamTaskStallMonitor.test.ts
+++ b/test/main/services/team/stallMonitor/TeamTaskStallMonitor.test.ts
@ -0,0 +1,87 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { TeamTaskStallMonitor } from '../../../../../src/main/services/team/stallMonitor/TeamTaskStallMonitor';
+
+describe('TeamTaskStallMonitor', () => {
+  afterEach(() => {
+    vi.useRealTimers();
+    vi.unstubAllEnvs();
+  });
+
+  it('runs end-to-end and notifies only after a second confirmed scan', async () => {
+    vi.useFakeTimers();
+    vi.stubEnv('CLAUDE_TEAM_TASK_STALL_MONITOR_ENABLED', 'true');
+    vi.stubEnv('CLAUDE_TEAM_TASK_STALL_ALERTS_ENABLED', 'true');
+    vi.stubEnv('CLAUDE_TEAM_TASK_STALL_SCAN_INTERVAL_MS', '1000');
+    vi.stubEnv('CLAUDE_TEAM_TASK_STALL_STARTUP_GRACE_MS', '1');
+    vi.stubEnv('CLAUDE_TEAM_TASK_STALL_ACTIVATION_GRACE_MS', '1');
+
+    const registry = {
+      start: vi.fn(),
+      stop: vi.fn(async () => undefined),
+      noteTeamChange: vi.fn(),
+      listActiveTeams: vi.fn(async () => ['demo']),
+    };
+    const snapshot = {
+      teamName: 'demo',
+      inProgressTasks: [{ id: 'task-a', displayId: 'abcd1234', subject: 'Task A' }],
+      reviewOpenTasks: [],
+      allTasksById: new Map([
+        ['task-a', { id: 'task-a', displayId: 'abcd1234', subject: 'Task A' }],
+      ]),
+    };
+    const snapshotSource = {
+      getSnapshot: vi.fn(async () => snapshot),
+    };
+    const policy = {
+      evaluateWork: vi.fn(() => ({
+        status: 'alert',
+        taskId: 'task-a',
+        branch: 'work',
+        signal: 'turn_ended_after_touch',
+        epochKey: 'task-a:epoch',
+        reason: 'Potential work stall.',
+      })),
+      evaluateReview: vi.fn(),
+    };
+    const journal = {
+      reconcileScan: vi
+        .fn()
+        .mockResolvedValueOnce([])
+        .mockResolvedValueOnce([
+          {
+            status: 'alert',
+            taskId: 'task-a',
+            branch: 'work',
+            signal: 'turn_ended_after_touch',
+            epochKey: 'task-a:epoch',
+            reason: 'Potential work stall.',
+          },
+        ]),
+      markAlerted: vi.fn(async () => undefined),
+    };
+    const notifier = {
+      notifyLead: vi.fn(async () => undefined),
+    };
+
+    const monitor = new TeamTaskStallMonitor(
+      registry as never,
+      snapshotSource as never,
+      policy as never,
+      journal as never,
+      notifier as never
+    );
+
+    monitor.start();
+    await vi.advanceTimersByTimeAsync(2_100);
+    await vi.advanceTimersByTimeAsync(2_100);
+
+    expect(snapshotSource.getSnapshot).toHaveBeenCalledTimes(2);
+    expect(notifier.notifyLead).toHaveBeenCalledTimes(1);
+    expect(journal.markAlerted).toHaveBeenCalledWith(
+      'demo',
+      'task-a:epoch',
+      expect.any(String)
+    );
+  });
+});
--- a/test/main/services/team/stallMonitor/TeamTaskStallPolicy.test.ts
+++ b/test/main/services/team/stallMonitor/TeamTaskStallPolicy.test.ts
@ -0,0 +1,460 @@
+import { describe, expect, it } from 'vitest';
+
+import { TeamTaskStallPolicy } from '../../../../../src/main/services/team/stallMonitor/TeamTaskStallPolicy';
+
+import type { TeamTaskStallExactRow, TeamTaskStallSnapshot } from '../../../../../src/main/services/team/stallMonitor/TeamTaskStallTypes';
+import type { BoardTaskActivityRecord } from '../../../../../src/main/services/team/taskLogs/activity/BoardTaskActivityRecord';
+import type { ParsedMessage } from '../../../../../src/main/types';
+import type { TeamTask } from '../../../../../src/shared/types';
+
+function createParsedMessage(overrides: Partial<ParsedMessage>): ParsedMessage {
+  return {
+    uuid: 'msg-default',
+    parentUuid: null,
+    type: 'assistant',
+    timestamp: new Date('2026-04-19T12:00:00.000Z'),
+    content: '',
+    isSidechain: true,
+    isMeta: false,
+    toolCalls: [],
+    toolResults: [],
+    ...overrides,
+  };
+}
+
+function createExactRow(overrides: Partial<TeamTaskStallExactRow> = {}): TeamTaskStallExactRow {
+  return {
+    filePath: '/tmp/session.jsonl',
+    sourceOrder: 1,
+    messageUuid: 'msg-touch',
+    timestamp: '2026-04-19T12:00:00.000Z',
+    parsedMessage: createParsedMessage({ uuid: 'msg-touch' }),
+    toolUseIds: [],
+    toolResultIds: [],
+    ...overrides,
+  };
+}
+
+function createRecord(overrides: Partial<BoardTaskActivityRecord> = {}): BoardTaskActivityRecord {
+  return {
+    id: 'rec-1',
+    timestamp: '2026-04-19T12:00:00.000Z',
+    task: {
+      locator: {
+        ref: 'task-a',
+        refKind: 'canonical',
+        canonicalId: 'task-a',
+      },
+      resolution: 'resolved',
+      taskRef: {
+        taskId: 'task-a',
+        displayId: 'abcd1234',
+        teamName: 'demo',
+      },
+    },
+    linkKind: 'board_action',
+    targetRole: 'subject',
+    actor: {
+      memberName: 'alice',
+      role: 'member',
+      sessionId: 'session-a',
+      isSidechain: true,
+    },
+    actorContext: {
+      relation: 'same_task',
+    },
+    action: {
+      canonicalToolName: 'task_start',
+      category: 'status',
+      toolUseId: 'tool-1',
+    },
+    source: {
+      messageUuid: 'msg-touch',
+      filePath: '/tmp/session.jsonl',
+      toolUseId: 'tool-1',
+      sourceOrder: 1,
+    },
+    ...overrides,
+  };
+}
+
+function createSnapshot(overrides: Partial<TeamTaskStallSnapshot>): TeamTaskStallSnapshot {
+  return {
+    teamName: 'demo',
+    scannedAt: '2026-04-19T12:30:00.000Z',
+    projectDir: '/tmp/project',
+    projectId: 'project-id',
+    leadName: 'team-lead',
+    transcriptFiles: ['/tmp/session.jsonl'],
+    activityReadsEnabled: true,
+    exactReadsEnabled: true,
+    activeTasks: [],
+    deletedTasks: [],
+    allTasksById: new Map(),
+    inProgressTasks: [],
+    reviewOpenTasks: [],
+    resolvedReviewersByTaskId: new Map(),
+    recordsByTaskId: new Map(),
+    freshnessByTaskId: new Map(),
+    exactRowsByFilePath: new Map(),
+    ...overrides,
+  };
+}
+
+describe('TeamTaskStallPolicy', () => {
+  const policy = new TeamTaskStallPolicy();
+
+  it('alerts for work stall after turn ended and threshold elapsed', () => {
+    const task: TeamTask = {
+      id: 'task-a',
+      displayId: 'abcd1234',
+      subject: 'Task A',
+      owner: 'alice',
+      status: 'in_progress',
+      workIntervals: [{ startedAt: '2026-04-19T11:50:00.000Z' }],
+    };
+    const record = createRecord();
+    const snapshot = createSnapshot({
+      activeTasks: [task],
+      allTasksById: new Map([['task-a', task]]),
+      inProgressTasks: [task],
+      recordsByTaskId: new Map([['task-a', [record]]]),
+      exactRowsByFilePath: new Map([
+        [
+          '/tmp/session.jsonl',
+          [
+            createExactRow({
+              messageUuid: 'msg-touch',
+              toolUseIds: ['tool-1'],
+            }),
+            createExactRow({
+              sourceOrder: 2,
+              messageUuid: 'msg-turn-end',
+              systemSubtype: 'turn_duration',
+              parsedMessage: createParsedMessage({
+                uuid: 'msg-turn-end',
+                type: 'system',
+              }),
+            }),
+          ],
+        ],
+      ]),
+    });
+
+    const evaluation = policy.evaluateWork({
+      now: new Date('2026-04-19T12:30:00.000Z'),
+      task,
+      snapshot,
+    });
+
+    expect(evaluation).toMatchObject({
+      status: 'alert',
+      taskId: 'task-a',
+      branch: 'work',
+      signal: 'turn_ended_after_touch',
+    });
+  });
+
+  it('fails closed on review branch when review has not started yet', () => {
+    const task: TeamTask = {
+      id: 'task-b',
+      displayId: 'deadbeef',
+      subject: 'Task B',
+      status: 'completed',
+      reviewState: 'review',
+      historyEvents: [
+        {
+          id: 'evt-review-requested',
+          type: 'review_requested',
+          timestamp: '2026-04-19T12:00:00.000Z',
+          from: 'none',
+          to: 'review',
+        },
+      ],
+    };
+
+    const evaluation = policy.evaluateReview({
+      now: new Date('2026-04-19T12:30:00.000Z'),
+      task,
+      snapshot: createSnapshot({
+        activeTasks: [task],
+        allTasksById: new Map([['task-b', task]]),
+        reviewOpenTasks: [task],
+      }),
+    });
+
+    expect(evaluation).toMatchObject({
+      status: 'skip',
+      taskId: 'task-b',
+      skipReason: 'no_open_review_window',
+    });
+  });
+
+  it('fails closed on review branch when reviewer cannot be resolved after review has started', () => {
+    const task: TeamTask = {
+      id: 'task-b2',
+      displayId: 'deadbe12',
+      subject: 'Task B2',
+      status: 'completed',
+      reviewState: 'review',
+      historyEvents: [
+        {
+          id: 'evt-review-started',
+          type: 'review_started',
+          timestamp: '2026-04-19T12:01:00.000Z',
+          from: 'review',
+          to: 'review',
+        },
+      ],
+    };
+
+    const evaluation = policy.evaluateReview({
+      now: new Date('2026-04-19T12:30:00.000Z'),
+      task,
+      snapshot: createSnapshot({
+        activeTasks: [task],
+        allTasksById: new Map([['task-b2', task]]),
+        reviewOpenTasks: [task],
+      }),
+    });
+
+    expect(evaluation).toMatchObject({
+      status: 'skip',
+      taskId: 'task-b2',
+      skipReason: 'reviewer_unresolved',
+    });
+  });
+
+  it('does not treat review_requested alone as started-review evidence', () => {
+    const task: TeamTask = {
+      id: 'task-review-requested-only',
+      displayId: 'feedbeef',
+      subject: 'Task review requested only',
+      status: 'completed',
+      reviewState: 'review',
+      historyEvents: [
+        {
+          id: 'evt-review-requested',
+          type: 'review_requested',
+          timestamp: '2026-04-19T12:00:00.000Z',
+          from: 'none',
+          to: 'review',
+          reviewer: 'bob',
+        },
+      ],
+    };
+
+    const evaluation = policy.evaluateReview({
+      now: new Date('2026-04-19T12:30:00.000Z'),
+      task,
+      snapshot: createSnapshot({
+        activeTasks: [task],
+        allTasksById: new Map([['task-review-requested-only', task]]),
+        reviewOpenTasks: [task],
+        resolvedReviewersByTaskId: new Map([
+          [
+            'task-review-requested-only',
+            { reviewer: 'bob', source: 'history_review_requested_reviewer' },
+          ],
+        ]),
+      }),
+    });
+
+    expect(evaluation).toMatchObject({
+      status: 'skip',
+      taskId: 'task-review-requested-only',
+      skipReason: 'no_open_review_window',
+    });
+  });
+
+  it('alerts for started-review stall after explicit review_start evidence', () => {
+    const task: TeamTask = {
+      id: 'task-c',
+      displayId: 'c0ffee12',
+      subject: 'Task C',
+      status: 'completed',
+      reviewState: 'review',
+      historyEvents: [
+        {
+          id: 'evt-review-requested',
+          type: 'review_requested',
+          timestamp: '2026-04-19T12:00:00.000Z',
+          from: 'none',
+          to: 'review',
+          reviewer: 'bob',
+        },
+        {
+          id: 'evt-review-started',
+          type: 'review_started',
+          timestamp: '2026-04-19T12:01:00.000Z',
+          from: 'review',
+          to: 'review',
+          actor: 'bob',
+        },
+      ],
+    };
+    const record = createRecord({
+      id: 'rec-review',
+      timestamp: '2026-04-19T12:01:00.000Z',
+      actor: {
+        memberName: 'bob',
+        role: 'member',
+        sessionId: 'session-b',
+        isSidechain: true,
+      },
+      actorContext: {
+        relation: 'same_task',
+        activePhase: 'review',
+      },
+      action: {
+        canonicalToolName: 'review_start',
+        category: 'review',
+        toolUseId: 'tool-review',
+      },
+      source: {
+        messageUuid: 'msg-review-touch',
+        filePath: '/tmp/review.jsonl',
+        toolUseId: 'tool-review',
+        sourceOrder: 1,
+      },
+    });
+
+    const evaluation = policy.evaluateReview({
+      now: new Date('2026-04-19T12:20:30.000Z'),
+      task,
+      snapshot: createSnapshot({
+        activeTasks: [task],
+        allTasksById: new Map([['task-c', task]]),
+        reviewOpenTasks: [task],
+        resolvedReviewersByTaskId: new Map([
+          ['task-c', { reviewer: 'bob', source: 'history_review_started_actor' }],
+        ]),
+        recordsByTaskId: new Map([['task-c', [record]]]),
+        exactRowsByFilePath: new Map([
+          [
+            '/tmp/review.jsonl',
+            [
+              createExactRow({
+                filePath: '/tmp/review.jsonl',
+                messageUuid: 'msg-review-touch',
+                toolUseIds: ['tool-review'],
+              }),
+              createExactRow({
+                filePath: '/tmp/review.jsonl',
+                sourceOrder: 2,
+                messageUuid: 'msg-review-turn-end',
+                systemSubtype: 'turn_duration',
+                parsedMessage: createParsedMessage({
+                  uuid: 'msg-review-turn-end',
+                  type: 'system',
+                }),
+              }),
+            ],
+          ],
+        ]),
+      }),
+    });
+
+    expect(evaluation).toMatchObject({
+      status: 'alert',
+      taskId: 'task-c',
+      branch: 'review',
+      signal: 'turn_ended_after_touch',
+    });
+  });
+
+  it('alerts for started-review stall when review_started actor is missing but same-task reviewer touch exists after the review start', () => {
+    const task: TeamTask = {
+      id: 'task-d',
+      displayId: 'ddaa5511',
+      subject: 'Task D',
+      status: 'completed',
+      reviewState: 'review',
+      historyEvents: [
+        {
+          id: 'evt-review-requested',
+          type: 'review_requested',
+          timestamp: '2026-04-19T12:00:00.000Z',
+          from: 'none',
+          to: 'review',
+          reviewer: 'bob',
+        },
+        {
+          id: 'evt-review-started',
+          type: 'review_started',
+          timestamp: '2026-04-19T12:01:00.000Z',
+          from: 'review',
+          to: 'review',
+        },
+      ],
+    };
+    const record = createRecord({
+      id: 'rec-review-comment',
+      timestamp: '2026-04-19T12:02:00.000Z',
+      actor: {
+        memberName: 'bob',
+        role: 'member',
+        sessionId: 'session-b',
+        isSidechain: true,
+      },
+      actorContext: {
+        relation: 'same_task',
+        activePhase: 'review',
+      },
+      action: {
+        canonicalToolName: 'task_add_comment',
+        category: 'comment',
+        toolUseId: 'tool-review-comment',
+      },
+      source: {
+        messageUuid: 'msg-review-comment',
+        filePath: '/tmp/review-missing-actor.jsonl',
+        toolUseId: 'tool-review-comment',
+        sourceOrder: 1,
+      },
+    });
+
+    const evaluation = policy.evaluateReview({
+      now: new Date('2026-04-19T12:20:30.000Z'),
+      task,
+      snapshot: createSnapshot({
+        activeTasks: [task],
+        allTasksById: new Map([['task-d', task]]),
+        reviewOpenTasks: [task],
+        resolvedReviewersByTaskId: new Map([
+          ['task-d', { reviewer: 'bob', source: 'history_review_requested_reviewer' }],
+        ]),
+        recordsByTaskId: new Map([['task-d', [record]]]),
+        exactRowsByFilePath: new Map([
+          [
+            '/tmp/review-missing-actor.jsonl',
+            [
+              createExactRow({
+                filePath: '/tmp/review-missing-actor.jsonl',
+                messageUuid: 'msg-review-comment',
+                toolUseIds: ['tool-review-comment'],
+              }),
+              createExactRow({
+                filePath: '/tmp/review-missing-actor.jsonl',
+                sourceOrder: 2,
+                messageUuid: 'msg-review-turn-end',
+                systemSubtype: 'turn_duration',
+                parsedMessage: createParsedMessage({
+                  uuid: 'msg-review-turn-end',
+                  type: 'system',
+                }),
+              }),
+            ],
+          ],
+        ]),
+      }),
+    });
+
+    expect(evaluation).toMatchObject({
+      status: 'alert',
+      taskId: 'task-d',
+      branch: 'review',
+      signal: 'turn_ended_after_touch',
+    });
+  });
+});
--- a/test/main/services/team/stallMonitor/TeamTaskStallSnapshotSource.test.ts
+++ b/test/main/services/team/stallMonitor/TeamTaskStallSnapshotSource.test.ts
@ -0,0 +1,142 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { TeamTaskStallSnapshotSource } from '../../../../../src/main/services/team/stallMonitor/TeamTaskStallSnapshotSource';
+
+describe('TeamTaskStallSnapshotSource', () => {
+  it('returns null when transcript context is unavailable', async () => {
+    const source = new TeamTaskStallSnapshotSource(
+      { getContext: vi.fn(async () => null) } as never,
+      {} as never,
+      {} as never,
+      {} as never,
+      {} as never,
+      {} as never,
+      {} as never
+    );
+
+    await expect(source.getSnapshot('demo')).resolves.toBeNull();
+  });
+
+  it('builds one batched snapshot and narrows exact/freshness reads to work and started-review candidates', async () => {
+    const activeTasks = [
+      { id: 'task-a', subject: 'A', status: 'in_progress' },
+      {
+        id: 'task-b',
+        subject: 'B',
+        status: 'completed',
+        reviewState: 'review',
+        historyEvents: [
+          {
+            id: 'evt-review-requested',
+            type: 'review_requested',
+            timestamp: '2026-04-19T12:00:00.000Z',
+            from: 'none',
+            to: 'review',
+            reviewer: 'alice',
+          },
+        ],
+      },
+    ];
+    const deletedTasks = [{ id: 'task-deleted', subject: 'D', status: 'deleted' }];
+    const transcriptContext = {
+      projectDir: '/tmp/project',
+      projectId: 'project-id',
+      config: {
+        members: [{ name: 'team-lead', role: 'team lead' }],
+      } as never,
+      sessionIds: ['session-a'],
+      transcriptFiles: ['/tmp/project/session-a.jsonl', '/tmp/project/session-b.jsonl'],
+    };
+    const rawMessages = [{ uuid: 'm1' }];
+    const recordsByTaskId = new Map([
+      [
+        'task-a',
+        [
+          {
+            id: 'r1',
+            source: {
+              filePath: '/tmp/project/session-b.jsonl',
+            },
+          },
+        ],
+      ],
+      [
+        'task-b',
+        [
+          {
+            id: 'r2',
+            source: {
+              filePath: '/tmp/project/session-a.jsonl',
+            },
+          },
+        ],
+      ],
+    ]);
+    const freshnessByTaskId = new Map([
+      ['task-a', { taskId: 'task-a', updatedAt: '2026-04-19T12:00:00.000Z', filePath: '/tmp/fresh.json' }],
+    ]);
+    const exactRowsByFilePath = new Map([['/tmp/project/session-b.jsonl', []]]);
+
+    const locator = {
+      getContext: vi.fn(async () => transcriptContext),
+    };
+    const taskReader = {
+      getTasks: vi.fn(async () => activeTasks),
+      getDeletedTasks: vi.fn(async () => deletedTasks),
+    };
+    const kanbanManager = {
+      getState: vi.fn(async () => ({
+        teamName: 'demo',
+        reviewers: ['alice'],
+        tasks: {
+          'task-b': {
+            column: 'review',
+            movedAt: '2026-04-19T12:00:00.000Z',
+            reviewer: 'alice',
+          },
+        },
+      })),
+    };
+    const transcriptReader = {
+      readFiles: vi.fn(async () => rawMessages),
+    };
+    const batchIndexer = {
+      buildIndex: vi.fn(() => recordsByTaskId),
+    };
+    const freshnessReader = {
+      readSignals: vi.fn(async () => freshnessByTaskId),
+    };
+    const exactRowReader = {
+      parseFiles: vi.fn(async () => exactRowsByFilePath),
+    };
+
+    const source = new TeamTaskStallSnapshotSource(
+      locator as never,
+      taskReader as never,
+      kanbanManager as never,
+      transcriptReader as never,
+      batchIndexer as never,
+      freshnessReader as never,
+      exactRowReader as never
+    );
+
+    const snapshot = await source.getSnapshot('demo');
+
+    expect(snapshot).not.toBeNull();
+    expect(batchIndexer.buildIndex).toHaveBeenCalledWith({
+      teamName: 'demo',
+      tasks: [...activeTasks, ...deletedTasks],
+      messages: rawMessages,
+    });
+    expect(freshnessReader.readSignals).toHaveBeenCalledWith('/tmp/project', ['task-a', 'task-b']);
+    expect(exactRowReader.parseFiles).toHaveBeenCalledWith(['/tmp/project/session-a.jsonl', '/tmp/project/session-b.jsonl']);
+    expect(snapshot?.inProgressTasks.map((task) => task.id)).toEqual(['task-a']);
+    expect(snapshot?.reviewOpenTasks.map((task) => task.id)).toEqual(['task-b']);
+    expect(snapshot?.leadName).toBe('team-lead');
+    expect(snapshot?.resolvedReviewersByTaskId.get('task-b')).toEqual({
+      reviewer: 'alice',
+      source: 'kanban_state',
+    });
+    expect(snapshot?.recordsByTaskId).toBe(recordsByTaskId);
+  });
+});
--- a/test/main/services/team/stallMonitor/featureGates.test.ts
+++ b/test/main/services/team/stallMonitor/featureGates.test.ts
@ -0,0 +1,37 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import {
+  getTeamTaskStallActivationGraceMs,
+  getTeamTaskStallScanIntervalMs,
+  getTeamTaskStallStartupGraceMs,
+  isTeamTaskStallAlertsEnabled,
+  isTeamTaskStallMonitorEnabled,
+} from '../../../../../src/main/services/team/stallMonitor/featureGates';
+
+afterEach(() => {
+  vi.unstubAllEnvs();
+});
+
+describe('stallMonitor feature gates', () => {
+  it('defaults both monitor and alerts to disabled', () => {
+    expect(isTeamTaskStallMonitorEnabled()).toBe(false);
+    expect(isTeamTaskStallAlertsEnabled()).toBe(false);
+    expect(getTeamTaskStallScanIntervalMs()).toBe(60_000);
+    expect(getTeamTaskStallStartupGraceMs()).toBe(180_000);
+    expect(getTeamTaskStallActivationGraceMs()).toBe(120_000);
+  });
+
+  it('parses truthy and falsy environment values', () => {
+    vi.stubEnv('CLAUDE_TEAM_TASK_STALL_MONITOR_ENABLED', 'true');
+    vi.stubEnv('CLAUDE_TEAM_TASK_STALL_ALERTS_ENABLED', 'off');
+    vi.stubEnv('CLAUDE_TEAM_TASK_STALL_SCAN_INTERVAL_MS', '1500');
+    vi.stubEnv('CLAUDE_TEAM_TASK_STALL_STARTUP_GRACE_MS', '2000');
+    vi.stubEnv('CLAUDE_TEAM_TASK_STALL_ACTIVATION_GRACE_MS', '3000');
+
+    expect(isTeamTaskStallMonitorEnabled()).toBe(true);
+    expect(isTeamTaskStallAlertsEnabled()).toBe(false);
+    expect(getTeamTaskStallScanIntervalMs()).toBe(1500);
+    expect(getTeamTaskStallStartupGraceMs()).toBe(2000);
+    expect(getTeamTaskStallActivationGraceMs()).toBe(3000);
+  });
+});