perf: diagnoistics improvements

electron/app-metrics.ts

@@ -4,6 +4,10 @@ export interface AppMetricsProcessSnapshot {
   pid: number;
   type: string;
   workingSetKb: number | null;
+  peakWorkingSetKb: number | null;
+  privateBytesKb: number | null;
+  creationTime: number | null;
+  cpuPercent: number | null;
 }
 
 export interface AppMetricsSnapshot {
@@ -17,7 +21,17 @@ export function collectAppMetricsSnapshot(): AppMetricsSnapshot {
     processes: app.getAppMetrics().map((metric) => ({
       pid: metric.pid,
       type: metric.type,
-      workingSetKb: metric.memory?.workingSetSize ?? null
+      workingSetKb: metric.memory?.workingSetSize ?? null,
+      peakWorkingSetKb: readOptionalKilobytes(metric.memory?.peakWorkingSetSize),
+      privateBytesKb: readOptionalKilobytes(metric.memory?.privateBytes),
+      creationTime: metric.creationTime ?? null,
+      cpuPercent: typeof metric.cpu?.percentCPUUsage === 'number'
+        ? Math.round(metric.cpu.percentCPUUsage * 10) / 10
+        : null
     }))
   };
 }
+
+function readOptionalKilobytes(value: number | undefined): number | null {
+  return typeof value === 'number' && value >= 0 ? value : null;
+}

electron/diagnostics/diagnostics.flags.spec.ts

@@ -8,7 +8,7 @@ import { isPerfDiagEnabled } from './diagnostics.flags';
 describe('isPerfDiagEnabled', () => {
   it('returns false when the flag is unset', () => {
     expect(isPerfDiagEnabled({}, false)).toBe(false);
-    expect(isPerfDiagEnabled({}, true)).toBe(false);
+    expect(isPerfDiagEnabled({}, true)).toBe(true);
   });
 
   it('returns true in development when METOYOU_PERF_DIAG is truthy', () => {
@@ -17,11 +17,12 @@ describe('isPerfDiagEnabled', () => {
     expect(isPerfDiagEnabled({ METOYOU_PERF_DIAG: 'on' }, false)).toBe(true);
   });
 
-  it('returns false in packaged builds unless force is set', () => {
-    expect(isPerfDiagEnabled({ METOYOU_PERF_DIAG: '1' }, true)).toBe(false);
-    expect(isPerfDiagEnabled({
-      METOYOU_PERF_DIAG: '1',
-      METOYOU_PERF_DIAG_FORCE: '1'
-    }, true)).toBe(true);
+  it('returns true in packaged Electron builds without env flags', () => {
+    expect(isPerfDiagEnabled({}, true)).toBe(true);
+    expect(isPerfDiagEnabled({ METOYOU_PERF_DIAG: '0' }, true)).toBe(true);
+  });
+
+  it('returns false in development when the flag is unset', () => {
+    expect(isPerfDiagEnabled({}, false)).toBe(false);
   });
 });

electron/diagnostics/diagnostics.flags.ts

@@ -17,13 +17,9 @@ export function isPerfDiagEnabled(
   env: NodeJS.ProcessEnv,
   isPackaged: boolean
 ): boolean {
-  if (!isTruthyFlag(env[PERF_DIAG_ENV])) {
-    return false;
+  if (isPackaged) {
+    return true;
   }
 
-  if (isPackaged && !isTruthyFlag(env[PERF_DIAG_FORCE_ENV])) {
-    return false;
-  }
-
-  return true;
+  return isTruthyFlag(env[PERF_DIAG_ENV]);
 }

electron/diagnostics/diagnostics.lifecycle.ts

@@ -1,11 +1,23 @@
 import {
   app,
   BrowserWindow,
-  ipcMain
+  ipcMain,
+  shell
 } from 'electron';
-import { collectAppMetricsSnapshot } from '../app-metrics';
+import { collectAppMetricsSnapshot, type AppMetricsSnapshot } from '../app-metrics';
+import { getMainWindow } from '../window/create-window';
+import { resolveReadablePath } from '../path-jail';
 import { sumWorkingSetKb } from './process-metrics.rules';
 import { isPerfDiagEnabled } from './diagnostics.flags';
+import { exceedsHighMemoryThreshold } from './high-memory-alert.rules';
+import { buildHighMemoryDiagnosticPayload } from './high-memory-snapshot.rules';
+import { collectImmediateRendererSamples } from './immediate-renderer-samples.collector';
+import { collectSessionContext } from './session-context.collector';
+import {
+  clearHighMemoryAlert,
+  readHighMemoryAlert,
+  writeHighMemoryAlert
+} from './high-memory-alert.store';
 import type { PerfDiagEntry } from './diagnostics.models';
 import { PerfDiagWriter } from './diagnostics.writer';
 
@@ -15,6 +27,8 @@ let activeWriter: PerfDiagWriter | null = null;
 let processPollTimer: NodeJS.Timeout | null = null;
 let diagnosticsEnabled = false;
 let ipcRegistered = false;
+let highMemoryAlertTriggeredThisSession = false;
+let sessionStartedAt = 0;
 
 export function isPerfDiagActive(): boolean {
   return diagnosticsEnabled;
@@ -43,6 +57,37 @@ export function ensurePerfDiagIpcRegistered(): void {
       return false;
     }
   });
+
+  ipcMain.handle('get-pending-high-memory-alert', async () => {
+    return readHighMemoryAlert(app.getPath('userData'));
+  });
+
+  ipcMain.handle('acknowledge-high-memory-alert', async () => {
+    await clearHighMemoryAlert(app.getPath('userData'));
+    return true;
+  });
+
+  ipcMain.handle('show-log-file-in-folder', async (_event, filePath: string) => {
+    if (typeof filePath !== 'string' || !filePath.trim()) {
+      return {
+        shown: false,
+        reason: 'missing-path'
+      };
+    }
+
+    const scopedPath = await resolveReadablePath(filePath);
+
+    if (!scopedPath) {
+      return {
+        shown: false,
+        reason: 'outside-app-data'
+      };
+    }
+
+    shell.showItemInFolder(scopedPath);
+
+    return { shown: true };
+  });
 }
 
 export function getActivePerfDiagWriter(): PerfDiagWriter | null {
@@ -64,9 +109,13 @@ export function startPerfDiagnostics(): PerfDiagWriter | null {
   });
 
   activeWriter = writer;
+  highMemoryAlertTriggeredThisSession = false;
+  sessionStartedAt = Date.now();
   registerProcessCrashHandlers(writer);
   startProcessMetricsPolling(writer);
 
+  const userDataPath = app.getPath('userData');
+
   writer.append({
     collectedAt: Date.now(),
     source: 'main',
@@ -78,6 +127,18 @@ export function startPerfDiagnostics(): PerfDiagWriter | null {
     }
   });
 
+  writer.append({
+    collectedAt: Date.now(),
+    source: 'main',
+    type: 'environment',
+    payload: {
+      ...collectSessionContext({
+        sessionStartedAt,
+        userDataPath
+      })
+    }
+  });
+
   return writer;
 }
 
@@ -195,6 +256,8 @@ function startProcessMetricsPolling(writer: PerfDiagWriter): void {
           processes: metrics.processes
         }
       });
+
+      void maybeTriggerHighMemoryAlert(writer, metrics, totalKb);
     } catch {
       // Collector failures must never affect the app.
     }
@@ -204,6 +267,64 @@ function startProcessMetricsPolling(writer: PerfDiagWriter): void {
   processPollTimer = setInterval(sample, PROCESS_POLL_INTERVAL_MS);
 }
 
+async function maybeTriggerHighMemoryAlert(
+  writer: PerfDiagWriter,
+  metrics: AppMetricsSnapshot,
+  totalWorkingSetKb: number | null
+): Promise<void> {
+  if (highMemoryAlertTriggeredThisSession || !exceedsHighMemoryThreshold(totalWorkingSetKb)) {
+    return;
+  }
+
+  highMemoryAlertTriggeredThisSession = true;
+
+  const detectedAt = Date.now();
+  const userDataPath = app.getPath('userData');
+  const immediateRendererEntries = await collectImmediateRendererSamples(getMainWindow());
+  const environment = collectSessionContext({
+    sessionStartedAt,
+    userDataPath
+  });
+
+  for (const entry of immediateRendererEntries) {
+    writer.append(entry);
+  }
+
+  writer.append({
+    collectedAt: detectedAt,
+    source: 'main',
+    type: 'environment',
+    payload: {
+      ...environment
+    }
+  });
+
+  writer.append({
+    collectedAt: detectedAt,
+    source: 'main',
+    type: 'high-memory',
+    payload: buildHighMemoryDiagnosticPayload({
+      detectedAt,
+      totalWorkingSetKb: totalWorkingSetKb ?? 0,
+      metrics,
+      environment,
+      mainProcessMemory: process.memoryUsage(),
+      ringEntries: writer.bufferedEntries,
+      immediateRendererEntries,
+      sessionId: writer.sessionId
+    })
+  });
+
+  await writer.flushSnapshot('high-memory-threshold');
+
+  await writeHighMemoryAlert(userDataPath, {
+    logFilePath: writer.snapshotFilePath,
+    detectedAt,
+    peakWorkingSetKb: totalWorkingSetKb ?? 0,
+    sessionId: writer.sessionId
+  });
+}
+
 function normalizeRendererEntry(entry: PerfDiagEntry): PerfDiagEntry {
   return {
     collectedAt: Number(entry.collectedAt) || Date.now(),

electron/diagnostics/diagnostics.models.ts

@@ -2,10 +2,12 @@ export type PerfDiagSource = 'main' | 'renderer';
 
 export type PerfDiagEntryType =
   | 'session'
+  | 'environment'
   | 'process'
   | 'store'
   | 'components'
   | 'heap'
+  | 'high-memory'
   | 'crash'
   | 'unresponsive';
 

electron/diagnostics/diagnostics.writer.ts

@@ -7,7 +7,7 @@ import {
   resolveDiagnosticsFilePath
 } from './diagnostics.rules';
 
-const DEFAULT_RING_CAPACITY = 120;
+const DEFAULT_RING_CAPACITY = 300;
 const FLUSH_DEBOUNCE_MS = 250;
 
 export interface PerfDiagWriterOptions {
@@ -18,6 +18,7 @@ export interface PerfDiagWriterOptions {
 
 export class PerfDiagWriter {
   private readonly filePath: string;
+  private readonly sessionIdValue: string;
   private readonly ringCapacity: number;
   private readonly pendingLines: string[] = [];
   private ring: PerfDiagEntry[] = [];
@@ -26,10 +27,15 @@ export class PerfDiagWriter {
   private disabled = false;
 
   constructor(options: PerfDiagWriterOptions) {
+    this.sessionIdValue = options.sessionId;
     this.filePath = resolveDiagnosticsFilePath(options.userDataPath, options.sessionId);
     this.ringCapacity = options.ringCapacity ?? DEFAULT_RING_CAPACITY;
   }
 
+  get sessionId(): string {
+    return this.sessionIdValue;
+  }
+
   get snapshotFilePath(): string {
     return this.filePath;
   }

electron/diagnostics/high-memory-alert.rules.spec.ts

@@ -0,0 +1,27 @@
+import {
+  describe,
+  expect,
+  it
+} from 'vitest';
+import {
+  exceedsHighMemoryThreshold,
+  formatWorkingSetGb,
+  HIGH_MEMORY_THRESHOLD_KB
+} from './high-memory-alert.rules';
+
+describe('high-memory-alert.rules', () => {
+  it('uses a 2 GiB working-set threshold', () => {
+    expect(HIGH_MEMORY_THRESHOLD_KB).toBe(2 * 1024 * 1024);
+  });
+
+  it('detects totals at or above the threshold', () => {
+    expect(exceedsHighMemoryThreshold(HIGH_MEMORY_THRESHOLD_KB - 1)).toBe(false);
+    expect(exceedsHighMemoryThreshold(HIGH_MEMORY_THRESHOLD_KB)).toBe(true);
+    expect(exceedsHighMemoryThreshold(HIGH_MEMORY_THRESHOLD_KB + 1024)).toBe(true);
+  });
+
+  it('formats working set totals in gigabytes', () => {
+    expect(formatWorkingSetGb(1536 * 1024)).toBe('1.50');
+    expect(formatWorkingSetGb(HIGH_MEMORY_THRESHOLD_KB)).toBe('2.00');
+  });
+});

electron/diagnostics/high-memory-alert.rules.ts

@@ -0,0 +1,11 @@
+/** 2 GiB working-set threshold for writing a diagnostics snapshot. */
+export const HIGH_MEMORY_THRESHOLD_KB = 2 * 1024 * 1024;
+
+export function exceedsHighMemoryThreshold(totalWorkingSetKb: number | null | undefined): boolean {
+  return typeof totalWorkingSetKb === 'number'
+    && totalWorkingSetKb >= HIGH_MEMORY_THRESHOLD_KB;
+}
+
+export function formatWorkingSetGb(totalWorkingSetKb: number): string {
+  return (totalWorkingSetKb / (1024 * 1024)).toFixed(2);
+}

electron/diagnostics/high-memory-alert.store.spec.ts

@@ -0,0 +1,64 @@
+import * as fsp from 'fs/promises';
+import * as os from 'os';
+import * as path from 'path';
+import {
+  afterEach,
+  describe,
+  expect,
+  it
+} from 'vitest';
+import {
+  clearHighMemoryAlert,
+  readHighMemoryAlert,
+  resolveHighMemoryAlertPath,
+  writeHighMemoryAlert
+} from './high-memory-alert.store';
+
+describe('high-memory-alert.store', () => {
+  const tempDirs: string[] = [];
+
+  afterEach(async () => {
+    await Promise.all(tempDirs.splice(0).map((dir) => fsp.rm(dir, {
+      recursive: true,
+      force: true
+    })));
+  });
+
+  it('writes and reads a pending startup alert record', async () => {
+    const userDataPath = await fsp.mkdtemp(path.join(os.tmpdir(), 'metoyou-high-memory-'));
+
+    tempDirs.push(userDataPath);
+
+    const record = {
+      logFilePath: path.join(userDataPath, 'diagnostics', 'perf-session.jsonl'),
+      detectedAt: 1_700_000_000_000,
+      peakWorkingSetKb: 2_200_000,
+      sessionId: 'session-1'
+    };
+
+    await writeHighMemoryAlert(userDataPath, record);
+
+    expect(resolveHighMemoryAlertPath(userDataPath)).toBe(
+      path.join(userDataPath, 'diagnostics', 'high-memory-pending.json')
+    );
+
+    expect(await readHighMemoryAlert(userDataPath)).toEqual(record);
+  });
+
+  it('clears the pending startup alert record', async () => {
+    const userDataPath = await fsp.mkdtemp(path.join(os.tmpdir(), 'metoyou-high-memory-'));
+
+    tempDirs.push(userDataPath);
+
+    await writeHighMemoryAlert(userDataPath, {
+      logFilePath: '/tmp/perf.jsonl',
+      detectedAt: Date.now(),
+      peakWorkingSetKb: 2_100_000,
+      sessionId: 'session-2'
+    });
+
+    await clearHighMemoryAlert(userDataPath);
+
+    expect(await readHighMemoryAlert(userDataPath)).toBeNull();
+  });
+});

electron/diagnostics/high-memory-alert.store.ts

@@ -0,0 +1,57 @@
+import * as fsp from 'fs/promises';
+import * as path from 'path';
+
+export interface HighMemoryAlertRecord {
+  logFilePath: string;
+  detectedAt: number;
+  peakWorkingSetKb: number;
+  sessionId: string;
+}
+
+export function resolveHighMemoryAlertPath(userDataPath: string): string {
+  return path.join(userDataPath, 'diagnostics', 'high-memory-pending.json');
+}
+
+export async function readHighMemoryAlert(userDataPath: string): Promise<HighMemoryAlertRecord | null> {
+  try {
+    const raw = await fsp.readFile(resolveHighMemoryAlertPath(userDataPath), 'utf8');
+    const parsed = JSON.parse(raw) as Partial<HighMemoryAlertRecord>;
+
+    if (
+      typeof parsed.logFilePath !== 'string'
+      || !parsed.logFilePath.trim()
+      || typeof parsed.detectedAt !== 'number'
+      || typeof parsed.peakWorkingSetKb !== 'number'
+      || typeof parsed.sessionId !== 'string'
+    ) {
+      return null;
+    }
+
+    return {
+      logFilePath: parsed.logFilePath,
+      detectedAt: parsed.detectedAt,
+      peakWorkingSetKb: parsed.peakWorkingSetKb,
+      sessionId: parsed.sessionId
+    };
+  } catch {
+    return null;
+  }
+}
+
+export async function writeHighMemoryAlert(
+  userDataPath: string,
+  record: HighMemoryAlertRecord
+): Promise<void> {
+  const filePath = resolveHighMemoryAlertPath(userDataPath);
+
+  await fsp.mkdir(path.dirname(filePath), { recursive: true });
+  await fsp.writeFile(filePath, `${JSON.stringify(record, null, 2)}\n`, 'utf8');
+}
+
+export async function clearHighMemoryAlert(userDataPath: string): Promise<void> {
+  try {
+    await fsp.unlink(resolveHighMemoryAlertPath(userDataPath));
+  } catch {
+    // Missing pending alert is fine.
+  }
+}

electron/diagnostics/high-memory-snapshot.rules.spec.ts

@@ -0,0 +1,201 @@
+import {
+  describe,
+  expect,
+  it
+} from 'vitest';
+import type { PerfDiagEntry } from './diagnostics.models';
+import {
+  buildHighMemoryDiagnosticPayload,
+  buildHighMemorySummary,
+  extractLatestRendererSamples,
+  extractProcessHistory,
+  formatMemoryUsageMb,
+  rankProcessesByWorkingSet,
+  summarizeRingBuffer
+} from './high-memory-snapshot.rules';
+
+function createProcess(overrides: Partial<{
+  pid: number;
+  type: string;
+  workingSetKb: number | null;
+  peakWorkingSetKb: number | null;
+  privateBytesKb: number | null;
+  creationTime: number | null;
+  cpuPercent: number | null;
+}> = {}) {
+  return {
+    pid: 1,
+    type: 'Tab',
+    workingSetKb: 1024,
+    peakWorkingSetKb: null,
+    privateBytesKb: null,
+    creationTime: null,
+    cpuPercent: null,
+    ...overrides
+  };
+}
+
+describe('high-memory-snapshot.rules', () => {
+  it('ranks processes by working set and computes share percentages', () => {
+    const tabProcess = createProcess({ pid: 1, type: 'Tab', workingSetKb: 512_000 });
+    const gpuProcess = createProcess({ pid: 2, type: 'GPU', workingSetKb: 1_536_000 });
+    const ranked = rankProcessesByWorkingSet([tabProcess, gpuProcess], 2_048_000);
+
+    expect(ranked[0]?.type).toBe('GPU');
+    expect(ranked[0]?.sharePercent).toBe(75);
+    expect(ranked[1]?.sharePercent).toBe(25);
+  });
+
+  it('extracts the latest renderer store, heap, and component samples', () => {
+    const entries: PerfDiagEntry[] = [
+      {
+        collectedAt: 1,
+        source: 'renderer',
+        type: 'store',
+        payload: { domains: { chat: 100 } }
+      },
+      {
+        collectedAt: 2,
+        source: 'renderer',
+        type: 'heap',
+        payload: { usedJsHeapMb: 120 }
+      },
+      {
+        collectedAt: 3,
+        source: 'renderer',
+        type: 'components',
+        payload: { suspectedLeaks: [{ name: 'ChatMessageItem', count: 40, expected: 20 }] }
+      },
+      {
+        collectedAt: 4,
+        source: 'renderer',
+        type: 'store',
+        payload: { domains: { chat: 500 } }
+      }
+    ];
+
+    expect(extractLatestRendererSamples(entries)).toEqual({
+      store: { domains: { chat: 500 } },
+      heap: { usedJsHeapMb: 120 },
+      components: { suspectedLeaks: [{ name: 'ChatMessageItem', count: 40, expected: 20 }] }
+    });
+  });
+
+  it('extracts recent process history from the ring buffer', () => {
+    const entries: PerfDiagEntry[] = [
+      {
+        collectedAt: 1,
+        source: 'main',
+        type: 'process',
+        payload: { totalWorkingSetKb: 1000 }
+      },
+      {
+        collectedAt: 2,
+        source: 'main',
+        type: 'session',
+        payload: { event: 'noop' }
+      },
+      {
+        collectedAt: 3,
+        source: 'main',
+        type: 'process',
+        payload: { totalWorkingSetKb: 2000 }
+      }
+    ];
+
+    expect(extractProcessHistory(entries)).toEqual([{ collectedAt: 1, totalWorkingSetKb: 1000 }, { collectedAt: 3, totalWorkingSetKb: 2000 }]);
+  });
+
+  it('summarizes ring buffer entry counts', () => {
+    expect(summarizeRingBuffer([
+      { collectedAt: 1, source: 'main', type: 'process', payload: {} },
+      { collectedAt: 2, source: 'renderer', type: 'heap', payload: {} },
+      { collectedAt: 3, source: 'main', type: 'process', payload: {} }
+    ])).toEqual({
+      'main:process': 2,
+      'renderer:heap': 1
+    });
+  });
+
+  it('builds a high-memory summary with threshold context', () => {
+    const summary = buildHighMemorySummary(
+      2_200_000,
+      [createProcess({ workingSetKb: 2_200_000 })],
+      1_700_000_000_000
+    );
+
+    expect(summary.totalWorkingSetGb).toBe('2.10');
+    expect(summary.thresholdGb).toBe('2.00');
+    expect(summary.topProcesses).toHaveLength(1);
+  });
+
+  it('builds a comprehensive high-memory diagnostic payload', () => {
+    const payload = buildHighMemoryDiagnosticPayload({
+      detectedAt: 1_700_000_000_000,
+      totalWorkingSetKb: 2_200_000,
+      metrics: {
+        collectedAt: 1_700_000_000_000,
+        processes: [
+          createProcess({
+            workingSetKb: 2_200_000,
+            peakWorkingSetKb: 2_300_000,
+            privateBytesKb: 1_800_000,
+            creationTime: 1,
+            cpuPercent: 12
+          })
+        ]
+      },
+      environment: { appVersion: '1.0.0' },
+      mainProcessMemory: {
+        rss: 64 * 1024 * 1024,
+        heapTotal: 32 * 1024 * 1024,
+        heapUsed: 16 * 1024 * 1024,
+        external: 8 * 1024 * 1024,
+        arrayBuffers: 1024
+      },
+      ringEntries: [
+        {
+          collectedAt: 1,
+          source: 'main',
+          type: 'process',
+          payload: { totalWorkingSetKb: 2_000_000 }
+        }
+      ],
+      immediateRendererEntries: [
+        {
+          collectedAt: 2,
+          source: 'renderer',
+          type: 'heap',
+          payload: { usedJsHeapMb: 300, route: '/room/abc' }
+        }
+      ],
+      sessionId: 'session-1'
+    });
+
+    expect(payload.event).toBe('high-memory-threshold');
+    expect(payload.summary).toMatchObject({
+      totalWorkingSetKb: 2_200_000
+    });
+
+    expect(payload.processHistory).toHaveLength(1);
+    expect(payload.recentRendererSamples).toEqual({
+      store: null,
+      heap: { usedJsHeapMb: 300, route: '/room/abc' },
+      components: null
+    });
+
+    expect(formatMemoryUsageMb({
+      rss: 64 * 1024 * 1024,
+      heapTotal: 32 * 1024 * 1024,
+      heapUsed: 16 * 1024 * 1024,
+      external: 8 * 1024 * 1024,
+      arrayBuffers: 1024
+    })).toEqual({
+      rssMb: 64,
+      heapTotalMb: 32,
+      heapUsedMb: 16,
+      externalMb: 8,
+      arrayBuffersMb: 0
+    });
+  });
+});

electron/diagnostics/high-memory-snapshot.rules.ts

@@ -0,0 +1,179 @@
+import type { AppMetricsProcessSnapshot, AppMetricsSnapshot } from '../app-metrics';
+import type { PerfDiagEntry } from './diagnostics.models';
+import { formatWorkingSetGb, HIGH_MEMORY_THRESHOLD_KB } from './high-memory-alert.rules';
+import type { SessionContextSnapshot } from './session-context.collector';
+
+export interface RankedProcessSnapshot extends AppMetricsProcessSnapshot {
+  sharePercent: number;
+}
+
+export interface HighMemorySummary {
+  detectedAt: number;
+  thresholdKb: number;
+  thresholdGb: string;
+  totalWorkingSetKb: number;
+  totalWorkingSetGb: string;
+  topProcesses: RankedProcessSnapshot[];
+}
+
+export interface LatestRendererSamples {
+  store: Record<string, unknown> | null;
+  heap: Record<string, unknown> | null;
+  components: Record<string, unknown> | null;
+}
+
+export function rankProcessesByWorkingSet(
+  processes: readonly AppMetricsProcessSnapshot[],
+  totalWorkingSetKb: number | null
+): RankedProcessSnapshot[] {
+  const total = totalWorkingSetKb ?? 0;
+
+  return [...processes]
+    .filter((process) => process.workingSetKb != null && process.workingSetKb > 0)
+    .sort((left, right) => (right.workingSetKb ?? 0) - (left.workingSetKb ?? 0))
+    .map((process) => ({
+      ...process,
+      sharePercent: total > 0
+        ? Math.round(((process.workingSetKb ?? 0) / total) * 1000) / 10
+        : 0
+    }));
+}
+
+export function extractLatestRendererSamples(entries: readonly PerfDiagEntry[]): LatestRendererSamples {
+  let store: Record<string, unknown> | null = null;
+  let heap: Record<string, unknown> | null = null;
+  let components: Record<string, unknown> | null = null;
+
+  for (let index = entries.length - 1; index >= 0; index -= 1) {
+    const entry = entries[index];
+
+    if (entry.source !== 'renderer') {
+      continue;
+    }
+
+    if (!store && entry.type === 'store') {
+      store = entry.payload;
+    }
+
+    if (!heap && entry.type === 'heap') {
+      heap = entry.payload;
+    }
+
+    if (!components && entry.type === 'components') {
+      components = entry.payload;
+    }
+
+    if (store && heap && components) {
+      break;
+    }
+  }
+
+  return {
+    store,
+    heap,
+    components
+  };
+}
+
+export function extractProcessHistory(
+  entries: readonly PerfDiagEntry[],
+  limit = 24
+): Record<string, unknown>[] {
+  const history: Record<string, unknown>[] = [];
+
+  for (let index = entries.length - 1; index >= 0; index -= 1) {
+    const entry = entries[index];
+
+    if (entry.type !== 'process') {
+      continue;
+    }
+
+    history.unshift({
+      collectedAt: entry.collectedAt,
+      ...entry.payload
+    });
+
+    if (history.length >= limit) {
+      break;
+    }
+  }
+
+  return history;
+}
+
+export function summarizeRingBuffer(entries: readonly PerfDiagEntry[]): Record<string, number> {
+  const counts: Record<string, number> = {};
+
+  for (const entry of entries) {
+    const key = `${entry.source}:${entry.type}`;
+
+    counts[key] = (counts[key] ?? 0) + 1;
+  }
+
+  return counts;
+}
+
+export function buildHighMemorySummary(
+  totalWorkingSetKb: number,
+  processes: readonly AppMetricsProcessSnapshot[],
+  detectedAt: number
+): HighMemorySummary {
+  return {
+    detectedAt,
+    thresholdKb: HIGH_MEMORY_THRESHOLD_KB,
+    thresholdGb: formatWorkingSetGb(HIGH_MEMORY_THRESHOLD_KB),
+    totalWorkingSetKb,
+    totalWorkingSetGb: formatWorkingSetGb(totalWorkingSetKb),
+    topProcesses: rankProcessesByWorkingSet(processes, totalWorkingSetKb).slice(0, 12)
+  };
+}
+
+export function formatMemoryUsageMb(memoryUsage: NodeJS.MemoryUsage): Record<string, number> {
+  return {
+    rssMb: roundMb(memoryUsage.rss),
+    heapTotalMb: roundMb(memoryUsage.heapTotal),
+    heapUsedMb: roundMb(memoryUsage.heapUsed),
+    externalMb: roundMb(memoryUsage.external),
+    arrayBuffersMb: roundMb(memoryUsage.arrayBuffers ?? 0)
+  };
+}
+
+export function buildHighMemoryDiagnosticPayload(input: {
+  detectedAt: number;
+  totalWorkingSetKb: number;
+  metrics: AppMetricsSnapshot;
+  environment: SessionContextSnapshot;
+  mainProcessMemory: NodeJS.MemoryUsage;
+  ringEntries: readonly PerfDiagEntry[];
+  immediateRendererEntries: readonly PerfDiagEntry[];
+  sessionId: string;
+}): Record<string, unknown> {
+  const mergedRingEntries = [...input.ringEntries, ...input.immediateRendererEntries];
+  const recentRendererSamples = extractLatestRendererSamples(mergedRingEntries);
+
+  return {
+    event: 'high-memory-threshold',
+    sessionId: input.sessionId,
+    summary: buildHighMemorySummary(
+      input.totalWorkingSetKb,
+      input.metrics.processes,
+      input.detectedAt
+    ),
+    environment: input.environment,
+    metrics: input.metrics,
+    mainProcessMemory: input.mainProcessMemory,
+    mainProcessMemoryMb: formatMemoryUsageMb(input.mainProcessMemory),
+    processHistory: extractProcessHistory(mergedRingEntries),
+    ringSummary: summarizeRingBuffer(mergedRingEntries),
+    recentRendererSamples,
+    immediateRendererSamples: input.immediateRendererEntries.map((entry) => ({
+      collectedAt: entry.collectedAt,
+      type: entry.type,
+      payload: entry.payload
+    }))
+  };
+}
+
+function roundMb(bytes: number): number {
+  return Math.round((bytes / (1024 * 1024)) * 100) / 100;
+}

electron/diagnostics/immediate-renderer-samples.collector.ts

@@ -0,0 +1,39 @@
+import type { BrowserWindow } from 'electron';
+import type { PerfDiagEntry } from './diagnostics.models';
+
+export async function collectImmediateRendererSamples(
+  window: BrowserWindow | null | undefined
+): Promise<PerfDiagEntry[]> {
+  if (!window || window.isDestroyed()) {
+    return [];
+  }
+
+  try {
+    const result = await window.webContents.executeJavaScript(`
+      (function () {
+        const collect = globalThis.__collectPerfDiagSample;
+
+        return typeof collect === 'function' ? collect() : [];
+      })()
+    `, true);
+
+    if (!Array.isArray(result)) {
+      return [];
+    }
+
+    return result
+      .filter((entry) => entry && typeof entry === 'object')
+      .map((entry) => normalizeImmediateRendererEntry(entry as Partial<PerfDiagEntry>));
+  } catch {
+    return [];
+  }
+}
+
+function normalizeImmediateRendererEntry(entry: Partial<PerfDiagEntry>): PerfDiagEntry {
+  return {
+    collectedAt: Number(entry.collectedAt) || Date.now(),
+    source: 'renderer',
+    type: entry.type ?? 'session',
+    payload: entry.payload ?? {}
+  };
+}

electron/diagnostics/index.ts

@@ -1,4 +1,16 @@
 export { isPerfDiagEnabled, PERF_DIAG_ENV, PERF_DIAG_FORCE_ENV } from './diagnostics.flags';
+export {
+  clearHighMemoryAlert,
+  readHighMemoryAlert,
+  resolveHighMemoryAlertPath,
+  writeHighMemoryAlert
+} from './high-memory-alert.store';
+export type { HighMemoryAlertRecord } from './high-memory-alert.store';
+export {
+  exceedsHighMemoryThreshold,
+  formatWorkingSetGb,
+  HIGH_MEMORY_THRESHOLD_KB
+} from './high-memory-alert.rules';
 export {
   attachRendererDiagnosticsHooks,
   ensurePerfDiagIpcRegistered,

electron/diagnostics/session-context.collector.ts

@@ -0,0 +1,91 @@
+import { app, BrowserWindow } from 'electron';
+import * as os from 'os';
+
+export interface SessionWindowSnapshot {
+  id: number;
+  title: string;
+  url: string | null;
+  focused: boolean;
+  visible: boolean;
+  destroyed: boolean;
+}
+
+export interface SessionContextSnapshot {
+  collectedAt: number;
+  sessionStartedAt: number;
+  uptimeMs: number;
+  appVersion: string;
+  electronVersion: string;
+  chromeVersion: string;
+  nodeVersion: string;
+  platform: NodeJS.Platform;
+  arch: string;
+  osType: string;
+  osRelease: string;
+  osVersion: string | null;
+  totalMemKb: number;
+  freeMemKb: number;
+  userDataPath: string;
+  appPath: string;
+  isPackaged: boolean;
+  locale: string;
+  windowCount: number;
+  windows: SessionWindowSnapshot[];
+}
+
+export function collectSessionContext(input: {
+  sessionStartedAt: number;
+  userDataPath: string;
+}): SessionContextSnapshot {
+  const collectedAt = Date.now();
+
+  return {
+    collectedAt,
+    sessionStartedAt: input.sessionStartedAt,
+    uptimeMs: Math.max(0, collectedAt - input.sessionStartedAt),
+    appVersion: app.getVersion(),
+    electronVersion: process.versions.electron ?? 'unknown',
+    chromeVersion: process.versions.chrome ?? 'unknown',
+    nodeVersion: process.versions.node ?? 'unknown',
+    platform: process.platform,
+    arch: process.arch,
+    osType: os.type(),
+    osRelease: os.release(),
+    osVersion: readOsVersion(),
+    totalMemKb: Math.round(os.totalmem() / 1024),
+    freeMemKb: Math.round(os.freemem() / 1024),
+    userDataPath: input.userDataPath,
+    appPath: app.getAppPath(),
+    isPackaged: app.isPackaged,
+    locale: app.getLocale(),
+    windowCount: BrowserWindow.getAllWindows().length,
+    windows: BrowserWindow.getAllWindows().map(collectWindowSnapshot)
+  };
+}
+
+function collectWindowSnapshot(window: BrowserWindow): SessionWindowSnapshot {
+  let url: string | null = null;
+
+  try {
+    url = window.webContents.getURL() || null;
+  } catch {
+    url = null;
+  }
+
+  return {
+    id: window.id,
+    title: window.getTitle(),
+    url,
+    focused: window.isFocused(),
+    visible: window.isVisible(),
+    destroyed: window.isDestroyed()
+  };
+}
+
+function readOsVersion(): string | null {
+  try {
+    return os.version?.() ?? null;
+  } catch {
+    return null;
+  }
+}

electron/preload.ts

@@ -259,6 +259,14 @@ export interface ElectronAPI {
     type: string;
     payload: Record<string, unknown>;
   }) => Promise<boolean>;
+  getPendingHighMemoryAlert: () => Promise<{
+    logFilePath: string;
+    detectedAt: number;
+    peakWorkingSetKb: number;
+    sessionId: string;
+  } | null>;
+  acknowledgeHighMemoryAlert: () => Promise<boolean>;
+  showLogFileInFolder: (filePath: string) => Promise<{ shown: boolean; reason?: string }>;
   getAppDataPath: () => Promise<string>;
   openCurrentDataFolder: () => Promise<boolean>;
   exportUserData: () => Promise<ExportUserDataResult>;
@@ -400,6 +408,9 @@ const electronAPI: ElectronAPI = {
   getAppMetrics: () => ipcRenderer.invoke('get-app-metrics'),
   isPerfDiagEnabled: () => ipcRenderer.invoke('perf-diag-is-enabled'),
   reportPerfDiagSample: (entry) => ipcRenderer.invoke('perf-diag-report', entry),
+  getPendingHighMemoryAlert: () => ipcRenderer.invoke('get-pending-high-memory-alert'),
+  acknowledgeHighMemoryAlert: () => ipcRenderer.invoke('acknowledge-high-memory-alert'),
+  showLogFileInFolder: (filePath) => ipcRenderer.invoke('show-log-file-in-folder', filePath),
   getAppDataPath: () => ipcRenderer.invoke('get-app-data-path'),
   openCurrentDataFolder: () => ipcRenderer.invoke('open-current-data-folder'),
   exportUserData: () => ipcRenderer.invoke('export-user-data'),