Route stats background mode through isolated daemon and defer in-app startup to live daemon (#58)

backlog/tasks/task-306 - Separate-background-stats-daemon-from-regular-SubMiner-app.md

@@ -0,0 +1,54 @@
+---
+id: TASK-306
+title: Separate background stats daemon from regular SubMiner app
+status: Done
+assignee: []
+created_date: '2026-04-27 00:56'
+updated_date: '2026-04-27 01:00'
+labels:
+  - stats
+  - runtime
+dependencies: []
+priority: high
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Background stats mode should run only the stats data/server pieces. It must not bring up tray UI or expose the regular mpv connection surface, and stopping should remain CLI-only.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 Launching stats background mode starts a separate stats daemon process rather than booting the regular SubMiner runtime.
+- [x] #2 Background stats mode does not create or keep a tray icon.
+- [x] #3 Background stats mode does not start mpv IPC/client surfaces that let mpv connect to the app.
+- [x] #4 Background stats mode remains stoppable through the stats stop command line path.
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Add entry-runtime tests for public stats background/stop daemon detection.
+2. Implement early public stats daemon command detection and route it before regular app boot.
+3. Run targeted tests and update task status/criteria.
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Implemented early public stats daemon routing in main-entry runtime. Direct `--stats-background` and `--stats-stop` now resolve to daemon control before single-instance lock and before loading `main.js`, matching the existing internal launcher daemon flags. Installed missing Bun dependencies to run targeted tests.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Summary:
+- Added `resolveStatsDaemonCommandAction` and updated entry detection so public `--stats-background` / `--stats-stop` invocations route through the isolated stats daemon control path.
+- Reused that action resolution in `stats-daemon-entry` so public stop commands map to stop instead of the default start path.
+- Added regression coverage for public daemon detection/action resolution.
+
+Verification:
+- `bun test src/main-entry-runtime.test.ts launcher/commands/command-modules.test.ts src/main/runtime/stats-cli-command.test.ts src/stats-daemon-control.test.ts`
+- `bun run typecheck`
+<!-- SECTION:FINAL_SUMMARY:END -->

backlog/tasks/task-307 - Defer-in-app-stats-server-to-running-background-stats-daemon.md

@@ -0,0 +1,58 @@
+---
+id: TASK-307
+title: Defer in-app stats server to running background stats daemon
+status: Done
+assignee: []
+created_date: '2026-04-27 01:57'
+updated_date: '2026-04-27 02:02'
+labels:
+  - stats
+  - runtime
+dependencies: []
+priority: high
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+When normal SubMiner app startup has stats auto-start enabled, it should detect an already-running background stats daemon and avoid starting a second in-app stats server. Stats overlay/dashboard URL resolution should point at the background daemon.
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [x] #1 If a live background stats daemon state exists for another process, in-app stats auto-start does not start a local stats server.
+- [x] #2 Stats URL resolution returns the background daemon URL when the background daemon is live.
+- [x] #3 Stale or dead background daemon state is cleared and normal in-app stats startup still works.
+- [x] #4 Regression tests cover the deferral behavior.
+<!-- AC:END -->
+
+## Implementation Plan
+
+<!-- SECTION:PLAN:BEGIN -->
+1. Add unit tests for stats server routing decisions around live/stale background daemon state.
+2. Implement a small routing helper used by main stats startup.
+3. Wire `ensureStatsServerStarted()` through the helper.
+4. Run targeted tests/typecheck/changelog lint and finalize the task.
+<!-- SECTION:PLAN:END -->
+
+## Implementation Notes
+
+<!-- SECTION:NOTES:BEGIN -->
+Extracted stats server URL routing into `src/main/runtime/stats-server-routing.ts` and wired `main.ts` through it. The helper returns the background daemon URL without calling local server startup when a live external daemon exists; dead/self-owned stale state is removed before falling back to local startup. Added the new test to `test:core:src`.
+<!-- SECTION:NOTES:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Summary:
+- Added a pure stats server routing helper that chooses between a live background daemon and local in-app stats server startup.
+- Updated main stats URL resolution to defer to another process's background daemon and only start the in-app server when no live daemon is available.
+- Added regression tests for live daemon deferral, dead daemon cleanup, self-owned stale state cleanup, and local server reuse.
+- Added the routing test to the core source test lane and added a changelog fragment.
+
+Verification:
+- `bun test src/main/runtime/stats-server-routing.test.ts src/main-entry-runtime.test.ts src/main/runtime/stats-cli-command.test.ts src/stats-daemon-control.test.ts`
+- `bun run test:core:src`
+- `bun run typecheck`
+- `bun run changelog:lint`
+<!-- SECTION:FINAL_SUMMARY:END -->

changes/306-stats-background-daemon.md

@@ -0,0 +1,4 @@
+type: fixed
+area: stats
+
+- Stats background mode now routes through the isolated stats daemon instead of starting the regular SubMiner app runtime.

changes/307-stats-background-deferral.md

@@ -0,0 +1,4 @@
+type: fixed
+area: stats
+
+- In-app stats startup now defers to an already-running background stats daemon instead of starting a second stats server.

package.json

@@ -48,7 +48,7 @@
     "test:plugin:src": "lua scripts/test-plugin-lua-compat.lua && lua scripts/test-plugin-start-gate.lua && lua scripts/test-plugin-binary-windows.lua",
     "test:launcher:smoke:src": "bun test launcher/smoke.e2e.test.ts",
     "test:launcher:src": "bun test launcher/config.test.ts launcher/config-domain-parsers.test.ts launcher/config/cli-parser-builder.test.ts launcher/config/args-normalizer.test.ts launcher/mpv.test.ts launcher/picker.test.ts launcher/parse-args.test.ts launcher/main.test.ts launcher/commands/command-modules.test.ts launcher/smoke.e2e.test.ts && bun run test:plugin:src",
-    "test:core:src": "bun test src/cli/args.test.ts src/cli/help.test.ts src/shared/setup-state.test.ts src/core/services/cli-command.test.ts src/core/services/field-grouping-overlay.test.ts src/core/services/numeric-shortcut-session.test.ts src/core/services/secondary-subtitle.test.ts src/core/services/mpv-render-metrics.test.ts src/core/services/overlay-content-measurement.test.ts src/core/services/mpv-control.test.ts src/core/services/mpv.test.ts src/core/services/runtime-options-ipc.test.ts src/core/services/runtime-config.test.ts src/core/services/yomitan-extension-paths.test.ts src/core/services/config-hot-reload.test.ts src/core/services/discord-presence.test.ts src/core/services/tokenizer.test.ts src/core/services/tokenizer/annotation-stage.test.ts src/core/services/tokenizer/parser-selection-stage.test.ts src/core/services/tokenizer/parser-enrichment-stage.test.ts src/core/services/subsync.test.ts src/core/services/overlay-bridge.test.ts src/core/services/overlay-shortcut-handler.test.ts src/core/services/stats-window.test.ts src/core/services/mining.test.ts src/core/services/anki-jimaku.test.ts src/core/services/jimaku-download-path.test.ts src/core/services/jellyfin.test.ts src/core/services/jellyfin-remote.test.ts src/core/services/immersion-tracker-service.test.ts src/core/services/overlay-runtime-init.test.ts src/core/services/app-ready.test.ts src/core/services/startup-bootstrap.test.ts src/core/services/subtitle-processing-controller.test.ts src/core/services/anilist/anilist-update-queue.test.ts src/core/services/anilist/rate-limiter.test.ts src/core/services/jlpt-token-filter.test.ts src/core/services/subtitle-position.test.ts src/core/utils/shortcut-config.test.ts src/main/runtime/first-run-setup-plugin.test.ts src/main/runtime/first-run-setup-service.test.ts src/main/runtime/first-run-setup-window.test.ts src/main/runtime/tray-runtime.test.ts src/main/runtime/tray-main-actions.test.ts src/main/runtime/tray-main-deps.test.ts src/main/runtime/tray-runtime-handlers.test.ts src/main/runtime/cli-command-context-main-deps.test.ts src/main/runtime/app-ready-main-deps.test.ts src/renderer/error-recovery.test.ts src/renderer/subtitle-render.test.ts src/renderer/handlers/mouse.test.ts src/renderer/handlers/keyboard.test.ts src/renderer/modals/jimaku.test.ts src/subsync/utils.test.ts src/main/anilist-url-guard.test.ts src/window-trackers/hyprland-tracker.test.ts src/window-trackers/x11-tracker.test.ts src/window-trackers/windows-helper.test.ts src/window-trackers/windows-tracker.test.ts launcher/config.test.ts launcher/config-domain-parsers.test.ts launcher/config/cli-parser-builder.test.ts launcher/config/args-normalizer.test.ts launcher/parse-args.test.ts launcher/main.test.ts launcher/commands/command-modules.test.ts launcher/setup-gate.test.ts stats/src/lib/api-client.test.ts",
+    "test:core:src": "bun test src/cli/args.test.ts src/cli/help.test.ts src/shared/setup-state.test.ts src/core/services/cli-command.test.ts src/core/services/field-grouping-overlay.test.ts src/core/services/numeric-shortcut-session.test.ts src/core/services/secondary-subtitle.test.ts src/core/services/mpv-render-metrics.test.ts src/core/services/overlay-content-measurement.test.ts src/core/services/mpv-control.test.ts src/core/services/mpv.test.ts src/core/services/runtime-options-ipc.test.ts src/core/services/runtime-config.test.ts src/core/services/yomitan-extension-paths.test.ts src/core/services/config-hot-reload.test.ts src/core/services/discord-presence.test.ts src/core/services/tokenizer.test.ts src/core/services/tokenizer/annotation-stage.test.ts src/core/services/tokenizer/parser-selection-stage.test.ts src/core/services/tokenizer/parser-enrichment-stage.test.ts src/core/services/subsync.test.ts src/core/services/overlay-bridge.test.ts src/core/services/overlay-shortcut-handler.test.ts src/core/services/stats-window.test.ts src/main/runtime/stats-server-routing.test.ts src/core/services/mining.test.ts src/core/services/anki-jimaku.test.ts src/core/services/jimaku-download-path.test.ts src/core/services/jellyfin.test.ts src/core/services/jellyfin-remote.test.ts src/core/services/immersion-tracker-service.test.ts src/core/services/overlay-runtime-init.test.ts src/core/services/app-ready.test.ts src/core/services/startup-bootstrap.test.ts src/core/services/subtitle-processing-controller.test.ts src/core/services/anilist/anilist-update-queue.test.ts src/core/services/anilist/rate-limiter.test.ts src/core/services/jlpt-token-filter.test.ts src/core/services/subtitle-position.test.ts src/core/utils/shortcut-config.test.ts src/main/runtime/first-run-setup-plugin.test.ts src/main/runtime/first-run-setup-service.test.ts src/main/runtime/first-run-setup-window.test.ts src/main/runtime/tray-runtime.test.ts src/main/runtime/tray-main-actions.test.ts src/main/runtime/tray-main-deps.test.ts src/main/runtime/tray-runtime-handlers.test.ts src/main/runtime/cli-command-context-main-deps.test.ts src/main/runtime/app-ready-main-deps.test.ts src/renderer/error-recovery.test.ts src/renderer/subtitle-render.test.ts src/renderer/handlers/mouse.test.ts src/renderer/handlers/keyboard.test.ts src/renderer/modals/jimaku.test.ts src/subsync/utils.test.ts src/main/anilist-url-guard.test.ts src/window-trackers/hyprland-tracker.test.ts src/window-trackers/x11-tracker.test.ts src/window-trackers/windows-helper.test.ts src/window-trackers/windows-tracker.test.ts launcher/config.test.ts launcher/config-domain-parsers.test.ts launcher/config/cli-parser-builder.test.ts launcher/config/args-normalizer.test.ts launcher/parse-args.test.ts launcher/main.test.ts launcher/commands/command-modules.test.ts launcher/setup-gate.test.ts stats/src/lib/api-client.test.ts",
     "test:core:dist": "bun test dist/cli/args.test.js dist/cli/help.test.js dist/core/services/cli-command.test.js dist/core/services/ipc.test.js dist/core/services/anki-jimaku-ipc.test.js dist/core/services/field-grouping-overlay.test.js dist/core/services/numeric-shortcut-session.test.js dist/core/services/secondary-subtitle.test.js dist/core/services/mpv-render-metrics.test.js dist/core/services/overlay-content-measurement.test.js dist/core/services/mpv-control.test.js dist/core/services/mpv.test.js dist/core/services/runtime-options-ipc.test.js dist/core/services/runtime-config.test.js dist/core/services/yomitan-extension-paths.test.js dist/core/services/config-hot-reload.test.js dist/core/services/discord-presence.test.js dist/core/services/tokenizer.test.js dist/core/services/tokenizer/annotation-stage.test.js dist/core/services/tokenizer/parser-selection-stage.test.js dist/core/services/tokenizer/parser-enrichment-stage.test.js dist/core/services/subsync.test.js dist/core/services/overlay-bridge.test.js dist/core/services/overlay-manager.test.js dist/core/services/overlay-shortcut-handler.test.js dist/core/services/mining.test.js dist/core/services/anki-jimaku.test.js dist/core/services/jimaku-download-path.test.js dist/core/services/jellyfin.test.js dist/core/services/jellyfin-remote.test.js dist/core/services/immersion-tracker-service.test.js dist/core/services/overlay-runtime-init.test.js dist/core/services/app-ready.test.js dist/core/services/startup-bootstrap.test.js dist/core/services/subtitle-processing-controller.test.js dist/core/services/anilist/anilist-token-store.test.js dist/core/services/anilist/anilist-update-queue.test.js dist/core/services/anilist/rate-limiter.test.js dist/core/services/jlpt-token-filter.test.js dist/core/services/subtitle-position.test.js dist/renderer/error-recovery.test.js dist/renderer/subtitle-render.test.js dist/renderer/handlers/mouse.test.js dist/renderer/handlers/keyboard.test.js dist/renderer/modals/jimaku.test.js dist/subsync/utils.test.js dist/main/anilist-url-guard.test.js dist/window-trackers/hyprland-tracker.test.js dist/window-trackers/x11-tracker.test.js dist/window-trackers/windows-helper.test.js dist/window-trackers/windows-tracker.test.js",
     "test:core:smoke:dist": "bun test dist/cli/help.test.js dist/core/services/runtime-config.test.js dist/core/services/ipc.test.js dist/core/services/overlay-manager.test.js dist/core/services/anilist/anilist-token-store.test.js dist/core/services/startup-bootstrap.test.js dist/renderer/error-recovery.test.js dist/main/anilist-url-guard.test.js dist/window-trackers/x11-tracker.test.js",
     "test:smoke:dist": "bun run test:config:smoke:dist && bun run test:core:smoke:dist",

src/main-entry-runtime.test.ts

@@ -5,6 +5,7 @@ import {
   normalizeLaunchMpvExtraArgs,
   normalizeStartupArgv,
   normalizeLaunchMpvTargets,
+  resolveStatsDaemonCommandAction,
   sanitizeHelpEnv,
   sanitizeLaunchMpvEnv,
   sanitizeStartupEnv,
@@ -164,6 +165,51 @@ test('stats-daemon entry helper detects internal daemon commands', () => {
   assert.equal(shouldHandleStatsDaemonCommandAtEntry(['SubMiner.AppImage', '--start'], {}), false);
 });
 
+test('stats-daemon entry helper detects public background stats commands', () => {
+  assert.equal(
+    shouldHandleStatsDaemonCommandAtEntry(
+      ['SubMiner.AppImage', '--stats', '--stats-background'],
+      {},
+    ),
+    true,
+  );
+  assert.equal(
+    shouldHandleStatsDaemonCommandAtEntry(['SubMiner.AppImage', '--stats', '--stats-stop'], {}),
+    true,
+  );
+  assert.equal(
+    shouldHandleStatsDaemonCommandAtEntry(['SubMiner.AppImage', '--stats-background'], {}),
+    true,
+  );
+  assert.equal(
+    shouldHandleStatsDaemonCommandAtEntry(['SubMiner.AppImage', '--stats-background'], {
+      ELECTRON_RUN_AS_NODE: '1',
+    }),
+    false,
+  );
+  assert.equal(shouldHandleStatsDaemonCommandAtEntry(['SubMiner.AppImage', '--stats'], {}), false);
+});
+
+test('stats-daemon entry helper resolves daemon action for public and internal commands', () => {
+  assert.equal(
+    resolveStatsDaemonCommandAction(['SubMiner.AppImage', '--stats-daemon-start']),
+    'start',
+  );
+  assert.equal(
+    resolveStatsDaemonCommandAction(['SubMiner.AppImage', '--stats-daemon-stop']),
+    'stop',
+  );
+  assert.equal(
+    resolveStatsDaemonCommandAction(['SubMiner.AppImage', '--stats', '--stats-background']),
+    'start',
+  );
+  assert.equal(
+    resolveStatsDaemonCommandAction(['SubMiner.AppImage', '--stats', '--stats-stop']),
+    'stop',
+  );
+  assert.equal(resolveStatsDaemonCommandAction(['SubMiner.AppImage', '--stats']), null);
+});
+
 test('sanitizeStartupEnv suppresses warnings and lsfg layer', () => {
   const env = sanitizeStartupEnv({
     VK_INSTANCE_LAYERS: 'foo:lsfg-vk:bar',

src/main-entry-runtime.ts

@@ -143,7 +143,17 @@ export function shouldHandleStatsDaemonCommandAtEntry(
   env: NodeJS.ProcessEnv,
 ): boolean {
   if (env.ELECTRON_RUN_AS_NODE === '1') return false;
-  return argv.includes('--stats-daemon-start') || argv.includes('--stats-daemon-stop');
+  return resolveStatsDaemonCommandAction(argv) !== null;
+}
+
+export function resolveStatsDaemonCommandAction(argv: string[]): 'start' | 'stop' | null {
+  if (argv.includes('--stats-daemon-stop') || argv.includes('--stats-stop')) {
+    return 'stop';
+  }
+  if (argv.includes('--stats-daemon-start') || argv.includes('--stats-background')) {
+    return 'start';
+  }
+  return null;
 }
 
 export function normalizeLaunchMpvTargets(argv: string[]): string[] {

src/main.ts

@@ -404,6 +404,7 @@ import {
   resolveBackgroundStatsServerUrl,
   writeBackgroundStatsServerState,
 } from './main/runtime/stats-daemon';
+import { createEnsureStatsServerUrlHandler } from './main/runtime/stats-server-routing';
 import { resolveLegacyVocabularyPosFromTokens } from './core/services/immersion-tracker/legacy-vocabulary-pos';
 import { createAnilistUpdateQueue } from './core/services/anilist/anilist-update-queue';
 import {
@@ -3170,11 +3171,7 @@ registerProtocolUrlHandlersHandler();
 const statsDistPath = path.join(__dirname, '..', 'stats', 'dist');
 const statsPreloadPath = path.join(__dirname, 'preload-stats.js');
 
-const ensureStatsServerStarted = (): string => {
+const startLocalStatsServer = (): void => {
-  const liveDaemon = readLiveBackgroundStatsDaemonState();
-  if (liveDaemon && liveDaemon.pid !== process.pid) {
-    return resolveBackgroundStatsServerUrl(liveDaemon);
-  }
   const tracker = appState.immersionTracker;
   if (!tracker) {
     throw new Error('Immersion tracker failed to initialize.');
@@ -3224,9 +3221,20 @@ const ensureStatsServerStarted = (): string => {
     appState.statsServer = statsServer;
   }
   appState.statsServer = statsServer;
-  return `http://127.0.0.1:${getResolvedConfig().stats.serverPort}`;
 };
 
+const ensureStatsServerStarted = createEnsureStatsServerUrlHandler({
+  currentPid: process.pid,
+  readBackgroundState: () => readBackgroundStatsServerState(statsDaemonStatePath),
+  removeBackgroundState: () => {
+    removeBackgroundStatsServerState(statsDaemonStatePath);
+  },
+  isProcessAlive: (pid) => isBackgroundStatsServerProcessAlive(pid),
+  hasLocalStatsServer: () => statsServer !== null,
+  startLocalStatsServer,
+  getConfiguredPort: () => getResolvedConfig().stats.serverPort,
+});
+
 const ensureBackgroundStatsServerStarted = (): {
   url: string;
   runningInCurrentProcess: boolean;
@@ -3247,13 +3255,15 @@ const ensureBackgroundStatsServerStarted = (): {
   }
 
   const port = getResolvedConfig().stats.serverPort;
-  const url = ensureStatsServerStarted();
+  const result = ensureStatsServerStarted();
-  writeBackgroundStatsServerState(statsDaemonStatePath, {
+  if (result.source === 'local') {
-    pid: process.pid,
+    writeBackgroundStatsServerState(statsDaemonStatePath, {
-    port,
+      pid: process.pid,
-    startedAtMs: Date.now(),
+      port,
-  });
+      startedAtMs: Date.now(),
-  return { url, runningInCurrentProcess: true };
+    });
+  }
+  return { url: result.url, runningInCurrentProcess: result.source === 'local' };
 };
 
 const stopBackgroundStatsServer = async (): Promise<{ ok: boolean; stale: boolean }> => {
@@ -3352,7 +3362,7 @@ const immersionTrackerStartupMainDeps: Parameters<
       registerStatsOverlayToggle({
         staticDir: statsDistPath,
         preloadPath: statsPreloadPath,
-        getApiBaseUrl: () => ensureStatsServerStarted(),
+        getApiBaseUrl: () => ensureStatsServerStarted().url,
         getToggleKey: () => getResolvedConfig().stats.toggleKey,
         resolveBounds: () => getCurrentOverlayGeometry(),
         onVisibilityChanged: (visible) => {
@@ -3407,7 +3417,7 @@ const runStatsCliCommand = createRunStatsCliCommandHandler({
     await createMecabTokenizerAndCheck();
   },
   getImmersionTracker: () => appState.immersionTracker,
-  ensureStatsServerStarted: () => statsStartupRuntime.ensureStatsServerStarted(),
+  ensureStatsServerStarted: () => statsStartupRuntime.ensureStatsServerStarted().url,
   ensureBackgroundStatsServerStarted: () =>
     statsStartupRuntime.ensureBackgroundStatsServerStarted(),
   stopBackgroundStatsServer: () => statsStartupRuntime.stopBackgroundStatsServer(),
@@ -4619,7 +4629,7 @@ async function dispatchSessionAction(request: SessionActionDispatchRequest): Pro
       toggleStatsOverlayWindow({
         staticDir: statsDistPath,
         preloadPath: statsPreloadPath,
-        getApiBaseUrl: () => ensureStatsServerStarted(),
+        getApiBaseUrl: () => ensureStatsServerStarted().url,
         getToggleKey: () => getResolvedConfig().stats.toggleKey,
         resolveBounds: () => getCurrentOverlayGeometry(),
         onVisibilityChanged: (visible) => {

src/main/runtime/stats-server-routing.test.ts

@@ -0,0 +1,86 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { createEnsureStatsServerUrlHandler } from './stats-server-routing';
+
+function createHarness(options?: {
+  state?: { pid: number; port: number; startedAtMs: number } | null;
+  processAlive?: boolean;
+  localServerStarted?: boolean;
+}) {
+  const calls: string[] = [];
+  let localServerStarted = options?.localServerStarted ?? false;
+  const handler = createEnsureStatsServerUrlHandler({
+    currentPid: 100,
+    readBackgroundState: () => {
+      calls.push('readBackgroundState');
+      return options?.state ?? null;
+    },
+    removeBackgroundState: () => {
+      calls.push('removeBackgroundState');
+    },
+    isProcessAlive: () => {
+      calls.push('isProcessAlive');
+      return options?.processAlive ?? true;
+    },
+    hasLocalStatsServer: () => localServerStarted,
+    startLocalStatsServer: () => {
+      calls.push('startLocalStatsServer');
+      localServerStarted = true;
+    },
+    getConfiguredPort: () => 6969,
+  });
+
+  return {
+    calls,
+    handler,
+  };
+}
+
+test('stats server routing defers to a live background daemon from another process', () => {
+  const { calls, handler } = createHarness({
+    state: { pid: 200, port: 7979, startedAtMs: 1 },
+    processAlive: true,
+  });
+
+  assert.deepEqual(handler(), { url: 'http://127.0.0.1:7979', source: 'foreign' });
+  assert.deepEqual(calls, ['readBackgroundState', 'isProcessAlive']);
+});
+
+test('stats server routing clears dead daemon state and starts local server', () => {
+  const { calls, handler } = createHarness({
+    state: { pid: 200, port: 7979, startedAtMs: 1 },
+    processAlive: false,
+  });
+
+  assert.deepEqual(handler(), { url: 'http://127.0.0.1:6969', source: 'local' });
+  assert.deepEqual(calls, [
+    'readBackgroundState',
+    'isProcessAlive',
+    'removeBackgroundState',
+    'startLocalStatsServer',
+  ]);
+});
+
+test('stats server routing clears self-owned stale state and starts local server', () => {
+  const { calls, handler } = createHarness({
+    state: { pid: 100, port: 7979, startedAtMs: 1 },
+    processAlive: true,
+  });
+
+  assert.deepEqual(handler(), { url: 'http://127.0.0.1:6969', source: 'local' });
+  assert.deepEqual(calls, [
+    'readBackgroundState',
+    'removeBackgroundState',
+    'startLocalStatsServer',
+  ]);
+});
+
+test('stats server routing reuses a started local stats server', () => {
+  const { calls, handler } = createHarness({
+    state: null,
+    localServerStarted: true,
+  });
+
+  assert.deepEqual(handler(), { url: 'http://127.0.0.1:6969', source: 'local' });
+  assert.deepEqual(calls, ['readBackgroundState', 'removeBackgroundState']);
+});

src/main/runtime/stats-server-routing.ts

@@ -0,0 +1,41 @@
+import type { BackgroundStatsServerState } from './stats-daemon';
+
+type EnsureStatsServerUrlDeps = {
+  currentPid: number;
+  readBackgroundState: () => BackgroundStatsServerState | null;
+  removeBackgroundState: () => void;
+  isProcessAlive: (pid: number) => boolean;
+  hasLocalStatsServer: () => boolean;
+  startLocalStatsServer: () => void;
+  getConfiguredPort: () => number;
+};
+
+function formatStatsServerUrl(port: number): string {
+  return `http://127.0.0.1:${port}`;
+}
+
+export type EnsureStatsServerUrlResult =
+  | { url: string; source: 'foreign' }
+  | { url: string; source: 'local' };
+
+export function createEnsureStatsServerUrlHandler(
+  deps: EnsureStatsServerUrlDeps,
+): () => EnsureStatsServerUrlResult {
+  return () => {
+    const state = deps.readBackgroundState();
+    if (!state) {
+      deps.removeBackgroundState();
+    } else if (state.pid === deps.currentPid && !deps.hasLocalStatsServer()) {
+      deps.removeBackgroundState();
+    } else if (!deps.isProcessAlive(state.pid)) {
+      deps.removeBackgroundState();
+    } else if (state.pid !== deps.currentPid) {
+      return { url: formatStatsServerUrl(state.port), source: 'foreign' };
+    }
+
+    if (!deps.hasLocalStatsServer()) {
+      deps.startLocalStatsServer();
+    }
+    return { url: formatStatsServerUrl(deps.getConfiguredPort()), source: 'local' };
+  };
+}

src/stats-daemon-entry.ts

@@ -2,7 +2,7 @@ import fs from 'node:fs';
 import path from 'node:path';
 import { spawn } from 'node:child_process';
 import { shell } from 'electron';
-import { sanitizeStartupEnv } from './main-entry-runtime';
+import { resolveStatsDaemonCommandAction, sanitizeStartupEnv } from './main-entry-runtime';
 import {
   isBackgroundStatsServerProcessAlive,
   readBackgroundStatsServerState,
@@ -44,7 +44,7 @@ function hasFlag(argv: string[], flag: string): boolean {
 
 function parseControlArgs(argv: string[], userDataPath: string): StatsDaemonControlArgs {
   return {
-    action: hasFlag(argv, '--stats-daemon-stop') ? 'stop' : 'start',
+    action: resolveStatsDaemonCommandAction(argv) ?? 'start',
     responsePath: readFlagValue(argv, '--stats-response-path'),
     openBrowser: hasFlag(argv, '--stats-daemon-open-browser'),
     daemonScriptPath: path.join(__dirname, 'stats-daemon-runner.js'),