diff --git a/package.json b/package.json
index 2e67017..af185f4 100644
--- a/package.json
+++ b/package.json
@@ -16,7 +16,7 @@
     "docs:build": "vitepress build docs",
     "docs:preview": "vitepress preview docs --host 0.0.0.0 --port 4173 --strictPort",
     "test:config": "pnpm run build && node --test dist/config/config.test.js",
-    "test:core": "pnpm run build && node --test dist/cli/args.test.js dist/cli/help.test.js dist/core/services/cli-command-service.test.js dist/core/services/numeric-shortcut-session-service.test.js dist/core/services/secondary-subtitle-service.test.js dist/core/services/mpv-render-metrics-service.test.js",
+    "test:core": "pnpm run build && node --test dist/cli/args.test.js dist/cli/help.test.js dist/core/services/cli-command-service.test.js dist/core/services/numeric-shortcut-session-service.test.js dist/core/services/secondary-subtitle-service.test.js dist/core/services/mpv-render-metrics-service.test.js dist/core/services/mpv-runtime-service.test.js",
     "test:subtitle": "pnpm run build && node --test dist/subtitle/stages.test.js dist/subtitle/pipeline.test.js",
     "generate:config-example": "pnpm run build && node dist/generate-config-example.js",
     "start": "pnpm run build && electron . --start",
diff --git a/src/core/services/mpv-runtime-service.test.ts b/src/core/services/mpv-runtime-service.test.ts
new file mode 100644
index 0000000..64c3fab
--- /dev/null
+++ b/src/core/services/mpv-runtime-service.test.ts
@@ -0,0 +1,69 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import {
+  playNextSubtitleRuntimeService,
+  replayCurrentSubtitleRuntimeService,
+  sendMpvCommandRuntimeService,
+  setMpvSubVisibilityRuntimeService,
+  showMpvOsdRuntimeService,
+} from "./mpv-runtime-service";
+
+test("showMpvOsdRuntimeService sends show-text when connected", () => {
+  const commands: (string | number)[][] = [];
+  showMpvOsdRuntimeService(
+    {
+      connected: true,
+      send: ({ command }) => {
+        commands.push(command);
+      },
+    },
+    "hello",
+  );
+  assert.deepEqual(commands, [["show-text", "hello", "3000"]]);
+});
+
+test("showMpvOsdRuntimeService logs fallback when disconnected", () => {
+  const logs: string[] = [];
+  showMpvOsdRuntimeService(
+    {
+      connected: false,
+      send: () => {},
+    },
+    "hello",
+    (line) => {
+      logs.push(line);
+    },
+  );
+  assert.deepEqual(logs, ["OSD (MPV not connected): hello"]);
+});
+
+test("mpv runtime command wrappers call expected client methods", () => {
+  const calls: string[] = [];
+  const client = {
+    connected: true,
+    send: ({ command }: { command: (string | number)[] }) => {
+      calls.push(`send:${command.join(",")}`);
+    },
+    replayCurrentSubtitle: () => {
+      calls.push("replay");
+    },
+    playNextSubtitle: () => {
+      calls.push("next");
+    },
+    setSubVisibility: (visible: boolean) => {
+      calls.push(`subVisible:${visible}`);
+    },
+  };
+
+  replayCurrentSubtitleRuntimeService(client);
+  playNextSubtitleRuntimeService(client);
+  sendMpvCommandRuntimeService(client, ["script-message", "x"]);
+  setMpvSubVisibilityRuntimeService(client, false);
+
+  assert.deepEqual(calls, [
+    "replay",
+    "next",
+    "send:script-message,x",
+    "subVisible:false",
+  ]);
+});
diff --git a/src/core/services/mpv-runtime-service.ts b/src/core/services/mpv-runtime-service.ts
new file mode 100644
index 0000000..3226826
--- /dev/null
+++ b/src/core/services/mpv-runtime-service.ts
@@ -0,0 +1,49 @@
+export interface MpvRuntimeClientLike {
+  connected: boolean;
+  send: (payload: { command: (string | number)[] }) => void;
+  replayCurrentSubtitle?: () => void;
+  playNextSubtitle?: () => void;
+  setSubVisibility?: (visible: boolean) => void;
+}
+
+export function showMpvOsdRuntimeService(
+  mpvClient: MpvRuntimeClientLike | null,
+  text: string,
+  fallbackLog: (text: string) => void = console.log,
+): void {
+  if (mpvClient && mpvClient.connected) {
+    mpvClient.send({ command: ["show-text", text, "3000"] });
+    return;
+  }
+  fallbackLog(`OSD (MPV not connected): ${text}`);
+}
+
+export function replayCurrentSubtitleRuntimeService(
+  mpvClient: MpvRuntimeClientLike | null,
+): void {
+  if (!mpvClient?.replayCurrentSubtitle) return;
+  mpvClient.replayCurrentSubtitle();
+}
+
+export function playNextSubtitleRuntimeService(
+  mpvClient: MpvRuntimeClientLike | null,
+): void {
+  if (!mpvClient?.playNextSubtitle) return;
+  mpvClient.playNextSubtitle();
+}
+
+export function sendMpvCommandRuntimeService(
+  mpvClient: MpvRuntimeClientLike | null,
+  command: (string | number)[],
+): void {
+  if (!mpvClient) return;
+  mpvClient.send({ command });
+}
+
+export function setMpvSubVisibilityRuntimeService(
+  mpvClient: MpvRuntimeClientLike | null,
+  visible: boolean,
+): void {
+  if (!mpvClient?.setSubVisibility) return;
+  mpvClient.setSubVisibility(visible);
+}
diff --git a/src/main.ts b/src/main.ts
index 8832b42..a893189 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -132,6 +132,13 @@ import {
   updateLastCardFromClipboardService,
 } from "./core/services/mining-runtime-service";
 import { startAppLifecycleService } from "./core/services/app-lifecycle-service";
+import {
+  playNextSubtitleRuntimeService,
+  replayCurrentSubtitleRuntimeService,
+  sendMpvCommandRuntimeService,
+  setMpvSubVisibilityRuntimeService,
+  showMpvOsdRuntimeService,
+} from "./core/services/mpv-runtime-service";
 import { showDesktopNotification } from "./core/utils/notification";
 import { openYomitanSettingsWindow } from "./core/services/yomitan-settings-service";
 import { tokenizeSubtitleService } from "./core/services/tokenizer-service";
@@ -851,13 +858,13 @@ function cycleSecondarySubMode(): void {
 }
 
 function showMpvOsd(text: string): void {
-  if (mpvClient && mpvClient.connected && mpvClient.send) {
-    mpvClient.send({
-      command: ["show-text", text, "3000"],
-    });
-  } else {
-    console.log("OSD (MPV not connected):", text);
-  }
+  showMpvOsdRuntimeService(
+    mpvClient,
+    text,
+    (line) => {
+      console.log(line);
+    },
+  );
 }
 
 const multiCopySession = createNumericShortcutSessionService({
@@ -1095,9 +1102,7 @@ function setVisibleOverlayVisible(visible: boolean): void {
       shouldBindVisibleOverlayToMpvSubVisibility(),
     isMpvConnected: () => Boolean(mpvClient && mpvClient.connected),
     setMpvSubVisibility: (mpvSubVisible) => {
-      if (mpvClient) {
-        mpvClient.setSubVisibility(mpvSubVisible);
-      }
+      setMpvSubVisibilityRuntimeService(mpvClient, mpvSubVisible);
     },
   });
 }
@@ -1134,16 +1139,10 @@ function handleMpvCommandFromIpc(command: (string | number)[]): void {
       );
     },
     showMpvOsd: (text) => showMpvOsd(text),
-    mpvReplaySubtitle: () => {
-      if (mpvClient) mpvClient.replayCurrentSubtitle();
-    },
-    mpvPlayNextSubtitle: () => {
-      if (mpvClient) mpvClient.playNextSubtitle();
-    },
-    mpvSendCommand: (rawCommand) => {
-      if (!mpvClient) return;
-      mpvClient.send({ command: rawCommand });
-    },
+    mpvReplaySubtitle: () => replayCurrentSubtitleRuntimeService(mpvClient),
+    mpvPlayNextSubtitle: () => playNextSubtitleRuntimeService(mpvClient),
+    mpvSendCommand: (rawCommand) =>
+      sendMpvCommandRuntimeService(mpvClient, rawCommand),
     isMpvConnected: () => Boolean(mpvClient && mpvClient.connected),
     hasRuntimeOptionsManager: () => runtimeOptionsManager !== null,
   });