diff --git a/extensions/microsoft/tts.test.ts b/extensions/microsoft/tts.test.ts
index 74438a5a0d4f..c8b01754b919 100644
--- a/extensions/microsoft/tts.test.ts
+++ b/extensions/microsoft/tts.test.ts
@@ -6,21 +6,8 @@ import { afterEach, beforeAll, describe, expect, it, vi } from "vitest";
 
 let edgeTTS: typeof import("./tts.js").edgeTTS;
 
-function createEdgeTTSDeps(
-  ttsPromise: (text: string, filePath: string) => Promise<void>,
-  onConstruct?: () => void,
-) {
-  return {
-    EdgeTTS: class {
-      constructor() {
-        onConstruct?.();
-      }
-
-      ttsPromise(text: string, filePath: string) {
-        return ttsPromise(text, filePath);
-      }
-    },
-  };
+function createEdgeTTSClient(ttsPromise: (text: string, filePath: string) => Promise<void>) {
+  return { ttsPromise };
 }
 
 const baseEdgeConfig = {
@@ -44,13 +31,12 @@ describe("edgeTTS empty audio validation", () => {
     }
   });
 
-  it("rejects blank text before constructing Edge TTS", async () => {
+  it("rejects blank text before calling Edge TTS", async () => {
     tempDir = mkdtempSync(path.join(tmpdir(), "tts-test-"));
     const outputPath = path.join(tempDir, "voice.mp3");
-    const onConstruct = vi.fn();
-    const deps = createEdgeTTSDeps(async (_text: string, filePath: string) => {
+    const ttsPromise = vi.fn(async (_text: string, filePath: string) => {
       writeFileSync(filePath, Buffer.from([0xff]));
-    }, onConstruct);
+    });
 
     await expect(
       edgeTTS(
@@ -60,10 +46,10 @@ describe("edgeTTS empty audio validation", () => {
           config: baseEdgeConfig,
           timeoutMs: 10000,
         },
-        deps,
+        createEdgeTTSClient(ttsPromise),
       ),
     ).rejects.toThrow("Microsoft TTS text cannot be empty");
-    expect(onConstruct).not.toHaveBeenCalled();
+    expect(ttsPromise).not.toHaveBeenCalled();
   });
 
   it("throws after one retry when the output file stays empty", async () => {
@@ -71,7 +57,7 @@ describe("edgeTTS empty audio validation", () => {
     const outputPath = path.join(tempDir, "voice.mp3");
     const calls: string[] = [];
 
-    const deps = createEdgeTTSDeps(async (text: string, filePath: string) => {
+    const tts = createEdgeTTSClient(async (text: string, filePath: string) => {
       calls.push(text);
       writeFileSync(filePath, "");
     });
@@ -84,7 +70,7 @@ describe("edgeTTS empty audio validation", () => {
           config: baseEdgeConfig,
           timeoutMs: 10000,
         },
-        deps,
+        tts,
       ),
     ).rejects.toThrow("Edge TTS produced empty audio file after retry");
     expect(calls).toEqual(["Hello", "Hello"]);
@@ -95,7 +81,7 @@ describe("edgeTTS empty audio validation", () => {
     const outputPath = path.join(tempDir, "voice.mp3");
     let stagedPath = "";
 
-    const deps = createEdgeTTSDeps(async (_text: string, filePath: string) => {
+    const tts = createEdgeTTSClient(async (_text: string, filePath: string) => {
       stagedPath = filePath;
       writeFileSync(filePath, Buffer.from([0xff, 0xfb, 0x90, 0x00]));
     });
@@ -108,7 +94,7 @@ describe("edgeTTS empty audio validation", () => {
           config: baseEdgeConfig,
           timeoutMs: 10000,
         },
-        deps,
+        tts,
       ),
     ).resolves.toBeUndefined();
     expect(stagedPath).not.toBe(outputPath);
@@ -123,7 +109,7 @@ describe("edgeTTS empty audio validation", () => {
     const outputPath = path.join(tempDir, "voice.mp3");
     const calls: string[] = [];
 
-    const deps = createEdgeTTSDeps(async (text: string, filePath: string) => {
+    const tts = createEdgeTTSClient(async (text: string, filePath: string) => {
       calls.push(text);
       writeFileSync(filePath, calls.length === 1 ? "" : Buffer.from([0xff, 0xfb, 0x90, 0x00]));
     });
@@ -136,7 +122,7 @@ describe("edgeTTS empty audio validation", () => {
           config: baseEdgeConfig,
           timeoutMs: 10000,
         },
-        deps,
+        tts,
       ),
     ).resolves.toBeUndefined();
     expect(calls).toEqual(["Hello", "Hello"]);
@@ -147,7 +133,7 @@ describe("edgeTTS empty audio validation", () => {
     const outputPath = path.join(tempDir, "voice.mp3");
     const calls: string[] = [];
 
-    const deps = createEdgeTTSDeps(async (text: string, filePath: string) => {
+    const tts = createEdgeTTSClient(async (text: string, filePath: string) => {
       calls.push(text);
       if (calls.length === 2) {
         writeFileSync(filePath, Buffer.from([0xff, 0xfb, 0x90, 0x00]));
@@ -162,7 +148,7 @@ describe("edgeTTS empty audio validation", () => {
           config: baseEdgeConfig,
           timeoutMs: 10000,
         },
-        deps,
+        tts,
       ),
     ).resolves.toBeUndefined();
     expect(calls).toEqual(["Hello", "Hello"]);
@@ -173,7 +159,7 @@ describe("edgeTTS empty audio validation", () => {
     const outputPath = path.join(tempDir, "voice.mp3");
     const calls: string[] = [];
 
-    const deps = createEdgeTTSDeps(async (text: string) => {
+    const tts = createEdgeTTSClient(async (text: string) => {
       calls.push(text);
       throw new Error("upstream timeout");
     });
@@ -186,7 +172,7 @@ describe("edgeTTS empty audio validation", () => {
           config: baseEdgeConfig,
           timeoutMs: 10000,
         },
-        deps,
+        tts,
       ),
     ).rejects.toThrow("upstream timeout");
     expect(calls).toEqual(["Hello"]);
diff --git a/extensions/microsoft/tts.ts b/extensions/microsoft/tts.ts
index 37304ed0b018..e925626ece31 100644
--- a/extensions/microsoft/tts.ts
+++ b/extensions/microsoft/tts.ts
@@ -5,31 +5,7 @@ import path from "node:path";
 import { writeExternalFileWithinRoot } from "openclaw/plugin-sdk/security-runtime";
 import { normalizeLowercaseStringOrEmpty } from "openclaw/plugin-sdk/string-coerce-runtime";
 
-type EdgeTTSDeps = {
-  EdgeTTS: new (
-    ...args: ConstructorParameters<typeof import("node-edge-tts").EdgeTTS>
-  ) => Pick<import("node-edge-tts").EdgeTTS, "ttsPromise">;
-};
-
-function isMissingOutputFileError(error: unknown): boolean {
-  return (
-    typeof error === "object" &&
-    error !== null &&
-    "code" in error &&
-    (error as { code?: unknown }).code === "ENOENT"
-  );
-}
-
-function readOutputSize(outputPath: string): number {
-  try {
-    return statSync(outputPath).size;
-  } catch (error) {
-    if (isMissingOutputFileError(error)) {
-      return 0;
-    }
-    throw error;
-  }
-}
+type EdgeTTSClient = Pick<import("node-edge-tts").EdgeTTS, "ttsPromise">;
 
 export function inferEdgeExtension(outputFormat: string): string {
   const normalized = normalizeLowercaseStringOrEmpty(outputFormat);
@@ -65,31 +41,37 @@ export async function edgeTTS(
     };
     timeoutMs: number;
   },
-  deps?: EdgeTTSDeps,
+  ttsOverride?: EdgeTTSClient,
 ): Promise<void> {
   const { text, outputPath, config, timeoutMs } = params;
   if (text.trim().length === 0) {
     throw new Error("Microsoft TTS text cannot be empty");
   }
 
-  const EdgeTTSClass = deps?.EdgeTTS ?? (await import("node-edge-tts")).EdgeTTS;
-  const tts = new EdgeTTSClass({
-    voice: config.voice,
-    lang: config.lang,
-    outputFormat: config.outputFormat,
-    saveSubtitles: config.saveSubtitles,
-    proxy: config.proxy,
-    rate: config.rate,
-    pitch: config.pitch,
-    volume: config.volume,
-    timeout: config.timeoutMs ?? timeoutMs,
-  });
+  const tts =
+    ttsOverride ??
+    new (await import("node-edge-tts")).EdgeTTS({
+      voice: config.voice,
+      lang: config.lang,
+      outputFormat: config.outputFormat,
+      saveSubtitles: config.saveSubtitles,
+      proxy: config.proxy,
+      rate: config.rate,
+      pitch: config.pitch,
+      volume: config.volume,
+      timeout: config.timeoutMs ?? timeoutMs,
+    });
 
+  await mkdir(path.dirname(outputPath), { recursive: true });
   for (let attempt = 0; attempt < 2; attempt += 1) {
-    const outputSize = await writeEdgeTtsOutput({
-      outputPath,
-      ttsPromise: async (tempPath) => {
+    let outputSize = 0;
+    await writeExternalFileWithinRoot({
+      rootDir: path.dirname(outputPath),
+      path: path.basename(outputPath),
+      write: async (tempPath) => {
+        writeFileSync(tempPath, "");
         await tts.ttsPromise(text, tempPath);
+        outputSize = statSync(tempPath).size;
       },
     });
     if (outputSize > 0) {
@@ -98,24 +80,3 @@ export async function edgeTTS(
   }
   throw new Error("Edge TTS produced empty audio file after retry");
 }
-
-async function writeEdgeTtsOutput(params: {
-  outputPath: string;
-  ttsPromise: (tempPath: string) => Promise<void>;
-}): Promise<number> {
-  const rootDir = path.dirname(params.outputPath);
-  await mkdir(rootDir, { recursive: true });
-  let outputSize = 0;
-  await writeExternalFileWithinRoot({
-    rootDir,
-    path: path.basename(params.outputPath),
-    write: async (tempPath) => {
-      await params.ttsPromise(tempPath);
-      outputSize = readOutputSize(tempPath);
-      if (outputSize === 0) {
-        writeFileSync(tempPath, "");
-      }
-    },
-  });
-  return outputSize;
-}