diff --git a/extensions/tts-local-cli/speech-provider-stream-error.test.ts b/extensions/tts-local-cli/speech-provider-stream-error.test.ts
new file mode 100644
index 00000000000..65de8dd7660
--- /dev/null
+++ b/extensions/tts-local-cli/speech-provider-stream-error.test.ts
@@ -0,0 +1,80 @@
+import { EventEmitter } from "node:events";
+import type { OpenClawConfig } from "openclaw/plugin-sdk/config-contracts";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+const spawnMock = vi.hoisted(() => vi.fn());
+
+vi.mock("node:child_process", async (importOriginal) => ({
+  ...(await importOriginal<typeof import("node:child_process")>()),
+  spawn: spawnMock,
+}));
+
+vi.mock("openclaw/plugin-sdk/media-runtime", () => ({
+  runFfmpeg: vi.fn(),
+}));
+
+import { buildCliSpeechProvider } from "./speech-provider.js";
+
+type MockChild = EventEmitter & {
+  stdout: EventEmitter;
+  stderr: EventEmitter;
+  stdin: EventEmitter & { end: () => void; write: (data: string) => void };
+  kill: ReturnType<typeof vi.fn<(signal?: NodeJS.Signals) => boolean>>;
+};
+
+function createMockChild(): MockChild {
+  const child = new EventEmitter() as MockChild;
+  child.stdout = new EventEmitter();
+  child.stderr = new EventEmitter();
+  const stdin = new EventEmitter() as EventEmitter & { end: () => void; write: () => void };
+  stdin.end = () => {};
+  stdin.write = () => {};
+  child.stdin = stdin;
+  child.kill = vi.fn(() => true);
+  return child;
+}
+
+const TEST_CFG = {} as OpenClawConfig;
+
+async function synthesize(child: MockChild) {
+  spawnMock.mockReturnValue(child);
+  const promise = buildCliSpeechProvider().synthesize({
+    text: "hello",
+    cfg: TEST_CFG,
+    providerConfig: { command: "/fake/tts", outputFormat: "wav", timeoutMs: 5000 },
+    providerOverrides: {},
+    timeoutMs: 5000,
+    target: "audio-file",
+  });
+  await vi.waitUntil(() => spawnMock.mock.calls.length > 0, { timeout: 2000 });
+  return { promise };
+}
+
+describe("CLI TTS provider stream error handling", () => {
+  afterEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("rejects on stdout stream error instead of silently returning truncated audio", async () => {
+    const child = createMockChild();
+    const { promise } = await synthesize(child);
+
+    child.stdout.emit("error", new Error("EPIPE: audio stream broken"));
+    child.emit("close", null, "SIGTERM");
+
+    await expect(promise).rejects.toThrow("CLI TTS stdout stream error");
+    expect(child.kill).toHaveBeenCalledOnce();
+  });
+
+  it("keeps synthesized audio when only the diagnostic stream errors", async () => {
+    const child = createMockChild();
+    const { promise } = await synthesize(child);
+
+    child.stdout.emit("data", Buffer.from("audio"));
+    child.stderr.emit("error", new Error("EPIPE: diagnostics stream broken"));
+    child.emit("close", 0);
+
+    await expect(promise).resolves.toMatchObject({ audioBuffer: Buffer.from("audio") });
+    expect(child.kill).not.toHaveBeenCalled();
+  });
+});
diff --git a/extensions/tts-local-cli/speech-provider.ts b/extensions/tts-local-cli/speech-provider.ts
index e1a05f8d023..21882564b10 100644
--- a/extensions/tts-local-cli/speech-provider.ts
+++ b/extensions/tts-local-cli/speech-provider.ts
@@ -204,46 +204,85 @@ async function runCli(params: {
   const args = baseArgs.map((a) => applyTemplate(a, ctx));
 
   return new Promise((resolve, reject) => {
-    let timedOut = false;
-    const timer = setTimeout(() => {
-      timedOut = true;
-      proc.kill();
-      // Escalate to SIGKILL if child ignores SIGTERM
-      setTimeout(() => proc.kill("SIGKILL"), 5000).unref();
-    }, params.timeoutMs);
-
     const env = params.env ? { ...process.env, ...params.env } : process.env;
     const proc = spawn(cmd, args, { cwd: params.cwd, env, stdio: ["pipe", "pipe", "pipe"] });
+    let settled = false;
+    let failure: Error | undefined;
+    let forceKillTimer: NodeJS.Timeout | undefined;
+
+    const clearTimers = () => {
+      clearTimeout(timer);
+      clearTimeout(forceKillTimer);
+    };
+    const rejectOnce = (error: Error) => {
+      if (settled) {
+        return;
+      }
+      settled = true;
+      clearTimers();
+      reject(error);
+    };
+    const terminate = () => {
+      proc.kill();
+      forceKillTimer = setTimeout(() => proc.kill("SIGKILL"), 5000);
+      forceKillTimer.unref();
+    };
+    const terminateFor = (error: Error) => {
+      // Keep one terminal cause across stream, process, and close events. Node
+      // may emit several of them for the same failed child lifecycle.
+      if (settled || failure) {
+        return;
+      }
+      failure = error;
+      clearTimeout(timer);
+      terminate();
+    };
+    const timer = setTimeout(() => {
+      terminateFor(new Error(`CLI TTS timed out after ${params.timeoutMs}ms`));
+    }, params.timeoutMs);
 
     const stdoutChunks: Buffer[] = [];
     const stderrChunks: Buffer[] = [];
     proc.stdout.on("data", (c) => stdoutChunks.push(c));
+    // stdout carries synthesized audio data. A stream error means the audio
+    // pipe broke mid-generation — reject so the caller does not silently
+    // receive truncated audio when the child later exits zero.
+    proc.stdout.on("error", (e) => {
+      terminateFor(new Error(`CLI TTS stdout stream error: ${e.message}`));
+    });
     proc.stderr.on("data", (c) => stderrChunks.push(c));
+    // stderr carries diagnostic logs only. Stream errors here are benign and
+    // should not crash the provider or affect audio output.
+    proc.stderr.on("error", () => {});
 
     proc.on("error", (e) => {
-      clearTimeout(timer);
-      reject(new Error(`CLI TTS failed: ${e.message}`));
+      rejectOnce(failure ?? new Error(`CLI TTS failed: ${e.message}`));
     });
 
     proc.on("close", (code) => {
-      clearTimeout(timer);
-      if (timedOut) {
-        return reject(new Error(`CLI TTS timed out after ${params.timeoutMs}ms`));
+      if (settled) {
+        clearTimers();
+        return;
+      }
+      if (failure) {
+        return rejectOnce(failure);
       }
       if (code !== 0) {
         const stderr = Buffer.concat(stderrChunks).toString("utf8");
-        return reject(new Error(`CLI TTS exit ${code}: ${stderr}`));
+        return rejectOnce(new Error(`CLI TTS exit ${code}: ${stderr}`));
       }
 
       const audioFile = findAudioFile(params.outputDir, params.filePrefix);
       if (audioFile) {
         if (!existsSync(audioFile)) {
-          return reject(new Error(`CLI TTS: output file not found at ${audioFile}`));
+          return rejectOnce(new Error(`CLI TTS: output file not found at ${audioFile}`));
         }
         const format = detectFormat(audioFile);
         if (!format) {
-          return reject(new Error(`CLI TTS: unknown format for ${audioFile}`));
+          return rejectOnce(new Error(`CLI TTS: unknown format for ${audioFile}`));
         }
+        settled = true;
+        clearTimers();
         return resolve({
           buffer: readFileSync(audioFile),
           actualFormat: format,
@@ -254,9 +293,11 @@ async function runCli(params: {
       const stdout = Buffer.concat(stdoutChunks);
       if (stdout.length > 0) {
         // Assume WAV for stdout output; could be MP3 but caller should convert if needed
+        settled = true;
+        clearTimers();
         return resolve({ buffer: stdout, actualFormat: "wav" });
       }
-      reject(new Error("CLI TTS produced no output"));
+      rejectOnce(new Error("CLI TTS produced no output"));
     });
 
     proc.stdin?.on("error", () => {}); // suppress EPIPE if child ignores stdin