diff --git a/packages/server/src/server/speech/providers/openai/test-utils/prefetched-playback.ts b/packages/server/src/server/speech/providers/openai/test-utils/prefetched-playback.ts
new file mode 100644
index 0000000000..406d3056f1
--- /dev/null
+++ b/packages/server/src/server/speech/providers/openai/test-utils/prefetched-playback.ts
@@ -0,0 +1,70 @@
+import { createServer } from "node:http";
+import { setTimeout as delay } from "node:timers/promises";
+import pino from "pino";
+import { OpenAITTS } from "../tts.js";
+import { TTSManager } from "../../../../agent/tts-manager.js";
+
+if (!global.gc) throw new Error("Run with --expose-gc");
+
+const sentences = ["First sentence.", "Second sentence.", "Third sentence."];
+const audio = sentences.map((_, index) => Buffer.alloc(192_000, index + 1));
+const requests: string[] = [];
+const server = createServer(async (request, response) => {
+  const chunks: Buffer[] = [];
+  for await (const chunk of request) chunks.push(Buffer.from(chunk));
+  const { input } = JSON.parse(Buffer.concat(chunks).toString()) as { input: string };
+  requests.push(input);
+  const body = audio[sentences.indexOf(input)];
+  response.writeHead(200, { "Content-Type": "audio/pcm", "Content-Length": body.length });
+  response.end(body);
+});
+
+await new Promise<void>((resolve) => server.listen(0, "127.0.0.1", resolve));
+const address = server.address();
+if (!address || typeof address === "string") throw new Error("Missing server address");
+const logger = pino({ level: "silent" });
+const provider = new OpenAITTS(
+  { apiKey: "test", baseUrl: `http://127.0.0.1:${address.port}/v1` },
+  logger,
+);
+const manager = new TTSManager("prefetched-playback", logger, provider);
+const emitted: { bytes: number; value: number; format: string }[] = [];
+
+try {
+  await manager.generateAndWaitForPlayback(
+    sentences.join(" "),
+    (message) => {
+      if (message.type !== "audio_output") return;
+      const buffer = Buffer.from(message.payload.audio, "base64");
+      emitted.push({ bytes: buffer.length, value: buffer[0], format: message.payload.format });
+      if (emitted.length === 1) {
+        // Hold the playback acknowledgement while the other responses are prefetched.
+        void (async () => {
+          while (requests.length < sentences.length) await delay(10);
+          for (let cycle = 0; cycle < 20; cycle++) {
+            await delay(25);
+            global.gc!();
+          }
+          manager.confirmAudioPlayed(message.payload.id);
+        })();
+      } else {
+        setImmediate(() => manager.confirmAudioPlayed(message.payload.id));
+      }
+    },
+    new AbortController().signal,
+    true,
+  );
+  console.log(JSON.stringify({ requests, emitted }));
+} finally {
+  manager.cleanup();
+  server.closeAllConnections();
+  await new Promise<void>((resolve, reject) => {
+    server.close((error) => {
+      if (error) {
+        reject(error);
+        return;
+      }
+      resolve();
+    });
+  });
+}
diff --git a/packages/server/src/server/speech/providers/openai/tts-playback.test.ts b/packages/server/src/server/speech/providers/openai/tts-playback.test.ts
new file mode 100644
index 0000000000..b7b2224144
--- /dev/null
+++ b/packages/server/src/server/speech/providers/openai/tts-playback.test.ts
@@ -0,0 +1,21 @@
+import { execFileSync } from "node:child_process";
+import { fileURLToPath } from "node:url";
+import { expect, test } from "vitest";
+
+test("prefetched speech survives garbage collection until its playback turn", () => {
+  const fixture = fileURLToPath(new URL("./test-utils/prefetched-playback.ts", import.meta.url));
+  const output = execFileSync(process.execPath, ["--expose-gc", "--import", "tsx", fixture], {
+    encoding: "utf8",
+    timeout: 15_000,
+  });
+
+  const result = JSON.parse(output);
+  expect(result.requests.sort()).toEqual(
+    ["First sentence.", "Second sentence.", "Third sentence."].sort(),
+  );
+  expect(result.emitted).toEqual([
+    { bytes: 192_000, value: 1, format: "pcm" },
+    { bytes: 192_000, value: 2, format: "pcm" },
+    { bytes: 192_000, value: 3, format: "pcm" },
+  ]);
+});
diff --git a/packages/server/src/server/speech/providers/openai/tts.ts b/packages/server/src/server/speech/providers/openai/tts.ts
index 31f7b5b263..49f43137ca 100644
--- a/packages/server/src/server/speech/providers/openai/tts.ts
+++ b/packages/server/src/server/speech/providers/openai/tts.ts
@@ -67,7 +67,9 @@ export class OpenAITTS implements TextToSpeechProvider {
           | "pcm",
       });
 
-      const audioStream = response.body as unknown as Readable;
+      // Prefetched speech can wait through playback of an earlier sentence. Consume
+      // the response here so fetch cannot collect it and cancel its unread body.
+      const audioStream = Readable.from([Buffer.from(await response.arrayBuffer())]);
 
       const duration = Date.now() - startTime;
       this.logger.debug({ duration }, "Speech synthesis stream ready");