diff --git a/extensions/googlechat/src/api.fetchok.transport.test.ts b/extensions/googlechat/src/api.fetchok.transport.test.ts
index 84e480deaf8b..bd560545318b 100644
--- a/extensions/googlechat/src/api.fetchok.transport.test.ts
+++ b/extensions/googlechat/src/api.fetchok.transport.test.ts
@@ -64,6 +64,7 @@ vi.mock("./auth.js", () => ({
 }));
 
 let deleteGoogleChatMessage: typeof import("./api.js").deleteGoogleChatMessage;
+let sendGoogleChatMessage: typeof import("./api.js").sendGoogleChatMessage;
 
 const account = {
   accountId: "default",
@@ -117,7 +118,7 @@ async function withinDeadline<T>(promise: Promise<T>, timeoutMs = 2_000): Promis
 
 describe("deleteGoogleChatMessage real guarded transport", () => {
   beforeAll(async () => {
-    ({ deleteGoogleChatMessage } = await import("./api.js"));
+    ({ deleteGoogleChatMessage, sendGoogleChatMessage } = await import("./api.js"));
   });
 
   beforeEach(() => {
@@ -133,6 +134,32 @@ describe("deleteGoogleChatMessage real guarded transport", () => {
     vi.restoreAllMocks();
   });
 
+  it("rejects malformed UTF-8 JSON through the real guarded transport", async () => {
+    const body = new Uint8Array([
+      ...new TextEncoder().encode('{"name":"spaces/'),
+      0xff,
+      ...new TextEncoder().encode('AAA"}'),
+    ]);
+    const server = createServer((_request, response) => {
+      response.writeHead(200, { "Content-Type": "application/json" });
+      response.end(body);
+    });
+
+    loopback.baseUrl = await listen(server);
+    try {
+      const outcome = await withinDeadline(
+        sendGoogleChatMessage({ account, space: "spaces/AAA", text: "hello" }).then(
+          () => undefined,
+          (error: unknown) => error,
+        ),
+      );
+      expect(outcome).toBeInstanceOf(Error);
+      expect((outcome as Error).message).toMatch(/malformed JSON response/);
+    } finally {
+      await closeServer(server);
+    }
+  });
+
   it("cancels a streaming authenticated DELETE before releasing its real dispatcher", async () => {
     let socketClosed = false;
     let receivedAuthorization: string | undefined;
diff --git a/extensions/googlechat/src/api.ts b/extensions/googlechat/src/api.ts
index 359cf803121c..ae85c4375477 100644
--- a/extensions/googlechat/src/api.ts
+++ b/extensions/googlechat/src/api.ts
@@ -6,6 +6,7 @@ import {
   parseMediaContentLength,
   readResponseTextSnippet,
 } from "openclaw/plugin-sdk/media-runtime";
+import { readProviderJsonResponse } from "openclaw/plugin-sdk/provider-http";
 import { readResponseWithLimit } from "openclaw/plugin-sdk/response-limit-runtime";
 import { fetchWithSsrFGuard } from "openclaw/plugin-sdk/ssrf-runtime";
 import type { ResolvedGoogleChatAccount } from "./accounts.js";
@@ -33,17 +34,12 @@ function resolveGoogleChatMediaTimeoutMs(maxBytes?: number): number {
 }
 
 async function readGoogleChatJsonResponse<T>(response: Response, label: string): Promise<T> {
-  const bytes = await readResponseWithLimit(response, GOOGLECHAT_JSON_RESPONSE_MAX_BYTES, {
+  return readProviderJsonResponse<T>(response, label, {
+    maxBytes: GOOGLECHAT_JSON_RESPONSE_MAX_BYTES,
     chunkTimeoutMs: GOOGLECHAT_RESPONSE_READ_IDLE_TIMEOUT_MS,
     onIdleTimeout: ({ chunkTimeoutMs }) =>
       new Error(`${label}: response body stalled after ${chunkTimeoutMs}ms`),
-    onOverflow: ({ maxBytes }) => new Error(`${label}: JSON response exceeds ${maxBytes} bytes`),
   });
-  try {
-    return JSON.parse(new TextDecoder().decode(bytes)) as T;
-  } catch (cause) {
-    throw new Error(`${label}: malformed JSON response`, { cause });
-  }
 }
 
 async function readGoogleChatErrorResponse(response: Response, label: string): Promise<string> {
diff --git a/extensions/googlechat/src/targets.test.ts b/extensions/googlechat/src/targets.test.ts
index a315bf0cba0c..5637183091a3 100644
--- a/extensions/googlechat/src/targets.test.ts
+++ b/extensions/googlechat/src/targets.test.ts
@@ -287,6 +287,43 @@ describe("googlechat group policy", () => {
   });
 });
 
+describe("googlechat API JSON response decoding", () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  it("rejects invalid UTF-8 in API JSON responses instead of corrupting identifiers", async () => {
+    const raw = Buffer.concat([
+      Buffer.from('{"name":"spaces/'),
+      Buffer.from([0xff]),
+      Buffer.from('AAA"}'),
+    ]);
+    vi.stubGlobal(
+      "fetch",
+      vi.fn().mockResolvedValue(new Response(new Uint8Array(raw), { status: 200 })),
+    );
+
+    await expect(
+      sendGoogleChatMessage({ account, space: "spaces/AAA", text: "hello" }),
+    ).rejects.toThrow(/malformed JSON response/);
+  });
+
+  it("keeps valid UTF-8 API JSON responses unchanged (negative control)", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi
+        .fn()
+        .mockResolvedValue(
+          new Response(new Uint8Array(Buffer.from('{"name":"spaces/AAA"}')), { status: 200 }),
+        ),
+    );
+
+    await expect(
+      sendGoogleChatMessage({ account, space: "spaces/AAA", text: "hello" }),
+    ).resolves.toEqual({ messageName: "spaces/AAA", threadName: undefined });
+  });
+});
+
 describe("downloadGoogleChatMedia", () => {
   afterEach(() => {
     unregisterGoogleChatManualApprovalFollowupSuppression("12345678-1234-1234-1234-123456789012");