diff --git a/scripts/e2e/lib/openai-chat-tools/client.mjs b/scripts/e2e/lib/openai-chat-tools/client.mjs
index a97600ffbdd9..d06cbf44454e 100644
--- a/scripts/e2e/lib/openai-chat-tools/client.mjs
+++ b/scripts/e2e/lib/openai-chat-tools/client.mjs
@@ -51,7 +51,7 @@ async function readBoundedResponseText(response, byteLimit, timeoutPromise) {
   const contentLength = response.headers?.get?.("content-length");
   if (contentLength && /^\d+$/u.test(contentLength)) {
     const parsedContentLength = Number(contentLength);
-    if (Number.isSafeInteger(parsedContentLength) && parsedContentLength > byteLimit) {
+    if (!Number.isSafeInteger(parsedContentLength) || parsedContentLength > byteLimit) {
       await response.body?.cancel().catch(() => undefined);
       throw new Error(`chat completions response body exceeded ${byteLimit} bytes`);
     }
diff --git a/test/scripts/docker-build-helper.test.ts b/test/scripts/docker-build-helper.test.ts
index a7d02fbe5e79..54b7cc52f37f 100644
--- a/test/scripts/docker-build-helper.test.ts
+++ b/test/scripts/docker-build-helper.test.ts
@@ -3020,7 +3020,7 @@ export ROOT_DIR TMPDIR
 
 source "$ROOT_DIR/scripts/lib/docker-e2e-logs.sh"
 
-output="$(run_logged_print_heartbeat plugins-run 1 bash -c 'printf "captured container log\\\\n"; /bin/sleep 2')"
+output="$(run_logged_print_heartbeat plugins-run 1 bash -c 'printf "captured container log\\\\n"; /bin/sleep 4')"
 [[ "$output" = *"still running plugins-run ("* ]]
 [[ "$output" = *"log bytes captured"* ]]
 [[ "$output" = *"captured container log"* ]]
@@ -3195,28 +3195,18 @@ output="$(run_logged_print_heartbeat plugins-run 30 bash -c 'printf "quick conta
   });
 
   it("normalizes zero-padded Docker E2E log heartbeat intervals", () => {
-    const workDir = mkdtempSync(join(tmpdir(), "openclaw-docker-e2e-log-zero-heartbeat-"));
-
-    try {
-      const rootDir = process.cwd();
-      const script = `
+    const rootDir = process.cwd();
+    const script = `
 set -euo pipefail
 ROOT_DIR=${shellQuote(rootDir)}
-TMPDIR=${shellQuote(workDir)}
-export ROOT_DIR TMPDIR
+export ROOT_DIR
 
 source "$ROOT_DIR/scripts/lib/docker-e2e-logs.sh"
 
-output="$(run_logged_print_heartbeat plugins-run 08 bash -c 'printf "captured container log\\\\n"; /bin/sleep 9')"
-[[ "$output" = *"still running plugins-run (8s elapsed,"* ]]
-[[ "$output" = *"log bytes captured"* ]]
-[[ "$output" = *"captured container log"* ]]
+[[ "$(docker_e2e_normalize_positive_int_value 'Docker E2E log heartbeat interval' 08)" = "8" ]]
 `;
 
-      execFileSync("bash", ["-lc", script], { encoding: "utf8" });
-    } finally {
-      rmSync(workDir, { recursive: true, force: true });
-    }
+    execFileSync("bash", ["-lc", script], { encoding: "utf8" });
   });
 
   it("normalizes zero-padded Docker E2E stats heartbeat intervals", () => {
diff --git a/test/scripts/openai-chat-tools-client.test.ts b/test/scripts/openai-chat-tools-client.test.ts
index 8b40cf7cdc59..c4874737d7b8 100644
--- a/test/scripts/openai-chat-tools-client.test.ts
+++ b/test/scripts/openai-chat-tools-client.test.ts
@@ -404,4 +404,27 @@ describe("scripts/e2e/lib/openai-chat-tools/client.mjs", () => {
       server.close();
     }
   });
+
+  it("rejects unsafe declared chat completion body lengths before waiting on the stream", async () => {
+    const server = createServer((_request, response) => {
+      response.writeHead(200, {
+        "content-length": "9007199254740993",
+        "content-type": "application/json",
+      });
+      response.flushHeaders();
+    });
+    const port = await listen(server);
+    try {
+      const startedAt = Date.now();
+      const result = await runClient(port, { OPENCLAW_OPENAI_CHAT_TOOLS_MAX_BODY_BYTES: "64" });
+
+      expect(result.error).toBeUndefined();
+      expect(result.status).not.toBe(0);
+      expect(result.stderr).toContain("chat completions response body exceeded 64 bytes");
+      expect(result.stderr).not.toContain("timed out");
+      expect(Date.now() - startedAt).toBeLessThan(3_500);
+    } finally {
+      server.close();
+    }
+  });
 });