diff --git a/scripts/test-parallel.mjs b/scripts/test-parallel.mjs
index ecc5e55617..0c5757baca 100644
--- a/scripts/test-parallel.mjs
+++ b/scripts/test-parallel.mjs
@@ -165,6 +165,20 @@ const WARNING_SUPPRESSION_FLAGS = [
   "--disable-warning=MaxListenersExceededWarning",
 ];
 
+const DEFAULT_CI_MAX_OLD_SPACE_SIZE_MB = 4096;
+const maxOldSpaceSizeMb = (() => {
+  // CI can hit Node heap limits (especially on large suites). Allow override, default to 4GB.
+  const raw = process.env.OPENCLAW_TEST_MAX_OLD_SPACE_SIZE_MB ?? "";
+  const parsed = Number.parseInt(raw, 10);
+  if (Number.isFinite(parsed) && parsed > 0) {
+    return parsed;
+  }
+  if (isCI && !isWindows) {
+    return DEFAULT_CI_MAX_OLD_SPACE_SIZE_MB;
+  }
+  return null;
+})();
+
 function resolveReportDir() {
   const raw = process.env.OPENCLAW_VITEST_REPORT_DIR?.trim();
   if (!raw) {
@@ -224,11 +238,18 @@ const runOnce = (entry, extraArgs = []) =>
       (acc, flag) => (acc.includes(flag) ? acc : `${acc} ${flag}`.trim()),
       nodeOptions,
     );
+    const heapFlag =
+      maxOldSpaceSizeMb && !nextNodeOptions.includes("--max-old-space-size=")
+        ? `--max-old-space-size=${maxOldSpaceSizeMb}`
+        : null;
+    const resolvedNodeOptions = heapFlag
+      ? `${nextNodeOptions} ${heapFlag}`.trim()
+      : nextNodeOptions;
     let child;
     try {
       child = spawn(pnpm, args, {
         stdio: "inherit",
-        env: { ...process.env, VITEST_GROUP: entry.name, NODE_OPTIONS: nextNodeOptions },
+        env: { ...process.env, VITEST_GROUP: entry.name, NODE_OPTIONS: resolvedNodeOptions },
         shell: isWindows,
       });
     } catch (err) {