diff --git a/scripts/lib/plain-gh.mjs b/scripts/lib/plain-gh.mjs
index da3773668e7..23e65db9e46 100644
--- a/scripts/lib/plain-gh.mjs
+++ b/scripts/lib/plain-gh.mjs
@@ -2,6 +2,8 @@ import { execFileSync, spawnSync } from "node:child_process";
 import fs from "node:fs";
 import path from "node:path";
 
+export const PLAIN_GH_MAX_BUFFER_BYTES = 32 * 1024 * 1024;
+
 function isExecutable(filePath) {
   try {
     fs.accessSync(filePath, fs.constants.X_OK);
@@ -71,6 +73,7 @@ export function execPlainGh(args, options = {}) {
   return execFileSync(ghBin, args, {
     ...options,
     env,
+    maxBuffer: options.maxBuffer ?? PLAIN_GH_MAX_BUFFER_BYTES,
   });
 }
 
@@ -80,5 +83,6 @@ export function spawnPlainGh(args, options = {}) {
   return spawnSync(ghBin, args, {
     ...options,
     env,
+    maxBuffer: options.maxBuffer ?? PLAIN_GH_MAX_BUFFER_BYTES,
   });
 }
diff --git a/test/scripts/plain-gh.test.ts b/test/scripts/plain-gh.test.ts
index 7874380dc48..e7520342c10 100644
--- a/test/scripts/plain-gh.test.ts
+++ b/test/scripts/plain-gh.test.ts
@@ -4,7 +4,7 @@ import { chmodSync, mkdirSync, mkdtempSync, readFileSync, rmSync, writeFileSync
 import { tmpdir } from "node:os";
 import path from "node:path";
 import { afterEach, describe, expect, it } from "vitest";
-import { plainGhEnv, resolvePlainGhBin } from "../../scripts/lib/plain-gh.mjs";
+import { execPlainGh, plainGhEnv, resolvePlainGhBin } from "../../scripts/lib/plain-gh.mjs";
 
 const tempDirs: string[] = [];
 
@@ -36,6 +36,21 @@ printf 'COLORTERM_SET=%s\\n' "\${COLORTERM+x}"
   return ghPath;
 }
 
+function makeLargeFakeGh(): string {
+  const dir = mkdtempSync(path.join(tmpdir(), "plain-gh-large-"));
+  tempDirs.push(dir);
+  const ghPath = path.join(dir, "gh");
+  writeFileSync(
+    ghPath,
+    `#!/usr/bin/env node
+const bytes = Number(process.env.PLAIN_GH_FAKE_BYTES ?? "0");
+process.stdout.write("x".repeat(bytes));
+`,
+  );
+  chmodSync(ghPath, 0o755);
+  return ghPath;
+}
+
 describe("plain gh helpers", () => {
   it("prefers OPENCLAW_GH_BIN over PATH shims", () => {
     const ghPath = makeFakeGh();
@@ -99,6 +114,22 @@ describe("plain gh helpers", () => {
     expect(readFileSync(outputPath, "utf8")).toContain("COLORTERM_SET=");
   });
 
+  it("captures large gh payloads by default", () => {
+    const ghPath = makeLargeFakeGh();
+    const bytes = 2 * 1024 * 1024;
+
+    const output = execPlainGh(["api", "large"], {
+      encoding: "utf8",
+      env: {
+        ...process.env,
+        OPENCLAW_GH_BIN: ghPath,
+        PLAIN_GH_FAKE_BYTES: String(bytes),
+      },
+    });
+
+    expect(output).toHaveLength(bytes);
+  });
+
   it("keeps the shell resolver on external gh binaries", () => {
     const helper = readFileSync("scripts/lib/plain-gh.sh", "utf8");