diff --git a/scripts/e2e/secret-provider-integrations.mjs b/scripts/e2e/secret-provider-integrations.mjs
index ed574f91469c..1fb53ff9e613 100644
--- a/scripts/e2e/secret-provider-integrations.mjs
+++ b/scripts/e2e/secret-provider-integrations.mjs
@@ -45,6 +45,11 @@ const OUTPUT_CAPTURE_LIMIT_BYTES = readPositiveInt(
   4 * 1024 * 1024,
   "OPENCLAW_SECRET_PROOF_OUTPUT_BYTES",
 );
+const RESOLVER_STDIN_LIMIT_BYTES = readPositiveInt(
+  process.env.OPENCLAW_SECRET_PROOF_RESOLVER_STDIN_BYTES,
+  1024 * 1024,
+  "OPENCLAW_SECRET_PROOF_RESOLVER_STDIN_BYTES",
+);
 const RESULTS_PATH =
   process.env.OPENCLAW_SECRET_PROOF_RESULTS_PATH?.trim() ||
   path.join(os.tmpdir(), `openclaw-secret-provider-e2e-results-${process.pid}.json`);
@@ -596,15 +601,36 @@ if (!storePath) {
   console.error("missing PROOF_SECRET_STORE_PATH");
   process.exit(4);
 }
+const stdinLimitBytes = ${RESOLVER_STDIN_LIMIT_BYTES};
 
 function readStdin() {
-  return new Promise((resolve) => {
+  return new Promise((resolve, reject) => {
     let body = "";
+    let bytes = 0;
+    let failed = false;
+    const fail = (error) => {
+      if (failed) {
+        return;
+      }
+      failed = true;
+      reject(error);
+    };
     process.stdin.setEncoding("utf8");
     process.stdin.on("data", (chunk) => {
+      bytes += Buffer.byteLength(chunk, "utf8");
+      if (bytes > stdinLimitBytes) {
+        fail(new Error(\`resolver stdin exceeded \${stdinLimitBytes} bytes\`));
+        process.stdin.destroy();
+        return;
+      }
       body += chunk;
     });
-    process.stdin.on("end", () => resolve(body));
+    process.stdin.on("error", fail);
+    process.stdin.on("end", () => {
+      if (!failed) {
+        resolve(body);
+      }
+    });
   });
 }
 
@@ -1835,6 +1861,7 @@ export {
   runCommand,
   startGateway,
   waitForManagedGatewayStatus,
+  writeProofPlugin,
 };
 
 if (process.argv[1] && import.meta.url === pathToFileURL(path.resolve(process.argv[1])).href) {
diff --git a/test/scripts/secret-provider-integrations.test.ts b/test/scripts/secret-provider-integrations.test.ts
index a7deed5495e9..73276b5fdf44 100644
--- a/test/scripts/secret-provider-integrations.test.ts
+++ b/test/scripts/secret-provider-integrations.test.ts
@@ -258,6 +258,7 @@ describe("secret provider integration proof harness", () => {
     ["OPENCLAW_SECRET_PROOF_COMMAND_MS", "150ms"],
     ["OPENCLAW_SECRET_PROOF_READY_MS", "0"],
     ["OPENCLAW_SECRET_PROOF_OUTPUT_BYTES", "4mb"],
+    ["OPENCLAW_SECRET_PROOF_RESOLVER_STDIN_BYTES", "4mb"],
   ])("rejects malformed proof env limit %s=%s", async (name, value) => {
     const previous = process.env[name];
     process.env[name] = value;
@@ -274,6 +275,48 @@ describe("secret provider integration proof harness", () => {
     }
   });
 
+  it("bounds generated resolver stdin before reading the secret store", async () => {
+    const root = makeTempDir();
+    const stateDir = path.join(root, "state");
+    fs.mkdirSync(stateDir, { recursive: true });
+    const storePath = path.join(stateDir, "proof-secret-store.json");
+    fs.writeFileSync(
+      storePath,
+      `${JSON.stringify({ mode: "ok", calls: 0, values: { "proof/id": "ok" } }, null, 2)}\n`,
+      "utf8",
+    );
+    const previousLimit = process.env.OPENCLAW_SECRET_PROOF_RESOLVER_STDIN_BYTES;
+    process.env.OPENCLAW_SECRET_PROOF_RESOLVER_STDIN_BYTES = "64";
+
+    try {
+      const proof = await import(
+        `${pathToFileURL(proofScriptPath).href}?case=resolver-stdin-${Date.now()}`
+      );
+      const plugin = proof.writeProofPlugin({ stateDir });
+      const result = spawnSync(process.execPath, [plugin.resolverPath], {
+        cwd: plugin.pluginRoot,
+        encoding: "utf8",
+        env: {
+          ...process.env,
+          PROOF_SECRET_STORE_PATH: storePath,
+        },
+        input: JSON.stringify({ ids: ["proof/id"], padding: "x".repeat(512) }),
+        timeout: 5_000,
+      });
+
+      expect(result.error).toBeUndefined();
+      expect(result.status).not.toBe(0);
+      expect(`${result.stderr}${result.stdout}`).toContain("resolver stdin exceeded 64 bytes");
+      expect(JSON.parse(fs.readFileSync(storePath, "utf8")).calls).toBe(0);
+    } finally {
+      if (previousLimit === undefined) {
+        delete process.env.OPENCLAW_SECRET_PROOF_RESOLVER_STDIN_BYTES;
+      } else {
+        process.env.OPENCLAW_SECRET_PROOF_RESOLVER_STDIN_BYTES = previousLimit;
+      }
+    }
+  });
+
   it("fails when proof temp cleanup cannot remove the root", async () => {
     const proof = await import(`${pathToFileURL(proofScriptPath).href}?case=cleanup-${Date.now()}`);
     const rmSync = vi.spyOn(fs, "rmSync").mockImplementation(() => {