diff --git a/scripts/docker-e2e-timings.mjs b/scripts/docker-e2e-timings.mjs
index 8c3f557a4d0a..968cddaf1dfd 100644
--- a/scripts/docker-e2e-timings.mjs
+++ b/scripts/docker-e2e-timings.mjs
@@ -5,6 +5,9 @@
 import fs from "node:fs";
 import { parsePositiveInt } from "./lib/numeric-options.mjs";
 
+const JSON_ARTIFACT_MAX_BYTES_ENV = "OPENCLAW_DOCKER_E2E_JSON_ARTIFACT_MAX_BYTES";
+const DEFAULT_JSON_ARTIFACT_MAX_BYTES = 16 * 1024 * 1024;
+
 function usage() {
   return "Usage: node scripts/docker-e2e-timings.mjs <summary.json|lane-timings.json> [--limit N]";
 }
@@ -41,7 +44,29 @@ function parseArgs(argv) {
 }
 
 function readJson(file) {
-  return JSON.parse(fs.readFileSync(file, "utf8"));
+  return JSON.parse(readJsonArtifactText(file));
+}
+
+function readJsonArtifactText(file) {
+  const maxBytes = readPositiveIntEnv(JSON_ARTIFACT_MAX_BYTES_ENV, DEFAULT_JSON_ARTIFACT_MAX_BYTES);
+  const stat = fs.statSync(file);
+  if (!stat.isFile()) {
+    throw new Error(`JSON artifact is not a file: ${file}`);
+  }
+  if (stat.size > maxBytes) {
+    throw new Error(`JSON artifact exceeded ${maxBytes} bytes: ${file} (${stat.size} bytes)`);
+  }
+  const text = fs.readFileSync(file, "utf8");
+  const bytes = Buffer.byteLength(text, "utf8");
+  if (bytes > maxBytes) {
+    throw new Error(`JSON artifact exceeded ${maxBytes} bytes: ${file} (${bytes} bytes)`);
+  }
+  return text;
+}
+
+function readPositiveIntEnv(name, fallback) {
+  const raw = process.env[name];
+  return raw === undefined || raw === "" ? fallback : parsePositiveInt(raw, name);
 }
 
 function seconds(value) {
diff --git a/scripts/docker-e2e.mjs b/scripts/docker-e2e.mjs
index 2ce290c2a5c1..df3f409bc334 100644
--- a/scripts/docker-e2e.mjs
+++ b/scripts/docker-e2e.mjs
@@ -2,6 +2,10 @@
 // Converts scheduler JSON into GitHub Actions outputs and compact markdown
 // summaries so the workflow does not duplicate Docker E2E planning logic.
 import fs from "node:fs";
+import { parsePositiveInt } from "./lib/numeric-options.mjs";
+
+const JSON_ARTIFACT_MAX_BYTES_ENV = "OPENCLAW_DOCKER_E2E_JSON_ARTIFACT_MAX_BYTES";
+const DEFAULT_JSON_ARTIFACT_MAX_BYTES = 16 * 1024 * 1024;
 
 function usage() {
   return [
@@ -13,7 +17,29 @@ function usage() {
 }
 
 function readJson(file) {
-  return JSON.parse(fs.readFileSync(file, "utf8"));
+  return JSON.parse(readJsonArtifactText(file));
+}
+
+function readJsonArtifactText(file) {
+  const maxBytes = readPositiveIntEnv(JSON_ARTIFACT_MAX_BYTES_ENV, DEFAULT_JSON_ARTIFACT_MAX_BYTES);
+  const stat = fs.statSync(file);
+  if (!stat.isFile()) {
+    throw new Error(`JSON artifact is not a file: ${file}`);
+  }
+  if (stat.size > maxBytes) {
+    throw new Error(`JSON artifact exceeded ${maxBytes} bytes: ${file} (${stat.size} bytes)`);
+  }
+  const text = fs.readFileSync(file, "utf8");
+  const bytes = Buffer.byteLength(text, "utf8");
+  if (bytes > maxBytes) {
+    throw new Error(`JSON artifact exceeded ${maxBytes} bytes: ${file} (${bytes} bytes)`);
+  }
+  return text;
+}
+
+function readPositiveIntEnv(name, fallback) {
+  const raw = process.env[name];
+  return raw === undefined || raw === "" ? fallback : parsePositiveInt(raw, name);
 }
 
 function boolOutput(value) {
diff --git a/test/scripts/docker-e2e-helper-cli.test.ts b/test/scripts/docker-e2e-helper-cli.test.ts
index d56b01e8c9f9..c2db152c83a5 100644
--- a/test/scripts/docker-e2e-helper-cli.test.ts
+++ b/test/scripts/docker-e2e-helper-cli.test.ts
@@ -5,14 +5,20 @@ import { tmpdir } from "node:os";
 import path from "node:path";
 import { describe, expect, it } from "vitest";
 
-function runHelper(script: string, ...args: string[]) {
-  return spawnSync(process.execPath, [script, ...args], {
+function runHelper(script: string, ...args: Array<string | Record<string, string>>) {
+  const maybeEnv = args.at(-1);
+  const env =
+    maybeEnv && typeof maybeEnv === "object"
+      ? (args.pop() as unknown as Record<string, string>)
+      : {};
+  return spawnSync(process.execPath, [script, ...(args as string[])], {
     cwd: process.cwd(),
     encoding: "utf8",
     env: {
       ...process.env,
       GH_FORCE_TTY: "0",
       NO_COLOR: "1",
+      ...env,
     },
   });
 }
@@ -36,6 +42,26 @@ describe("Docker E2E helper CLIs", () => {
     expect(result.stderr).not.toContain("at file:");
   });
 
+  it("rejects oversized scheduler helper JSON artifacts without a Node stack trace", () => {
+    const root = mkdtempSync(`${tmpdir()}/openclaw-docker-e2e-helper-`);
+    try {
+      const file = path.join(root, "summary.json");
+      writeFileSync(file, `${JSON.stringify({ filler: "x".repeat(128) })}\n`, "utf8");
+
+      const result = runHelper("scripts/docker-e2e.mjs", "failed-reruns", file, {
+        OPENCLAW_DOCKER_E2E_JSON_ARTIFACT_MAX_BYTES: "64",
+      });
+
+      expect(result.status).toBe(1);
+      expect(result.stdout).toBe("");
+      expect(result.stderr).toContain("JSON artifact exceeded 64 bytes");
+      expect(result.stderr).not.toContain("Error:");
+      expect(result.stderr).not.toContain("at file:");
+    } finally {
+      rmSync(root, { force: true, recursive: true });
+    }
+  });
+
   it("prints timings help without treating --help as an artifact path", () => {
     const result = runHelper("scripts/docker-e2e-timings.mjs", "--help");
 
@@ -56,6 +82,26 @@ describe("Docker E2E helper CLIs", () => {
     expect(result.stderr).not.toContain("at file:");
   });
 
+  it("rejects oversized timing JSON artifacts without a Node stack trace", () => {
+    const root = mkdtempSync(`${tmpdir()}/openclaw-docker-e2e-timings-`);
+    try {
+      const file = path.join(root, "summary.json");
+      writeFileSync(file, `${JSON.stringify({ filler: "x".repeat(128) })}\n`, "utf8");
+
+      const result = runHelper("scripts/docker-e2e-timings.mjs", file, {
+        OPENCLAW_DOCKER_E2E_JSON_ARTIFACT_MAX_BYTES: "64",
+      });
+
+      expect(result.status).toBe(1);
+      expect(result.stdout).toBe("");
+      expect(result.stderr).toContain("JSON artifact exceeded 64 bytes");
+      expect(result.stderr).not.toContain("Error:");
+      expect(result.stderr).not.toContain("at file:");
+    } finally {
+      rmSync(root, { force: true, recursive: true });
+    }
+  });
+
   it("rejects missing timings limits without a Node stack trace", () => {
     const result = runHelper("scripts/docker-e2e-timings.mjs", "summary.json", "--limit");