diff --git a/scripts/github/dependency-guard.mjs b/scripts/github/dependency-guard.mjs
index f91e08de608..dcdbcbd7df1 100644
--- a/scripts/github/dependency-guard.mjs
+++ b/scripts/github/dependency-guard.mjs
@@ -6,6 +6,7 @@ export const dependencyChangeMarker = "<!-- openclaw:dependency-guard -->";
 export const dependencyGraphGuardMarker = "<!-- openclaw:dependency-graph-guard -->";
 export const dependencyChangedLabel = "dependencies-changed";
 export const allowDependenciesCommand = "/allow-dependencies-change";
+export const GITHUB_ERROR_BODY_MAX_BYTES = 64 * 1024;
 
 const maxListedFiles = 25;
 const securityTeamSlug = process.env.OPENCLAW_SECURITY_TEAM_SLUG ?? "openclaw-secops";
@@ -312,7 +313,55 @@ export function renderBlockedDependencyComment({
   ].join("\n");
 }
 
-function githubApi(token) {
+function githubErrorBodyTooLarge(maxBytes) {
+  return new Error(`GitHub error response body exceeded ${maxBytes} bytes`);
+}
+
+export async function readBoundedGitHubErrorText(response, maxBytes = GITHUB_ERROR_BODY_MAX_BYTES) {
+  const contentLength = Number(response.headers.get("content-length") ?? "");
+  if (Number.isSafeInteger(contentLength) && contentLength > maxBytes) {
+    await response.body?.cancel().catch(() => undefined);
+    throw githubErrorBodyTooLarge(maxBytes);
+  }
+  if (!response.body) {
+    return "";
+  }
+
+  const reader = response.body.getReader();
+  const decoder = new TextDecoder();
+  const chunks = [];
+  let totalBytes = 0;
+  let canceled = false;
+
+  try {
+    for (;;) {
+      const { done, value } = await reader.read();
+      if (done) {
+        const tail = decoder.decode();
+        if (tail) {
+          chunks.push(tail);
+        }
+        break;
+      }
+
+      totalBytes += value.byteLength;
+      if (totalBytes > maxBytes) {
+        canceled = true;
+        await reader.cancel().catch(() => undefined);
+        throw githubErrorBodyTooLarge(maxBytes);
+      }
+      chunks.push(decoder.decode(value, { stream: true }));
+    }
+  } finally {
+    if (!canceled) {
+      reader.releaseLock();
+    }
+  }
+
+  return chunks.join("");
+}
+
+export function githubApi(token) {
   const baseHeaders = {
     accept: "application/vnd.github+json",
     authorization: `Bearer ${token}`,
@@ -328,9 +377,13 @@ function githubApi(token) {
       return null;
     }
     if (!response.ok) {
-      const error = new Error(
-        `${response.status} ${response.statusText}: ${await response.text()}`,
-      );
+      let errorText;
+      try {
+        errorText = await readBoundedGitHubErrorText(response);
+      } catch (bodyError) {
+        errorText = bodyError instanceof Error ? bodyError.message : String(bodyError);
+      }
+      const error = new Error(`${response.status} ${response.statusText}: ${errorText}`);
       error.status = response.status;
       throw error;
     }
diff --git a/test/scripts/dependency-guard-script.test.ts b/test/scripts/dependency-guard-script.test.ts
index cb6d0f606e8..8750c8043ee 100644
--- a/test/scripts/dependency-guard-script.test.ts
+++ b/test/scripts/dependency-guard-script.test.ts
@@ -1,14 +1,17 @@
 import { describe, expect, it } from "vitest";
 import {
+  GITHUB_ERROR_BODY_MAX_BYTES,
   dependencyGuardCommentHeadSha,
   dependencyFieldChanges,
   dependencyOverrideExpectedSha,
   findDependencyOverrideCommand,
   findDependencyOverrideCommandAsync,
+  githubApi,
   isDependencyGuardAuthorizedForHead,
   isDependencyFile,
   isDependencyManifest,
   isPackageLockfile,
+  readBoundedGitHubErrorText,
   renderAuthorizedDependencyComment,
   renderBlockedDependencyComment,
   renderClearedDependencyGuardComment,
@@ -269,4 +272,54 @@ describe("dependency guard script", () => {
     expect(sanitizeDisplayValue("abc\u0000def")).toBe("abc?def");
     expect(sanitizeDisplayValue("x".repeat(300))).toHaveLength(240);
   });
+
+  it("bounds GitHub error bodies by content-length", async () => {
+    const response = new Response("ignored", {
+      headers: { "content-length": String(GITHUB_ERROR_BODY_MAX_BYTES + 1) },
+    });
+
+    await expect(readBoundedGitHubErrorText(response)).rejects.toThrow(
+      `GitHub error response body exceeded ${GITHUB_ERROR_BODY_MAX_BYTES} bytes`,
+    );
+  });
+
+  it("bounds GitHub error bodies by streamed bytes", async () => {
+    const response = new Response(
+      new ReadableStream({
+        start(controller) {
+          controller.enqueue(new Uint8Array(GITHUB_ERROR_BODY_MAX_BYTES + 1));
+          controller.close();
+        },
+      }),
+    );
+
+    await expect(readBoundedGitHubErrorText(response)).rejects.toThrow(
+      `GitHub error response body exceeded ${GITHUB_ERROR_BODY_MAX_BYTES} bytes`,
+    );
+  });
+
+  it("preserves GitHub status when an error body exceeds the cap", async () => {
+    const originalFetch = globalThis.fetch;
+    globalThis.fetch = (() =>
+      Promise.resolve(
+        new Response(
+          new ReadableStream({
+            start(controller) {
+              controller.enqueue(new Uint8Array(GITHUB_ERROR_BODY_MAX_BYTES + 1));
+              controller.close();
+            },
+          }),
+          { status: 403, statusText: "Forbidden" },
+        ),
+      )) as typeof fetch;
+
+    try {
+      await expect(githubApi("token").request("/repos/openclaw/openclaw")).rejects.toMatchObject({
+        message: `403 Forbidden: GitHub error response body exceeded ${GITHUB_ERROR_BODY_MAX_BYTES} bytes`,
+        status: 403,
+      });
+    } finally {
+      globalThis.fetch = originalFetch;
+    }
+  });
 });