diff --git a/packages/cli/src/config/extensions/github_fetch.test.ts b/packages/cli/src/config/extensions/github_fetch.test.ts
new file mode 100644
index 0000000000..fe6edbedb2
--- /dev/null
+++ b/packages/cli/src/config/extensions/github_fetch.test.ts
@@ -0,0 +1,199 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi, afterEach, beforeEach } from 'vitest';
+import * as https from 'node:https';
+import { EventEmitter } from 'node:events';
+import { fetchJson, getGitHubToken } from './github_fetch.js';
+import type { ClientRequest, IncomingMessage } from 'node:http';
+
+vi.mock('node:https');
+
+describe('getGitHubToken', () => {
+  const originalToken = process.env['GITHUB_TOKEN'];
+
+  afterEach(() => {
+    if (originalToken) {
+      process.env['GITHUB_TOKEN'] = originalToken;
+    } else {
+      delete process.env['GITHUB_TOKEN'];
+    }
+  });
+
+  it('should return the token if GITHUB_TOKEN is set', () => {
+    process.env['GITHUB_TOKEN'] = 'test-token';
+    expect(getGitHubToken()).toBe('test-token');
+  });
+
+  it('should return undefined if GITHUB_TOKEN is not set', () => {
+    delete process.env['GITHUB_TOKEN'];
+    expect(getGitHubToken()).toBeUndefined();
+  });
+});
+
+describe('fetchJson', () => {
+  const getMock = vi.mocked(https.get);
+
+  afterEach(() => {
+    vi.resetAllMocks();
+  });
+
+  it('should fetch and parse JSON successfully', async () => {
+    getMock.mockImplementationOnce((_url, _options, callback) => {
+      const res = new EventEmitter() as IncomingMessage;
+      res.statusCode = 200;
+      (callback as (res: IncomingMessage) => void)(res);
+      res.emit('data', Buffer.from('{"foo":'));
+      res.emit('data', Buffer.from('"bar"}'));
+      res.emit('end');
+      return new EventEmitter() as ClientRequest;
+    });
+    await expect(fetchJson('https://example.com/data.json')).resolves.toEqual({
+      foo: 'bar',
+    });
+  });
+
+  it('should handle redirects (301 and 302)', async () => {
+    // Test 302
+    getMock.mockImplementationOnce((_url, _options, callback) => {
+      const res = new EventEmitter() as IncomingMessage;
+      res.statusCode = 302;
+      res.headers = { location: 'https://example.com/final' };
+      (callback as (res: IncomingMessage) => void)(res);
+      res.emit('end');
+      return new EventEmitter() as ClientRequest;
+    });
+    getMock.mockImplementationOnce((url, _options, callback) => {
+      expect(url).toBe('https://example.com/final');
+      const res = new EventEmitter() as IncomingMessage;
+      res.statusCode = 200;
+      (callback as (res: IncomingMessage) => void)(res);
+      res.emit('data', Buffer.from('{"success": true}'));
+      res.emit('end');
+      return new EventEmitter() as ClientRequest;
+    });
+
+    await expect(fetchJson('https://example.com/redirect')).resolves.toEqual({
+      success: true,
+    });
+
+    // Test 301
+    getMock.mockImplementationOnce((_url, _options, callback) => {
+      const res = new EventEmitter() as IncomingMessage;
+      res.statusCode = 301;
+      res.headers = { location: 'https://example.com/final-permanent' };
+      (callback as (res: IncomingMessage) => void)(res);
+      res.emit('end');
+      return new EventEmitter() as ClientRequest;
+    });
+    getMock.mockImplementationOnce((url, _options, callback) => {
+      expect(url).toBe('https://example.com/final-permanent');
+      const res = new EventEmitter() as IncomingMessage;
+      res.statusCode = 200;
+      (callback as (res: IncomingMessage) => void)(res);
+      res.emit('data', Buffer.from('{"permanent": true}'));
+      res.emit('end');
+      return new EventEmitter() as ClientRequest;
+    });
+
+    await expect(
+      fetchJson('https://example.com/redirect-perm'),
+    ).resolves.toEqual({ permanent: true });
+  });
+
+  it('should reject on non-200/30x status code', async () => {
+    getMock.mockImplementationOnce((_url, _options, callback) => {
+      const res = new EventEmitter() as IncomingMessage;
+      res.statusCode = 404;
+      (callback as (res: IncomingMessage) => void)(res);
+      res.emit('end');
+      return new EventEmitter() as ClientRequest;
+    });
+
+    await expect(fetchJson('https://example.com/error')).rejects.toThrow(
+      'Request failed with status code 404',
+    );
+  });
+
+  it('should reject on request error', async () => {
+    const error = new Error('Network error');
+    getMock.mockImplementationOnce(() => {
+      const req = new EventEmitter() as ClientRequest;
+      req.emit('error', error);
+      return req;
+    });
+
+    await expect(fetchJson('https://example.com/error')).rejects.toThrow(
+      'Network error',
+    );
+  });
+
+  describe('with GITHUB_TOKEN', () => {
+    const originalToken = process.env['GITHUB_TOKEN'];
+
+    beforeEach(() => {
+      process.env['GITHUB_TOKEN'] = 'my-secret-token';
+    });
+
+    afterEach(() => {
+      if (originalToken) {
+        process.env['GITHUB_TOKEN'] = originalToken;
+      } else {
+        delete process.env['GITHUB_TOKEN'];
+      }
+    });
+
+    it('should include Authorization header if token is present', async () => {
+      getMock.mockImplementationOnce((_url, options, callback) => {
+        expect(options.headers).toEqual({
+          'User-Agent': 'gemini-cli',
+          Authorization: 'token my-secret-token',
+        });
+        const res = new EventEmitter() as IncomingMessage;
+        res.statusCode = 200;
+        (callback as (res: IncomingMessage) => void)(res);
+        res.emit('data', Buffer.from('{"foo": "bar"}'));
+        res.emit('end');
+        return new EventEmitter() as ClientRequest;
+      });
+      await expect(fetchJson('https://api.github.com/user')).resolves.toEqual({
+        foo: 'bar',
+      });
+    });
+  });
+
+  describe('without GITHUB_TOKEN', () => {
+    const originalToken = process.env['GITHUB_TOKEN'];
+
+    beforeEach(() => {
+      delete process.env['GITHUB_TOKEN'];
+    });
+
+    afterEach(() => {
+      if (originalToken) {
+        process.env['GITHUB_TOKEN'] = originalToken;
+      }
+    });
+
+    it('should not include Authorization header if token is not present', async () => {
+      getMock.mockImplementationOnce((_url, options, callback) => {
+        expect(options.headers).toEqual({
+          'User-Agent': 'gemini-cli',
+        });
+        const res = new EventEmitter() as IncomingMessage;
+        res.statusCode = 200;
+        (callback as (res: IncomingMessage) => void)(res);
+        res.emit('data', Buffer.from('{"foo": "bar"}'));
+        res.emit('end');
+        return new EventEmitter() as ClientRequest;
+      });
+
+      await expect(fetchJson('https://api.github.com/user')).resolves.toEqual({
+        foo: 'bar',
+      });
+    });
+  });
+});
diff --git a/packages/cli/src/config/extensions/github_fetch.ts b/packages/cli/src/config/extensions/github_fetch.ts
index 3940275699..a4f9d29b70 100644
--- a/packages/cli/src/config/extensions/github_fetch.ts
+++ b/packages/cli/src/config/extensions/github_fetch.ts
@@ -10,7 +10,10 @@ export function getGitHubToken(): string | undefined {
   return process.env['GITHUB_TOKEN'];
 }
 
-export async function fetchJson<T>(url: string): Promise<T> {
+export async function fetchJson<T>(
+  url: string,
+  redirectCount: number = 0,
+): Promise<T> {
   const headers: { 'User-Agent': string; Authorization?: string } = {
     'User-Agent': 'gemini-cli',
   };
@@ -21,6 +24,18 @@ export async function fetchJson<T>(url: string): Promise<T> {
   return new Promise((resolve, reject) => {
     https
       .get(url, { headers }, (res) => {
+        if (res.statusCode === 302 || res.statusCode === 301) {
+          if (redirectCount >= 10) {
+            return reject(new Error('Too many redirects'));
+          }
+          if (!res.headers.location) {
+            return reject(new Error('No location header in redirect response'));
+          }
+          fetchJson<T>(res.headers.location!, redirectCount++)
+            .then(resolve)
+            .catch(reject);
+          return;
+        }
         if (res.statusCode !== 200) {
           return reject(
             new Error(`Request failed with status code ${res.statusCode}`),