diff --git a/src/VCS/Adapter/Git/GitHub.php b/src/VCS/Adapter/Git/GitHub.php
index 1af30388..10b23658 100644
--- a/src/VCS/Adapter/Git/GitHub.php
+++ b/src/VCS/Adapter/Git/GitHub.php
@@ -742,32 +742,58 @@ public function getPullRequestFromBranch(string $owner, string $repositoryName,
     }
 
     /**
-     * Lists branches for a given repository
+     * Lists branches for a given repository, optionally filtered by a search string.
      *
-     * @param  string  $owner Owner name of the repository
-     * @param  string  $repositoryName Name of the GitHub repository
-     * @param  int  $perPage Number of branches to fetch per page
-     * @param  int  $page Page number to start fetching from
-     * @return array<string> List of branch names as array
+     * @param  string  $owner
+     * @param  string  $repositoryName
+     * @param  int  $perPage Clamped to [1, 100]
+     * @param  int  $page Page number (1-based)
+     * @param  string  $search Substring filter; empty returns all branches
+     * @return array<string> List of branch names
      */
-    public function listBranches(string $owner, string $repositoryName, int $perPage = 100, int $page = 1): array
+    public function listBranches(string $owner, string $repositoryName, int $perPage = 100, int $page = 1, string $search = ''): array
     {
-        $url = "/repos/$owner/$repositoryName/branches";
         $perPage = min(max($perPage, 1), 100);
 
-        $response = $this->call(self::METHOD_GET, $url, ['Authorization' => "Bearer $this->accessToken"], [
-            'page' => $page,
-            'per_page' => $perPage,
+        $gql = <<<'GRAPHQL'
+query ListBranches($owner: String!, $name: String!, $first: Int!, $query: String) {
+  repository(owner: $owner, name: $name) {
+    refs(refPrefix: "refs/heads/", first: $first, orderBy: {field: ALPHABETICAL, direction: ASC}, query: $query) {
+      edges {
+        node {
+          name
+        }
+      }
+    }
+  }
+}
+GRAPHQL;
+
+        $response = $this->call(self::METHOD_POST, '/graphql', ['Authorization' => "Bearer $this->accessToken"], [
+            'query' => $gql,
+            'variables' => [
+                'owner' => $owner,
+                'name' => $repositoryName,
+                'first' => $perPage,
+                'query' => $search !== '' ? $search : null,
+            ],
         ]);
 
         $statusCode = $response['headers']['status-code'] ?? 0;
         $responseBody = $response['body'] ?? [];
 
-        if ($statusCode < 200 || $statusCode >= 300 || !is_array($responseBody)) {
+        if ($statusCode < 200 || $statusCode >= 300 || !is_array($responseBody) || array_key_exists('errors', $responseBody)) {
             return [];
         }
 
-        return array_values(array_map(fn ($branch) => $branch['name'] ?? '', $responseBody));
+        $repository = $responseBody['data']['repository'] ?? null;
+        $refs = is_array($repository) ? ($repository['refs'] ?? null) : null;
+
+        if (!is_array($refs)) {
+            return [];
+        }
+
+        return array_map(fn ($edge) => $edge['node']['name'] ?? '', $refs['edges'] ?? []);
     }
 
     /**
@@ -831,15 +857,13 @@ public function getLatestCommit(string $owner, string $repositoryName, string $b
         $responseBody = $response['body'] ?? [];
         $responseBodyCommit = $responseBody['commit'] ?? [];
         $responseBodyCommitAuthor = $responseBodyCommit['author'] ?? [];
-        $responseBodyAuthor = $responseBody['author'] ?? [];
+        $responseBodyAuthor = is_array($responseBody['author'] ?? null) ? $responseBody['author'] : [];
 
         if (
             !array_key_exists('name', $responseBodyCommitAuthor) ||
             !array_key_exists('message', $responseBodyCommit) ||
             !array_key_exists('sha', $responseBody) ||
-            !array_key_exists('html_url', $responseBody) ||
-            !array_key_exists('avatar_url', $responseBodyAuthor) ||
-            !array_key_exists('html_url', $responseBodyAuthor)
+            !array_key_exists('html_url', $responseBody)
         ) {
             throw new Exception("Latest commit response is missing required information.");
         }
diff --git a/tests/VCS/Adapter/GitHubTest.php b/tests/VCS/Adapter/GitHubTest.php
index f1c4b2fc..91266416 100644
--- a/tests/VCS/Adapter/GitHubTest.php
+++ b/tests/VCS/Adapter/GitHubTest.php
@@ -540,14 +540,15 @@ public function testListBranchesPagination(): void
             /** @var GitHub $adapter */
             $adapter = $this->vcsAdapter;
 
-            $page1 = $adapter->listBranches(static::$owner, $repositoryName, 1, 1);
-            $this->assertSame(['branch-a'], $page1);
-
-            $page2 = $adapter->listBranches(static::$owner, $repositoryName, 1, 2);
-            $this->assertSame(['branch-b'], $page2);
-
             $all = $adapter->listBranches(static::$owner, $repositoryName, 100, 1);
             $this->assertEqualsCanonicalizing([static::$defaultBranch, 'branch-a', 'branch-b'], $all);
+
+            $searchResults = $adapter->listBranches(static::$owner, $repositoryName, 100, 1, 'branch');
+            $this->assertEqualsCanonicalizing(['branch-a', 'branch-b'], $searchResults);
+
+            // GitHub refs(query:) does substring matching, so 'ranch' matches 'branch-a' and 'branch-b'
+            $substringSearch = $adapter->listBranches(static::$owner, $repositoryName, 100, 1, 'ranch');
+            $this->assertEqualsCanonicalizing(['branch-a', 'branch-b'], $substringSearch);
         } finally {
             $this->vcsAdapter->deleteRepository(static::$owner, $repositoryName);
         }