diff --git a/fastcode/loader.py b/fastcode/loader.py
index 87977b9..6d2272e 100644
--- a/fastcode/loader.py
+++ b/fastcode/loader.py
@@ -10,10 +10,11 @@
 from typing import Dict, List, Optional, Any
 import logging
 from git import Repo, GitCommandError
+from pathspec import PathSpec
+from pathspec.patterns import GitWildMatchPattern
 
 from .utils import (
     is_supported_file,
-    should_ignore_path,
     get_repo_name_from_url,
     normalize_path,
     ensure_dir,
@@ -228,19 +229,39 @@ def scan_files(self) -> List[Dict[str, Any]]:
         files = []
         total_size = 0
         max_file_size_bytes = self.max_file_size_mb * 1024 * 1024
-        
+        ignore_spec = PathSpec.from_lines(GitWildMatchPattern, effective_ignore)
+
+        def is_ignored_repo_relative(rel_path: str, *, is_dir: bool = False) -> bool:
+            """Match ignore patterns against normalized repo-relative paths."""
+            normalized = normalize_path(rel_path)
+            if ignore_spec.match_file(normalized):
+                return True
+            # Directory-style patterns (e.g. "output/" or ".venv/") are most
+            # reliable with a trailing slash candidate.
+            if is_dir and ignore_spec.match_file(f"{normalized}/"):
+                return True
+            return False
+
         for root, dirs, filenames in os.walk(self.repo_path):
-            # Filter out ignored directories
-            dirs[:] = [d for d in dirs if not should_ignore_path(
-                os.path.join(root, d), effective_ignore
-            )]
+            # Filter ignored directories using repo-relative paths so gitwildmatch
+            # patterns like "output/" or ".venv/" match consistently.
+            filtered_dirs = []
+            for d in dirs:
+                abs_dir_path = os.path.join(root, d)
+                rel_dir_path = normalize_path(
+                    os.path.relpath(abs_dir_path, self.repo_path)
+                )
+                if is_ignored_repo_relative(rel_dir_path, is_dir=True):
+                    continue
+                filtered_dirs.append(d)
+            dirs[:] = filtered_dirs
 
             for filename in filenames:
                 file_path = os.path.join(root, filename)
-                relative_path = os.path.relpath(file_path, self.repo_path)
+                relative_path = normalize_path(os.path.relpath(file_path, self.repo_path))
 
                 # Check if should ignore
-                if should_ignore_path(relative_path, effective_ignore):
+                if is_ignored_repo_relative(relative_path):
                     continue
                 
                 # Check if supported extension
@@ -347,4 +368,3 @@ def cleanup(self):
     def __del__(self):
         """Cleanup on deletion"""
         self.cleanup()
-