diff --git a/.claude/skills/convert-to-company-docs/convert.py b/.claude/skills/convert-to-company-docs/convert.py
index fde150d06..386dbf0ca 100644
--- a/.claude/skills/convert-to-company-docs/convert.py
+++ b/.claude/skills/convert-to-company-docs/convert.py
@@ -26,6 +26,32 @@
     sys.exit(1)
 
 
+# M-05: Allowed directories for file access (path restriction)
+ALLOWED_UPLOAD_DIRS = [
+    'knowledge/',
+    'docs/',
+    'agents/',
+    'core/',
+    'logs/',
+]
+
+PROJECT_ROOT = Path(os.environ.get('CLAUDE_PROJECT_DIR', '.')).resolve()
+
+
+def _is_path_allowed(file_path: str) -> bool:
+    """
+    M-05: Validate that file path is within allowed directories.
+    Prevents converting arbitrary files (e.g., .env, credentials) to Google Docs.
+    """
+    try:
+        resolved = Path(file_path).resolve()
+        rel = resolved.relative_to(PROJECT_ROOT)
+        rel_str = str(rel).replace('\\', '/')
+        return any(rel_str.startswith(prefix) for prefix in ALLOWED_UPLOAD_DIRS)
+    except (ValueError, RuntimeError):
+        return False
+
+
 # Cores Company (RGB normalizado 0-1)
 COLORS = {
     'background': {'red': 0.953, 'green': 0.953, 'blue': 0.953},      # #F3F3F3
@@ -314,6 +340,12 @@ def convert(self, md_path: str, folder_id: str = None) -> dict:
             print(f"ERRO: Arquivo nao encontrado: {md_path}")
             return None
 
+        # M-05: Validate file path is within allowed directories
+        if not _is_path_allowed(md_path):
+            print(f"ERRO [SECURITY]: Conversao bloqueada — path fora dos diretorios permitidos: {md_path}")
+            print(f"  Diretorios permitidos: {ALLOWED_UPLOAD_DIRS}")
+            return None
+
         # Autenticar
         if not self.docs_service:
             if not self.authenticate():
diff --git a/.claude/skills/sync-docs/gdrive_sync.py b/.claude/skills/sync-docs/gdrive_sync.py
index 1f0517ddd..46f170d1a 100644
--- a/.claude/skills/sync-docs/gdrive_sync.py
+++ b/.claude/skills/sync-docs/gdrive_sync.py
@@ -23,6 +23,35 @@
     sys.exit(1)
 
 
+# M-05: Allowed directories for upload (path restriction)
+ALLOWED_UPLOAD_DIRS = [
+    'knowledge/',
+    'docs/',
+    'agents/',
+    'core/',
+    'logs/',
+]
+
+PROJECT_ROOT = Path(os.environ.get('CLAUDE_PROJECT_DIR', '.')).resolve()
+
+
+def _is_upload_path_allowed(local_path: str) -> bool:
+    """
+    M-05: Validate that upload path is within allowed directories.
+    Prevents uploading arbitrary files (e.g., .env, credentials) to Google Drive.
+    """
+    try:
+        resolved = Path(local_path).resolve()
+        # Must be under project root
+        rel = resolved.relative_to(PROJECT_ROOT)
+        rel_str = str(rel).replace('\\', '/')
+        # Must start with one of the allowed prefixes
+        return any(rel_str.startswith(prefix) for prefix in ALLOWED_UPLOAD_DIRS)
+    except (ValueError, RuntimeError):
+        # relative_to raises ValueError if not relative
+        return False
+
+
 class GDriveSync:
     """Sincronizador de arquivos com Google Drive usando OAuth."""
 
@@ -204,6 +233,12 @@ def upload_file(self, local_path: str, folder_id: str = None, folder_name: str =
             print(f"ERRO: Arquivo nao encontrado: {local_path}")
             return None
 
+        # M-05: Validate upload path is within allowed directories
+        if not _is_upload_path_allowed(local_path):
+            print(f"ERRO [SECURITY]: Upload bloqueado — path fora dos diretorios permitidos: {local_path}")
+            print(f"  Diretorios permitidos: {ALLOWED_UPLOAD_DIRS}")
+            return None
+
         # Determina pasta destino
         target_folder_id = folder_id
         if not target_folder_id:
diff --git a/.claude/skills/sync-docs/reauth.py b/.claude/skills/sync-docs/reauth.py
index 2e5c0fd54..35af5c8e0 100644
--- a/.claude/skills/sync-docs/reauth.py
+++ b/.claude/skills/sync-docs/reauth.py
@@ -21,9 +21,9 @@
     'https://www.googleapis.com/auth/drive.file'
 ]
 
-# Paths
-OAUTH_KEYS = Path(r"~/.config/mcp-gdrive/gcp-oauth.keys.json")
-TOKEN_FILE = Path(r"~/.config/mcp-gdrive/.gdrive-server-credentials.json")
+# Paths — use Path.home() for cross-platform ~ expansion (M-06 fix)
+OAUTH_KEYS = Path.home() / ".config" / "mcp-gdrive" / "gcp-oauth.keys.json"
+TOKEN_FILE = Path.home() / ".config" / "mcp-gdrive" / ".gdrive-server-credentials.json"
 
 
 def main():