diff --git a/oai.py b/oai.py
index 991d679..d58266b 100644
--- a/oai.py
+++ b/oai.py
@@ -4647,18 +4647,42 @@ def chat():
             # PROCESS FILE ATTACHMENTS
             # ============================================================
             text_part = user_input
-            for match in re.finditer(r'@([^\s]+)', user_input):
+            file_attachments = []
+            content_blocks = []
+            
+            # Smart file detection with extension whitelist
+            # Only matches files with known extensions or clear path prefixes
+            # 
+            # Valid matches:
+            #   @/path/to/file
+            #   @~/file.txt
+            #   @./script.py
+            #   @report.pdf
+            #
+            # Excludes:
+            #   @domain.com (no whitelisted extension)
+            #   @mail.server.eu (TLD not in whitelist)
+            #   user@domain.com (email pattern)
+            #   Diagnostic-Code: @server.eu (TLD not in whitelist)
+            
+            file_pattern = r'(?:^|\s)@((?:[~/][\S]+)|(?:\.[\S]+)|(?:[\w][\w-]*\.(?:py|txt|md|log|json|csv|pdf|png|jpg|jpeg|gif|bmp|webp|svg|ico|zip|tar|gz|bz2|7z|rar|xz|js|ts|jsx|tsx|vue|html|css|scss|sass|less|xml|yaml|yml|toml|ini|conf|cfg|env|properties|sh|bash|zsh|fish|bat|cmd|ps1|c|cpp|cc|cxx|h|hpp|hxx|java|class|jar|war|rb|go|rs|swift|kt|kts|php|sql|db|sqlite|sqlite3|lock|gitignore|dockerignore|editorconfig|eslintrc|prettierrc|babelrc|nvmrc|npmrc|pyc|pyo|pyd|so|dll|dylib|exe|app|dmg|pkg|deb|rpm|apk|ipa|wasm|proto|graphql|graphqls|grpc|avro|parquet|orc|feather|arrow|hdf5|h5|mat|r|rdata|rds|pkl|pickle|joblib|npy|npz|safetensors|onnx|pt|pth|ckpt|pb|tflite|mlmodel|coreml|rknn)))(?=\s|$)'
+            
+            for match in re.finditer(file_pattern, user_input, re.IGNORECASE):
                 file_path = match.group(1)
                 expanded_path = os.path.expanduser(os.path.abspath(file_path))
+                
                 if not os.path.exists(expanded_path) or os.path.isdir(expanded_path):
                     console.print(f"[bold red]File not found or is a directory: {expanded_path}[/]")
                     continue
+                
                 file_size = os.path.getsize(expanded_path)
                 if file_size > 10 * 1024 * 1024:
                     console.print(f"[bold red]File too large (>10MB): {expanded_path}[/]")
                     continue
+                
                 mime_type, _ = mimetypes.guess_type(expanded_path)
                 file_ext = os.path.splitext(expanded_path)[1].lower()
+                
                 try:
                     with open(expanded_path, 'rb') as f:
                         file_data = f.read()
@@ -4704,7 +4728,9 @@ def chat():
                     console.print(f"[bold red]Error reading file {expanded_path}: {e}[/]")
                     app_logger.error(f"File read error for {expanded_path}: {e}")
                     continue
-            text_part = re.sub(r'@([^\s]+)', '', text_part).strip()
+            
+            # Remove file attachments from text (use same pattern as file detection)
+            text_part = re.sub(file_pattern, lambda m: m.group(0)[0] if m.group(0)[0].isspace() else '', text_part).strip()
 
             # Build message content
             if text_part or content_blocks:
@@ -4716,6 +4742,7 @@ def chat():
                 console.print("[bold red]Prompt cannot be empty.[/]")
                 continue
 
+
             # ============================================================
             # BUILD API MESSAGES
             # ============================================================