Terminal Controller for MCP

Instructions

Insert content at specific row(s) in a file

Args:
    path: Path to the file
    content: Content to insert (string or JSON object)
    row: Row number to insert at (0-based, optional)
    rows: List of row numbers to insert at (0-based, optional)

Returns:
    Operation result information

Implementation Reference

• terminal_controller.py:400-504 (handler)

  The main handler function for the 'insert_file_content' MCP tool. It handles inserting string or JSON content into a file at specified row(s) (0-based indexing), or appending if no row specified. Supports creating directories/files if needed, handles line endings, and provides detailed error messages.

  @mcp.tool()
  async def insert_file_content(path: str, content: str, row: int = None, rows: list = None) -> str:
      """
      Insert content at specific row(s) in a file
      
      Args:
          path: Path to the file
          content: Content to insert (string or JSON object)
          row: Row number to insert at (0-based, optional)
          rows: List of row numbers to insert at (0-based, optional)
      
      Returns:
          Operation result information
      """
      try:
          # Handle different content types
          if not isinstance(content, str):
              try:
                  import json
                  content = json.dumps(content, indent=4, sort_keys=False, ensure_ascii=False, default=str)
              except Exception as e:
                  return f"Error: Unable to convert content to JSON string: {str(e)}"
              
          # Ensure content ends with a newline if it doesn't already
          if content and not content.endswith('\n'):
              content += '\n'
              
          # Create file if it doesn't exist
          directory = os.path.dirname(os.path.abspath(path))
          if not os.path.exists(directory):
              os.makedirs(directory, exist_ok=True)
              
          if not os.path.exists(path):
              with open(path, 'w', encoding='utf-8') as file:
                  pass
              
          with open(path, 'r', encoding='utf-8', errors='replace') as file:
              lines = file.readlines()
          
          # Ensure all existing lines end with newlines
          for i in range(len(lines)):
              if lines[i] and not lines[i].endswith('\n'):
                  lines[i] += '\n'
          
          # Prepare lines for insertion
          content_lines = content.splitlines(True)  # Keep line endings
          
          # Handle inserting at specific rows
          if rows is not None:
              if not isinstance(rows, list):
                  return "Error: 'rows' parameter must be a list of integers."
                  
              # Sort rows in descending order to avoid changing indices during insertion
              rows = sorted(rows, reverse=True)
              
              for r in rows:
                  if not isinstance(r, int) or r < 0:
                      return "Error: Row numbers must be non-negative integers."
                      
                  if r > len(lines):
                      # If row is beyond the file, append necessary empty lines
                      lines.extend(['\n'] * (r - len(lines)))
                      lines.extend(content_lines)
                  else:
                      # Insert content at each specified row
                      for line in reversed(content_lines):
                          lines.insert(r, line)
              
              # Write back to the file
              with open(path, 'w', encoding='utf-8') as file:
                  file.writelines(lines)
                  
              return f"Successfully inserted content at rows {rows} in '{path}'."
              
          # Handle inserting at a single row
          elif row is not None:
              if not isinstance(row, int) or row < 0:
                  return "Error: Row number must be a non-negative integer."
                  
              if row > len(lines):
                  # If row is beyond the file, append necessary empty lines
                  lines.extend(['\n'] * (row - len(lines)))
                  lines.extend(content_lines)
              else:
                  # Insert content at the specified row
                  for line in reversed(content_lines):
                      lines.insert(row, line)
              
              # Write back to the file
              with open(path, 'w', encoding='utf-8') as file:
                  file.writelines(lines)
                  
              return f"Successfully inserted content at row {row} in '{path}'."
          
          # If neither row nor rows specified, append to the end
          else:
              with open(path, 'a', encoding='utf-8') as file:
                  file.write(content)
              return f"Successfully appended content to '{path}'."
              
      except PermissionError:
          return f"Error: No permission to modify file '{path}'."
      except Exception as e:
          return f"Error inserting content: {str(e)}"