Office Word MCP Server

Instructions

Implementation Reference

• word_document_server/tools/protection_tools.py:225-276 (handler)

  The primary handler function implementing the unprotect_document tool. It decrypts password-protected Word documents using msoffcrypto, overwrites the original file with decrypted content, handles file permissions, and provides detailed error messages for invalid passwords or formats.

  async def unprotect_document(filename: str, password: str) -> str:
      """Remove password protection from a Word document.
  
      Args:
          filename: Path to the Word document
          password: Password that was used to protect the document
      """
      filename = ensure_docx_extension(filename)
  
      if not os.path.exists(filename):
          return f"Document {filename} does not exist"
  
      # Check if file is writeable
      is_writeable, error_message = check_file_writeable(filename)
      if not is_writeable:
          return f"Cannot modify document: {error_message}"
  
      try:
          # Read the encrypted file content
          with open(filename, "rb") as infile:
              encrypted_data = infile.read()
  
          # Create an msoffcrypto file object from the encrypted data
          file = msoffcrypto.OfficeFile(io.BytesIO(encrypted_data))
          file.load_key(password=password) # Set the password for decryption
  
          # Decrypt the data into an in-memory buffer
          decrypted_data_io = io.BytesIO()
          file.decrypt(outfile=decrypted_data_io) # Pass the buffer as the 'outfile' argument
  
          # Overwrite the original file with the decrypted data
          with open(filename, "wb") as outfile:
              outfile.write(decrypted_data_io.getvalue())
  
          return f"Document {filename} decrypted successfully."
  
      except msoffcrypto.exceptions.InvalidKeyError:
           return f"Failed to decrypt document {filename}: Incorrect password."
      except msoffcrypto.exceptions.InvalidFormatError:
           return f"Failed to decrypt document {filename}: File is not encrypted or is not a supported Office format."
      except Exception as e:
          # Attempt to restore encrypted file content on failure
          try:
              if 'encrypted_data' in locals():
                  with open(filename, "wb") as outfile:
                      outfile.write(encrypted_data)
                  return f"Failed to decrypt document {filename}: {str(e)}. Encrypted file restored."
              else:
                   return f"Failed to decrypt document {filename}: {str(e)}. Could not restore encrypted file."
          except Exception as restore_e:
               return f"Failed to decrypt document {filename}: {str(e)}. Also failed to restore encrypted file: {str(restore_e)}"

• word_document_server/main.py:291-295 (registration)

  The registration of the 'unprotect_document' tool using the @mcp.tool() decorator in the main server file. This sync wrapper delegates execution to the async implementation in protection_tools.

  @mcp.tool()
  def unprotect_document(filename: str, password: str):
      """Remove password protection from a Word document."""
      return protection_tools.unprotect_document(filename, password)