Serena

Instructions

Implementation Reference

• src/serena/tools/config_tools.py:37-55 (handler)

  The SwitchModesTool class implements the execution logic (handler) for the 'switch_modes' tool. It accepts a list of mode names, loads the corresponding SerenaAgentMode instances, sets them on the agent, and returns a detailed confirmation including prompts and active tools.

  class SwitchModesTool(Tool, ToolMarkerOptional):
      """
      Activates modes by providing a list of their names
      """
  
      def apply(self, modes: list[str]) -> str:
          """
          Activates the desired modes, like ["editing", "interactive"] or ["planning", "one-shot"]
  
          :param modes: the names of the modes to activate
          """
          mode_instances = [SerenaAgentMode.load(mode) for mode in modes]
          self.agent.set_modes(mode_instances)
  
          # Inform the Agent about the activated modes and the currently active tools
          result_str = f"Successfully activated modes: {', '.join([mode.name for mode in mode_instances])}" + "\n"
          result_str += "\n".join([mode_instance.prompt for mode_instance in mode_instances]) + "\n"
          result_str += f"Currently active tools: {', '.join(self.agent.get_active_tool_names())}"
          return result_str

• src/serena/tools/tools_base.py:357-367 (registration)

  The ToolRegistry singleton automatically discovers and registers all subclasses of Tool in the 'serena.tools' package, including SwitchModesTool, deriving its name 'switch_modes' and marking it as optional.

  def __init__(self) -> None:
      self._tool_dict: dict[str, RegisteredTool] = {}
      for cls in iter_subclasses(Tool):
          if not any(cls.__module__.startswith(pkg) for pkg in tool_packages):
              continue
          is_optional = issubclass(cls, ToolMarkerOptional)
          name = cls.get_name_from_cls()
          if name in self._tool_dict:
              raise ValueError(f"Duplicate tool name found: {name}. Tool classes must have unique names.")
          self._tool_dict[name] = RegisteredTool(tool_class=cls, is_optional=is_optional, tool_name=name)

• src/serena/tools/tools_base.py:119-129 (helper)

  The get_name_from_cls class method in the base Tool class converts 'SwitchModesTool' to the tool name 'switch_modes' used for registration and MCP exposure.

  def get_name_from_cls(cls) -> str:
      name = cls.__name__
      if name.endswith("Tool"):
          name = name[:-4]
      # convert to snake_case
      name = "".join(["_" + c.lower() if c.isupper() else c for c in name]).lstrip("_")
      return name
  
  def get_name(self) -> str:
      return self.get_name_from_cls()

• src/serena/agent.py:226-227 (registration)

  In SerenaAgent.__init__, all registered tools including SwitchModesTool are instantiated from the ToolRegistry and stored in self._all_tools for later exposure.

  # instantiate all tool classes
  self._all_tools: dict[type[Tool], Tool] = {tool_class: tool_class(self) for tool_class in ToolRegistry().get_all_tool_classes()}