Pokemon Showdown MCP Server

Instructions

Implementation Reference

• mcpkmn_showdown/pokemon_server.py:334-362 (handler)

  MCP server tool handler for get_type_effectiveness. Parses arguments, delegates computation to data_loader.get_type_effectiveness, and formats a human-readable response describing the multiplier and effectiveness.

      elif name == "get_type_effectiveness":
          attack_type = arguments["attack_type"]
          defend_types = arguments["defend_types"]
          multiplier = loader.get_type_effectiveness(attack_type, defend_types)
  
          # Describe the effectiveness
          if multiplier == 0:
              desc = "No effect (immune)"
          elif multiplier == 0.25:
              desc = "Not very effective (0.25x)"
          elif multiplier == 0.5:
              desc = "Not very effective (0.5x)"
          elif multiplier == 1:
              desc = "Normal effectiveness (1x)"
          elif multiplier == 2:
              desc = "Super effective (2x)"
          elif multiplier == 4:
              desc = "Super effective (4x)"
          else:
              desc = f"{multiplier}x"
  
          response = f"""## Type Effectiveness
  
  **{attack_type.capitalize()}** vs **{'/'.join(t.capitalize() for t in defend_types)}**
  
  **Multiplier:** {multiplier}x
  **Result:** {desc}
  """
          return [TextContent(type="text", text=response)]

• mcpkmn_showdown/pokemon_server.py:241-259 (registration)

  Registration of the get_type_effectiveness tool in @server.list_tools(), defining name, description, and input schema.

  Tool(
      name="get_type_effectiveness",
      description="Calculate type effectiveness multiplier for an attack against a Pokemon's types.",
      inputSchema={
          "type": "object",
          "properties": {
              "attack_type": {
                  "type": "string",
                  "description": "The attacking move's type (e.g., 'electric', 'fire')"
              },
              "defend_types": {
                  "type": "array",
                  "items": {"type": "string"},
                  "description": "List of the defending Pokemon's types (e.g., ['water', 'flying'])"
              }
          },
          "required": ["attack_type", "defend_types"]
      }
  ),

• mcpkmn_showdown/data_loader.py:168-195 (helper)

  Helper method in PokemonDataLoader that implements the core type effectiveness logic by loading typechart.json and multiplying effectiveness values for each defending type.

  def get_type_effectiveness(
      self, attack_type: str, defend_types: list[str]
  ) -> float:
      """
      Calculate type effectiveness multiplier.
  
      Args:
          attack_type: The attacking move's type
          defend_types: List of defending Pokemon's types
  
      Returns:
          Effectiveness multiplier (0, 0.25, 0.5, 1, 2, 4)
      """
      self.load_all()
  
      attack_type = attack_type.lower()
      defend_types = [t.lower() for t in defend_types]
  
      multiplier = 1.0
  
      # Type chart maps defending type -> attacking type -> multiplier
      for defend_type in defend_types:
          type_data = self.typechart.get(defend_type, {})
          eff = type_data.get(attack_type, 1.0)
          multiplier *= eff
  
      return multiplier