Home Assistant MCP Server

Instructions

Implementation Reference

• src/index.ts:195-205 (handler)

  The handler function for the 'get_entity_state' tool. It retrieves the state of the specified Home Assistant entity using the haClient and returns it as a formatted JSON string in the tool response.

  case "get_entity_state": {
    const entity = await haClient.getState(args?.entity_id as string);
    return {
      content: [
        {
          type: "text",
          text: JSON.stringify(entity, null, 2),
        },
      ],
    };
  }

• src/index.ts:113-126 (schema)

  Tool schema definition including name, description, and input schema for 'get_entity_state', registered in the list_tools response.

  {
    name: "get_entity_state",
    description: "Get the current state and attributes of a specific entity",
    inputSchema: {
      type: "object",
      properties: {
        entity_id: {
          type: "string",
          description: "The entity ID (e.g., 'light.living_room')",
        },
      },
      required: ["entity_id"],
    },
  },

• src/index.ts:54-56 (helper)

  Helper method in HomeAssistantClient class that performs the actual API call to retrieve the entity state from Home Assistant.

  async getState(entityId: string): Promise<HAEntity> {
    return this.fetch(`states/${entityId}`);
  }

• src/index.ts:15-21 (schema)

  TypeScript interface defining the structure of a Home Assistant entity state, used by the get_entity_state tool.

  interface HAEntity {
    entity_id: string;
    state: string;
    attributes: Record<string, any>;
    last_changed: string;
    last_updated: string;
  }