get_expense

Instructions

Implementation Reference

• src/tools/expenses.ts:39-57 (handler)

  The GetExpenseHandler class that implements the 'get_expense' tool logic. It validates input (expects expense_id), fetches the expense from the Harvest API, and returns the result.

  class GetExpenseHandler implements ToolHandler {
    constructor(private readonly config: BaseToolConfig) {}
  
    async execute(args: Record<string, any>): Promise<CallToolResult> {
      try {
        const inputSchema = z.object({ expense_id: z.number().int().positive() });
        const { expense_id } = validateInput(inputSchema, args, 'get expense');
        
        logger.info('Fetching expense from Harvest API', { expenseId: expense_id });
        const expense = await this.config.harvestClient.getExpense(expense_id);
        
        return {
          content: [{ type: 'text', text: JSON.stringify(expense, null, 2) }],
        };
      } catch (error) {
        return handleMCPToolError(error, 'get_expense');
      }
    }
  }

• src/tools/expenses.ts:158-172 (registration)

  Registration of the 'get_expense' tool with its name, description, input schema (expense_id required), and handler binding (new GetExpenseHandler(config)).

  {
    tool: {
      name: 'get_expense',
      description: 'Retrieve a specific expense by ID with complete details including receipts and billing information.',
      inputSchema: {
        type: 'object',
        properties: {
          expense_id: { type: 'number', description: 'The ID of the expense to retrieve' },
        },
        required: ['expense_id'],
        additionalProperties: false,
      },
    },
    handler: new GetExpenseHandler(config),
  },

• src/tools/expenses.ts:44-44 (schema)

  Inline input schema for get_expense using zod: expects expense_id as a positive integer.

  const inputSchema = z.object({ expense_id: z.number().int().positive() });

• src/client/expenses-client.ts:45-61 (helper)

  The ExpensesClient.getExpense() API client method that makes the actual HTTP GET request to /expenses/{expenseId}.

  async getExpense(expenseId: number): Promise<any> {
    try {
      this.logger.debug('Fetching expense', { expenseId });
      const response: AxiosResponse = await this.client.get(`/expenses/${expenseId}`);
      
      this.logger.info('Successfully retrieved expense', {
        expenseId: response.data.id,
        totalCost: response.data.total_cost,
        spentDate: response.data.spent_date
      });
      
      return response.data;
    } catch (error) {
      this.logger.error('Failed to retrieve expense', { expenseId, error: (error as Error).message });
      throw error;
    }
  }

• src/server.ts:139-139 (registration)

  The 'get_expense' tool name is listed under the 'expenses' category mapping in the server, enabling tool filtering by category.

  'expenses': ['list_expenses', 'get_expense', 'create_expense', 'update_expense', 'delete_expense', 'list_expense_categories'],