/**
* @file Card Expenses Resource Handler
* @version 1.0.0
* @description Handles Brex card expenses resource requests
*/
import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { ReadResourceRequestSchema } from "@modelcontextprotocol/sdk/types.js";
import { ResourceTemplate } from "../models/resourceTemplate.js";
import { logDebug, logError } from "../utils/logger.js";
import { BrexClient } from "../services/brex/client.js";
import {
ListExpensesParams,
ExpenseType,
ExpenseStatus,
Expense
} from "../services/brex/expenses-types.js";
// Get Brex client
function getBrexClient(): BrexClient {
return new BrexClient();
}
// Define card expenses resource template
const cardExpensesTemplate = new ResourceTemplate("brex://expenses/card{/id}");
/**
* Checks if an object is a card expense (has expected properties)
* @param obj The object to check
* @returns true if the object appears to be a valid expense
*/
function isCardExpense(obj: any): obj is Expense {
return obj &&
typeof obj === 'object' &&
'id' in obj;
}
/**
* Normalize card expense data to ensure required fields are present
*/
function normalizeCardExpense(expense: any, id?: string): any {
// Create a copy to avoid modifying the original
const normalizedExpense = { ...expense };
// Ensure required fields
if (!normalizedExpense.id) normalizedExpense.id = id || "unknown-" + Math.random().toString(36).substring(2, 9);
if (!normalizedExpense.updated_at) normalizedExpense.updated_at = new Date().toISOString();
if (!normalizedExpense.status) normalizedExpense.status = ExpenseStatus.SUBMITTED; // Default status
// Format merchant information
if (normalizedExpense.merchant) {
if (typeof normalizedExpense.merchant === 'object') {
const merchantName = normalizedExpense.merchant.raw_descriptor || 'Unknown Merchant';
(normalizedExpense as any).merchant_name = merchantName;
if (!normalizedExpense.merchant.raw_descriptor) {
(normalizedExpense.merchant as any).raw_descriptor = 'Unknown';
}
}
} else if (normalizedExpense.merchant_id) {
normalizedExpense.merchant = {
raw_descriptor: 'Merchant ID: ' + normalizedExpense.merchant_id,
id: normalizedExpense.merchant_id
};
(normalizedExpense as any).merchant_name = 'Merchant ID: ' + normalizedExpense.merchant_id;
}
// Format budget information
if (normalizedExpense.budget_id && !normalizedExpense.budget) {
normalizedExpense.budget = {
id: normalizedExpense.budget_id,
name: 'Budget ID: ' + normalizedExpense.budget_id
};
}
return normalizedExpense;
}
/**
* Registers the card expenses resource handler with the server
* @param server The MCP server instance
*/
export function registerCardExpensesResource(server: Server): void {
server.registerCapabilities({
resources: {
"brex://expenses/card{/id}": {
description: "Brex card expenses",
mimeTypes: ["application/json"],
}
}
});
// Use the standard approach with setRequestHandler
server.setRequestHandler(ReadResourceRequestSchema, async (request, extra) => {
const uri = request.params.uri;
// Check if this handler should process this URI
if (!uri.startsWith("brex://expenses/card")) {
return { handled: false }; // Not handled by this handler
}
logDebug(`Reading card expenses resource: ${uri}`);
// Get Brex client
const brexClient = getBrexClient();
// Parse parameters from URI
const params = cardExpensesTemplate.parse(uri);
if (!params.id) {
// List all card expenses
try {
logDebug("Fetching all card expenses from Brex API");
const listParams: ListExpensesParams = {
expense_type: [ExpenseType.CARD],
limit: 50,
expand: ['merchant', 'budget'] // Always expand merchant and budget information
};
const cardExpenses = await brexClient.getCardExpenses(listParams);
logDebug(`Successfully fetched ${cardExpenses.items.length} card expenses`);
return {
contents: [{
uri: uri,
mimeType: "application/json",
text: JSON.stringify(cardExpenses.items, null, 2)
}]
};
} catch (error) {
logError(`Failed to fetch card expenses: ${error instanceof Error ? error.message : String(error)}`);
throw error;
}
} else {
// Get specific card expense
try {
logDebug(`Fetching card expense ${params.id} from Brex API`);
const cardExpense = await brexClient.getCardExpense(params.id, {
expand: ['merchant', 'budget', 'location', 'department', 'receipts.download_uris'],
load_custom_fields: true
});
if (!isCardExpense(cardExpense)) {
logError(`Invalid card expense data received for card expense ID: ${params.id}`);
throw new Error('Invalid card expense data received');
}
logDebug(`Successfully fetched card expense ${params.id}`);
return {
contents: [{
uri: uri,
mimeType: "application/json",
text: JSON.stringify(cardExpense, null, 2)
}]
};
} catch (error) {
logError(`Failed to fetch card expense ${params.id}: ${error instanceof Error ? error.message : String(error)}`);
throw error;
}
}
});
}
