Brex MCP Server

/** * @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 { ResourceTemplate } from "../models/resourceTemplate.js"; import { logDebug, logError } from "../utils/logger.js"; import { BrexClient } from "../services/brex/client.js"; import { ListExpensesParams, Expense } from "../services/brex/expenses-types.js"; import { parseQueryParams } from "../models/common.js"; import { limitExpensesPayload } from "../utils/responseLimiter.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: unknown): obj is Expense { return typeof obj === 'object' && obj !== null && 'id' in obj; } // normalizeCardExpense helper intentionally removed as unused /** * Registers the card expenses resource handler with the server * @param server The MCP server instance */ export function registerCardExpensesCapabilities(server: Server): void { server.registerCapabilities({ resources: { "brex://expenses/card{/id}": { description: "Brex card expenses (list or by ID); supports fields & summary_only", mimeTypes: ["application/json"], } } }); } export function canHandleCardExpensesUri(uri: string): boolean { return uri.startsWith("brex://expenses/card"); } export async function readCardExpensesUri(uri: string): Promise<any> { logDebug(`Reading card expenses resource: ${uri}`); const brexClient = getBrexClient(); const params = cardExpensesTemplate.parse(uri); if (!params.id) { try { const listParams: ListExpensesParams = { limit: 50, expand: ['merchant', 'budget'] }; const cardExpenses = await brexClient.getCardExpenses(listParams); const qp = parseQueryParams(uri); const fields = qp.fields ? qp.fields.split(',').map(s => s.trim()).filter(Boolean) : undefined; const summaryOnly = qp.summary_only === 'true'; const limited = limitExpensesPayload(cardExpenses.items as any, { summaryOnly, fields, hardTokenLimit: 24000 }); return { contents: [{ uri, mimeType: 'application/json', text: JSON.stringify(limited.items, null, 2) }] } as any; } catch (error) { logError(`Failed to fetch card expenses: ${error instanceof Error ? error.message : String(error)}`); throw error; } } else { try { const cardExpense = await brexClient.getCardExpense(params.id, { expand: ['merchant','budget','location','department','receipts.download_uris'], load_custom_fields: true }); if (!isCardExpense(cardExpense)) throw new Error('Invalid card expense data received'); const qp = parseQueryParams(uri); const fields = qp.fields ? qp.fields.split(',').map(s => s.trim()).filter(Boolean) : undefined; const summaryOnly = qp.summary_only === 'true'; const limited = limitExpensesPayload([cardExpense] as any, { summaryOnly, fields, hardTokenLimit: 24000 }); return { contents: [{ uri, mimeType: 'application/json', text: JSON.stringify(limited.items[0] || {}, null, 2) }] } as any; } catch (error) { logError(`Failed to fetch card expense ${params.id}: ${error instanceof Error ? error.message : String(error)}`); throw error; } } }