Brex MCP Server

A Model Context Protocol (MCP) server for integrating with the Brex API, enabling AI agents to interact with financial data and resources.

Overview

This MCP server provides a bridge between AI agents and the Brex financial platform, allowing agents to:

Retrieve account information and transactions
Access expense data and receipts
Manage budget resources and spend limits
View team information

The server implements standardized resource handlers and tools following the MCP specification, enabling secure and efficient access to financial data.

Features

Resources

Account Resources

brex://accounts - List all accounts
brex://accounts/{id} - Access specific account details

Expense Resources

brex://expenses - List all expenses with pagination
brex://expenses/{id} - Access specific expense details
brex://expenses/card - List all card expenses
brex://expenses/card/{id} - Access specific card expense details

Note: Expense resources automatically expand merchant and budget information to display human-readable names instead of IDs.

Budget Resources

brex://budgets - List all budgets with pagination
brex://budgets/{id} - Access specific budget details
brex://spend_limits - List all spend limits
brex://spend_limits/{id} - Access specific spend limit details
brex://budget_programs - List all budget programs
brex://budget_programs/{id} - Access specific budget program details

Team Resources

brex://users/me - Get current user information

Tools

Receipt Management

match_receipt - Match a receipt with existing expenses
upload_receipt - Upload a receipt for a specific expense

Expense Management

update_expense - Update details for a card expense (memo, category, etc.)
get_all_expenses - Get all expenses with filtering options and expanded merchant/budget information
get_all_card_expenses - Get all card expenses with filtering options and expanded merchant/budget information

Note: For security reasons, tools that create, update, or delete budgets, spend limits, and budget programs are not implemented in this version.

Installation

Prerequisites

Node.js v18 or higher
Brex API access token

Setup

Clone this repository:

git clone https://github.com/dennisonbertram/brex-mcp-server.git
cd brex-mcp-server

Install dependencies:

npm install

Create a .env file with your Brex API token:

BREX_API_KEY=your_token_here
BREX_API_URL=https://platform.brexapis.com
PORT=3000
NODE_ENV=development
RATE_LIMIT_REQUESTS=1000
RATE_LIMIT_WINDOW_MS=60000
LOG_LEVEL=info

Build the server:

npm run build

Configuration with Claude

To use with Claude Desktop, you need to add the server to Claude's configuration file:

On macOS: ~/Library/Application Support/Claude/claude_desktop_config.json On Windows: %APPDATA%\Claude\claude_desktop_config.json

Open Claude for Desktop and go to settings by clicking on the Claude menu and selecting "Settings..."
Click on "Developer" in the left sidebar, then click "Edit Config"
Update the configuration file with the Brex MCP server settings:

{
  "mcpServers": {
    "brex-server": {
      "command": "node",
      "args": [
        "/path/to/brex-mcp-server/build/index.js"
      ],
      "env": {
        "BREX_API_KEY": "your_brex_api_key_here",
        "BREX_API_URL": "https://platform.brexapis.com",
        "PORT": "3000",
        "NODE_ENV": "development",
        "RATE_LIMIT_REQUESTS": "1000",
        "RATE_LIMIT_WINDOW_MS": "60000",
        "LOG_LEVEL": "info"
      }
    }
  }
}

Make sure to:

Replace /path/to/brex-mcp-server with the actual path where you installed the server
Replace your_brex_api_key_here with your actual Brex API key
Use absolute paths for the server location

Only the BREX_API_KEY and BREX_API_URL values are required; the other environment variables have sensible defaults but can be customized if needed.

Save the file and restart Claude for Desktop
Verify the server is working by checking for the hammer icon in the bottom right corner of the input box

Development

For development with auto-rebuild:

npm run dev

Lint your code:

npm run lint

Run tests:

npm run test

Debugging

Since MCP servers communicate over stdio, debugging can be challenging. We recommend using the MCP Inspector for debugging.

Security Considerations

This server implements several security measures:

Read-only operations for sensitive financial resources
No storage of API credentials in code
Rate limiting for API requests
Proper error handling and logging

Implementation Status

For a detailed implementation plan and status of various features, see documentation/implementation_plan.md.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Author

Dennison Bertram - dennison@dennisonbertram.com