Brex MCP Server

What is Brex MCP Server?

Brex MCP Server is a Model Context Protocol server that provides AI assistants read-only access to the Brex API for expenses, budgets, transactions, and accounts. It is optimized for safe, small responses with projection, pagination, and batching.

How to use Brex MCP Server?

Install the npm package globally (npm install -g mcp-brex), then add it to your MCP client by providing a Brex API key. For Claude Code, run claude mcp add brex --env BREX_API_KEY=your_key -- npx mcp-brex. For Claude Desktop, add the configuration to claude_desktop_config.json.

Key features of Brex MCP Server

• Resources for expenses, budgets, spend limits, budget programs, transactions, and documentation.
• Read-only tools for budgets, spend limits, expenses, card statements, transactions, and accounts.
• Write tools for matching and uploading receipts.
• Pagination, date/status/amount filtering, and nested object expansion control.
• Resources accept summary_only and fields parameters to minimize payload size.

Use cases of Brex MCP Server

• Query and filter company expenses by date, status, amount, or merchant.
• Retrieve budget details and spend limits for financial oversight.
• Access card and cash transactions for reconciliation and audit.
• Upload or match receipts to existing expenses via natural language.
• Integrate Brex financial data into an AI assistant for quick answers.

FAQ from Brex MCP Server

What does Brex MCP Server do?

It connects AI assistants to the Brex API, allowing read-only retrieval of expenses, budgets, transactions, and accounts, plus receipt matching/upload.

What are the dependencies?

Node.js and npm are required. An active Brex API key must be provided as the BREX_API_KEY environment variable.

Where does Brex data live?

Data is fetched live from the Brex API. The server does not store any Brex data locally.

What transports and authentication are used?

The server uses stdio transport (MCP protocol) and authenticates via a Brex API key set as an environment variable.

Are there any limits or restrictions?

Cash endpoints require additional Brex scopes (return 403 if missing). Pagination is limited to page_size ≤50 and max_items ≤200. Large expansions can produce very large payloads; filtering is strongly recommended.