Can the agent truly issue a real, functioning corporate card?

Yes! The `brex_create_card` logic specifically maps to creating a virtual limit card. By default, it operates completely valid via Visa/Mastercard configurations matching Brex internals. The agent handles setting its name and tying it strictly to the user id.

What acts as the final authentication key for Brex?

You only need a `User Token`. Brex explicitly supports personal workflow automation using `user_tokens` which perfectly mimic your permissions. It typically begins literally with the string `user_token_` followed by hashes.

Will vendor payments via AI require external 2FA from my side?

To enforce safety in the integration, the `approval_type` parameter when sending vendor money defaults to `'MANUAL'`. This means the AI structures all the math, formatting, routing inputs perfectly but leaves the final 'Accept' button queued on your dashboard.

How can I see my user lists across Brex?

Run a request on `brex_list_users`. The AI will natively stream the company's organizational tree mapping the emails to Brex UUIDs required for triggering corporate card injections.

Brex MCP Server for Mastra AI 10 tools — connect in under 2 minutes

Name: Brex
Availability: InStock
Author: Vinkius

docs.mastra.ai/docs/agents/mcp-tools

Built by Vinkius GDPR 10 Tools SDK

Mastra AI is a TypeScript-native agent framework built for modern web stacks. Connect Brex through the Vinkius and Mastra agents discover all tools automatically — type-safe, streaming-ready, and deployable anywhere Node.js runs.

Get MCP Server for AI Agents

ASK AI ABOUT THIS MCP SERVER

Open in ChatGPT Open in Claude Open in Perplexity

Vinkius supports streamable HTTP and SSE.

typescript

import { Agent } from "@mastra/core/agent";
import { createMCPClient } from "@mastra/mcp";
import { openai } from "@ai-sdk/openai";

async function main() {
  // Your Vinkius token — get it at cloud.vinkius.com
  const mcpClient = await createMCPClient({
    servers: {
      "brex": {
        url: "https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp",
      },
    },
  });

  const tools = await mcpClient.getTools();
  const agent = new Agent({
    name: "Brex Agent",
    instructions:
      "You help users interact with Brex " +
      "using 10 tools.",
    model: openai("gpt-4o"),
    tools,
  });

  const result = await agent.generate(
    "What can I do with Brex?"
  );
  console.log(result.text);
}

main();

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* Every MCP server runs on Vinkius-managed infrastructure inside AWS - a purpose-built runtime with per-request V8 isolates, Ed25519 signed audit chains, and sub-40ms cold starts optimized for native MCP execution. See our infrastructure

About Brex MCP Server

The Brex MCP Server bridges standard large language models directly via the platform.brexapis.com to your startup's core spend engine. By delivering a single static User Token, you enable the most flexible financial assistant available.

Mastra's agent abstraction provides a clean separation between LLM logic and Brex tool infrastructure. Connect 10 tools through the Vinkius and use Mastra's built-in workflow engine to chain tool calls with conditional logic, retries, and parallel execution — deployable to any Node.js host in one command.

What you can do

Agile Employee Onboarding — brex_create_user directly provisions employees with their associated hierarchical structure. Follow it up with brex_create_card to hand them digital spend capacity securely limited.
Accounting Snapshots — You don't need to load the Brex dash to trace down runaway expenses. Trigger brex_list_transactions to pull highly contextualized raw CSV data into your AI workspace.
Accounts Payable Controls — Draft and approve external entity vendors via brex_create_vendor and initiate routing payments brex_pay_vendor seamlessly, letting internal routing protocols map out the wires.

The Brex MCP Server exposes 10 tools through the Vinkius. Connect it to Mastra AI in under two minutes — no API keys to rotate, no infrastructure to provision, no vendor lock-in. Your configuration, your data, your control.

How to Connect Brex to Mastra AI via MCP

Follow these steps to integrate the Brex MCP Server with Mastra AI.

Install dependencies

Run npm install @mastra/core @mastra/mcp @ai-sdk/openai

Replace the token

Replace [YOUR_TOKEN_HERE] with your Vinkius token

Run the agent

Save to agent.ts and run with npx tsx agent.ts

Explore tools

Mastra discovers 10 tools from Brex via MCP

Why Use Mastra AI with the Brex MCP Server

Mastra AI provides unique advantages when paired with Brex through the Model Context Protocol.

Mastra's agent abstraction provides a clean separation between LLM logic and tool infrastructure — add Brex without touching business code

Built-in workflow engine chains MCP tool calls with conditional logic, retries, and parallel execution for complex automation

TypeScript-native: full type inference for every Brex tool response with IDE autocomplete and compile-time checks

One-command deployment to any Node.js host — Vercel, Railway, Fly.io, or your own infrastructure

Brex + Mastra AI Use Cases

Practical scenarios where Mastra AI combined with the Brex MCP Server delivers measurable value.

Automated workflows: build multi-step agents that query Brex, process results, and trigger downstream actions in a typed pipeline

SaaS integrations: embed Brex as a first-class tool in your product's AI features with Mastra's clean agent API

Background jobs: schedule Mastra agents to query Brex on a cron and store results in your database automatically

Multi-agent systems: create specialist agents that collaborate using Brex tools alongside other MCP servers

Brex MCP Tools for Mastra AI (10)

These 10 tools become available when you connect Brex to Mastra AI via MCP:

brex_create_card

Useful for giving employees isolated cards for SaaS subscriptions. Issue a dynamic Virtual Corporate Card

brex_create_user

You must provide a valid email, first name, and last name. Invite a new employee / user to Brex

brex_create_vendor

Create a Vendor in AP (Accounts Payable)

brex_get_balance

Get main cash balance of the Brex Cash accounts

brex_list_budgets

List budget programs assigned to teams

brex_list_cards

List all issued cards across the company

brex_list_transactions

Sweep historical Brex card and account transactions

brex_list_users

List all users in the Brex company account

brex_list_vendors

List saved Vendors inside Brex AP

brex_pay_vendor

Orchestrate a vendor payment (Send Money)

Example Prompts for Brex in Mastra AI

Ready-to-use prompts you can give your Mastra AI agent to start working with Brex immediately.

"Invite the new engineer 'John Carter' via email john@company.com into Brex. After you get his ID, spin him up a Virtual Card with a $1K limit immediately."

"Check the core cash settlement. How much Treasury base balance do we stand at? Extract only active Checking values."

"Pull all corporate expenses tracked over the past 30 days focusing entirely on our AWS hosting and digital footprints."