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 LangChain 10 tools — connect in under 2 minutes

Name: Brex
Availability: InStock
Author: Vinkius

python.langchain.com/docs/integrations/tools/mcp

Built by Vinkius GDPR 10 Tools Framework

LangChain is the leading Python framework for composable LLM applications. Connect Brex through Vinkius and LangChain agents can call every tool natively. combine them with retrievers, memory, and output parsers for sophisticated AI pipelines.

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.

python

import asyncio
from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain_openai import ChatOpenAI
from langgraph.prebuilt import create_react_agent

async def main():
    # Your Vinkius token. get it at cloud.vinkius.com
    async with MultiServerMCPClient({
        "brex": {
            "transport": "streamable_http",
            "url": "https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp",
        }
    }) as client:
        tools = client.get_tools()
        agent = create_react_agent(
            ChatOpenAI(model="gpt-4o"),
            tools,
        )
        response = await agent.ainvoke({
            "messages": [{
                "role": "user",
                "content": "Using Brex, show me what tools are available.",
            }]
        })
        print(response["messages"][-1].content)

asyncio.run(main())

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High SecurityEnterprise-grade

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DLPData protection

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Ed25519Audit chain

<40msKill switch

Stream every event to Splunk, Datadog, or your own webhook in real-time

* 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.

LangChain's ecosystem of 500+ components combines seamlessly with Brex through native MCP adapters. Connect 10 tools via Vinkius and use ReAct agents, Plan-and-Execute strategies, or custom agent architectures. with LangSmith tracing giving full visibility into every tool call, latency, and token cost.

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 LangChain 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 LangChain via MCP

Follow these steps to integrate the Brex MCP Server with LangChain.

Install dependencies

Run pip install langchain langchain-mcp-adapters langgraph langchain-openai

Replace the token

Replace [YOUR_TOKEN_HERE] with your Vinkius token

Run the agent

Save the code and run python agent.py

Explore tools

The agent discovers 10 tools from Brex via MCP

Why Use LangChain with the Brex MCP Server

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

The largest ecosystem of integrations, chains, and agents. combine Brex MCP tools with 500+ LangChain components

Agent architecture supports ReAct, Plan-and-Execute, and custom strategies with full MCP tool access at every step

LangSmith tracing gives you complete visibility into tool calls, latencies, and token usage for production debugging

Memory and conversation persistence let agents maintain context across Brex queries for multi-turn workflows

Brex + LangChain Use Cases

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

RAG with live data: combine Brex tool results with vector store retrievals for answers grounded in both real-time and historical data

Autonomous research agents: LangChain agents query Brex, synthesize findings, and generate comprehensive research reports

Multi-tool orchestration: chain Brex tools with web scrapers, databases, and calculators in a single agent run

Production monitoring: use LangSmith to trace every Brex tool call, measure latency, and optimize your agent's performance

Brex MCP Tools for LangChain (10)

These 10 tools become available when you connect Brex to LangChain 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 LangChain

Ready-to-use prompts you can give your LangChain 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."

Troubleshooting Brex MCP Server with LangChain

Common issues when connecting Brex to LangChain through the Vinkius, and how to resolve them.

MultiServerMCPClient not found

Install: pip install langchain-mcp-adapters

Brex + LangChain FAQ

Common questions about integrating Brex MCP Server with LangChain.

How does LangChain connect to MCP servers?

Use langchain-mcp-adapters to create an MCP client. LangChain discovers all tools and wraps them as native LangChain tools compatible with any agent type.

Which LangChain agent types work with MCP?

All agent types including ReAct, OpenAI Functions, and custom agents work with MCP tools. The tools appear as standard LangChain tools after the adapter wraps them.