Brex with OpenAI Agents SDK

How to integrate Brex MCP with OpenAI Agents SDK

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Introduction Also integrate Brex with TL;DR What is OpenAI Agents SDK What is the Brex MCP server Supported Tools & Triggers Creating MCP Server - Stand-alone vs Composio SDK Step-by-step Guide Complete Code Conclusion How to build Brex MCP Agent with another framework Explore Other Toolkits FAQ

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Introduction

This guide walks you through connecting Brex to the OpenAI Agents SDK using the Composio tool router. By the end, you'll have a working Brex agent that can create a new card for our intern, get the latest account statement pdf, add an expense for last week's conference through natural language commands.

This guide will help you understand how to give your OpenAI Agents SDK agent real control over a Brex account through Composio's Brex MCP server.

Before we dive in, let's take a quick look at the key ideas and tools involved.

Also integrate Brex with

Claude Agent SDK Claude Code Claude Cowork Codex OpenClaw Hermes CLI Google ADK LangChain Vercel AI SDK Mastra AI LlamaIndex CrewAI

TL;DR

Here's what you'll learn:

Get and set up your OpenAI and Composio API keys
Install the necessary dependencies
Initialize Composio and create a Tool Router session for Brex
Configure an AI agent that can use Brex as a tool
Run a live chat session where you can ask the agent to perform Brex operations

What is OpenAI Agents SDK?

The OpenAI Agents SDK is a lightweight framework for building AI agents that can use tools and maintain conversation state. It provides a simple interface for creating agents with hosted MCP tool support.

Key features include:

Hosted MCP Tools: Connect to external services through hosted MCP endpoints
SQLite Sessions: Persist conversation history across interactions
Simple API: Clean interface with Agent, Runner, and tool configuration
Streaming Support: Real-time response streaming for interactive applications

What is the Brex MCP server, and what's possible with it?

The Brex MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Brex account. It provides structured and secure access to your company's financial tools, so your agent can perform actions like managing cards, tracking expenses, creating budgets, and retrieving account details on your behalf.

Card creation and management: Instantly issue new cards, assign them to users or vendors, and control spending limits via your agent.
Automated expense tracking: Let your agent create and log expenses, helping you keep company finances organized and up to date.
Budget and department setup: Quickly create budgets for teams or projects and set up new departments without manual effort.
Account and statement retrieval: Fetch detailed account information and download statements whenever you need financial insights or records.
User and location management: Add new users or locations to your Brex account, making it easy to scale as your business grows.

Supported Tools & Triggers

Tools

Add Webhook Group MembersAdd webhook subscription members to a webhook group.

Archive BudgetArchive a budget to mark it as inactive and prevent future expenses.

Archive Spend LimitArchive a spend limit in Brex.

Create BudgetCreate a new budget for departments or projects.

Create Spend Limit (Budget V1)Tool to create a new Spend Limit (Budget) in Brex.

Create CardCreate a new card and assign it to a user.

Create DepartmentCreate a new department.

Create Document Upload for ReferralCreate a document upload URL for a referral and return a pre-signed S3 upload URL.

Create ExpenseCreate a new expense.

Create Custom FieldCreate a new custom field in Brex.

Create Field ValuesCreate custom field values for a specific Brex field.

Create LocationCreate a new location.

Create Referral RequestTool to create a new referral to Brex for onboarding.

Create Spend LimitTool to create a spend limit in Brex.

Create Job TitleCreate a new job title.

Create UserCreate a new user in the Brex account.

Create VendorCreate a new vendor in Brex for payment operations.

Create Webhook GroupTool to create a webhook group for targeting webhook subscriptions.

Create Webhook SubscriptionRegister a new webhook subscription to receive real-time notifications for Brex events.

Delete FieldTool to delete a custom field by Brex ID.

Delete Field ValuesDelete custom field values for a specific field.

Delete VendorDelete a vendor by ID.

Get Account StatementsGet finalized statements for the primary cash account.

Get Budget DetailsGet detailed information about a specific budget.

Get Card DetailsGet detailed information about a specific card.

Get Card ExpenseTool to retrieve detailed information about a specific card expense by its ID.

Get Card NumberGet card number, CVV, and expiration date for a specific card.

Get Card TransactionsGet settled card transactions for the primary card account.

Get Company Cash AccountsRetrieve all cash (deposit) accounts for the company.

Get Company DetailsGet company information associated with the OAuth2 access token.

Get Department By IDGet detailed information about a specific department by ID.

Get ExpenseTool to get details of a specific expense by ID.

Get Field By IDTool to retrieve a custom field by its Brex ID.

Get Field Value By IDTool to retrieve a specific field value by field ID and field value ID.

Get Legal EntityTool to retrieve a legal entity by its ID from Brex.

Get Location By IDGet detailed information about a specific location by ID.

Get Referral By IDTool to retrieve a specific referral by its ID from Brex.

Get Spend Limit By IDTool to get detailed information about a specific spend limit by its ID.

Get Spend LimitsGet spend limits configuration.

Get Title by IDGet detailed information about a specific job title by ID.

Get Transaction by IDGet details of a specific transaction by ID.

Get Card TransactionsGet card transactions from the primary Brex account.

Get Transactions by Amount RangeGet card transactions filtered by amount range and date period.

Search Transactions by DescriptionSearch and filter card transactions by description text.

Get User LimitRetrieves the monthly spending limit and available balance for a specific Brex user.

Get User ProfileGet user profile information from Brex Team API.

Get Vendor By IDTool to get vendor details by ID.

Get Webhook GroupTool to retrieve details of a specific webhook group by ID.

Get Webhook SubscriptionTool to retrieve details of a specific webhook subscription by ID.

List Budget ProgramsTool to list all budget programs in the organization.

List BudgetsList all budgets and show available amounts across all cards.

List Card AccountsTool to list all card accounts for the company.

List CardsList all cards associated with the account.

List Card StatementsTool to list finalized statements for primary card accounts.

List DepartmentsList all departments in the organization.

List ExpensesTool to list expenses from the Brex platform.

List Field ValuesTool to list values under a custom field.

List Legal EntitiesTool to list all legal entities in the Brex account with pagination support.

List LocationsList all locations in the organization.

List ReferralsTool to list all referrals created in the Brex account.

List Job TitlesList all job titles in the organization.

List TransfersLists transfers for the account.

List TripsLists trips according to the filters passed in the query string.

List UsersList all users in the Brex account.

List VendorsList all vendors.

List Webhook Group MembersTool to list all members of a webhook group.

List Webhook GroupsTool to list all webhook groups.

List Webhook SecretsTool to retrieve webhook signing secrets for validating incoming webhook messages from Brex.

List Webhook SubscriptionsTool to list all registered webhook subscriptions.

Create Receipt MatchCreates a receipt match request and returns a pre-signed S3 upload URI.

Create Receipt Upload for ExpenseCreates a receipt upload request for a specific card expense and returns a pre-signed S3 upload URL.

Set User LimitSet or update the monthly spending limit for a Brex user.

Transfer CardTransfer a card to a different user.

Update BudgetUpdate an existing budget's configuration in Brex.

Update Spend Limit (V1)Tool to update a Spend Limit (budget) using the v1 API.

Update Card LimitsUpdate spending limits and controls for a Brex card.

Update Card StatusUpdate the status of a Brex card by locking, unlocking, or terminating it.

Update ExpenseTool to update an expense by its ID.

Update FieldTool to update a custom field in Brex.

Update Field ValuesTool to update custom field values in Brex for a specific field.

Update Spend LimitUpdates an existing Brex spend limit by its ID.

Update UserUpdate user details.

Update VendorTool to update vendor information in Brex.

Update Webhook SubscriptionUpdates an existing Brex webhook subscription's configuration.

What is the Composio tool router, and how does it fit here?

What is Composio SDK?

Composio's Composio SDK helps agents find the right tools for a task at runtime. You can plug in multiple toolkits (like Gmail, HubSpot, and GitHub), and the agent will identify the relevant app and action to complete multi-step workflows. This can reduce token usage and improve the reliability of tool calls. Read more here: Getting started with Composio SDK

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Composio SDK works

The Composio SDK follows a three-phase workflow:

Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Prerequisites

Before starting, make sure you have:

Composio API Key and OpenAI API Key
Primary know-how of OpenAI Agents SDK
A live Brex project
Some knowledge of Python or Typescript

Getting API Keys for OpenAI and Composio

OpenAI API Key

Go to the OpenAI dashboard and create an API key. You'll need credits to use the models, or you can connect to another model provider.
Keep the API key safe.

Composio API Key

Log in to the Composio dashboard.
Go to Settings and copy your API key.

Install dependencies

pip install composio_openai_agents openai-agents python-dotenv

Install the Composio SDK and the OpenAI Agents SDK.

Set up environment variables

bash

OPENAI_API_KEY=sk-...your-api-key
COMPOSIO_API_KEY=your-api-key
USER_ID=composio_user@gmail.com

Create a .env file and add your OpenAI and Composio API keys.

Import dependencies

import asyncio
import os
from dotenv import load_dotenv

from composio import Composio
from composio_openai_agents import OpenAIAgentsProvider
from agents import Agent, Runner, HostedMCPTool, SQLiteSession

What's happening:

You're importing all necessary libraries.
The Composio and OpenAIAgentsProvider classes are imported to connect your OpenAI agent to Composio tools like Brex.

Set up the Composio instance

load_dotenv()

api_key = os.getenv("COMPOSIO_API_KEY")
user_id = os.getenv("USER_ID")

if not api_key:
    raise RuntimeError("COMPOSIO_API_KEY is not set. Create a .env file with COMPOSIO_API_KEY=your_key")

# Initialize Composio
composio = Composio(api_key=api_key, provider=OpenAIAgentsProvider())

What's happening:

load_dotenv() loads your .env file so OPENAI_API_KEY and COMPOSIO_API_KEY are available as environment variables.
Creating a Composio instance using the API Key and OpenAIAgentsProvider class.

Create a Tool Router session

# Create a Brex Tool Router session
session = composio.create(
    user_id=user_id,
    toolkits=["brex"]
)

mcp_url = session.mcp.url

What is happening:

You give the Tool Router the user id and the toolkits you want available. Here, it is only brex.
The router checks the user's Brex connection and prepares the MCP endpoint.
The returned session.mcp.url is the MCP URL that your agent will use to access Brex.
This approach keeps things lightweight and lets the agent request Brex tools only when needed during the conversation.

Configure the agent

# Configure agent with MCP tool
agent = Agent(
    name="Assistant",
    model="gpt-5",
    instructions=(
        "You are a helpful assistant that can access Brex. "
        "Help users perform Brex operations through natural language."
    ),
    tools=[
        HostedMCPTool(
            tool_config={
                "type": "mcp",
                "server_label": "tool_router",
                "server_url": mcp_url,
                "headers": {"x-api-key": api_key},
                "require_approval": "never",
            }
        )
    ],
)

What's happening:

We're creating an Agent instance with a name, model (gpt-5), and clear instructions about its purpose.
The agent's instructions tell it that it can access Brex and help with queries, inserts, updates, authentication, and fetching database information.
The tools array includes a HostedMCPTool that connects to the MCP server URL we created earlier.
The headers dict includes the Composio API key for secure authentication with the MCP server.
require_approval: 'never' means the agent can execute Brex operations without asking for permission each time, making interactions smoother.

Start chat loop and handle conversation

print("\nComposio Tool Router session created.")

chat_session = SQLiteSession("conversation_openai_toolrouter")

print("\nChat started. Type your requests below.")
print("Commands: 'exit', 'quit', or 'q' to end\n")

async def main():
    try:
        result = await Runner.run(
            agent,
            "What can you help me with?",
            session=chat_session
        )
        print(f"Assistant: {result.final_output}\n")
    except Exception as e:
        print(f"Error: {e}\n")

    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in {"exit", "quit", "q"}:
            print("Goodbye!")
            break

        result = await Runner.run(
            agent,
            user_input,
            session=chat_session
        )
        print(f"Assistant: {result.final_output}\n")

asyncio.run(main())

What's happening:

The program prints a session URL that you visit to authorize Brex.
After authorization, the chat begins.
Each message you type is processed by the agent using Runner.run().
The responses are printed to the console, and conversations are saved locally using SQLite.
Typing exit, quit, or q cleanly ends the chat.

Complete Code

Here's the complete code to get you started with Brex and OpenAI Agents SDK:

import asyncio
import os
from dotenv import load_dotenv

from composio import Composio
from composio_openai_agents import OpenAIAgentsProvider
from agents import Agent, Runner, HostedMCPTool, SQLiteSession

load_dotenv()

api_key = os.getenv("COMPOSIO_API_KEY")
user_id = os.getenv("USER_ID")

if not api_key:
    raise RuntimeError("COMPOSIO_API_KEY is not set. Create a .env file with COMPOSIO_API_KEY=your_key")

# Initialize Composio
composio = Composio(api_key=api_key, provider=OpenAIAgentsProvider())

# Create Tool Router session
session = composio.create(
    user_id=user_id,
    toolkits=["brex"]
)
mcp_url = session.mcp.url

# Configure agent with MCP tool
agent = Agent(
    name="Assistant",
    model="gpt-5",
    instructions=(
        "You are a helpful assistant that can access Brex. "
        "Help users perform Brex operations through natural language."
    ),
    tools=[
        HostedMCPTool(
            tool_config={
                "type": "mcp",
                "server_label": "tool_router",
                "server_url": mcp_url,
                "headers": {"x-api-key": api_key},
                "require_approval": "never",
            }
        )
    ],
)

print("\nComposio Tool Router session created.")

chat_session = SQLiteSession("conversation_openai_toolrouter")

print("\nChat started. Type your requests below.")
print("Commands: 'exit', 'quit', or 'q' to end\n")

async def main():
    try:
        result = await Runner.run(
            agent,
            "What can you help me with?",
            session=chat_session
        )
        print(f"Assistant: {result.final_output}\n")
    except Exception as e:
        print(f"Error: {e}\n")

    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in {"exit", "quit", "q"}:
            print("Goodbye!")
            break

        result = await Runner.run(
            agent,
            user_input,
            session=chat_session
        )
        print(f"Assistant: {result.final_output}\n")

asyncio.run(main())

Conclusion

This was a starter code for integrating Brex MCP with OpenAI Agents SDK to build a functional AI agent that can interact with Brex.

Key features:

Hosted MCP tool integration through Composio's Tool Router
SQLite session persistence for conversation history
Simple async chat loop for interactive testing

You can extend this by adding more toolkits, implementing custom business logic, or building a web interface around the agent.

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TOOLKIT MARKETPLACE

FAQ

What are the differences in Tool Router MCP and Brex MCP?

With a standalone Brex MCP server, the agents and LLMs can only access a fixed set of Brex tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Brex and many other apps based on the task at hand, all through a single MCP endpoint.

Can I use Tool Router MCP with OpenAI Agents SDK?

Yes, you can. OpenAI Agents SDK fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Brex tools.

Can I manage the permissions and scopes for Brex while using Tool Router?

Yes, absolutely. You can configure which Brex scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

How safe is my data with Composio Tool Router?

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Brex data and credentials are handled as safely as possible.

Used by agents from

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Harsha GaddipatiCo-founder, Slashy

Karan skipped his own birthday party to fix our critical issue. It was 10 pm and he diverted his Waymo to help us instead. This really sets the bar, shows you the commitment you need to have when users rely on your software.

Abhi AryaCo-founder, Opennote

A lot of students tell us that the moment their connected tools start talking to each other inside Opennote feels almost magical. The agent just knows them, and it has immensely helped in keeping new users on the platform.

Nirman DaveCEO, Zams

We chose Composio over Pipedream because it delivered depth where it mattered. It supported niche tools and tricky edge cases that other platforms simply ignored. Giving us confidence to scale without compromising.

Ryan YuFounder, Extra Thursday

As a solo builder, shipping fast is life or death. The only way I can outcompete incumbents is by outmanoeuvring them. Getting bogged down in the complexities of managing agent auth would have been a death sentence for Extra Thursday.

Tomisin JenrolaFounder & CEO, SwarmZero

Before partnering with Composio, adding tool integrations was a slow, resource-intensive process. Each integration could take weeks or months of engineering time, and maintaining them meant constantly keeping up with API changes.

Jerome LeclancheCo-Founder, Ingram Technologies

With hands-on help from their founder, we integrated Gmail and Google Drive in just 30 minutes. This level of personal support and commitment is exactly what startups should strive for.

Harsha GaddipatiCo-founder, Slashy

Abhi AryaCo-founder, Opennote

Nirman DaveCEO, Zams

Ryan YuFounder, Extra Thursday

Tomisin JenrolaFounder & CEO, SwarmZero

Jerome LeclancheCo-Founder, Ingram Technologies

With hands-on help from their founder, we integrated Gmail and Google Drive in just 30 minutes. This level of personal support and commitment is exactly what startups should strive for.

Harsha GaddipatiCo-founder, Slashy

Abhi AryaCo-founder, Opennote

Nirman DaveCEO, Zams

Ryan YuFounder, Extra Thursday

Tomisin JenrolaFounder & CEO, SwarmZero

Jerome LeclancheCo-Founder, Ingram Technologies

With hands-on help from their founder, we integrated Gmail and Google Drive in just 30 minutes. This level of personal support and commitment is exactly what startups should strive for.

How to integrate Brex MCP with OpenAI Agents SDK

Table of Contents

Connect Brex without Auth hassles

Introduction

Also integrate Brex with

TL;DR

What is OpenAI Agents SDK?

What is the Brex MCP server, and what's possible with it?

Supported Tools & Triggers

What is the Composio tool router, and how does it fit here?

What is Composio SDK?

How the Composio SDK works

Step-by-step Guide

Prerequisites

Getting API Keys for OpenAI and Composio

Install dependencies

Set up environment variables

Import dependencies

Set up the Composio instance

Create a Tool Router session

Configure the agent

Start chat loop and handle conversation

Complete Code

Conclusion

How to build Brex MCP Agent with another framework

Claude Agent SDK

Claude Code

Claude Cowork

Codex

OpenClaw

Hermes

CLI

Google ADK

LangChain

Vercel AI SDK

Mastra AI

LlamaIndex

CrewAI

Explore Other Toolkits

Stripe

Alpha vantage

Altoviz

FAQ

What are the differences in Tool Router MCP and Brex MCP?

Can I use Tool Router MCP with OpenAI Agents SDK?

Can I manage the permissions and scopes for Brex while using Tool Router?

How safe is my data with Composio Tool Router?

Used by agents from

Never worry about agent reliability