How to integrate Brex MCP with Codex

Codex is one of the most popular coding harnesses out there. And MCP makes the experience even better. With Brex MCP integration, you can draft, triage, summarise emails, and much more, all without leaving the terminal or the app, whichever you prefer.

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Oauth2Api Key

Brex provides corporate credit cards and spend management tailored for startups and tech businesses. It helps optimize company cash flow, streamline accounting, and accelerate business growth.

84 Tools

Introduction

Codex is one of the most popular coding harnesses out there. And MCP makes the experience even better. With Brex MCP integration, you can draft, triage, summarise emails, and much more, all without leaving the terminal or the app, whichever you prefer.

Also integrate Brex with

OpenAI Agents SDKClaude Agent SDKClaude CodeClaude CoworkOpenClawHermesCLIGoogle ADKLangChainVercel AI SDKMastra AILlamaIndexCrewAI

Why use Composio?

Apart from a managed and hosted MCP server, you will get:

  • CodeAct: A dedicated workbench that allows GPT to write its code to handle complex tool chaining. Reduces to-and-fro with LLMs for frequent tool calling.
  • Large tool responses: Handle them to minimise context rot.
  • Dynamic just-in-time access to 20,000 tools across 1000+ other Apps for cross-app workflows. It loads the tools you need, so GPTs aren't overwhelmed by tools you don't need.

How to install Brex MCP in Codex

Run the setup command

Run this command in your terminal to add the Composio MCP server to Codex.

Terminal

It will initiate the authentication in a browser window, authorize Codex to access your Composio account.

Composio authentication page

(Optional) Authenticate with OAuth

To authenticate manually, run the login command to open a browser window and authorize Codex to access your Composio account.

bash
codex mcp login composio

Verify the connection

Run codex mcp list to confirm Composio appears as a registered MCP server.

bash
codex mcp list

Codex App

Codex App follows the same approach as VS Code.

  1. Click ⚙️ on the bottom left → MCP Servers → + Add servers → Streamable HTTP:
  2. Fill the header and Key fields with { "x-consumer-api-key" = "ck_*******" }.
  3. The Key is the Composio API key, that you can find on dashboard.composio.dev
  4. Click on Authenticate and authorize Codex to your Composio account and you're all set.
Codex App MCP setup
  1. Restart and verify if it's there in .codex/config.toml
bash
[mcp_servers.composio]
url = "https://connect.composio.dev/mcp"
http_headers = { "x-consumer-api-key" = "ck_*******" }

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.

Conclusion

You've successfully integrated Brex with Codex using Composio's MCP server. Now you can interact with Brex directly from your terminal, VS Code, or the Codex App using natural language commands.

Key benefits of this setup:

  • Seamless integration across CLI, VS Code, and standalone app
  • Natural language commands for Brex operations
  • Managed authentication through Composio
  • Access to 20,000+ tools across 1000+ apps for cross-app workflows
  • CodeAct workbench for complex tool chaining

Next steps:

  • Try asking Codex to perform various Brex operations
  • Explore cross-app workflows by connecting more toolkits
  • Build automation scripts that leverage Codex's AI capabilities
TOOLS

Supported Tools

Every Brex action and event your agent gets out of the box.

Add Webhook Group Members

Add webhook subscription members to a webhook group.

Archive Budget

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

Archive Spend Limit

Archive a spend limit in Brex.

Create Budget

Create a new budget for departments or projects.

Create Spend Limit (Budget V1)

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

Create Card

Create a new card and assign it to a user.

Create Department

Create a new department.

Create Document Upload for Referral

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

Create Expense

Create a new expense.

Create Custom Field

Create a new custom field in Brex.

Create Field Values

Create custom field values for a specific Brex field.

Create Location

Create a new location.

Create Referral Request

Tool to create a new referral to Brex for onboarding.

Create Spend Limit

Tool to create a spend limit in Brex.

Create Job Title

Create a new job title.

Create User

Create a new user in the Brex account.

Create Vendor

Create a new vendor in Brex for payment operations.

Create Webhook Group

Tool to create a webhook group for targeting webhook subscriptions.

Create Webhook Subscription

Register a new webhook subscription to receive real-time notifications for Brex events.

Delete Field

Tool to delete a custom field by Brex ID.

Delete Field Values

Delete custom field values for a specific field.

Delete Vendor

Delete a vendor by ID.

Get Account Statements

Get finalized statements for the primary cash account.

Get Budget Details

Get detailed information about a specific budget.

Get Card Details

Get detailed information about a specific card.

Get Card Expense

Tool to retrieve detailed information about a specific card expense by its ID.

Get Card Number

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

Get Card Transactions

Get settled card transactions for the primary card account.

Get Company Cash Accounts

Retrieve all cash (deposit) accounts for the company.

Get Company Details

Get company information associated with the OAuth2 access token.

Get Department By ID

Get detailed information about a specific department by ID.

Get Expense

Tool to get details of a specific expense by ID.

Get Field By ID

Tool to retrieve a custom field by its Brex ID.

Get Field Value By ID

Tool to retrieve a specific field value by field ID and field value ID.

Get Legal Entity

Tool to retrieve a legal entity by its ID from Brex.

Get Location By ID

Get detailed information about a specific location by ID.

Get Referral By ID

Tool to retrieve a specific referral by its ID from Brex.

Get Spend Limit By ID

Tool to get detailed information about a specific spend limit by its ID.

Get Spend Limits

Get spend limits configuration.

Get Title by ID

Get detailed information about a specific job title by ID.

Get Transaction by ID

Get details of a specific transaction by ID.

Get Card Transactions

Get card transactions from the primary Brex account.

Get Transactions by Amount Range

Get card transactions filtered by amount range and date period.

Search Transactions by Description

Search and filter card transactions by description text.

Get User Limit

Retrieves the monthly spending limit and available balance for a specific Brex user.

Get User Profile

Get user profile information from Brex Team API.

Get Vendor By ID

Tool to get vendor details by ID.

Get Webhook Group

Tool to retrieve details of a specific webhook group by ID.

Get Webhook Subscription

Tool to retrieve details of a specific webhook subscription by ID.

List Budget Programs

Tool to list all budget programs in the organization.

List Budgets

List all budgets and show available amounts across all cards.

List Card Accounts

Tool to list all card accounts for the company.

List Cards

List all cards associated with the account.

List Card Statements

Tool to list finalized statements for primary card accounts.

List Departments

List all departments in the organization.

List Expenses

Tool to list expenses from the Brex platform.

List Field Values

Tool to list values under a custom field.

List Legal Entities

Tool to list all legal entities in the Brex account with pagination support.

List Locations

List all locations in the organization.

List Referrals

Tool to list all referrals created in the Brex account.

List Job Titles

List all job titles in the organization.

List Transfers

Lists transfers for the account.

List Trips

Lists trips according to the filters passed in the query string.

List Users

List all users in the Brex account.

List Vendors

List all vendors.

List Webhook Group Members

Tool to list all members of a webhook group.

List Webhook Groups

Tool to list all webhook groups.

List Webhook Secrets

Tool to retrieve webhook signing secrets for validating incoming webhook messages from Brex.

List Webhook Subscriptions

Tool to list all registered webhook subscriptions.

Create Receipt Match

Creates a receipt match request and returns a pre-signed S3 upload URI.

Create Receipt Upload for Expense

Creates a receipt upload request for a specific card expense and returns a pre-signed S3 upload URL.

Set User Limit

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

Transfer Card

Transfer a card to a different user.

Update Budget

Update an existing budget's configuration in Brex.

Update Spend Limit (V1)

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

Update Card Limits

Update spending limits and controls for a Brex card.

Update Card Status

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

Update Expense

Tool to update an expense by its ID.

Update Field

Tool to update a custom field in Brex.

Update Field Values

Tool to update custom field values in Brex for a specific field.

Update Spend Limit

Updates an existing Brex spend limit by its ID.

Update User

Update user details.

Update Vendor

Tool to update vendor information in Brex.

Update Webhook Subscription

Updates an existing Brex webhook subscription's configuration.

FRAMEWORKS

How to build Brex MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Brex MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Brex MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Brex MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Brex MCP with Claude Cowork

OpenClaw logo

OpenClaw

Use Brex MCP with OpenClaw

Hermes logo

Hermes

Use Brex MCP with Hermes

CLI logo

CLI

Use Brex MCP with CLI

Google ADK logo

Google ADK

Use Brex MCP with Google ADK

LangChain logo

LangChain

Use Brex MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Brex MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Brex MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Brex MCP with LlamaIndex

CrewAI logo

CrewAI

Use Brex MCP with CrewAI

FAQ

Frequently asked questions

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.

Yes, you can. Codex 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.

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.

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.

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