Finance & Accounting · Brex + Claude
Brex MCP with Claude: Automate Expenses and Spend Analytics
The short answer
Claude works with Brex through the Model Context Protocol (MCP), an open standard that acts like a secure adapter between the two. Once connected with permissions your organisation controls, Claude can read transactions and cards, prepare expense reports, and answer spend questions in natural language, while people approve consequential actions.
What is Brex?
Brex provides corporate credit cards and spend management for startups and technology businesses. Finance teams use it to issue company cards, control budgets, track employee spending and manage company cash flow. Founders, finance leads and operations managers use it to see where money goes and to keep accounting tidy as the business grows.
How Claude connects to Brex through MCP
The Model Context Protocol (MCP) is an open standard that lets Claude securely use other software. Think of it as a universal adapter between Claude and a tool like Brex. Your organisation decides exactly what Claude may see and do, and access can be withdrawn at any time.
Once Brex is connected, Claude can typically read transactions, review card activity, look up expenses and generate spend summaries. It can answer questions such as which teams overspent last month, or which transactions are missing receipts. Claude can also draft expense reports from the data it finds.
Permissions and approvals keep people in charge. Access is limited to the minimum needed, and actions such as changing a card limit or submitting a report are routed to a named approver before they take effect. Every request is recorded in an audit log so finance can review what happened and why.
What you can automate
Monthly expense report preparation
At month end, Claude gathers each employee's Brex transactions, matches them to receipts and categories, and drafts a complete expense report. Finance reviews the draft, flags exceptions and approves it. Staff spend less time chasing receipts and the close is faster.
Missing receipt reminders
Claude scans recent card transactions for items without receipts or memos and prepares a short, friendly reminder for each cardholder. Teams keep records complete without a manual chase, and auditors find fewer gaps at year end.
Plain-English spend analytics
Leaders can ask questions such as how much went on software subscriptions this quarter compared with last. Claude pulls the figures from Brex and answers in clear sentences with a short summary. This helps founders make budget decisions without waiting for a report.
Policy breach checks
Claude compares transactions against the company's spending policy, for example category limits or merchant restrictions, and lists anything that needs a closer look. Finance decides what to do, so the review is faster and more consistent.
Card request triage
When a team asks for a new company card or a higher limit, Claude collects the details, checks them against budget information and prepares a recommendation. A finance approver makes the final decision, which keeps control with the business.
An end-to-end workflow: Month-end close for a growing software company
TriggerThe first working day of each month, when the finance team starts the close.
Claude retrieves all card transactions from Brex for the previous month.
It matches each transaction to a receipt stored in the shared finance folder in Microsoft 365.
It assigns categories and flags items missing receipts or breaching policy limits.
It drafts expense reports for each employee and posts a summary to the finance channel in the team's ticketing system.
Cardholders receive reminders for any missing items, and the finance lead reviews the exceptions.
Approved reports are exported to the accounting system for posting.
OutcomeTypically, the close takes less time, receipts are more complete, and the finance lead spends the review on exceptions rather than data entry.
How we set it up
Free automation audit
We review how your finance team handles cards, expenses and month-end close, and identify the workflows worth automating with Brex and Claude.
Secure connection
We connect Claude to Brex using the sign-in method your account supports, either OAuth sign-in or an API key, with least-privilege access so Claude sees only what it needs.
Workflow design
We design the end-to-end process across Brex and your other systems such as Microsoft 365, your accounting software or ticketing tool, and define which actions need human approval.
Testing on real cases
We test the workflow against past months and real transactions, checking accuracy and tuning categories, thresholds and approval rules before anything goes live.
Launch, monitoring and training
We launch with audit logs and monitoring in place, then train your finance and operations staff so they can use, review and adjust the workflow confidently.
Who benefits
- Finance lead or controller
- Faster month-end close and fewer receipt chases, with a clear audit trail for every approval.
- Founder or CEO
- Plain-English answers about spending and cash flow without waiting for a manual report.
- Operations manager
- Less administrative work on card requests and policy checks, so more time goes to running the business.
- Employees who hold company cards
- Clear, friendly reminders and simpler expense reporting instead of last-minute scrambling.
Security and control
- Least-privilege access, so Claude only sees and does what your organisation permits.
- Named human approval for consequential actions such as changing limits or submitting reports.
- Complete audit logs of every request Claude makes through the connection.
- Regular reviews of permissions, and the ability to revoke access at any time.
- Testing on real past cases before launch, with monitoring after go-live.
For teams in the US, UK, India and the Middle East
Organisations in the United States and the United Kingdom are served with hosting that meets their data protection expectations, and we design access controls to match each jurisdiction. Companies in India are subject to the Digital Personal Data Protection Act, 2023, and we build workflows that respect its consent and purpose requirements. Businesses in the Middle East, including the UAE and Saudi Arabia, are covered by their local data protection laws, and custom applications can be hosted in the region that best fits your requirements.
Learn more about Claude and MCP
Anthropic's AI model and assistant.
Secure links between Claude and business tools.
How engineers build and change software with Claude.
Hosted agents that run multi-step work.
The open standard Claude uses to connect to tools.
Frequently asked questions
What does the Brex MCP server do?
The Brex MCP server is the connector that lets Claude securely access your Brex account. It exposes information such as transactions and cards, and it can carry out permitted actions. Your organisation controls which permissions are granted, so Claude works only within the boundaries you set.
Is connecting Brex to Claude secure?
Security depends on how the connection is set up. We use the sign-in method your account supports, either OAuth sign-in or an API key, apply least-privilege access, and record every request in an audit log. Consequential actions are routed to a human approver. We never guarantee compliance outcomes, but we design for strong control.
What can Claude actually do with Brex?
Typically, Claude can read transactions and card activity, summarise spending, draft expense reports, flag missing receipts and answer spend questions in plain English. Actions such as changing limits can be enabled only where your policy allows, with approval before they take effect.
How long does setup take?
Timelines vary with the size of your finance operation and the number of workflows involved. A focused first workflow often takes a few weeks from the free audit to launch, including testing on real past cases and staff training. We confirm the timeline during the audit.
Which Brex plan or permissions do I need?
Connecting Brex through MCP or the API requires an account with the appropriate access granted by your administrator. The exact requirements depend on your Brex setup, so we check your account and the permissions needed during the free automation audit.