Brex MCP server and Claude connector: what it does, what it can change, how to connect

Brex hosts a beta MCP server (api.brex.com/mcp): 44 tools, mostly read, with limited expense edits. OAuth or API key; Claude and ChatGPT apps. Verified 21 Oct 2026.

Official MCP server · read & limited write (hosted, beta)
Claude connector · read & limited write (per Brex support)
ChatGPT app · read & limited write (per Brex support)

Hosting: Remote HTTP, hosted by Brex: https://api.brex.com/mcp, also behind the Claude connector and ChatGPT app. No local server.
Auth: OAuth (recommended) or a Brex API token as a Bearer header. Each user sees only what their Brex role allows.
Read / write: Mostly read. 44 tools per Brex's developer docs; writes limited to memo, receipt and attendee edits on card expenses and assigning card expenses to a spend limit, plus an export job and feedback. No approvals or payments. Brex's support page also says card admins can create, lock and ship cards in Claude and ChatGPT; its developer docs say card management isn't available.
Works with: Claude.ai, Claude Desktop, Claude Code, ChatGPT, Codex, Cursor, Slackbot and any MCP client that supports HTTP transport
Plan requirement: Not documented by Brex beyond admin enablement. Claude Team/Enterprise and ChatGPT Enterprise need an admin to add Brex; Slackbot needs Slack Business+ or Enterprise+.
Last changed: 2026-03 (Brex connector added to the Claude directory)
Verification: Verified 21 Oct 2026 by theFinanceStack · confidence: high

What can an agent do with Brex through MCP?

Mostly lookups. Brex lists 44 tools; a handful change data, and none approve expenses or reveal card numbers. Brex's support page says card admins can create cards and assign a limit to a card in Claude and ChatGPT, which its developer docs say isn't available yet.

What it reads

Each tool needs a matching Brex permission. Read tools cover:

Users and org structure
Expenses and analytics
Cards and limits
Bank accounts and transactions
Bills and vendors
Accounting records and GL accounts
Travel and policy

How writes behave

Brex documents no draft or review step for the write tools, so treat them as applying immediately.

Card management

Brex's pages disagree. Check the tool list your client shows.

Brex source	What it says
Support page	Card admins can also create, lock and cancel cards in Claude and ChatGPT.
Developer docs	Card management is not yet available.

Can

Look up users, departments, locations, entities, cost centres and roles
Read expenses (including missing-receipt checks) and policy; ask analytics questions (admins)
Read card metadata, spend limits and reimbursement payout dates
Read bank accounts, balances, transactions, bills, vendors, accounting records, GL accounts and travel (with permission)
Bulk-update memos, upload receipts from URLs, replace attendees, assign expenses to a spend limit (no draft step documented)
Start an expense export; send feedback to Brex

Cannot

Approve or reject expenses (per Brex's developer docs and support page)
Return raw card numbers, CVVs or expiry dates; Brex says it will not expose them
Create reimbursements or change a team's transactions; Brex points to the dashboard
Exceed the signed-in user's Brex permissions or the API token's scopes

What access does it get?

The connection acts as one Brex user, limited by their role and the granted scopes; Brex's OAuth metadata names 22 scopes.

Where	Scopes and permissions (as documented)	Admin requirement
Brex MCP server (api.brex.com/mcp), OAuth	The server's OAuth metadata lists: openid, offline_access, email, users.readonly, departments.readonly, locations.readonly, titles.readonly, legal_entities.readonly, cards.readonly, cards, companies.readonly, budgets.readonly, travel.trips.readonly, expenses.card.readonly, expenses.card, expenses.bill, accounts.cash.readonly, vendors.readonly, accounting.integration.read, accounting.record.read, fields.read, field_values.read.	An account or card admin accepts the Developer API agreement and enables the feature; then each user signs in. Revoke sessions in Settings › Personal settings › Connected integrations.
Brex MCP server, API token	Whatever scopes the token carries. Brex says each tool needs a matching Brex permission and recommends restricted tokens with only the scopes you need, but doesn't map scopes to tools.	Only account or card admins can create tokens (Settings › Developer).
Claude connector and ChatGPT app	Not documented by the vendor as named scopes. You approve a permission request at sign-in; access follows your Brex role.	Claude Team/Enterprise: an admin adds Brex. ChatGPT: a workspace admin enables and publishes the app and can limit its actions.

How do I connect it?

A Brex admin enables the feature; then each user adds Brex in Claude or ChatGPT, or adds https://api.brex.com/mcp to any MCP client.

Brex admin: accept the Developer API agreement in Settings › Developer, then enable the feature (developer docs: Settings › Beta features › Brex in AI assistants; support page: Settings › Early access › Brex MCP access).
Claude Team/Enterprise admin: Organization settings › Connectors › Browse connectors, search Brex, add it to the team.
Each user: open https://claude.com/connectors/brex or Customize › Connectors, select Brex › Connect, sign in and approve the permission request.
Desktop alternative documented by Brex: the config below (Node.js 20+), then restart.

{
  "mcpServers": {
    "brex": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://api.brex.com/mcp"]
    }
  }
}

The Claude listing shows 10 read tools; Brex's support page says the connector can also edit memos, receipts, attendees and limits on your own transactions.

What should a finance team watch for?

The server is beta and Brex's pages disagree on card management, so check the live tool list before giving an agent admin rights.

Brex labels the server beta; tools may change. Its support page lists card creation and cancellation for card admins, its developer docs say card management isn't available, and the OAuth metadata includes a write-level cards scope.
Brex documents no draft or review step for the write tools (update_expense_memo, upload_card_expense_receipt_from_urls, replace_attendees_for_card_expense, assign_limit_for_card_expenses), so treat them as applying immediately. Brex recommends requiring approval in your AI client before actions run; keep that on.
Memos, merchant names and receipt text are free text. An injected instruction in one could push the agent to rewrite memos or reassign limits in bulk. Brex's support page also lists card creation and cancellation for card admins, so on an admin login the same trick could issue or cancel cards. Keep approval on and consider connecting as a non-admin user.
An API token in a client config file sits in plain text, often in a synced folder. Brex says use environment variables and never commit tokens; prefer OAuth.
Brex says data shared with Claude or ChatGPT is processed under your AI plan and that provider's policies; its MCP pages say nothing on training.
Brex documents no MCP rate limits. Several list tools (users, limits, trips, bookings, group events) paginate with no documented page size or maximum, and spend analytics is limited to account or card admins. Review MCP activity in the Dashboard API logs.
The OAuth metadata includes a write-level expenses.bill scope, though Brex documents no bill write tool.

How could finance teams and accounting firms use it?

Read access suits spend questions and month-end checks; the few write tools suit expense tidy-up that a person confirms.

Inside a company

Ask for spend by department, merchant or card for the month without building an export.
List expenses missing receipts or memos and draft memo wording for cardholders to confirm.
Check remaining spend limits and reimbursement payout dates for employee questions.
Pull bills, vendors and bank transactions for a cash or AP summary.

At an accounting firm

Before month-end, list a client's card expenses missing receipts, memos or attendees for follow-up.
Compare Brex accounting records with GL accounts to spot mapping gaps (needs Brex's manage-mappings permission).
Summarise travel and vendor spend for a client review meeting.
Answer client staff policy questions from the Brex expense policy, checked by a person.

Whatever the use, keep a person approving anything that changes Brex or your ledger, and leave approvals and card changes in the Brex dashboard.

Want Brex connected to Claude for your team?

We configure scoped connections and a review step before anything changes your books. Fixed fee.

Book a 30-minute setup call

Change log

Date	Change	Source
2026-10-21	Developer docs re-checked: beta, 44 tools, no approvals or card management	developer.brex.com/docs/mcp
2026-10-21	Support page adds Codex and Slackbot, an Early access path, and card management for card admins	www.brex.com/support/using-brex-in-ai-apps
2026-03	Brex connector added to the Claude directory (10 tools listed, Anthropic verified)	claude.com/connectors/brex

FAQ

Is this official?

Yes. Brex hosts the server and documents it on developer.brex.com and its support site. The Claude listing is published by Brex and marked Anthropic verified.

Is it free?

Brex doesn't document a charge or plan requirement for MCP. You need a Brex account where an admin has enabled the feature, and an AI client plan that allows connectors.

Does it change data in Brex?

A little: it can edit memos, receipts, attendees and spend-limit assignment on card expenses. No approvals; Brex's pages disagree on card management.

Is my data used to train models?

Brex's MCP pages don't say. Check Brex's privacy policy and your AI provider's terms before connecting.

Can my accountant use it on my behalf?

Brex doesn't document this. Each connection acts as the Brex user who signs in, with that user's permissions, so an accountant would connect with a Brex login of their own.

Something wrong or out of date? Tell us and we'll email you when it's fixed.

Sources

Verified by theFinanceStack, 21 Oct 2026. Vendor list on the CFO Software Market Map courtesy of Jason Staats; AI connectivity data by theFinanceStack. Not tax, compliance or financial advice.