brex

name

brex

description

Brex combines corporate cards, business accounts, expense management, bill pay, and travel booking into a single AI-powered financial operations platform—offering unified spend control, real-time visibility, automated workflows, and modern treasury tools designed for startups and enterprises across 120+ countries. Read and write Brex data through One: budgets, cards, fields, users, webhookgroups, spendlimits and more, 107 actions with real parameter documentation. Use whenever the user asks to look something up in Brex, create or update a record there, or build code against the Brex API.

Brex through One

Brex combines corporate cards, business accounts, expense management, bill pay, and travel booking into a single AI-powered financial operations platform—offering unified spend control, real-time visibility, automated workflows, and modern treasury tools designed for startups and enterprises across 120+ countries.

One exposes Brex through four MCP tools. The table below carries real action ids from One's knowledge base, so for a common operation you can skip search and go straight to reading the action's parameters.

How to run an action

1. Find the action in the table below, or call search_one_platform_actions with platform brex if it is not listed.
2. Call get_one_action_knowledge with the action id. Do this every time, including for actions in this table. The table gives you the id, not the parameters.
3. Call execute_one_action with parameters copied from that knowledge.

Never guess a parameter name, a body field, or an enum value. The knowledge has the real schema, and a guessed field is either a 400 or a silent write of the wrong thing.

Before you start

Call list_one_integrations once and confirm Brex is connected. If it is missing, the user has not connected it: say so and point them at https://app.withone.ai rather than reaching for raw HTTP.

Each connection carries an access field. If it reports {"policy": "methods", "methods": ["GET"]} the agent is read-only here, so plan a read-only answer instead of attempting a write that will be refused.

Before a write

Creates, updates, deletes and sends land on a real Brex account and cannot be recalled. State the action and the specific target in one line before the first write in a task, and let the user stop you. Reads need no confirmation.

Actions

Budgets

Action	Method	Path	Action id
Get a Budget by ID	GET	/v2/budgets/{{id}}	conn_mod_def::GJ094hSR8nE::Z4He1qh-SfGiP8JuXyLXww
Get a Spend Limit by ID	GET	/v1/budgets/{{id}}	conn_mod_def::GJ09-jcQaTU::ZmKtsfSmQOyi8XzCA4luzw
List Budgets	GET	/v2/budgets	conn_mod_def::GJ094q6dtMY::1uQwvjk6R928D49LMnzCrw
List Spend Limits	GET	/v1/budgets	conn_mod_def::GJ09-qOKmWE::oFeeoTxJQku6eUilAEGYQA
Archive a Budget	POST	/v2/budgets/{{id}}/archive	conn_mod_def::GJ094RIHbtQ::VnWj4-OmSYewvpL6Uur_8w
Archive a Spend Limit	POST	/v1/budgets/{{id}}/archive	conn_mod_def::GJ09-SSCsRM::atiUQpjvTFSlLRcGfzVBBA
Create a Spend Limit	POST	/v1/budgets	conn_mod_def::GJ09-aEiULY::G5M1llCBTEm4DWpYPpI49A
Create Budget	POST	/v2/budgets	conn_mod_def::GJ094Z8EAKM::_MF_lncnRcO0Fr2Cuor5jA
Update a Budget	PUT	/v2/budgets/{{id}}	conn_mod_def::GJ094y8cYgw::OrUQReSGQqyXexDH-ie8iQ
Update a Spend Limit	PUT	/v1/budgets/{{id}}	conn_mod_def::GJ09-yXPMqU::LYPOEFUoSzy6snCkEFLzTw

Cards

Action	Method	Path	Action id
Get a Card by ID	GET	/v2/cards/{{id}}	conn_mod_def::GJ095qR_g1A::S1bdeKmfSY2UULkfPz4FhQ
Get a Card’s PAN Details (Number, CVV, Expiration) by Card ID	GET	/v2/cards/{{id}}/pan	conn_mod_def::GJ095xhI9E0::LNnZWV98SMOHeSTWUghA5w
List a User's Cards	GET	/v2/cards	conn_mod_def::GJ0957OpT8c::C6Pta84jR9mOSEIbNvsLZQ
Create Card	POST	/v2/cards	conn_mod_def::GJ095bDDDVk::LcleiXRPSGCbxp6T-Ey0OA
Create Secure Email to Send a Card Number	POST	/v2/cards/{{id}}/secure_email	conn_mod_def::GJ095jUdSSg::AxkEqJyIS1y5v7CnhGfu3g
Lock a Card	POST	/v2/cards/{{id}}/lock	conn_mod_def::GJ096EFZiD8::VYkaHzkCS82WHo1TUy1YnA
Terminate a Card	POST	/v2/cards/{{id}}/terminate	conn_mod_def::GJ096MkXwuo::Ea8INFq6Q8qJv22Eim2XCQ
Unlock a Card	POST	/v2/cards/{{id}}/unlock	conn_mod_def::GJ096U9kb0k::ygqaRoRBS9u1kHT9mxSs4g
Update a Card	PUT	/v2/cards/{{id}}	conn_mod_def::GJ096dUt9rA::3QD34XwtS0Kf6o_rO9sQyw

Fields

Action	Method	Path	Action id
Get a Custom Field by ID	GET	/v1/fields/{{id}}	conn_mod_def::GJ098cFzsT4::kjprY9IYQQqCrJ4jMsqmoQ
List Custom Fields	GET	/v1/fields	conn_mod_def::GJ098jpRfZ0::HwPEaaKiRaaOcdD9Q3Gl9g
Create a Custom Field	POST	/v1/fields	conn_mod_def::GJ098OVll-M::4BfehzxESoScoQ0DdGUnfw
Delete a Custom Field	DELETE	/v1/fields/{{id}}	conn_mod_def::GJ098VLn0-A::1kGrEdWlTQCd7TnarYZ41A
Delete Custom Field Values for a Field	DELETE	/v1/fields/{{fieldId}}/values	conn_mod_def::GJ097r1GRbA::sFkOimd2QaKNdTjMl4UkRA
Update a Custom Field by ID	PUT	/v1/fields/{{id}}	conn_mod_def::GJ098re5A20::Btz8COYhTGeGm4zfv7HGsQ
Update Custom Field Values for a Field	PUT	/v1/fields/{{fieldId}}/values	conn_mod_def::GJ098HZye_g::dVSg9uS3TKeaVhQlsPwA6Q

Users

Action	Method	Path	Action id
Get a User by ID	GET	/v2/users/{{id}}	conn_mod_def::GJ0-BWEsxw0::68flA6RlT7q-tGYihTmgYQ
Get a User's Monthly Limit	GET	/v2/users/{{id}}/limit	conn_mod_def::GJ0-BMiy6CY::NweIPpT6SAyvZ4sM0imBmw
Get Current User (Me)	GET	/v2/users/me	conn_mod_def::GJ0-BFh4i10::IXrOiqwHQOK5iRLIIX4BYg
List Users	GET	/v2/users	conn_mod_def::GJ0-BnrPjkQ::Q-e0PfRqRhORLFrV4dYVSQ
Invite a User (Create Employee User)	POST	/v2/users	conn_mod_def::GJ0-BdpzCk0::siTev4WbSW2SXSqXhoakDg
Set a User’s Monthly Limit	POST	/v2/users/{{id}}/limit	conn_mod_def::GJ0-Bu1Sw18::IMszeI5rQcWiSmTV4P3kXQ
Update a User	PUT	/v2/users/{{id}}	conn_mod_def::GJ0-B2IRdY8::We8zScfjSd6YbkYz6c6Fdw

WebhookGroups

Action	Method	Path	Action id
Get a Webhook Group	GET	/v1/webhooks/groups/{{id}}	conn_mod_def::GJ0-C0iZzHg::xzvmyA_kQuK7ITa7kYPfdg
List Webhook Groups	GET	/v1/webhooks/groups	conn_mod_def::GJ0-DIa_9bs::MDYtbqQyRRWLUGEOgQUVkw
Add Members to a Webhook Group	POST	/v1/webhooks/groups/{{id}}/add_members	conn_mod_def::GJ0-Cfo1R-o::gqGL-7D-R8-1p9aq4xHTXQ
Create Webhook Group	POST	/v1/webhooks/groups	conn_mod_def::GJ0-CnclD-g::_UVxPqwaQZqe70Ryf3wbmg
Delete a Webhook Group	DELETE	/v1/webhooks/groups/{{id}}	conn_mod_def::GJ0-Ct-Ky5k::gqqcZaQ_SZWsFSqDZFL_6g
Remove Members from a Webhook Group	POST	/v1/webhooks/groups/{{id}}/remove_members	conn_mod_def::GJ0-DP4eMvc::i88rXJFbQgqoYwqzgwytHw

SpendLimits

Action	Method	Path	Action id
Get a Spend Limit by ID	GET	/v2/spend_limits/{{id}}	conn_mod_def::GJ09_In2RyI::LvSNpbBbQ1qY46Tgs1dWvg
List Spend Limits	GET	/v2/spend_limits	conn_mod_def::GJ09_S1cUAI::ZKwYdk58StmuqRG3G_sESw
Archive a Spend Limit	POST	/v2/spend_limits/{{id}}/archive	conn_mod_def::GJ09-5-NW48::PDKBAUb3R82PvGVW7JrwtA
Create a Spend Limit	POST	/v2/spend_limits	conn_mod_def::GJ09_BT98E0::Lm1l00KvRzifamScj3fI2A
Update a Spend Limit	PUT	/v2/spend_limits/{{id}}	conn_mod_def::GJ09_akvas4::dxnurbUlS9eSosHSMCXrKQ

Vendors

Action	Method	Path	Action id
Get a Vendor by ID	GET	/v1/vendors/{{id}}	conn_mod_def::GJ0-CJuCKUQ::TjPoRtC1TvW5cwAWnIkHpQ
List Vendors	GET	/v1/vendors	conn_mod_def::GJ0-CQ8zLE0::i4jAiDt8Q7ijS-f0tEP7rA
Create a Vendor	POST	/v1/vendors	conn_mod_def::GJ0-B818eQs::vrRMP0NwRHiK5vAgEzr9-w
Delete a Vendor	DELETE	/v1/vendors/{{id}}	conn_mod_def::GJ0-CDi1Cyk::wRcWezJUTBS2IVYjriqcZw
Update a Vendor by ID	PUT	/v1/vendors/{{id}}	conn_mod_def::GJ0-CYYMraQ::lxXAWbAUSyu1WOf2tltEfQ

AccountingRecords

Action	Method	Path	Action id
Get an Accounting Record by ID	GET	/v3/accounting/records/{{recordId}}	conn_mod_def::GJ0923uFS6I::_EmPvppoR_204Pq8BCOIug
Query Accounting Records	GET	/v3/accounting/records	conn_mod_def::GJ093BIFOpc::uJPuqrHdSreZhlkuRBfOsQ
Report Accounting Export Results	POST	/v3/accounting/records/export-results	conn_mod_def::GJ093JAcjVg::t-l1880GT0On7KK8MN-OFA

CashAccounts

Action	Method	Path	Action id
Get a Cash Account by ID	GET	/v2/accounts/cash/{{id}}	conn_mod_def::GJ093QJF94w::K2EZflKJSZSeBMsZ4FHOKA
Get Primary Cash Account	GET	/v2/accounts/cash/primary	conn_mod_def::GJ093Z9RFtQ::VbimbEyuQxGLc4cF3BUMog
List Cash Accounts	GET	/v2/accounts/cash	conn_mod_def::GJ093wPzYr4::0a03YGaYQ26Y4Y7ooC3xpw

CardExpenses

Action	Method	Path	Action id
Get a Card Expense (Deprecated)	GET	/v1/expenses/card/{{expenseId}}	conn_mod_def::GJ094-oyHxA::8ZLT6C0NQUq9MUbapNOV4Q
List Card Expenses (Deprecated)	GET	/v1/expenses/card	conn_mod_def::GJ095LnbzvY::PpIyAglWQ4-tYKe1x0AXGQ
Update a Card Expense	PUT	/v1/expenses/card/{{expenseId}}	conn_mod_def::GJ095TN566o::fFaJD2aiQZGpPRY85MgNeA

Departments

Action	Method	Path	Action id
Get a Department by ID	GET	/v2/departments/{{id}}	conn_mod_def::GJ0968IOP_s::x7giJ4UeRU-HQIKPLfnnyw
List Departments	GET	/v2/departments	conn_mod_def::GJ097D5fbk8::DOA-wx7ZSoCrIDxiOKDOTw
Create a Department	POST	/v2/departments	conn_mod_def::GJ096wZQjL0::N3M9cF_fQI2AGopMCt7RTw

Locations

Action	Method	Path	Action id
Get a Location by ID	GET	/v2/locations/{{id}}	conn_mod_def::GJ099Tbk_6Q::2nGPYn1-T-igp_hGIuenJw
List Locations	GET	/v2/locations	conn_mod_def::GJ099a0inm8::bQ0hI4QYRIeoCIKDK_fYbw
Create a Location	POST	/v2/locations	conn_mod_def::GJ099Mshx74::EesIgOV3Q32sBV410aPYBA

Referrals

Action	Method	Path	Action id
Get a Referral by ID	GET	/v1/referrals/{{id}}	conn_mod_def::GJ09-CB4hy0::KosZEak9RKK-p71KOAwpCA
List Referrals	GET	/v1/referrals	conn_mod_def::GJ09-LNCCNA::5fOtI1u8Q0qRN6xis5GsFA
Create a Referral	POST	/v1/referrals	conn_mod_def::GJ0994trJYk::rXBxH9urSrm_PtpkCQr9Sw

Titles

Action	Method	Path	Action id
Get a Title by ID	GET	/v2/titles/{{id}}	conn_mod_def::GJ09_oCbYmc::r2T_FfoNSUOaM1lACPD3yg
List Titles	GET	/v2/titles	conn_mod_def::GJ09_xi0pgg::Ff9Sp2qHR_-lSkWc0MFLHg
Create Title	POST	/v2/titles	conn_mod_def::GJ09_hrGH7c::ZFpUdxmJQWKWUhsgPg6Fwg

Transfers

Action	Method	Path	Action id
Get a Transfer by ID	GET	/v1/transfers/{{id}}	conn_mod_def::GJ0-AZHSgG0::eQJcLhUbRbyW3eF2Rl0g4g
List Transfers	GET	/v1/transfers	conn_mod_def::GJ0-AhHYLi0::pIYcmKy7TwC-CwgISi4sJg
Create a Transfer	POST	/v1/transfers	conn_mod_def::GJ0-AR7RCds::yH4ECUvZRAWttp7Nmhq-KA

Webhooks

Action	Method	Path	Action id
List Webhooks	GET	/v1/webhooks	conn_mod_def::GJ0-DmclgXs::g34Xt9SoQuuQQWdk4EXZcQ
Register a Webhook Subscription	POST	/v1/webhooks	conn_mod_def::GJ0-DtrCIsg::65NaMVHAR6CQ0VAk7h8qDQ
Unregister a Webhook Subscription	DELETE	/v1/webhooks/{{id}}	conn_mod_def::GJ0-D0gLrHU::-IfWQwPOQpGltc5CApahRw

AccountingIntegrations

Action	Method	Path	Action id
Disconnect an Accounting Integration	POST	/v3/accounting/integration/{{integrationId}}/disconnect	conn_mod_def::GJ092m79CGU::IUufMP50SKWxFw4qfIivnw
Reactivate an Accounting Integration	POST	/v3/accounting/integration/{{integrationId}}/reactivate	conn_mod_def::GJ092v69bNo::aWHwOaOVSJmG7LjW46br5A

BudgetPrograms

Action	Method	Path	Action id
Get a Budget Program by ID	GET	/v1/budget_programs/{{id}}	conn_mod_def::GJ094A5dTng::oNcKTqJETgCAOz9UiBcNgg
List Budget Programs	GET	/v1/budget_programs	conn_mod_def::GJ094JurFNY::OvIkMHe2S4qI646WCjvuEA

Expenses

Action	Method	Path	Action id
Get an Expense	GET	/v1/expenses/{{id}}	conn_mod_def::GJ097Lsr2hw::4g33DV8xSOiEZTXeufIweQ
List Expenses	GET	/v1/expenses	conn_mod_def::GJ097YIcyGU::TP-jfrcmSt-m0zqjKZw9YA

CustomFieldValues

Action	Method	Path	Action id
List a Custom Field’s Values	GET	/v1/fields/{{fieldId}}/values	conn_mod_def::GJ0978k3IFo::ZsUnqqeHT-CNrZn8yMaqsw
Create Values for a Custom Field	POST	/v1/fields/{{fieldId}}/values	conn_mod_def::GJ097gw-QSI::iYgs6MuSQvWeRl9zWoOnnA

LegalEntities

Action	Method	Path	Action id
Get a Legal Entity	GET	/v2/legal_entities/{{id}}	conn_mod_def::GJ0982Zso6E::uOMOAh-QQw2i9GfVF6-Muw
List Legal Entities	GET	/v2/legal_entities	conn_mod_def::GJ0989jTCLs::0F31SOIpRhWi-4HmF3-uzg

TripBookings

Action	Method	Path	Action id
Get a Trip Booking	GET	/v1/trips/{{tripId}}/bookings/{{bookingId}}	conn_mod_def::GJ0-AqL91cc::n6e_yag-TaGsU_PhHUsuig
List a Trip’s Bookings	GET	/v1/trips/{{tripId}}/bookings	conn_mod_def::GJ0-A3du5LQ::kgcZM8q2Q1Gz0Ke0BrIJfg

Trips

Action	Method	Path	Action id
Get a Trip by ID	GET	/v1/trips/{{tripId}}	conn_mod_def::GJ0-Awavz7k::HRlOtYUeRsuJG_SnxNnghw
List Trips	GET	/v1/trips	conn_mod_def::GJ0-A_EQEBQ::sEW9aPEtT_qE1_Fx6SwdQw

This lists 90 of 107 actions. For anything not here, call search_one_platform_actions with platform brex. The full catalog is at https://www.withone.ai/knowledge/brex.

When a call fails

The error comes from Brex, not from One. A 400 or 422 means your parameters do not match the schema, so re-read the knowledge and fix the field. A 401 or 403 means the connection needs re-authorizing, which no retry will fix. A 404 means the id is not on this account. A 429 means slow down. Never retry a write more than once: the first attempt may have landed.

Full catalog: https://www.withone.ai/knowledge/brex

Integration knowledge by One (withone.ai), licensed under One-Knowledge-1.0. Attribution must be preserved in derivative works.