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
- Find the action in the table below, or call
search_one_platform_actions with platform brex if it is not listed.
- 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.
- 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.
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