Generate a user token from the Brex Dashboard under Settings > Developer, or use OAuth2 with authorization server https://accounts-api.brex.com/oauth2/default
Pass the token as a Bearer value in the Authorization header on all requests
Fetch card transactions with GET /v2/transactions/card/primary, filtering by posted_at_start and posted_at_end
Retrieve expense records with GET /v1/expenses/card to access merchant data, receipts, and coding
Update expense memo or department coding with PATCH /v1/expenses/card/{expense_id}
Known gotchas
User tokens expire after 30 days of inactivity; implement token refresh or use a long-lived service token for server-side automation
Only employees with the account admin or card admin role can generate API tokens; regular employees use OAuth
Scope selection at token creation is permanent for that token; request all needed scopes upfront
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp