# BFF guidelines

Follow root AGENTS.md. This is an independent Go module; Sendico is an external
provider, not a local module dependency. Never add sibling-path replacements,
shared database access or internal Sendico discovery/messaging dependencies.

Keep HTTP DTOs/mappers, application models/use cases and provider adapters distinct.
Resolve ownership from the authenticated SXCHNGE principal and server-side mappings.
Only adapters may expose provider transport types internally. Adapted code belongs
to SXCHNGE; record source revision and changes in PROVENANCE.md.

Review the complete backend contribution before delivery. Run `make test-backend`
and `make lint-backend` at the repository root. Add behavioral tests for changed
boundaries and failure paths. Errors returned publicly must be stable typed codes;
never expose raw provider errors, secrets, document contents or credentials.