# ifc-alignment horizontal instructions
Scope: horizontal layout and exact horizontal segment parameters. Follow the crate `../../AGENTS.md`.
## Owns
- segment order/transition
- line/arc/spiral parameter views
- horizontal continuity diagnostics
## Does not own
- polyline approximation
- vertical/cant projection
- road design policy
## Growth map
`layout.rs`, `segment.rs`, `transition.rs`. These source owners already compile as private scaffold modules. Replace a module's planned-owner marker with its first real contract and tests; do not add parallel placeholders. Keep views, resolution, validation, and neutral output in
separate files.