# Phase 112: Layer Graph Contract - Context

**Gathered:** 2026-04-11
**Status:** Implemented and verified
**Mode:** First implementation phase for `v1.60`

<domain>
## Phase Boundary

Open `v1.60` by locking a test contract for the flexible layer-graph surface.

</domain>

<decisions>
## Implementation Decisions

### Locked decisions

- expose `L3-A`, `L3-R`, and `L3-D` as production-visible subplanes
- make the `L4 -> L3-R` return law explicit and durable
- require both helper-level and real service/CLI coverage

</decisions>

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*Phase: 112-layer-graph-contract*
*Context captured on 2026-04-11 after Phase 112 implementation and verification*
