fsl-designlisted

# FSL Design Layer Use this skill after a requirements contract exists or the user explicitly asks for engineering design. The design layer is an ordinary kernel `spec` plus an optional refinement mapping back to the requirements layer. That mapping is the **refinement seam, not a plain baton pass**: the design must refine the (frozen) requirements contract, and `fslc refine` verifies the seam. When a seam breaks, repair the design or the mapping — not the upper contract, unless a human revises it. Before writing syntax, read `../fsl/SKILL.md` and `../fsl/reference.md` for the shared FSL verifier workflow and language rules. When working inside this repository, read `examples/e2e/3_design.fsl` and `examples/e2e/3_refines_2.fsl` for the main pattern, `examples/layers/` for a compact chain, and `examples/bank/` or `examples/refinement_liveness/` when the task is mostly refinement. Use `fsl-design-review` instead when the user asks for a design review, SOLID judgment, substitutability, or variant comparison. ## Boundary Produce design-layer artifacts only: - A kernel `spec` for internal design state and actions - A refinement mapping from design to requirements when a stable requirement spec exists - Verification/refinement commands and result interpretation - Optional `testgen`, `replay`, or `typestate` handoff plan Do not rewrite business policies or PM requirements to make the design pass. If the upper contract is too strict or ambiguous, report the counterexample and