# Proposed Crate Layout
Recommended layout (implemented as a scaffold in this repository):
```text
dtcs/
Cargo.toml
SPEC.md # repository root — authoritative spec
docs/
editorial/ # specification authoring process
implementation/ # this guide set
examples/
tests/
src/
lib.rs
model/
mod.rs
contract.rs
metadata.rs
interface.rs
types.rs
semantics.rs
expression.rs
action.rs
function.rs
rule.rs
lineage.rs
versioning.rs
extension.rs
registry.rs
parser/
mod.rs
yaml.rs
json.rs
validation/
mod.rs
phases.rs
field_index.rs
lineage.rs
structural.rs
types.rs
references.rs
semantics.rs
extensions.rs
diagnostics/
mod.rs
codes.rs
diagnostic.rs
severity.rs
category.rs
stage.rs
report.rs
compatibility/
mod.rs
plan/
mod.rs
cli/
mod.rs
bin/
dtcs.rs
examples/
tests/
fixtures/
```
Keep modules small and aligned with `SPEC.md`.