Concepts

Typra is emitter-only: it generates model and protocol surfaces, but it does not ship runtime service implementations or product-specific contracts.

Emitter boundary

Typra owns reusable emitter behavior:

• Type graph discovery and lowering.
• Scalar coercion and factory expansion.
• Polymorphic dispatch.
• Provider-specific wire names.
• Generated-file markers and manifest metadata.
• Generated tests and reference docs.

Product-specific TypeSpec contracts and hand-authored runtime adapters stay in the consuming product repository.

Decorators

Typra includes decorators such as @sample, @abstract, @coerce, @@factory, @@method, @@knownAs, @@defaultFor, and @@protocol.

@sample(#{ kind: "text", text: "hello" })
model TextContent extends FixtureContent {
  kind: "text";
  text: string;
}

Generated files

Generated files include Typra markers, and the emitter records a generated-file manifest for each output root. Consumers can declare protected hand-authored boundaries in verifier config:

{
  "protectedPaths": ["src/adapters/**"],
  "hydrationZones": ["src/extensions/**"]
}

The emitter records hydration seam metadata for generated protocol adapters, while runtime behavior remains hand-authored by the consuming project.