leonard_contract

The pure-Dart extension contract for Leonard — the Flutter-free types a host implements and exposes, so a Flutter binding (leonard_flutter) and a non-Flutter VM-service host (leonard_host) build on identical contracts.

Contains:

• LeonardExtension / LeonardTool — the extension + tool authoring contract.
• PerceptionExtension — the observation mixin (buildPerception() -> Component), built on genesis_perception.
• ExtensionRegistry — extension lifecycle dispatch, the handshake manifest, and tool merging.
• dispatchToolToEnvelope / decodeServiceExtensionParams — VM-service dispatch helpers.

Perception is pull-free: buildPerception() is a synchronous read of state kept current by an out-of-band watcher — never make it async.

class ExampleExtension extends LeonardExtension with PerceptionExtension {
  @override
  Component buildPerception() => const ExamplePerception();

  // Remaining LeonardExtension members omitted.
}

Extensions written against the deprecated Genesis Seed typedef remain source-compatible because it is an identity-preserving alias for Component. New code should use the canonical spelling.

Pre-1.0 and experimental; APIs may change before 1.0.