> Canonical guide: https://developers.foxlight.ai/build/
> Contract snapshots: Skulk 2.0.0 (b0af39c79b6b7102b2478062904f1d7cc8619975); SDK 0.4.0 (31bb090b8f64689f87514e48385e22b6ad94a6c2). Check the installed runtime when versions differ.

# Build for Skulk

A capability is an operation with a versioned descriptor: clients discover its input and output schemas, then negotiate a call against that exact contract. A plugin packages one or more capabilities with configuration, permissions, setup and lifecycle. An application can also declare a web surface that appears in Skulk’s dashboard.

## Start here

1. [Get the SDK](https://developers.foxlight.ai/build/get-sdk/): availability, supported environment and delivery.
2. [Build a managed echo child](https://developers.foxlight.ai/build/sdk/first-child/): define a descriptor, authenticate startup and answer a call.
3. [Choose a contract](https://developers.foxlight.ai/build/guides/choose-a-contract/): unary, streaming or a durable operation.
4. [Try the examples](https://developers.foxlight.ai/build/examples/): echo, duplex streams and job identity.
5. [Follow Video Studio](https://developers.foxlight.ai/build/tutorials/video-studio/): turn those building blocks into a complete application.

## Build your application

| Question                                        | Guide                                                                          |
| ----------------------------------------------- | ------------------------------------------------------------------------------ |
| How do peers know what I do?                    | [Descriptors](https://developers.foxlight.ai/build/descriptors/)                                             |
| How do I exchange audio or incremental results? | [Managed streaming](https://developers.foxlight.ai/build/sdk/streams/)                                       |
| How do I track work that takes minutes?         | [Durable jobs](https://developers.foxlight.ai/build/guides/durable-jobs/)                                    |
| How does my UI appear in the dashboard?         | [Application interfaces](https://developers.foxlight.ai/build/application-interfaces/)                       |
| How do I declare configuration and access?      | [Manifests](https://developers.foxlight.ai/build/manifest/) and [permissions](https://developers.foxlight.ai/build/permissions/)           |
| How do I distribute and verify a plugin?        | [Catalogs](https://developers.foxlight.ai/build/catalogs/) and [qualification](https://developers.foxlight.ai/build/guides/qualification/) |

## SDK and host roles

The capability SDK is the child authoring interface. Skulk and the managed host supply discovery, admission, process supervision and installation authority. Your application owns its behavior, external effects, resource cleanup and truthful readiness. The SDK does not supply a model engine or mount models automatically.

[SDK module reference](https://developers.foxlight.ai/build/sdk/reference/contracts/) covers exact signatures and field contracts. [Foxlight Docs](https://docs.foxlight.ai/) owns installation, inference and HTTP endpoint reference.