> Canonical guide: https://developers.foxlight.ai/build/tutorials/video-studio/ > Contract snapshots: Skulk 2.0.0 (b0af39c79b6b7102b2478062904f1d7cc8619975); SDK 0.4.0 (31bb090b8f64689f87514e48385e22b6ad94a6c2). Check the installed runtime when versions differ. # Build an application like Video Studio You know how to call a model API. How do you turn that into an application people can discover, install and use through Skulk? Video Studio is a worked example. It has a browser interface, a library of reference images and clips, prompt rewriting, a render queue and saved takes. It runs as a managed capability application and asks Skulk to run the model inference. This tutorial follows the actual implementation, then gives you a small SDK exercise to run yourself. You do **not** need to understand distributed inference or implement an engine to write this kind of application. ## What you will learn By the end, you should be able to explain and implement: - A discoverable operation with typed input and output contracts. - A managed child that authenticates to its host and answers health checks. - A read-only plan that resolves a request before expensive work starts. - A durable operation that survives a lost caller response and tracks an external job. - Cancellation, restart and uncertain submission without silently duplicating work. - Application-owned media and a browser interface discovered through Skulk. - Tests that exercise these boundaries without needing a GPU for every run. ## Start with these words | Word | What it means here | | --------------- | -------------------------------------------------------------------------------------- | | Fabric | The Skulk cluster and its discoverable services and capabilities. | | Capability | A versioned operation a caller can discover and invoke, such as `video.plan`. | | Descriptor | The capability's contract: identity, schemas, I/O mode and revision. | | Plugin / bundle | The installable application package, its manifest and declared permissions. | | Managed child | Your application's supervised process, communicating with its host through the SDK. | | Host / owner | The component that launches, authenticates, supervises and admits calls to that child. | | Operation | A durable record of application work that lasts beyond one short invocation. | | Backend job | The work accepted by another service—in Studio, a Skulk video-generation job. | | Surface | An application interface declared by the bundle and reported ready by the child. | A capability is an API contract; a surface is an interface to an application. A plugin can provide both. ## Two ways to read **New to capabilities?** Follow the chapters in order. First run [managed echo](https://developers.foxlight.ai/build/examples/echo/); later run the [local operation exercise](https://developers.foxlight.ai/build/tutorials/video-studio/workshop/). The exercise uses a fake backend, so it needs the SDK but no mounted model. **Already building an application?** Start with [render lifecycle](https://developers.foxlight.ai/build/tutorials/video-studio/render-lifecycle/), [application interface](https://developers.foxlight.ai/build/tutorials/video-studio/application/) and [testing](https://developers.foxlight.ai/build/tutorials/video-studio/testing/). | Chapter | The question it answers | | -------------------------------------------------------------------------- | ---------------------------------------------------------- | | [1. Application architecture](https://developers.foxlight.ai/build/tutorials/video-studio/architecture/) | What lives in my application, and what does Skulk do? | | [2. Contracts and manifests](https://developers.foxlight.ai/build/tutorials/video-studio/contracts/) | How does a caller know what my application can do? | | [3. Startup and dispatch](https://developers.foxlight.ai/build/tutorials/video-studio/child/) | What code runs when the host starts my process? | | [4. Planning and readiness](https://developers.foxlight.ai/build/tutorials/video-studio/planning/) | How do I resolve and review work against the live cluster? | | [5. Durable rendering](https://developers.foxlight.ai/build/tutorials/video-studio/render-lifecycle/) | How does a short call safely start a long render? | | [6. Prompt refinement](https://developers.foxlight.ai/build/tutorials/video-studio/refinement/) | How does a second model-powered workflow use the same SDK? | | [7. Assets and saved takes](https://developers.foxlight.ai/build/tutorials/video-studio/assets/) | Where do application files and durable state belong? | | [8. Browser interface](https://developers.foxlight.ai/build/tutorials/video-studio/application/) | How does the UI reach the child and appear in Skulk? | | [9. Local SDK exercise](https://developers.foxlight.ai/build/tutorials/video-studio/workshop/) | Can I run a durable operation without a GPU? | | [10. Testing and diagnosis](https://developers.foxlight.ai/build/tutorials/video-studio/testing/) | How do I prove my integration works and find failures? | | [11. Packaging and installation](https://developers.foxlight.ai/build/tutorials/video-studio/packaging/) | How does source become a supervised, signed application? | ## Code and prerequisites Code blocks labelled `studio:...` are excerpts from Video Studio revision `5cf917fed8387943bec7b27eea882b598a73c3fe`. They belong in the surrounding Studio package and are **not standalone programs**. The local exercise is a separate, complete teaching example. Repository paths identify where to look when reading the Studio source. The SDK interface is **0.4.0**, Python **3.13+**. Check [current SDK availability](https://developers.foxlight.ai/build/get-sdk/) before trying installation; this guide does not assume a public package index exists. A working Studio deployment also needs a compatible managed host and a qualified, mounted video model. Prompt refinement needs ready chat capacity as well. [Foxlight Docs](https://docs.foxlight.ai/skulk/next/) owns Skulk installation, model setup and the normative HTTP API. This tutorial teaches the application integration rather than maintaining another copy of those contracts.