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

# Get the capability SDK

The capability SDK is the Python authoring package for applications that run as managed Skulk capabilities. The documentation targets **SDK 0.4.0**, **Python 3.13+** and managed **protocol 4**. Unary protocol-3 children remain in the compatibility window; new streaming implementations require protocol 4.

:::note Package delivery is not open yet
The interface is documented here, but a public download and verified platform/interpreter wheel matrix have not been published. There is no working public `pip install skulk-capability-sdk` command to recommend today. You can read all guides and copy the tutorial examples without signing in.
:::

## If you already have an approved wheel

Create an isolated Python 3.13 environment, install the supplied wheel using your normal Python package tooling, then check the installed version:

```python
from importlib.metadata import version
from skulk_capability_sdk.contracts import Descriptor

print(version("skulk-capability-sdk"))
print(Descriptor.__name__)
```

A successful import proves package installation, not compatibility with a running Skulk host. Next, complete the [managed child tutorial](https://developers.foxlight.ai/build/sdk/first-child/) and [qualification guide](https://developers.foxlight.ai/build/guides/qualification/).

## What you receive

The authoring package exposes seven documented modules: contracts, wire, streams, storage, operations, database and serving. It does not supply private host administration or publisher implementation. Public guides explain those boundaries so developers can distinguish authoring code from installing, signing and operating a capability.

Use the type information and reference for your exact SDK version. Package installation and signed capability installation are separate steps: the latter uses the operator’s normal trust and permission review.