Inside the skills library: why every download is hash-verified.

The skills library on this site is free. No paywall, no login. You browse, you download a zip, you drop the SKILL.md into your agent's skills directory, and it runs.

What is less visible is what happens between "you click download" and "the file lands on your machine" — and that part is where most of the engineering went.

A skill is code you hand to an agent.

A Claude skill is a set of instructions an AI agent follows with real access to your files, your terminal, and often your accounts. Installing one is closer to installing a shell script than saving a bookmark. If the content changes between the moment we reviewed it and the moment you download it, you are running something nobody checked.

That is not a hypothetical. Skills that mirror public repositories inherit every future change of those repositories — including changes made after you decided to trust them.

Pin to the commit, verify the bytes.

So the library does two things on every skill that mirrors a public source:

Content pinning. Each skill's manifest points at an exact commit SHA, not a branch. The upstream author can keep working; your download comes from the precise version we reviewed, forever. A moving main branch can never silently change what we serve.

Hash verification. Every file in the skill carries a sha256 hash in the manifest. At download time the content is re-verified against those hashes before it is zipped. If a single byte differs, the download fails loudly instead of shipping quietly.

On skill pages you'll see the provenance badge: the source repository, the short commit reference, and the file count. That line is generated from the manifest, not typed by hand — if it renders, it was verified.

Why bother, on a free product?

Because the library is the front door of how we work. The same discipline that pins a free skill to a commit is the discipline that runs a client's ad account, touches a CRM, or automates a document pipeline. Businesses in regulated industries — where most of our partners operate — don't get to treat "the automation did something unexpected" as a learning experience.

A free resource that handles integrity carelessly would be an honest preview of careless paid work. This is the opposite bet: show the standard on the thing anyone can inspect.

Where it goes from here.

The library grows continuously — new skills get reviewed, pinned, and published on a rolling basis. The deeper systems (full workflows, implementation guides, the tooling we run internally) live in The Compound.

Download something, read the SKILL.md before you run it — always, including ours — and check the hash line if you want to see the receipts.