The three things people mean
An agent skill. A folder of instructions — a description of when to use it, and the procedure — that an agent discovers and loads when the job comes up. This is the sense that has taken over the word since 2025, and it is what this glossary means by "skill" unless it says otherwise.
A voice-assistant skill. The older sense: a third-party app for a voice platform, published to a store, invoked by name. Amazon's Alexa established it, and tens of thousands of them exist. It is a product in a catalogue, not a document an agent reads.
A capability, plainly. "The model has good summarisation skills" is ordinary English and means nothing technical. Vendors use it this way in marketing, which is where most of the confusion begins.
Three different things share this word. Find out which one somebody means before agreeing to anything.
How to tell which one you are being sold
- Ask what gets installed. A file or folder you can open and read is an agent skill; an entry in a store is a voice app; nothing at all means somebody meant capability.
- Ask who invokes it. An agent skill is chosen by the model from its description; a voice skill is invoked by a person saying its name.
- Ask where it runs. An agent skill runs inside your agent's own session, with whatever access that agent has. A voice skill runs on the platform's infrastructure.
- Ask what it can do on its own. Neither kind grants abilities by itself — an agent skill directs what a model already can do, and a voice app is limited to what its platform exposes.
Why the collision matters
Because the security question is different in each case, and the word hides that. Installing a voice skill grants a third party a defined slot in a platform's permission model. Installing an agent skill puts instructions in front of a model that already holds your credentials and your files, with no store, no review and no sandbox between the author and your session.
It matters for buying, too. "Our product has skills" can mean a published integration in somebody's catalogue, or a Markdown file in a repository, or nothing but a claim about the underlying model. Those are three different amounts of work and three different things to maintain.
What this glossary means by it
The agent sense. When we say a skill, we mean a packaged set of instructions an agent loads on demand — the sense defined in agent-skill, and the one our public directory indexes.
We keep that directory because the same shift underlies this whole vocabulary: work that used to happen on a website now happens inside an assistant, and the instructions the assistant follows are as much a published artefact as any page. A skill that describes your category is a description of your market written by somebody else, and it is worth knowing what it says.
Frequently asked questions
If someone says "we support skills", what should I ask?
Ask to see one. Whichever sense they mean, there is something concrete to look at — a file, a store listing, or nothing — and the answer settles the question in a sentence where an argument about definitions would not.
Are Alexa skills and agent skills related at all?
Only by name. One is a third-party app in a platform's catalogue, invoked by a person; the other is a document an agent chooses to read. They come from different eras and different architectures, and no technique transfers between them.
Is a skill a feature of the model or of the software around it?
Of the software around it. The model supplies the capability; a skill supplies the instructions on how a particular job is done, and the harness supplies the mechanism for loading it at the right moment.
Do I need skills to use an AI assistant well?
No. They pay off when the same job recurs and the same instructions have to be repeated — that is precisely the case they were invented for. For one-off work, a good prompt is the whole answer.
Asked out loud
spoken, not typedThe same term in the words somebody uses speaking to an assistant rather than typing into a box — written from the situation, which is why each one carries the situation it came from.
You probably do not. Ask whether they mean a folder of instructions your agent would load, or an app published to a voice platform's store — those are completely different projects, and only the first one is what most people mean by the word today.
Written-down know-how for one job, filed where an agent can find it and read it when that job comes up. The older meaning — an app for a voice assistant — still exists, so it is worth checking which one is being discussed.
It depends on which kind. An agent skill is instructions handed to a model that already has your access, with nobody reviewing them in between, so read the file before installing it. A voice-platform skill is constrained by the platform's own permissions, which is a different and narrower risk.