Skill, Tool, or Agent?

Skills, tools, and agents all feel like "things that do stuff," which makes it hard to know which is best for a given task that you're trying to automate. Here's how I think about it.

1. Is it mostly custom code with defined inputs and outputs? It's a tool.
2. Is it a mostly a custom prompt with some optional assets on disk? It's a skill.
3. Is it a "mode of operation" that uses tools and skills with a specific set of permissions and settings? It's an agent.

The reality is that there usually isn't just one right answer. There's more than one way to build a clanker skin a cat.

From "smallest" to "largest", in terms of how much code and prompting is involved, I typically think of them like this:

1. Tools
2. Skills
3. Agents