Is a skill the same thing as a plug-in?

In practice they play the same role: third-party code and context that extend what the system can do. The difference is that a skill targets an autonomous agent, so it runs without anyone confirming each step.

How many skills should an agent have?

The fewest it needs to do its job. Every added skill widens what the agent can touch, and therefore what it can break. If a skill hasn't been used in months, remove it.

← Full glossary

Agent skill

build

skill · AI skill · agent capability pack

A packaged unit of capability you install into an agent so it knows how to do one specific thing: instructions, tool access and sometimes code. It ships like a plug-in used to ship, and installs just as casually.

The skill has become the unit of exchange in the agent ecosystem. Nobody hands over whole agents any more; they hand over capabilities any agent can load. Salesforce and Anthropic ship 37 pre-built sales skills inside Claude (Salesforce, 2026-08-26), and in parallel a set of vendors has appeared whose entire job is vetting the ones circulating in the open. For whoever runs the thing, a skill cuts both ways. Upside: it shortens the path from idea to useful agent, because you aren't rewriting logic somebody already packaged. Downside: it is third-party software executing with your permissions, and hardly anyone tracks which one is installed where.

How it differs from

Tool: A tool is a function the agent can call. A skill is the package that teaches it when to call it, on what criteria and in what order.
MCP server: MCP is the protocol and service exposing data or functions to the agent. The skill is the know-how that consumes that access.
System prompt: The prompt configures the whole agent. A skill is added and removed like a module, without touching anything else.

Examples

A bank-reconciliation skill that teaches an agent to read a statement, match it against the ERP and flag the gaps.
The 37 sales skills Salesforce packages to work live pipeline data from inside Claude.

FAQ

Is a skill the same thing as a plug-in?: In practice they play the same role: third-party code and context that extend what the system can do. The difference is that a skill targets an autonomous agent, so it runs without anyone confirming each step.
How many skills should an agent have?: The fewest it needs to do its job. Every added skill widens what the agent can touch, and therefore what it can break. If a skill hasn't been used in months, remove it.

Sources & further reading

Salesforce — Claudeforce · 2026-08-26
TechCrunch — AIR raises $50M to vet agent skills and add-ons · 2026-09-01

Agent skill

How it differs from

Examples

FAQ

Related terms

Sources & further reading