Skill arguments let you parameterize a skill so it can be reused across different inputs without duplicating the whole file.

What it does

You define placeholders in the skill body and users pass values when they invoke the skill. For example, /newblog "topic" can substitute the topic into the instructions. The argument syntax is documented with the skill's description so users know what to pass. It turns static skills into small functions.

When to use it

Skills that operate on a variable target (filename, topic, URL).
Parameterized workflows like "write a blog about X" or "review file Y".
Reducing skill proliferation - one parametric skill beats ten near-identical ones.
Encoding team conventions with per-invocation overrides.

Gotchas

Document argument names and formats in the skill description or the skill's README.
Quoting matters. Arguments with spaces need quotes on the command line.
Optional arguments still require a placeholder strategy - decide on defaults explicitly.

Official docs: https://code.claude.com/docs/en/skills.md#pass-arguments-to-skills