SKM-K03 · Warning
`compatibility` is longer than 500 characters
The specification caps `compatibility` at 500 characters.
What the rule is
The specification caps the optional `compatibility` field — used to state environment requirements like the intended product, system packages, or network access — at 500 characters.
No runtime documents what happens when this limit is exceeded; the constraint comes from the specification's own field table, and this rule flags the violation itself rather than a documented runtime consequence.
Where it comes from
- Agent Skills — SpecificationSpecification
Which runtimes enforce it
| Runtime | Effect | Note |
|---|---|---|
| Claude Code | Not documented | The spec states the limit; no runtime documents what happens past it. |
| Codex | Not documented | The spec states the limit; no runtime documents what happens past it. |
| Cursor | Not documented | The spec states the limit; no runtime documents what happens past it. |
| OpenClaw | Not documented | The spec states the limit; no runtime documents what happens past it. |
| Hermes Agent | Not documented | The spec states the limit; no runtime documents what happens past it. |
How to fix it
- Shorten `compatibility` to under 500 characters, keeping only the environment requirements that actually gate whether the skill can run.
Elsewhere
- SKILL.md, the formatThe full frontmatter field table this rule is drawn from.
- Agent Skills Not WorkingThe diagnostic reference this rule’s portability and failure evidence comes from.
- All rulesEvery check the validator runs, grouped by class.