Lint rules

tricks lint checks skills against 27 rules, generated here from the rule table in the source. See Lint for ignoring rules (for the whole repo or one skill), inline disables and --strict.

NT1xx — Spec conformance

The Agent Skills specification, cross-checked against the reference validator skills-ref.

Code	Default	Rule
NT101	error	frontmatter name is missing
NT102	error	name must be 1-64 lowercase letters (any script), digits and single hyphens
NT103	error	name must match the skill folder name
NT104	error	description is missing or empty
NT105	error	description exceeds 1024 characters
NT106	error	compatibility exceeds 500 characters
NT107	error	metadata must be a map of string keys to string values
NT108	error	SKILL.md has no valid YAML frontmatter
NT110	warning	skill file is named skill.md; use SKILL.md (Claude Code only loads the uppercase name)

NT2xx — Structure

Links, files, paths and size.

Code	Default	Rule
NT201	error	broken relative link
NT202	error	referenced script does not exist
NT203	warning	absolute or home-relative path
NT204	warning	reference nested more than one level deep
NT205	warning	SKILL.md longer than 500 lines
NT206	warning	SKILL.md body longer than ~5000 tokens

NT3xx — Triggering quality

Whether agents will pick the skill at the right time.

Code	Default	Rule
NT301	warning	description lacks a “use when …” trigger clause
NT302	warning	description shorter than 60 characters
NT303	error	duplicate skill name in source repo
NT304	warning	description nearly duplicates another skill’s (they will compete for triggering)
NT305	warning	description written in first or second person

NT4xx — Agent compatibility

Keys and characters specific agents or tools handle differently.

Code	Default	Rule
NT401	warning	agent-specific frontmatter key but that agent is not targeted
NT402	info	unknown frontmatter key (preserved)
NT403	warning	non-ASCII characters in frontmatter (APM rejects them)

NT5xx — Safety

Content that should never reach a privileged agent unnoticed.

Code	Default	Rule
NT501	error	hidden or bidirectional Unicode character
NT502	error	possible secret
NT503	warning	script downloads and executes remote code
NT504	warning	overly broad allowed-tools