Plugin-authoring guidance caps skill length at 500 lines but sets no maximum line length

[taminomara]

Summary

The plugin-authoring guidance caps SKILL.md length at 500 lines but sets no maximum line length. Agent guidance is looser still: it has no body line-count cap or line-length rule at all, only a frontmatter description character budget.

Where the cap lives

• han-plugin-builder/skills/guidance/references/skill-building-guidance/progressive-disclosure.md (line 36) — "keep the SKILL.md body under 500 lines... Treat 500 lines as the ceiling, not the target." No line-length rule.
• han-plugin-builder/skills/guidance/references/skill-building-guidance/cowork-specific-skill-instructions.md (lines 167, 249) — repeats the 500-line cap. No line-length rule.
• han-plugin-builder/skills/guidance/references/agent-building-guidelines/ — the only length guidance is agent-description-length.md (description char budget: 1024 target, ~1500 hard signal). No body line-count or line-length rule for agents.

Why it matters

The 500-line cap exists to bound how much content a skill loads into the model's context window and to keep bloaty skills from distracting agents. But a line is unbounded in length, so a line-count cap alone is a leaky proxy for content volume: 500 very long lines can blow past the intended budget. Without a line-length bound (or a more direct measure), the 500-line ceiling doesn't reliably do the job it exists for.

Open question

Not just "what max line length" — the real question is which lever is right:

• a per-line character cap (e.g. 80 / 100 / 120, or semantic line breaks / one sentence per line), or
• a total character or token budget that measures content volume directly, or
• keeping the line-count cap and adding a line-length bound so it stops being a leaky proxy.

Scope to decide alongside it: does it apply to agent bodies and references/ files too, not just SKILL.md? Hard cap or recommendation? A judgment call, or something a formatter/linter enforces?