agentsclimarketplace

Skill authoring

Skill ulpi-io/plugin-marketplace/plugins/pproenca/skills/skill-authoring

A curated collection of 7,800+ agent skills for Claude Desktop, sourced from skills.sh

Install
npx -y skills add ulpi-io/plugin-marketplace --skill skill-authoring

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

2 things to look at

  • no licenseNo license file was found in the repository. Code published without one is not open source by default, so using it at work is a question for whoever answers licensing questions where you are.
  • 1 stars1 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.

What its author says it does

Copied from the file, not written here

Guidelines for writing Agent Skills that comply with the agentskills.io specification. WHEN: "create a skill", "new skill", "write a skill", "skill template", "skill structure", "review skill", "skill PR", "skill compliance", "SKILL.md format", "skill frontmatter", "skill best practices".

The file declares its own license as MIT. That is the author’s claim about this one file, and it is not the same thing as the license GitHub reports for the repository, which is listed with the other numbers below.

SKILL.md

3.2 KB, as published. Nobody here has run it

Skill Authoring Guide

This skill provides guidance for writing Agent Skills that comply with the agentskills.io specification.

When to Use

  • Creating a new skill for this repository
  • Reviewing a skill PR for compliance
  • Checking if an existing skill follows best practices
  • Understanding token budgets and progressive disclosure

Constraints

  • name: 1-64 chars, lowercase + hyphens, match directory
  • description: 1-1024 chars, ≤60 words, explain WHAT and WHEN
  • Use WHEN: with quoted trigger phrases (preferred over USE FOR:)
  • Do NOT use DO NOT USE FOR: (keyword contamination on Sonnet)
  • Use inline double-quoted strings (not >- folded scalars)
  • SKILL.md: <500 tokens (soft), <5000 (hard)
  • references/*.md: <1000 tokens each

Structure

  • SKILL.md (required) - Instructions
  • references/ (optional) - Detailed docs
  • scripts/ (optional) - Executable code

Frontmatter: name (lowercase-hyphens), description (WHAT + WHEN)

Progressive Disclosure

Metadata (~100 tokens) loads at startup. SKILL.md (<5000 tokens) loads on activation. References load only when explicitly linked (not on activation). Keep SKILL.md lean.

Reference Loading

References are JIT (just-in-time) loaded:

  • Only files explicitly linked via [text](references/file.md) load
  • Link to files, not folders - [Recipes](references/recipes/README.md) not [Recipes](references/recipes/)
  • Each file loads in full (not sections)
  • No caching between requests - write self-contained files
  • Use recipes/services patterns for multi-option skills

See REFERENCE-LOADING.md for details.

Validation

# Run from the scripts directory
cd scripts
npm run references              # Validate all skill links
npm run tokens -- check         # Check token limits

Integrity Checks

When reviewing or authoring skills, verify:

  1. No broken links - All referenced files exist
  2. No orphaned references - All reference files are linked
  3. Token budgets - References under 1000 tokens (split if exceeded)
  4. No duplicates - Consolidate repeated content
  5. No out-of-place guidance - Service-specific content belongs in service-specific references

See Validation for detailed procedures.

Reference Documentation

Keep looking

Skills are one crate of 328,083. Ordering is by how many stacks a row turns up in, so the top of any crate is what has actually been picked rather than what has the most stars.