skill-authoring

skill-authoring is a skill for Claude Code, Codex from pproenca/dot-skills. It costs 91 tokens per session (1,674 once invoked), scanned A, original, MIT.

A guide to designing and maintaining skills, MCP tools, and other capabilities for coding agents. MCP is a standard way for an agent to connect to external tools and services.

In plain words
What is it for?
Use it when creating or reviewing a SKILL.md file, improving activation descriptions, organising progressive instructions, testing skill behaviour, or designing agent tools.
Why use it?
It helps make capabilities activate for the right requests, expose clear instructions, and avoid wasting the agent's limited context.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Claude Code.

Good fit Use it when creating or reviewing a SKILL.md file, improving activation descriptions, organising progressive instructions, testing skill behaviour, or designing agent tools.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pproenca/dot-skills/skill-authoring
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add pproenca/dot-skills --skill skill-authoring
Clone the repo
git clone --depth 1 https://github.com/pproenca/dot-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for skill-authoring

README.md
[![agentmods](https://agentmods.dev/badge/skills/pproenca/dot-skills/skill-authoring.svg)](https://agentmods.dev/skills/pproenca/dot-skills/skill-authoring)
Your own site
<a href="https://agentmods.dev/skills/pproenca/dot-skills/skill-authoring"><img src="https://agentmods.dev/badge/skills/pproenca/dot-skills/skill-authoring.svg" alt="Measured on agentmods" height="20"></a>
Per session 91 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,674 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Rogue Agent · line 3
    Skill modifies its own code, configuration, or behavior at runtime. Self-modification enables an agent to escalate privileges, disable safety constraints, or install persistent backdoors.
    Fix: Prevent the skill from modifying its own code, SKILL.md, or configuration files. Treat skill files as read-only at runtime.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00091 $0.01674
Opus 5 $0.00046 $0.00837
Sonnet 5 $0.00018 $0.00335
Haiku 4.5 $0.00009 $0.00167

Measured 8d ago against content hash d205ddd3ed97, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

skill-authoring scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/.curated/skill-authoring/SKILL.md · 141 lines

How it starts

The opening of the file, as written. The whole thing — 141 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AI Agent Skills Best Practices

Design and development guide for AI agent skills, including Claude Code skills and MCP tools. Contains 46 rules across 8 categories, prioritized by impact to guide skill creation, review, and optimization.

When to Apply

  • Creating new Claude Code skills or MCP tools
  • Writing or reviewing SKILL.md metadata and descriptions
  • Optimizing skill trigger reliability
  • Structuring content for progressive disclosure
  • Testing skill activation and behavior
  • Designing tool interfaces for agent workflows

Core Principles

1. Descriptions drive activation. Claude selects skills based on description matching against user intent. Include specific capabilities, trigger keywords, and negative cases. A skill with a vague description activates inconsistently or never.

2. Front-load critical instructions. Claude may truncate long content. Place non-negotiable rules in the first 100 lines. Bury important constraints at the end and they get ignored.

3. Progressive disclosure saves tokens. Load detailed content only when needed. A 2000-line skill wastes context on every activation. Structure as: SKILL.md (overview) → references/ (details) → scripts/ (execution).

4. Test activation, not just execution. A skill that works perfectly but never triggers provides zero value. Test with real user phrases, synonyms, and edge cases before deployment.

5. One skill per domain. Overlapping skills create activation conflicts. Split by clear boundaries (language, framework, workflow stage) with distinct trigger keywords.

Rule Categories

Priority Category Impact Prefix
1 Skill Metadata Design CRITICAL meta-
2 Description Engineering CRITICAL desc-
3 Content Structure HIGH struct-
4 Trigger Optimization HIGH trigger-
5 Progressive Disclosure MEDIUM-HIGH prog-
6 MCP Tool Design MEDIUM mcp-
7 Testing and Validation MEDIUM test-
8 Maintenance and Distribution LOW-MEDIUM maint-

Read the full file on GitHub · 141 lines

Files

What ships with it

51 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 141 lines · 91 tokens per session scan A d205ddd3ed97

Subscribe to this mod's changes

skill-authoring is a skill published in the GitHub repository pproenca/dot-skills (203 stars, last pushed 23d ago), licensed MIT. It adds 91 tokens to every session and 1,674 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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