skill-authoring

skill-authoring is a skill for Claude Code, Codex from yimwoo/hotl-plugin. It costs 29 tokens per session (713 once invoked), scanned A, original, MIT.

Guidance for writing and reviewing skills, agent instructions, commands, and other files that shape how coding agents behave.

In plain words
What is it for?
Use it to define a behavior change, choose whether it belongs in a skill or another instruction type, write precise triggers and rules, verify the result, and update related indexes or copies.
Why use it?
It helps make instructions clear, reusable, testable, and consistent wherever they are exposed.

Skill for Claude CodeCodex

Part of the hotl plugin — 20 skills, 9 commands, 1 agent, 1 hook shipped together

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.

agentmods
npx agentmods add skills/yimwoo/hotl-plugin/skill-authoring
Any agent
npx skills add yimwoo/hotl-plugin --skill skill-authoring
Clone the repo
git clone --depth 1 https://github.com/yimwoo/hotl-plugin

Made for: Claude Code, Codex.

Or install hotl, the plugin that ships this one along with the rest of its 20 skills, 9 commands, 1 agent, 1 hook.

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/yimwoo/hotl-plugin/skill-authoring.svg)](https://agentmods.dev/skills/yimwoo/hotl-plugin/skill-authoring)
Your own site
<a href="https://agentmods.dev/skills/yimwoo/hotl-plugin/skill-authoring"><img src="https://agentmods.dev/badge/skills/yimwoo/hotl-plugin/skill-authoring.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 713 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00029 $0.00713
Opus 5 $0.00015 $0.00357
Sonnet 5 $0.00006 $0.00143
Haiku 4.5 $0.00003 $0.00071

Measured 5d ago against content hash 679ba5c6b5f4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, 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 5d 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/skill-authoring/SKILL.md · 83 lines

How it starts

The opening of the file, as written. The whole thing — 83 lines — stays where its author put it; the contents beside it link to each section on GitHub.

HOTL Skill Authoring

Overview

HOTL skills are behavior-shaping code. Treat changes to skill text, agent prompts, command routers, and adapter instructions with the same care as production logic: define the failure mode, make the desired behavior explicit, verify the change, and update every index or mirror that exposes it.

When To Use

Use this before changing:

  • skills/*/SKILL.md
  • agents/*.md
  • commands/*.md
  • cline/rules/*.md
  • adapter templates that steer agent behavior
  • docs that define skill invocation or routing

Do not use it for ordinary product docs, generated reports, or local project README edits unless they change how agents should behave.

Process

  1. State the behavior change

    • What agent behavior is wrong, missing, or ambiguous?
    • What prompt or session exposed the issue?
    • Is the change broadly useful, or project-specific?
  2. Choose the right abstraction

    • Skill: reusable workflow or process the user can invoke.
    • Agent: isolated specialist with a stable output contract.
    • Inline prompt: short role text used by one skill only.
    • Script/lint: deterministic rule that should not depend on model judgment.
  3. Write trigger-only frontmatter

    • name: kebab-case, no command-name collision.
    • description: says when to activate, not the workflow steps.
    • Avoid descriptions that summarize the process; agents may follow the summary and skip the body.
  4. Keep behavior text testable

    • Use direct rules for invariants.
    • Add red flags for common rationalizations.
    • Prefer short, concrete examples over long narratives.
    • Separate heavy references or templates into adjacent files only when they reduce the main skill's noise.
  5. Update routing and mirrors

    • Add new skills to skills/using-hotl/SKILL.md.
    • Update docs/skills.md, README tables, and Codex docs for user-visible skill changes.
    • Update Cline rules or adapter templates when their behavior mirrors the changed skill.

Read the full file on GitHub · 83 lines

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. 5d ago First seen · 83 lines · 29 tokens per session scan A 679ba5c6b5f4

Subscribe to this mod's changes

skill-authoring is a skill published in the GitHub repository yimwoo/hotl-plugin (26 stars, last pushed 2mo ago), licensed MIT. It adds 29 tokens to every session and 713 once invoked, about $0.0001 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.

Related

Other skills, from other repositories

first-plan-co-change-analysis

Skill que constrói o Co-change Graph - "quando arquivo X muda, qual outro arquivo geralmente muda junto?". Use durante Discovery e em /fp:cochange. Baseado em git history. Detecta arquivos co-dependentes que devem ser editados juntos para evitar PRs incompletos. v0.3.0+ usa engine nativo Rust quando disponível…

vynazevedo/first-plan · 88 tokens

first-plan-protocol

Esta skill DEVE ser carregada em qualquer comando do plugin first-plan. Define o protocolo PLAN-FIRST (Discovery -> Plan -> Approval -> Execution -> Report), as 7 regras invioláveis e o comportamento esperado em cada fase. Ative quando o usuário invocar /fp: ou mencionar "first-plan", "context compilation", "discovery…

vynazevedo/first-plan · 81 tokens

first-plan-provenance-tracker

Skill que define o schema de proveniência e o sistema de freshness tracking para findings em .first-plan/. Use durante Discovery e refresh para registrar source (file:line@SHA), TTL, confidence inicial e cadeia de supersedeção. Aplica decay de confidence baseado em idade.

vynazevedo/first-plan · 64 tokens

first-plan-reconciliation

Skill que define Spec-Code Reconciliation - matching contínuo entre artefatos de intenção (docs, specs, JIRA, GitHub issues) e implementação (código, testes, PRs). Use durante Discovery e em /fp:check para identificar feature ja implementada, em flight, drifted ou abandonada.

vynazevedo/first-plan · 70 tokens

first-plan-git-intelligence

Skill que extrai inteligência do git history - heatmap de atividade, ownership, branches/PRs in-flight. Use durante Discovery e em /fp:hot, /fp:owner, /fp:in-flight. Tudo via comandos git read-only.

vynazevedo/first-plan · 58 tokens

first-plan-lens-engine

Skill que define o motor de detecção e roteamento de stack lenses do first-plan. Mapeia manifestos (go.mod, package.json, etc) -> stack -> papel -> lens skill correspondente. Use quando precisar decidir qual lens aplicar a uma pasta durante Discovery, ou quando estender suporte a uma nova stack.

vynazevedo/first-plan · 70 tokens