mstar-skill-authoring

mstar-skill-authoring is a skill for Claude Code from btspoony/mstar-harness. It costs 96 tokens per session (2,395 once invoked), scanned A, original, MIT.

A writing guide for creating, rewriting, reviewing, and optimizing agent skills. It covers when a skill should activate, how much instruction it should contain, and how to verify that changes improve agent behavior.

In plain words
What is it for?
Use it to design a new skill, revise its instructions or description, move detailed material into reference files, and test its behavior in different coding environments.
Why use it?
It helps prevent skills from being too vague, too long, or triggered for unrelated tasks.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions Claude Code; mentions AGENTS.md; mentions Codex.

Part of the morning-star-harness plugin — 23 skills, 5 commands, 14 agents, 2 hooks shipped together

Good fit Use it to design a new skill, revise its instructions or description, move detailed material into reference files, and test its behavior in different coding environments.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/btspoony/mstar-harness/mstar-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 btspoony/mstar-harness --skill mstar-skill-authoring
Clone the repo
git clone --depth 1 https://github.com/btspoony/mstar-harness

Made for: Claude Code.

Or install morning-star-harness, the plugin that ships this one along with the rest of its 23 skills, 5 commands, 14 agents, 2 hooks.

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 mstar-skill-authoring

README.md
[![agentmods](https://agentmods.dev/badge/skills/btspoony/mstar-harness/mstar-skill-authoring/github.svg)](https://agentmods.dev/skills/btspoony/mstar-harness/mstar-skill-authoring)
Your own site
<a href="https://agentmods.dev/skills/btspoony/mstar-harness/mstar-skill-authoring"><img src="https://agentmods.dev/badge/skills/btspoony/mstar-harness/mstar-skill-authoring/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for mstar-skill-authoring

Your own site · 80×15
<a href="https://agentmods.dev/skills/btspoony/mstar-harness/mstar-skill-authoring"><img src="https://agentmods.dev/badge/skills/btspoony/mstar-harness/mstar-skill-authoring.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 96 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,395 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 pass 7 Sept 2026
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 $0.00096 $0.02395
Opus 5 $0.00048 $0.01197
Sonnet 5 $0.00019 $0.00479
Haiku 4.5 $0.00010 $0.00239

Measured 11d ago against content hash b39850249701, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

mstar-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 11d 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/mstar-skill-authoring/SKILL.md · 182 lines

How it starts

The opening of the file, as written. The whole thing — 182 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Authoring

本 skill 约束如何编写、审查与验证 任意 agent skill(SKILL.md)。面向 skill 工作,不是普通应用实现。

Load Order

在本 harness 仓库内工作时:先 Read mstar-harness-core(加载 / 冲突裁决);仓库维护另遵根目录 AGENTS.md

在其它仓库 / 宿主上使用本 skill 时:按当地入口文档加载;本文件的原则与门控仍然适用。

改现有 skill 时:读完被改 skill 及其 SSOT 引用;禁止仅为文风重写相邻 skill。

详细 writer 流程与输出模板 → references/skillsbench-authoring.md(需要完整循环时再读)。

Workflow

主链:按「Frontmatter Contract」先定触发契约(原则 3)→ 按「Body 必须回答的 5 问」写默认紧凑 body(原则 2)→ 变体细节按「Progressive Disclosure」进 references/ / templates/ / scripts/ → 行为塑形改动按「验证门控(Evidence,原则 4 + 6)」留 paired 证据 → 按「Review Template」自审并完成「完成时主动说明」三问。

6 条作者原则(Decision Rules,必须遵守)

来源:SkillsBench 大规模实验。违反任一都会降低 agent 性能。

# 原则 强制动作
1 专家流程优先 先提取真实操作步骤、决策标准、约束、API 坑与失败恢复;模型只做编辑器。禁止把一键生成稿当最终版。
2 紧凑程序性 body 只答 5 问(见下);详例 / 长文档进 references/,按需加载。过长 body 几乎无提升甚至负提升。
3 路由最小化 任务真正需要时才加载;目标 1–3 个 skill。description 必须具体到可精准匹配,避免无关激活。
4 按 model+harness 实测 文件可移植 ≠ 行为可移植。在实际使用的模型与宿主(omp / Cursor / Codex / Claude Code 等)分别验证触发、执行、token、回归。
5 只补模型缺口 编码内部约定、受监管流程、脆弱 API、专业判断、反复失败模式。不写模型已会的通用知识。
6 每次改动=受控实验 必须有 paired 证据(with vs without,或 before/after + 可观察标准)。held-out / 压力场景未提升则拒绝合入。禁止“感觉更好”。

Body 必须回答的 5 问

合格 SKILL.md 清晰回答:

  1. 何时加载?(触发 / 排除)
  2. 按什么顺序与关键决策点执行?
  3. 哪些约束 / 不变量绝不可违反?
  4. 正确结果长什么样?(成功标准 / 证据)
  5. 主路径不够时打开哪些额外资源?

答不进这 5 问的内容 → 删或移到 references/

运行时别名(runtime alias map)

已发布的 mstar-* 专题 skill 允许运行时模式lintFiveQuestion(body, "runtime"))用锁定别名表回答同一问题(引擎常量 RUNTIME_HEADING_ALIASES):

问题 运行时别名(标题子串,大小写不敏感)
Workflow processplaybook
Decision Rules hard rulescore rulesrulegatenot to dored flags反模式红线规则门禁
Evidence output format证据
References dependencies关系
  • 别名表是锁定表:改表必须同步引擎回归测试与 corpus。
  • 新写 / greenfield skill(authoring / strict)仍要求 canonical 标题;运行时别名只豁免已发布专题 skill 的机械 lint,不豁免语义——别名标题必须真实回答对应问题,正文不得因别名而缩水。

Read the full file on GitHub · 182 lines

Files

What ships with it

2 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. 11d ago First seen · 182 lines · 96 tokens per session scan A b39850249701

Subscribe to this mod's changes

mstar-skill-authoring is a skill published in the GitHub repository btspoony/mstar-harness (58 stars, last pushed today), licensed MIT. It adds 96 tokens to every session and 2,395 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.