skill-library-mission

skill-library-mission is a skill for Claude Code from athola/claude-night-market. It costs 40 tokens per session (1,484 once invoked), scanned B, original, MIT.

A repeatable process for collecting a project's unwritten knowledge and packaging it as reusable instructions in a skill library. It covers discovery, writing, and review.

In plain words
What is it for?
Use it to create a project-wide library of skills, preserve team practices, and update an existing library when the project has changed.
Why use it?
It reduces repeated explanations and helps new engineers or coding sessions work consistently without relying on one expert.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: reads .claude/ paths.

Part of the attune plugin — 14 skills, 11 commands, 2 agents shipped together

Good fit Use it to create a project-wide library of skills, preserve team practices, and update an existing library when the project has changed.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/athola/claude-night-market/skill-library-mission
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 athola/claude-night-market --skill skill-library-mission
Clone the repo
git clone --depth 1 https://github.com/athola/claude-night-market

Made for: Claude Code.

Or install attune, the plugin that ships this one along with the rest of its 14 skills, 11 commands, 2 agents.

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-library-mission

README.md
[![agentmods](https://agentmods.dev/badge/skills/athola/claude-night-market/skill-library-mission/github.svg)](https://agentmods.dev/skills/athola/claude-night-market/skill-library-mission)
Your own site
<a href="https://agentmods.dev/skills/athola/claude-night-market/skill-library-mission"><img src="https://agentmods.dev/badge/skills/athola/claude-night-market/skill-library-mission/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 skill-library-mission

Your own site · 80×15
<a href="https://agentmods.dev/skills/athola/claude-night-market/skill-library-mission"><img src="https://agentmods.dev/badge/skills/athola/claude-night-market/skill-library-mission.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,484 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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: 2 findings, up to medium

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 →

  • medium Excessive Agency · line 142
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
  • medium Agent Snooping · line 167
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
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 $0.00040 $0.01484
Opus 5 $0.00020 $0.00742
Sonnet 5 $0.00008 $0.00297
Haiku 4.5 $0.00004 $0.00148

Measured 9d ago against content hash c1a8f247c662, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade B, and why

skill-library-mission scanned grade B with 1 finding 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 9d 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.

Enumerates other installed skillsmediumAgent snooping

Other skills' SKILL.md files reveal prompts, capabilities and secrets that should be invisible to peers.

`ls .claude/skills/ | head -5`
plugins/attune/skills/skill-library-mission/SKILL.md · 168 lines

How it starts

The opening of the file, as written. The whole thing — 168 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Library Mission

Overview

A retiring distinguished fellow's final task: package everything the project knows into a skill library under .claude/skills/, so that cheaper sessions and newer engineers can carry the project forward at the same standard. This skill turns that one-off exercise into a repeatable mission with three gated phases: discover, author, review.

The mission produced its first library in this repository on 2026-07-02 (15 skills, mission skill-library-2026-07-02). The generalized dispatch prompt distilled from that run is preserved verbatim in references/mission-prompt.md.

When To Use

  • A repository has deep tribal knowledge and no .claude/skills/ library, and future sessions (human or model) must operate without the current expert.
  • An existing project library has drifted and needs a full re-discovery and re-review pass.
  • Onboarding cost is high: the same questions get re-answered and the same dead ends get re-fought across sessions.

When NOT To Use

Situation Use instead
Authoring or improving one skill Skill(abstract:skill-authoring)
Skills shipped inside a plugin Skill(plugin-dev:skill-development)
Auditing existing skills only Skill(abstract:skills-eval)
Full project lifecycle (code, not knowledge) Skill(attune:mission-orchestrator)

Mission Shape

Run as an attune mission with custom phases so the run survives interruption and records user directives:

{
  "mission_id": "skill-library-YYYY-MM-DD",
  "type": "custom",
  "phases": ["discover", "author", "review", "report"],
  "artifacts": { "library_root": ".claude/skills/" }
}

Save this to .attune/mission-state.json, advance current_phase at each gate, and record every user decision and override in decisions / directive_overrides. A later session must be able to resume from the state file alone.

Phase 1: Discover

No authoring happens in this phase. Investigate like an incoming principal engineer:

Read the full file on GitHub · 168 lines

Files

What ships with it

4 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. 9d ago First seen · 168 lines · 40 tokens per session scan B c1a8f247c662

Subscribe to this mod's changes

skill-library-mission is a skill published in the GitHub repository athola/claude-night-market (337 stars, last pushed 2d ago), licensed MIT. It adds 40 tokens to every session and 1,484 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it B with 1 finding (enumerates other installed skills). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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