librarian

librarian is a skill for Claude Code from jdforsythe/forge. It costs 145 tokens per session (4,645 once invoked), scanned B, original, MIT.

A library-maintenance skill for reviewing agents, skills, and templates. It finds duplicates, outdated items, broken references, and candidates for merging, archiving, or promotion.

In plain words
What is it for?
Use it to audit the library, check its inventory and references, detect stale or orphaned items, and produce recommendations for cleanup.
Why use it?
It helps keep a growing collection useful by reducing clutter and identifying items that need attention.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions Claude Code.

Part of the forge plugin — 4 skills, 3 agents 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/jdforsythe/forge/librarian
Any agent
npx skills add jdforsythe/forge --skill librarian
Clone the repo
git clone --depth 1 https://github.com/jdforsythe/forge

Made for: Claude Code.

Or install forge, the plugin that ships this one along with the rest of its 4 skills, 3 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 librarian

README.md
[![agentmods](https://agentmods.dev/badge/skills/jdforsythe/forge/librarian.svg)](https://agentmods.dev/skills/jdforsythe/forge/librarian)
Your own site
<a href="https://agentmods.dev/skills/jdforsythe/forge/librarian"><img src="https://agentmods.dev/badge/skills/jdforsythe/forge/librarian.svg" alt="Measured on agentmods" height="20"></a>
Per session 145 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,645 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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 $0.00145 $0.04645
Opus 5 $0.00072 $0.02322
Sonnet 5 $0.00029 $0.00929
Haiku 4.5 $0.00015 $0.00464

Measured 6d ago against content hash c4d40f94bd51, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade B, and why

librarian 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 6d 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.

Asks the agent to reveal its instructionsmediumSystem prompt leakage

Directions to print, repeat or translate the system prompt extract configuration the operator did not intend to expose.

All items have been used within the last 90 days. Quality tiers are up to date. All template references resolve to existing agents. All citations trace to docs/research/source-index.md and no item shows reasoning-echo in
skills/librarian/SKILL.md · 406 lines

How it starts

The opening of the file, as written. The whole thing — 406 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Librarian

The curation and maintenance engine for the Forge library. Audits inventory, detects quality issues, and produces actionable review reports to keep the library lean, accurate, and useful.


Expert Vocabulary Payload

Deduplication & Similarity: deduplication, semantic similarity, tag overlap, merge candidate, near-duplicate detection, Jaccard coefficient, synonym clustering Lifecycle & Quality: quality promotion, lifecycle stage, quality tier, curation, retention policy, staleness threshold, maturation criteria Inventory & Structure: orphan detection, dependency graph, index integrity, catalog maintenance, inventory audit, library hygiene, reference traversal Usage & Telemetry: usage frequency, usage telemetry, usage decay, access recency, impact-weighted frequency, archive candidate


Anti-Pattern Watchlist

Hoarder Library

  • Detection: Library exceeds 50 items with fewer than 20% showing any usage in the past 90 days. The index grows monotonically — items are added but never removed.
  • Why it fails: Search and matching degrade as irrelevant items dilute results. Users lose trust in library quality when most items are stale or broken. Cognitive overhead increases with every unused entry.
  • Resolution: Flag all items with zero usage in the past 90 days for review. Present the list sorted by staleness (oldest unused first). Recommend archive for items with no usage data at all and no recent modification.

Premature Deletion

  • Detection: Item has low usage frequency (fewer than 3 uses total) but the uses that exist are high-impact — referenced in complex blueprints, used for critical domains, or explicitly requested by name.
  • Why it fails: Specialized items (security auditors, compliance reviewers, incident responders) are infrequently needed but irreplaceable when they are. Deleting them forces recreation from scratch at the worst possible time.
  • Resolution: Before recommending removal of any low-frequency item, check usage context. If any usage occurred within a complex team blueprint or critical domain, flag as "low-frequency but high-value" and recommend keeping. Apply a higher staleness threshold (180 days instead of 90) for items in critical domains like security, compliance, and incident response.

Read the full file on GitHub · 406 lines

Files

What ships with it

3 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. 6d ago First seen · 406 lines · 145 tokens per session scan B c4d40f94bd51

Subscribe to this mod's changes

librarian is a skill published in the GitHub repository jdforsythe/forge (151 stars, last pushed 2mo ago), licensed MIT. It adds 145 tokens to every session and 4,645 once invoked, about $0.0007 per session on Opus 5. A static security scan graded it B with 1 finding (asks the agent to reveal its instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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