agentmods.dev

skill-builder

skill-builder is a skill for Claude Code from drayline/rootnode-skills. It costs 205 tokens per session (6,906 once invoked), scanned A, original, no licence file.

A toolkit for building and checking Skill files: packaged instructions and supporting files that extend an AI coding assistant. It covers design checks, testing, packaging, quality review, and description improvement.

In plain words
What is it for?
Use it to turn a Skill specification into deployable files, validate the result, run evaluations, and iterate on quality.
Why use it?
It helps catch problems before a Skill is deployed and provides a repeatable way to improve its behaviour. A Skill file is a bundle of instructions and optional resources that an assistant can use for a task.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the rootnode-skill-builder plugin — 1 skill shipped together

not rated 40repo changed 3d ago A scan 205 tokens custom licence

Good fit Use it to turn a Skill specification into deployable files, validate the result, run evaluations, and iterate on quality.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/drayline/rootnode-skills/skill-builder
View source ↗ drayline/rootnode-skills rootnode.design
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 drayline/rootnode-skills --skill skill-builder
Clone the repo
git clone --depth 1 https://github.com/drayline/rootnode-skills

Made for: Claude Code.

Or install rootnode-skill-builder, the plugin that ships this one along with the rest of its 1 skill.

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-builder

README.md
[![agentmods](https://agentmods.dev/badge/skills/drayline/rootnode-skills/skill-builder/github.svg)](https://agentmods.dev/skills/drayline/rootnode-skills/skill-builder)
Your own site
<a href="https://agentmods.dev/skills/drayline/rootnode-skills/skill-builder"><img src="https://agentmods.dev/badge/skills/drayline/rootnode-skills/skill-builder/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-builder

Your own site · 80×15
<a href="https://agentmods.dev/skills/drayline/rootnode-skills/skill-builder"><img src="https://agentmods.dev/badge/skills/drayline/rootnode-skills/skill-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 205 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 6,906 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.
Origin unknown 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 $0.00205 $0.06906
Opus 5.5 $0.00082 $0.02762
Sonnet 5.5 $0.00041 $0.01381
Haiku 4.5 $0.00020 $0.00691

Measured 3d ago against content hash f58363425912, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

skill-builder 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 3d ago.

The scan reads SKILL.md. This mod also ships 8 executable files (eval-viewer/generate_review.py, scripts/__init__.py, scripts/aggregate_benchmark.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

plugins/rootnode-skill-builder/skills/skill-builder/SKILL.md · 434 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

Files

What ships with it

24 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. 3d ago Changed f58363425912
  2. 4d ago First seen · 434 lines · 205 tokens per session scan A 64f0198da241

Subscribe to this mod's changes

skill-builder is a skill published in the GitHub repository drayline/rootnode-skills (40 stars, last pushed 4d ago), with no licence file. It adds 205 tokens to every session and 6,906 once invoked, about $0.0008 per session on Opus 5.5. 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 2026-11-03.

Building agentsClaude Codeagent-skillsai-toolsanthropicawesome-claude-promptsclaude-ai
Related

skill-builder compared with skills from other repositories

skill-builder next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
skill-builderdrayline/rootnode-skillsSkill404d agononeA205Claude Code
microservices-architecturetravisjneuman/.claudeSkill1072d agoMITA30Claude Code, Codex
accessibility-a11ytravisjneuman/.claudeSkill1072d agoMITA26Claude Code, Codex
ai-ml-developmenttravisjneuman/.claudeSkill1072d agoMITA43Claude Code, Codex
android-developmenttravisjneuman/.claudeSkill1072d agoMITA33Claude Code, Codex
audio-productiontravisjneuman/.claudeSkill1072d agoMITA33Claude Code, Codex
authentication-patternstravisjneuman/.claudeSkill1072d agoMITA28Claude Code, Codex