ferrox-using-skills

ferrox-using-skills is a skill for Claude Code from FerroxLabs/ferrox-factory. It costs 0 tokens per session (912 once invoked), scanned A, original, MIT.

A development method called test-driven development, or TDD, where you write a test that fails, add the smallest code to pass it, and then improve the design. A test is a check that verifies software behaves as expected.

In plain words
What is it for?
Use it before writing code for new features, bug fixes, refactoring, or behavior changes, following the failing-test, passing-code, and cleanup cycle.
Why use it?
It provides a concrete description of the required behavior before implementation begins. This helps catch misunderstandings and limits unnecessary code during features, fixes, and refactoring.

Skill for Claude Code

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

Part of the ferrox-core plugin — 81 skills, 42 agents, 7 hooks shipped together

Good fit Use it before writing code for new features, bug fixes, refactoring, or behavior changes, following the failing-test, passing-code, and cleanup cycle.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ferroxlabs/ferrox-factory/ferrox-using-skills
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 FerroxLabs/ferrox-factory --skill ferrox-using-skills
Clone the repo
git clone --depth 1 https://github.com/FerroxLabs/ferrox-factory

Made for: Claude Code.

Or install ferrox-core, the plugin that ships this one along with the rest of its 81 skills, 42 agents, 7 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 ferrox-using-skills

README.md
[![agentmods](https://agentmods.dev/badge/skills/ferroxlabs/ferrox-factory/ferrox-using-skills/github.svg)](https://agentmods.dev/skills/ferroxlabs/ferrox-factory/ferrox-using-skills)
Your own site
<a href="https://agentmods.dev/skills/ferroxlabs/ferrox-factory/ferrox-using-skills"><img src="https://agentmods.dev/badge/skills/ferroxlabs/ferrox-factory/ferrox-using-skills/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 ferrox-using-skills

Your own site · 80×15
<a href="https://agentmods.dev/skills/ferroxlabs/ferrox-factory/ferrox-using-skills"><img src="https://agentmods.dev/badge/skills/ferroxlabs/ferrox-factory/ferrox-using-skills.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 912 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 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 $0.00000 $0.00912
Opus 5 $0.00000 $0.00456
Sonnet 5 $0.00000 $0.00182
Haiku 4.5 $0.00000 $0.00091

Measured 9d ago against content hash c5242f0abe46, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

ferrox-using-skills 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 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.

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-vendored/ferrox-using-skills/SKILL.md · 65 lines

How it starts

The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Adapted from Superpowers using-superpowers by Obra (MIT) — see NOTICE.

This is the fork's single skill-invocation mandate. It is the ONLY skill that carries the <!-- ferrox:skill-invocation-mandate --> marker; no discipline skill carries it.

The Rule

If there is even a real chance a skill applies to what you are about to do, you MUST invoke it before responding or acting — including before clarifying questions, exploring the codebase, or reading files. If the skill turns out to be wrong for the situation, you don't have to follow it, but you check first.

Then announce "Using [skill] to [purpose]" and follow the skill exactly. If it has a checklist, create a todo per item.

This is not negotiable. You cannot rationalize your way out of checking.

The Ferrox Surfacing Model

Ferrox Factory pairs a context-engineered lifecycle spine with Superpowers' per-task discipline as the floor. Two layers, both surfaced through this one mandate:

  • Macro flow: the Ferrox lifecycle skills own the shape of the work: discuss → plan → execute → verify (plus the phase/milestone/audit machinery). Route project-level intent through these; do not invent a competing process vocabulary.
  • Micro-discipline floor — the vendored Ferrox disciplines are the quality floor inside a task:
    • ferrox-test-driven-development — before writing implementation code for any feature or bugfix.
    • ferrox-systematic-debugging — before proposing a fix for any bug, test failure, or unexpected behavior.
    • ferrox-verification-before-completion — before claiming work is complete, fixed, or passing; evidence before assertions, always.
    • ferrox-requesting-code-review — when completing tasks or major features, before merging.
    • ferrox-receiving-code-review — when acting on review feedback, before implementing suggestions.

Read the full file on GitHub · 65 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. 9d ago First seen · 65 lines · 0 tokens per session scan A c5242f0abe46

Subscribe to this mod's changes

ferrox-using-skills is a skill published in the GitHub repository FerroxLabs/ferrox-factory (22 stars, last pushed 1mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 912 tokens. 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.