aghub: Skill for Claude Code

.agents/skills/harden/SKILL.md

harden is a skill for Claude Code from AkaraChen/aghub. It costs 62 tokens per session (2,184 once invoked), scanned A, a copy of harden, MIT.

An interface resilience guide for handling failures, unusual input, long text, multiple languages, and empty data. Internationalization, or i18n, means preparing software for different languages, writing systems, dates, and number formats.

In plain words
What is it for?
Adding error and empty states, testing long or unusual text, supporting right-to-left languages, handling network and API failures, and checking large lists or numbers.
Why use it?
It helps find problems that only appear outside ideal test data, such as broken layouts, failed requests, unreadable translations, or missing content.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter. Also seen: positional $N argument; installed under .agents/ (shared by several agents).

This is AkaraChen/aghub's own configuration. It tells Claude Code how to work on aghub itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything aghub configures →

Reuse

Borrowing it

Nothing to install: this file belongs to AkaraChen/aghub. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/AkaraChen/aghub/main/.agents/skills/harden/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/AkaraChen/aghub

Made for: Claude Code.

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 harden

README.md
[![agentmods](https://agentmods.dev/badge/skills/akarachen/aghub/harden.svg)](https://agentmods.dev/skills/akarachen/aghub/harden)
Your own site
<a href="https://agentmods.dev/skills/akarachen/aghub/harden"><img src="https://agentmods.dev/badge/skills/akarachen/aghub/harden.svg" alt="Measured on agentmods" height="20"></a>
Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,184 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 94% copy Near-identical to another mod 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 $0.00062 $0.02184
Opus 5 $0.00031 $0.01092
Sonnet 5 $0.00012 $0.00437
Haiku 4.5 $0.00006 $0.00218

Measured 8d ago against content hash 3bbc45c6969d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

harden 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 8d 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.

Origin

This is a copy

94% identical to harden — 168 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/harden/SKILL.md · 390 lines

How it starts

The opening of the file, as written. The whole thing — 390 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Strengthen interfaces against edge cases, errors, internationalization issues, and real-world usage scenarios that break idealized designs.

Assess Hardening Needs

Identify weaknesses and edge cases:

  1. Test with extreme inputs:

    • Very long text (names, descriptions, titles)
    • Very short text (empty, single character)
    • Special characters (emoji, RTL text, accents)
    • Large numbers (millions, billions)
    • Many items (1000+ list items, 50+ options)
    • No data (empty states)
  2. Test error scenarios:

    • Network failures (offline, slow, timeout)
    • API errors (400, 401, 403, 404, 500)
    • Validation errors
    • Permission errors
    • Rate limiting
    • Concurrent operations
  3. Test internationalization:

    • Long translations (German is often 30% longer than English)
    • RTL languages (Arabic, Hebrew)
    • Character sets (Chinese, Japanese, Korean, emoji)
    • Date/time formats
    • Number formats (1,000 vs 1.000)
    • Currency symbols

CRITICAL: Designs that only work with perfect data aren't production-ready. Harden against reality.

Hardening Dimensions

Systematically improve resilience:

Text Overflow & Wrapping

Long text handling:

/* Single line with ellipsis */
.truncate {
	overflow: hidden;
	text-overflow: ellipsis;
	white-space: nowrap;
}

/* Multi-line with clamp */
.line-clamp {
	display: -webkit-box;
	-webkit-line-clamp: 3;
	-webkit-box-orient: vertical;
	overflow: hidden;
}

/* Allow wrapping */
.wrap {
	word-wrap: break-word;
	overflow-wrap: break-word;
	hyphens: auto;
}

Flex/Grid overflow:

/* Prevent flex items from overflowing */
.flex-item {
	min-width: 0; /* Allow shrinking below content size */
	overflow: hidden;
}

/* Prevent grid items from overflowing */
.grid-item {
	min-width: 0;
	min-height: 0;
}

Responsive text sizing:

  • Use clamp() for fluid typography
  • Set minimum readable sizes (14px on mobile)
  • Test text scaling (zoom to 200%)
  • Ensure containers expand with text

Read the full file on GitHub · 390 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. 8d ago First seen · 390 lines · 62 tokens per session scan A 3bbc45c6969d

Subscribe to this mod's changes

harden is a skill published in the GitHub repository AkaraChen/aghub (266 stars, last pushed 5d ago), licensed MIT. It adds 62 tokens to every session and 2,184 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to harden, differing in 168 lines, and is treated as a copy.

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