llm.log: Skill for Claude Code

.agents/skills/harden/SKILL.md

harden is a skill for Claude Code from lanesket/llm.log. It costs 32 tokens per session (2,178 once invoked), scanned A, a copy of harden, MIT.

A review and improvement process for making interfaces handle unusual inputs, failures, different languages, and other real-world conditions.

In plain words
What is it for?
Use it to check long or missing content, errors, permissions, slow connections, translations, right-to-left languages, dates, numbers, currencies, and large lists.
Why use it?
It prevents designs that work only with short English text, perfect data, fast networks, and successful requests.

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 lanesket/llm.log's own configuration. It tells Claude Code how to work on llm.log 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 llm.log configures →

Reuse

Borrowing it

Nothing to install: this file belongs to lanesket/llm.log. 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/lanesket/llm.log/main/.agents/skills/harden/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/lanesket/llm.log

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/lanesket/llm.log/harden/github.svg)](https://agentmods.dev/skills/lanesket/llm.log/harden)
Your own site
<a href="https://agentmods.dev/skills/lanesket/llm.log/harden"><img src="https://agentmods.dev/badge/skills/lanesket/llm.log/harden/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 harden

Your own site · 80×15
<a href="https://agentmods.dev/skills/lanesket/llm.log/harden"><img src="https://agentmods.dev/badge/skills/lanesket/llm.log/harden.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 32 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,178 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 92% 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 $0.00032 $0.02178
Opus 5 $0.00016 $0.01089
Sonnet 5 $0.00006 $0.00436
Haiku 4.5 $0.00003 $0.00218

Measured 9d ago against content hash a45487856647, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, 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 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.

Origin

This is a copy

92% identical to harden — 11 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 · 357 lines

How it starts

The opening of the file, as written. The whole thing — 357 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 · 357 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 · 357 lines · 32 tokens per session scan A a45487856647

Subscribe to this mod's changes

harden is a skill published in the GitHub repository lanesket/llm.log (22 stars, last pushed 5mo ago), licensed MIT. It adds 32 tokens to every session and 2,178 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 92% identical to harden, differing in 11 lines, and is treated as a copy.

Related

Other skills, from other repositories

internationalization

Plan and run a multi-language or multi-region site. Use this skill when adding new locales, choosing URL structure for languages (subfolders vs subdomains vs ccTLDs), implementing hreflang, planning translation workflow, handling currency and date formats, designing for RTL languages, or auditing a stalled…

rampstackco/claude-skills · 123 tokens

software-localisation

Implements production-grade i18n/l10n for React, Vue, Angular, and Next.js with ICU format and RTL support. Use when setting up or debugging localisation.

vasilyu1983/AI-Agents-public · 39 tokens

dev-i18n

Internationalization (i18n) and localization (l10n) for web and mobile applications. Libraries next-intl, react-i18next, vue-i18n, formatjs, flutterlocalizations, ARB. Trigger when the user wants to add multiple languages, extract strings, handle plurals, date/number formats, or when translation files are detected.

christopherlouet/claude-base · 79 tokens

dev-nextjs

Next.js development (App Router, Server Components, caching, streaming). Trigger when the user works with Next.js, modifies app/, pages/, next.config, or talks about RSC, Server Actions, Route Handlers, middleware.

christopherlouet/claude-base · 50 tokens

qa-design

UI/UX design audit and verification of web best practices, including responsive/mobile-first breakpoints. Trigger when the user wants to audit the design, verify the UI/UX, check responsive behaviour, or improve the user interface.

christopherlouet/claude-base · 48 tokens

dev-frontend-design

Distinctive UI design with strong art direction. Trigger when the user wants to create an interface, a landing page, a visual component, or when frontend code creation is detected without a defined design direction.

christopherlouet/claude-base · 45 tokens