s4h-logic

s4h-logic is a skill for Claude Code from human-avatar/skills-for-humanity. It costs 77 tokens per session (1,459 once invoked), scanned A, original, MIT.

A logic-analysis guide that routes arguments, plans, and systems to checks for sound reasoning, contradictions, causes, dependencies, or constraints.

In plain words
What is it for?
Use it to validate arguments, find contradictions, map dependencies, analyse constraints, or repair faulty reasoning.
Why use it?
It helps reveal whether conclusions follow from their premises and where a plan or document contains broken reasoning.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: names the AskUserQuestion tool.

Part of the skills-for-humanity plugin — 197 skills, 1 hook shipped together

Good fit Use it to validate arguments, find contradictions, map dependencies, analyse constraints, or repair faulty reasoning.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/human-avatar/skills-for-humanity/s4h-logic
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 human-avatar/skills-for-humanity --skill s4h-logic
Clone the repo
git clone --depth 1 https://github.com/human-avatar/skills-for-humanity

Made for: Claude Code.

Or install skills-for-humanity, the plugin that ships this one along with the rest of its 197 skills, 1 hook.

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 s4h-logic

README.md
[![agentmods](https://agentmods.dev/badge/skills/human-avatar/skills-for-humanity/s4h-logic/github.svg)](https://agentmods.dev/skills/human-avatar/skills-for-humanity/s4h-logic)
Your own site
<a href="https://agentmods.dev/skills/human-avatar/skills-for-humanity/s4h-logic"><img src="https://agentmods.dev/badge/skills/human-avatar/skills-for-humanity/s4h-logic/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 s4h-logic

Your own site · 80×15
<a href="https://agentmods.dev/skills/human-avatar/skills-for-humanity/s4h-logic"><img src="https://agentmods.dev/badge/skills/human-avatar/skills-for-humanity/s4h-logic.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 77 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,459 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Memory Poisoning · line 121
    Skill manipulates agent memory, state, or stored context. Memory corruption can alter personality, override safety rules, or cause unpredictable behavior.
    Fix: Protect agent memory and state from modification by untrusted content. Use read-only memory for critical instructions and validate all state changes.
How audits are shown
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 $0.00077 $0.01459
Opus 5 $0.00039 $0.00730
Sonnet 5 $0.00015 $0.00292
Haiku 4.5 $0.00008 $0.00146

Measured 9d ago against content hash c4cf0adc1071, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

s4h-logic 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/s4h-logic/SKILL.md · 122 lines

How it starts

The opening of the file, as written. The whole thing — 122 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Logic

Applies logical analysis to arguments, plans, reasoning, and systems. Diagnoses what kind of logical work is needed and applies the right tool.

Which tool fits

You need to... Tool
Full council pressure-test with peer review logic-council
Fast comprehensive logic report logic-check
Validate whether premises support a conclusion argument-validation
Find internal contradictions in a document or spec consistency-check
Map causal relationships and dependencies causality-mapping
Map the constraint landscape for a decision or plan constraint-mapping
Fix broken reasoning — not just diagnose, but repair logic-fixer

Routing Decision

Framing check: Confirm the argument or reasoning being examined before routing. State the argument being examined and the claim at stake in one sentence, then use AskUserQuestion:

  • Question: "I'm reading this as: [your one-sentence framing of the specific argument or reasoning and what's at stake]. Is that right?"

  • Header: "Framing"

  • Options:

    • Yes — proceed — framing is correct
    • Adjust — one element is off; user will correct it before you continue
    • Reframe — different situation than read; incorporate the correction before proceeding
  • Complex argument worth thorough pressure-testing → logic-council (multi-advisor + peer review)

  • Need a complete logic review quickly → logic-check (all dimensions, no overhead)

  • Specific argument with a conclusion that needs validating → argument-validation

  • Document or spec that might contain contradictions → consistency-check

  • Need to understand what causes what, or what breaks if X changes → causality-mapping

  • Unclear what's actually negotiable or fixed in a situation → constraint-mapping

  • Have broken reasoning and want it repaired → logic-fixer

  • Unclear → logic-check (comprehensive starting point that surfaces which deeper tool is needed)

Confirm Direction

Read the full file on GitHub · 122 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 · 122 lines · 77 tokens per session scan A c4cf0adc1071

Subscribe to this mod's changes

s4h-logic is a skill published in the GitHub repository human-avatar/skills-for-humanity (223 stars, last pushed 1mo ago), licensed MIT. It adds 77 tokens to every session and 1,459 once invoked, about $0.0004 per session on Opus 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 2026-09-03.

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