s4h-information-entropy

s4h-information-entropy is a skill for Claude Code from human-avatar/skills-for-humanity. It costs 74 tokens per session (2,105 once invoked), scanned A, original, MIT.

A way to measure uncertainty and how much a piece of information changes what you expect, using Shannon’s entropy measure.

In plain words
What is it for?
Use it to assess uncertainty in messages or datasets and decide what results deserve the most attention or should change your view.
Why use it?
It helps separate surprising, useful information from predictable reports that add little and chaotic data that is hard to interpret.

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 assess uncertainty in messages or datasets and decide what results deserve the most attention or should change your view.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/human-avatar/skills-for-humanity/s4h-information-entropy
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-information-entropy
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-information-entropy

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/human-avatar/skills-for-humanity/s4h-information-entropy"><img src="https://agentmods.dev/badge/skills/human-avatar/skills-for-humanity/s4h-information-entropy.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,105 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 pass 7 Sept 2026
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 $0.00074 $0.02105
Opus 5 $0.00037 $0.01052
Sonnet 5 $0.00015 $0.00421
Haiku 4.5 $0.00007 $0.00211

Measured 9d ago against content hash 795654a45785, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

s4h-information-entropy 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-information-entropy/SKILL.md · 137 lines

How it starts

The opening of the file, as written. The whole thing — 137 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Information: Entropy

In 1948, Claude Shannon defined information in terms of surprise. The information content of a message is the degree to which it reduces your uncertainty. A message you could have predicted perfectly carries zero information — it tells you nothing you didn't already know. A completely unexpected message carries maximum information. Shannon called this quantity entropy, borrowing the term from thermodynamics: like physical entropy, it measures disorder and unpredictability.

Shannon entropy is defined as H = −∑ p(x) log₂ p(x) across all possible outcomes. The maximum entropy of a source is achieved when all outcomes are equally likely — pure unpredictability. Minimum entropy is achieved when one outcome is certain — pure predictability. Applied practically: a quarterly report that always says roughly the same thing carries low entropy. A dataset where any measurement could be anything carries high entropy. Neither extreme is ideal — maximum entropy is overwhelming, minimum entropy is uninformative.

Norbert Wiener extended this framework through cybernetics to argue that information is what distinguishes organisation from chaos in any self-regulating system. A thermostat carries information about temperature; the information is what allows the system to maintain order. Wiener's key insight: the entropic arrow runs toward decay unless information is actively used to correct it. Systems without good information channels become entropic — they drift.

Andrei Kolmogorov gave entropy a computational interpretation: the algorithmic complexity of a string is the length of the shortest program that can generate it. A truly random sequence cannot be compressed — it has maximum Kolmogorov complexity. A highly ordered sequence can be compressed to a short description — it has low complexity. The two frameworks — Shannon's probabilistic entropy and Kolmogorov's algorithmic complexity — converge: low-entropy sources are compressible; high-entropy sources are not.

The practical application is calibrating attention and weight. When a source has low entropy (high predictability), each new message from it should update you very little. When a source has high entropy (high surprise rate), each new message carries real information and deserves genuine engagement. Most people give equal attention to all messages regardless of their information content — this is the calibration error this skill corrects.


Read the full file on GitHub · 137 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 · 137 lines · 74 tokens per session scan A 795654a45785

Subscribe to this mod's changes

s4h-information-entropy is a skill published in the GitHub repository human-avatar/skills-for-humanity (223 stars, last pushed 1mo ago), licensed MIT. It adds 74 tokens to every session and 2,105 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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