measuring-ai-proficiency: Skill for Claude Code

.claude/skills/simplify-and-harden/SKILL.md

simplify-and-harden is a skill for Claude Code from pskoett/measuring-ai-proficiency. It costs 71 tokens per session (5,488 once invoked), scanned A, original, MIT.

A post-completion review method for checking code changes for simpler structure, obvious bugs, security issues, confusing logic, and missing small documentation updates.

In plain words
What is it for?
Use it after a non-trivial coding task to reread changed code, simplify it, look for brittle assumptions, and add small useful documentation where needed.
Why use it?
Coding agents often stop as soon as the requested change works. This adds a focused review while the agent still remembers the problem and its decisions.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: reads .claude/ paths; mentions CLAUDE.md; mentions Claude Code.

This is pskoett/measuring-ai-proficiency's own configuration. It tells Claude Code how to work on measuring-ai-proficiency 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 measuring-ai-proficiency configures →

Reuse

Borrowing it

Nothing to install: this file belongs to pskoett/measuring-ai-proficiency. 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/pskoett/measuring-ai-proficiency/main/.claude/skills/simplify-and-harden/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/pskoett/measuring-ai-proficiency

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 simplify-and-harden

README.md
[![agentmods](https://agentmods.dev/badge/skills/pskoett/measuring-ai-proficiency/simplify-and-harden/github.svg)](https://agentmods.dev/skills/pskoett/measuring-ai-proficiency/simplify-and-harden)
Your own site
<a href="https://agentmods.dev/skills/pskoett/measuring-ai-proficiency/simplify-and-harden"><img src="https://agentmods.dev/badge/skills/pskoett/measuring-ai-proficiency/simplify-and-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 simplify-and-harden

Your own site · 80×15
<a href="https://agentmods.dev/skills/pskoett/measuring-ai-proficiency/simplify-and-harden"><img src="https://agentmods.dev/badge/skills/pskoett/measuring-ai-proficiency/simplify-and-harden.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 71 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,488 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 $0.00071 $0.05488
Opus 5 $0.00036 $0.02744
Sonnet 5 $0.00014 $0.01098
Haiku 4.5 $0.00007 $0.00549

Measured 11d ago against content hash 714e8514921a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

simplify-and-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 11d 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.

.claude/skills/simplify-and-harden/SKILL.md · 520 lines

How it starts

The opening of the file, as written. The whole thing — 520 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Skill: Simplify & Harden

Install

npx skills add pskoett/pskoett-ai-skills/skills/simplify-and-harden

For CI-only execution, use:

npx skills add pskoett/pskoett-ai-skills/skills/simplify-and-harden-ci

Metadata

Field Value
Skill ID simplify-and-harden
Version 0.1.0
Trigger Post-completion hook
Author Peter Skøtt Pedersen
Category Code Quality / Security
Priority Recommended

Rationale and Philosophy

When a coding agent completes a task, it holds peak contextual understanding of the problem, the solution, and the tradeoffs it made along the way. This context degrades immediately -- the next task wipes the slate. Simplify & Harden exploits that peak context window to perform two focused review passes before the agent moves on.

Most agents solve the ticket and stop. This skill turns "done" into "done well."

The operating philosophy is a deliberate "fresh eyes" self-review before moving on: carefully re-read all newly written code and all existing code modified in the task, and look hard for obvious bugs, errors, confusing logic, brittle assumptions, naming issues, and missed hardening opportunities. The goal is not to expand scope or rewrite the solution -- it is to use peak context to perform a disciplined first review pass while the agent still remembers the intent behind every change.

Best Use with Independent Review

This skill is a post-completion self-pass and does not replace an independent review pass.

Recommended flow:

  1. Implement the task.
  2. Run Simplify & Harden to clean, harden, and document non-obvious decisions.
  3. Run an independent review pass for severity-ordered findings.
  4. Merge only after both passes are addressed.

If the two disagree, treat the independent review findings as the external gate and either fix or explicitly waive findings.

Read the full file on GitHub · 520 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 11d ago First seen · 520 lines · 71 tokens per session scan A 714e8514921a

Subscribe to this mod's changes

simplify-and-harden is a skill published in the GitHub repository pskoett/measuring-ai-proficiency (11 stars, last pushed 1mo ago), licensed MIT. It adds 71 tokens to every session and 5,488 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 2026-08-31.