sharp-edges

sharp-edges is a skill for Claude Code, Codex from vigolium/piolium. It costs 74 tokens per session (2,515 once invoked), scanned A, a copy of sharp-edges, MIT.

A review of APIs, settings, and interfaces for choices that make security mistakes easy. An API is a way for code to use a library or service; a configuration schema defines available settings.

In plain words
What is it for?
Use it when reviewing library APIs, configuration options, cryptographic interfaces, or authentication and authorization designs.
Why use it?
It finds designs where the simplest or default usage is unsafe, even when the documentation explains the correct approach. The goal is to make safe use the easiest path for developers.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/vigolium/piolium/sharp-edges
Any agent
npx skills add vigolium/piolium --skill sharp-edges
Clone the repo
git clone --depth 1 https://github.com/vigolium/piolium

Made for: Claude Code, Codex.

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 sharp-edges

README.md
[![agentmods](https://agentmods.dev/badge/skills/vigolium/piolium/sharp-edges.svg)](https://agentmods.dev/skills/vigolium/piolium/sharp-edges)
Your own site
<a href="https://agentmods.dev/skills/vigolium/piolium/sharp-edges"><img src="https://agentmods.dev/badge/skills/vigolium/piolium/sharp-edges.svg" alt="Measured on agentmods" 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 2,515 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 88% 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 $0.00074 $0.02515
Opus 5 $0.00037 $0.01257
Sonnet 5 $0.00015 $0.00503
Haiku 4.5 $0.00007 $0.00251

Measured 4d ago against content hash 38e1aca2a418, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sharp-edges 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 4d 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

88% identical to sharp-edges — 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.

skills/sharp-edges/SKILL.md · 293 lines

How it starts

The opening of the file, as written. The whole thing — 293 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Sharp Edges Analysis

Evaluates whether APIs, configurations, and interfaces are resistant to developer misuse. Identifies designs where the "easy path" leads to insecurity.

When to Use

  • Reviewing API or library design decisions
  • Auditing configuration schemas for dangerous options
  • Evaluating cryptographic API ergonomics
  • Assessing authentication/authorization interfaces
  • Reviewing any code that exposes security-relevant choices to developers

When NOT to Use

  • Implementation bugs (use standard code review)
  • Business logic flaws (use domain-specific analysis)
  • Performance optimization (different concern)

Core Principle

The pit of success: Secure usage should be the path of least resistance. If developers must understand cryptography, read documentation carefully, or remember special rules to avoid vulnerabilities, the API has failed.

Rationalizations to Reject

Rationalization Why It's Wrong Required Action
"It's documented" Developers don't read docs under deadline pressure Make the secure choice the default or only option
"Advanced users need flexibility" Flexibility creates footguns; most "advanced" usage is copy-paste Provide safe high-level APIs; hide primitives
"It's the developer's responsibility" Blame-shifting; you designed the footgun Remove the footgun or make it impossible to misuse
"Nobody would actually do that" Developers do everything imaginable under pressure Assume maximum developer confusion
"It's just a configuration option" Config is code; wrong configs ship to production Validate configs; reject dangerous combinations
"We need backwards compatibility" Insecure defaults can't be grandfather-claused Deprecate loudly; force migration

Sharp Edge Categories

1. Algorithm/Mode Selection Footguns

APIs that let developers choose algorithms invite choosing wrong ones.

The JWT Pattern (canonical example):

  • Header specifies algorithm: attacker can set "alg": "none" to bypass signatures
  • Algorithm confusion: RSA public key used as HMAC secret when switching RS256→HS256
  • Root cause: Letting untrusted input control security-critical decisions

Read the full file on GitHub · 293 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. 4d ago First seen · 293 lines · 74 tokens per session scan A 38e1aca2a418

Subscribe to this mod's changes

sharp-edges is a skill published in the GitHub repository vigolium/piolium (132 stars, last pushed 1mo ago), licensed MIT. It adds 74 tokens to every session and 2,515 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 88% identical to sharp-edges, differing in 11 lines, and is treated as a copy.

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