What is invariant-guard-correctness?

A correctness-first method for designing familiar algorithms. It writes down the function's contract, loop invariant, stopping argument, and boundary cases before implementation.

Use it when writing or reviewing algorithms such as binary search, especially when correctness matters more than a quick implementation.

It helps prevent off-by-one errors and incorrect behavior in loops, recursion, in-place changes, and boundary conditions. A loop invariant is a statement that remains true at each step of a loop.

invariant-guard-correctness — Skill for Claude Code by findscripter

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 findscripter/everything-skills --skill invariant-guard-correctness

Clone the repo

git clone --depth 1 https://github.com/findscripter/everything-skills

Made for: Claude Code.

Or install 00-meta, the plugin that ships this one along with the rest of its 43 skills.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/findscripter/everything-skills/invariant-guard-correctness/github.svg)](https://agentmods.dev/skills/findscripter/everything-skills/invariant-guard-correctness)

Your own site

<a href="https://agentmods.dev/skills/findscripter/everything-skills/invariant-guard-correctness"><img src="https://agentmods.dev/badge/skills/findscripter/everything-skills/invariant-guard-correctness/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/findscripter/everything-skills/invariant-guard-correctness"><img src="https://agentmods.dev/badge/skills/findscripter/everything-skills/invariant-guard-correctness.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 113 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,633 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 unknown 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.

Model	Per session	Once invoked
Fable 5.1	$0.00113	$0.03633
Opus 5.5	$0.00045	$0.01453
Sonnet 5.5	$0.00023	$0.00727
Haiku 4.5	$0.00011	$0.00363

Measured today against content hash 9be386e583da, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

invariant-guard-correctness 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 today.

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.

00-meta/invariant-guard-correctness/SKILL.md · 157 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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.

today First seen · 157 lines · 113 tokens per session scan A 9be386e583da

Subscribe to this mod's changes

invariant-guard-correctness is a skill published in the GitHub repository findscripter/everything-skills (11 stars, last pushed today), with no licence file. It adds 113 tokens to every session and 3,633 once invoked, about $0.0005 per session on Opus 5.5. 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 2026-11-12.

Debugging agent-skills ai-agents chinese 公众号

invariant-guard-correctness next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
invariant-guard-correctnessfindscripter/everything-skills	Skill	11	today	none	A	113	Claude Code
systematic-debuggingWade-DevCode/awesome-coding-skills-cn	Skill	7	5mo ago	MIT	A	31	Claude Code, Codex
concurrency-safetyWade-DevCode/awesome-coding-skills-cn	Skill	7	5mo ago	MIT	A	27	Claude Code, Codex
error-handlingWade-DevCode/awesome-coding-skills-cn	Skill	7	5mo ago	MIT	A	24	Claude Code, Codex
performance-profilingWade-DevCode/awesome-coding-skills-cn	Skill	7	5mo ago	MIT	A	21	Claude Code, Codex
systematic-debuggingjnMetaCode/superpowers-zh	Skill	8.5k	2d ago	MIT	A	24	Claude Code
diagnosing-superpowersjnMetaCode/superpowers-zh	Skill	8.5k	2d ago	MIT	A	111	Claude Code