magnus-bindings

magnus-bindings is a skill for Claude Code, Codex from Goldziher/ai-rulez. It costs 58 tokens per session (309 once invoked), scanned A, original, MIT.

Guidance for connecting a Rust library to Ruby as a native extension, so Ruby code can use Rust classes and methods.

In plain words
What is it for?
Use it when building or reviewing Magnus-based Ruby bindings, including compilation, testing, and packaging the result as a Ruby gem.
Why use it?
It helps avoid unsafe memory handling, incorrect error conversion, and problems with Ruby’s runtime lock or garbage collector.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when building or reviewing Magnus-based Ruby bindings, including compilation, testing, and packaging the result as a Ruby gem.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/goldziher/ai-rulez/magnus-bindings
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 Goldziher/ai-rulez --skill magnus-bindings
Clone the repo
git clone --depth 1 https://github.com/Goldziher/ai-rulez

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 magnus-bindings

README.md
[![agentmods](https://agentmods.dev/badge/skills/goldziher/ai-rulez/magnus-bindings/github.svg)](https://agentmods.dev/skills/goldziher/ai-rulez/magnus-bindings)
Your own site
<a href="https://agentmods.dev/skills/goldziher/ai-rulez/magnus-bindings"><img src="https://agentmods.dev/badge/skills/goldziher/ai-rulez/magnus-bindings/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 magnus-bindings

Your own site · 80×15
<a href="https://agentmods.dev/skills/goldziher/ai-rulez/magnus-bindings"><img src="https://agentmods.dev/badge/skills/goldziher/ai-rulez/magnus-bindings.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 309 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 $0.00058 $0.00309
Opus 5 $0.00029 $0.00154
Sonnet 5 $0.00012 $0.00062
Haiku 4.5 $0.00006 $0.00031

Measured 12d ago against content hash 2ed42b0713ea, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

magnus-bindings 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 12d 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.

internal/builtins/bindings/magnus/skills/magnus-bindings/SKILL.md · 17 lines

What it actually says

  • Use magnus crate for Ruby native extensions. Define classes with magnus::define_class.
  • Map Rust types to Ruby using TryConvert and IntoValue traits. Return Result<T, magnus::Error>.
  • Use magnus::function! macro for defining Ruby methods. Use magnus::method! for instance methods.
  • Map Rust errors to specific Ruby exceptions: magnus::Error::new(exception::runtime_error(), msg).
  • Build with rb_sys crate and magnus-build for compilation. Use rake-compiler for gem distribution.
  • Support Ruby 3.2+ with multiple ABI versions.
  • Test bindings from Ruby using RSpec or Minitest. Test error handling and edge cases.
  • Keep Ruby wrapper gem thin — business logic in Rust, Ruby provides idiomatic API.
  • Handle Ruby's GVL (Global VM Lock) — release for CPU-intensive Rust code.
  • Use TypedData for wrapping Rust structs as Ruby objects with proper GC integration.
  • Anti-patterns: panics in Ruby methods, unsafe without SAFETY comments, manual memory management.
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. 12d ago First seen · 17 lines · 58 tokens per session scan A 2ed42b0713ea

Subscribe to this mod's changes

magnus-bindings is a skill published in the GitHub repository Goldziher/ai-rulez (141 stars, last pushed 4d ago), licensed MIT. It adds 58 tokens to every session and 309 once invoked, about $0.0003 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 2026-08-30.

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