codex

codex is a skill for Claude Code, Codex from rijuvashisht/Magneto. It costs 0 tokens per session (858 once invoked), scanned A, original, MIT.

A code-review workflow that sends the same code change to several language models for independent review. It records their findings in a review report and measures how often they agree.

In plain words
What is it for?
Use it for second opinions on a code diff, pass-or-fail review gates, adversarial challenges, and confidence-ranked findings.
Why use it?
One reviewer can miss bugs or raise a questionable concern. Agreement between multiple reviewers helps distinguish likely problems from model-specific noise.

Skill for Claude CodeCodex

Which agent this was written for is unclear — built for gstack. Also seen: positional $N argument; mentions Codex; built for gstack.

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/rijuvashisht/magneto/codex
Any agent
npx skills add rijuvashisht/Magneto --skill codex
Clone the repo
git clone --depth 1 https://github.com/rijuvashisht/Magneto

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 codex

README.md
[![agentmods](https://agentmods.dev/badge/skills/rijuvashisht/magneto/codex.svg)](https://agentmods.dev/skills/rijuvashisht/magneto/codex)
Your own site
<a href="https://agentmods.dev/skills/rijuvashisht/magneto/codex"><img src="https://agentmods.dev/badge/skills/rijuvashisht/magneto/codex.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 858 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00000 $0.00858
Opus 5 $0.00000 $0.00429
Sonnet 5 $0.00000 $0.00172
Haiku 4.5 $0.00000 $0.00086

Measured 6d ago against content hash 250584c59b2d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

codex 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 6d 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.

src/templates/magneto-skills/skills/codex/SKILL.md · 107 lines

How it starts

The opening of the file, as written. The whole thing — 107 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/codex — Cross-Model Second Opinion with Convergence Scoring

Role: Cross-Model Reviewer Inputs: current diff or target code Outputs: review-report.md with multi-model analysis Audit actions: codex.started, codex.convergence_scored, codex.completed


Why This Skill Exists — The Moat

Single-model review has blind spots. /codex runs the SAME diff through 2-3 different LLMs simultaneously and scores their convergence:

  • 3/3 agree on a finding → high confidence, probably a real bug
  • 2/3 agree → medium confidence, worth investigating
  • 1/3 flagged uniquely → could be insight the others missed, or model-specific noise

gstack's /codex uses one OpenAI model. Magneto's /codex uses all configured runners.

Configuration

Runners are pulled from Magneto's existing runner registry. Default for /codex:

  • OpenAI gpt-4o (if OPENAI_API_KEY set)
  • Anthropic Claude (if ANTHROPIC_API_KEY set)
  • Ollama local (if Ollama reachable)

Configure in .magneto/codex.config.json:

{
  "runners": ["openai", "anthropic", "ollama"],
  "timeout": 60000,
  "costBudget": 0.50
}

Modes

magneto codex review    # pass/fail gate
magneto codex challenge # adversarial: actively try to break the code
magneto codex consult   # open-ended Q&A with cross-model input

The Protocol

Step 1: Build the review prompt

Load:

  • The diff (or target files)
  • Knowledge graph context (affected communities + god nodes)
  • Memory patterns relevant to changed files

Single prompt, sent to all runners in parallel.

Step 2: Run in parallel

magneto run --runner openai --mode review < prompt.md > openai-review.json &
magneto run --runner anthropic --mode review < prompt.md > anthropic-review.json &
magneto run --runner ollama --mode review < prompt.md > ollama-review.json &
wait

Step 3: Score convergence

For each finding:

  • Normalize across models (same file + line + category → same finding)
  • Count how many models flagged it
  • Tag as HIGH (3/3), MEDIUM (2/3), UNIQUE (1/3)

Read the full file on GitHub · 107 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. 6d ago First seen · 107 lines · 0 tokens per session scan A 250584c59b2d

Subscribe to this mod's changes

codex is a skill published in the GitHub repository rijuvashisht/Magneto (6 stars, last pushed 2mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 858 tokens. 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.

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