codex-unified: Skill for Codex

.codex/skills/code-review-change-size/SKILL.md

code-review-change-size is a skill for Codex from MikeManifold/codex-unified. It costs 12 tokens per session (91 once invoked), scanned A, a copy of code-review-change-size, Apache-2.0.

Guidance for keeping code changes small enough to review. It sets an 800-line limit for most changes and a 500-line target for complex logic.

In plain words
What is it for?
Checking a code diff, deciding whether work should be split, and identifying the smallest useful stage to submit first.
Why use it?
Large changes are harder to understand and review, so this guidance helps split them into smaller, coherent stages when needed.

Skill for Codex

Written for Codex: installed under .codex/.

This is MikeManifold/codex-unified's own configuration. It tells Codex how to work on codex-unified 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 codex-unified configures →

Reuse

Borrowing it

Nothing to install: this file belongs to MikeManifold/codex-unified. 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/MikeManifold/codex-unified/main/.codex/skills/code-review-change-size/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/MikeManifold/codex-unified

Made for: 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 code-review-change-size

README.md
[![agentmods](https://agentmods.dev/badge/skills/mikemanifold/codex-unified/code-review-change-size.svg)](https://agentmods.dev/skills/mikemanifold/codex-unified/code-review-change-size)
Your own site
<a href="https://agentmods.dev/skills/mikemanifold/codex-unified/code-review-change-size"><img src="https://agentmods.dev/badge/skills/mikemanifold/codex-unified/code-review-change-size.svg" alt="Measured on agentmods" height="20"></a>
Per session 12 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 91 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 100% 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 5.1 $0.00012 $0.00091
Opus 5 $0.00006 $0.00046
Sonnet 5 $0.00002 $0.00018
Haiku 4.5 $0.00001 $0.00009

Measured 7d ago against content hash e8184218e0f0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

code-review-change-size 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 7d 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

100% identical to code-review-change-size — 0 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.

.codex/skills/code-review-change-size/SKILL.md · 12 lines

What it actually says

Unless the change is mechanical the total number of changed lines should not exceed 800 lines. For complex logic changes the size should be under 500 lines.

If the change is larger, explain whether it can be split into reviewable stages and identify the smallest coherent stage to land first. Base the staging suggestion on the actual diff, dependencies, and affected call sites.

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. 7d ago First seen · 12 lines · 12 tokens per session scan A e8184218e0f0

Subscribe to this mod's changes

code-review-change-size is a skill published in the GitHub repository MikeManifold/codex-unified (2 stars, last pushed 18d ago), licensed Apache-2.0. It adds 12 tokens to every session and 91 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to code-review-change-size, differing in 0 lines, and is treated as a copy.