codex-in-claude: Skill for Claude Code

.agents/skills/prek/SKILL.md

prek is a skill for Claude Code from briandconnelly/codex-in-claude. It costs 67 tokens per session (2,118 once invoked), scanned A, a copy of prek, MIT.

A Rust-based replacement for pre-commit, a tool that runs checks automatically from Git hooks before code is committed.

In plain words
What is it for?
Use it to install and run pre-commit, pre-push, and commit-message checks, manage their runtimes, and validate hook configuration.
Why use it?
It helps catch formatting problems, lint errors, invalid files, and other issues before they enter the repository.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: installed under .agents/ (shared by several agents).

This is briandconnelly/codex-in-claude's own configuration. It tells Claude Code how to work on codex-in-claude 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-in-claude configures →

Part of the codex-in-claude plugin — 8 skills, 1 MCP server shipped together

Reuse

Borrowing it

Nothing to install: this file belongs to briandconnelly/codex-in-claude. 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/briandconnelly/codex-in-claude/main/.agents/skills/prek/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/briandconnelly/codex-in-claude

Made for: Claude Code.

Or install codex-in-claude, the plugin that ships this one along with the rest of its 8 skills, 1 MCP server.

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 prek

README.md
[![agentmods](https://agentmods.dev/badge/skills/briandconnelly/codex-in-claude/prek/github.svg)](https://agentmods.dev/skills/briandconnelly/codex-in-claude/prek)
Your own site
<a href="https://agentmods.dev/skills/briandconnelly/codex-in-claude/prek"><img src="https://agentmods.dev/badge/skills/briandconnelly/codex-in-claude/prek/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 prek

Your own site · 80×15
<a href="https://agentmods.dev/skills/briandconnelly/codex-in-claude/prek"><img src="https://agentmods.dev/badge/skills/briandconnelly/codex-in-claude/prek.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 67 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,118 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 91% 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 $0.00067 $0.02118
Opus 5 $0.00034 $0.01059
Sonnet 5 $0.00013 $0.00424
Haiku 4.5 $0.00007 $0.00212

Measured 10d ago against content hash ea649de91ba7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

prek 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 10d 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

91% identical to prek — 14 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.

.agents/skills/prek/SKILL.md · 220 lines

How it starts

The opening of the file, as written. The whole thing — 220 lines — stays where its author put it; the contents beside it link to each section on GitHub.

prek

Use this skill when the user wants to set up or run Git hooks with prek.

prek is a Rust reimplementation of pre-commit. Its main job is to run hooks that check code and repository files before commit or on demand: formatters, linters, validators, security checks, and custom project checks.

Start with the public docs

Use the LLM-oriented index first:

Per that file, prefer explicit markdown docs when you need details:

What prek is for

Use prek to:

  • run hooks that check source code and repo contents
  • install Git hook shims such as pre-commit, pre-push, and commit-msg
  • run the same hook ecosystem used by pre-commit
  • manage hook runtimes and toolchains for supported languages
  • validate configs, update pinned hook revisions, and inspect configured hooks

Typical jobs for hooks run by prek:

  • formatting and linting code
  • validating YAML, JSON, TOML, XML, and similar files
  • preventing merge-conflict markers, private keys, oversized files, and bad line endings

Authoring configs

For new configs, prefer prek.toml.

Read the full file on GitHub · 220 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. 10d ago First seen · 220 lines · 67 tokens per session scan A ea649de91ba7

Subscribe to this mod's changes

prek is a skill published in the GitHub repository briandconnelly/codex-in-claude (3 stars, last pushed today), licensed MIT. It adds 67 tokens to every session and 2,118 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 91% identical to prek, differing in 14 lines, and is treated as a copy.

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