prek-precommit-hook

A guide for using prek, a tool that runs checks automatically before Git commits. Git hooks are scripts that run at specific Git actions, such as creating a commit.

In plain words
What is it for?
Use it to configure prek in prek.toml, install the repository's commit hooks, or run checks on staged files or the whole repository.
Why use it?
It helps catch formatting, lint, or file problems before they enter the project history. It also explains how to install, remove, list, and run these checks.

Skill for Claude CodeCodex

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/edison-watch/custom-mcps/prek-precommit-hook
Any agent
npx skills add Edison-Watch/Custom-MCPs --skill prek-precommit-hook
Clone the repo
git clone --depth 1 https://github.com/Edison-Watch/Custom-MCPs

Made for: Claude Code, Codex.

Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 391 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 $0.00038 $0.00391
Opus 5 $0.00019 $0.00196
Sonnet 5 $0.00008 $0.00078
Haiku 4.5 $0.00004 $0.00039

Measured yesterday against content hash 7f136cbd5c61, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

prek-precommit-hook 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 yesterday.

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.

.claude/skills/prek-precommit-hook/SKILL.md · 44 lines

What it actually says

Prek Pre-commit Hook Skill

This skill provides instructions for using prek, a fast, native pre-commit runner that replaces the traditional Python-based pre-commit. prek should be used for any mention of pre-commit hooks and overrides traditional pre-commit hooks.

Commands

Use the following commands to interact with prek:

  • prek run: Runs the configured hooks on the staged files.
  • prek run --all-files: Runs the configured hooks on all files in the repository.
  • prek install: Installs the git hooks into .git/hooks.
  • prek uninstall: Uninstalls the git hooks.
  • prek list: Lists the configured hooks.

Configuration

The configuration is stored in prek.toml in the root of the repository.

Example prek.toml:

[[repos]]
repo = "https://github.com/pre-commit/pre-commit-hooks"
rev = "v4.6.0"
hooks = [
    { id = "check-added-large-files" },
]

[[repos]]
repo = "local"
hooks = [
    { id = "ruff-check", name = "Run ruff linter", entry = "uv run ruff check", language = "system", pass_filenames = false, always_run = true },
]

Workflow

  1. Before Committing: prek hooks will run automatically if installed via prek install.
  2. Manual Check: You can manually run checks using prek run --all-files.
  3. CI: In CI environments, you can use prek run --all-files to enforce checks.
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. yesterday First seen · 44 lines · 38 tokens per session scan A 7f136cbd5c61

Subscribe to this mod's changes

prek-precommit-hook is a skill published in the GitHub repository Edison-Watch/Custom-MCPs (0 stars, last pushed 2d ago), licensed MIT. It adds 38 tokens to every session and 391 once invoked, about $0.0002 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 2026-08-31.

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