Pre-commit Config Validator

Validate .pre-commit-config.yaml files for structure, repository entries, hook definitions, local hooks, and best practices. 23 rules across 5 categories.

Security Scan

The skill is internally consistent: a local Python-based validator for .pre-commit-config.yaml that ships a single script and requires no credentials or installs.

Purpose & Capability

Name/description match the included assets: SKILL.md documents running scripts/precommit_validator.py to validate .pre-commit-config.yaml files and the repository contains a ~25KB Python script that implements those checks.

Instruction Scope

SKILL.md only instructs running the included Python script against specific files (validate, repos, hooks, lint, formats). The instructions do not ask the agent to read unrelated system state, environment variables, or to transmit data to external endpoints.

Install Mechanism

No install spec is provided (instruction-only with bundled script). The script appears to use only Python stdlib (argparse, json, re, pathlib, etc.) and provides a minimal YAML parser fallback, so there is no third-party package download or archive extraction in the install process.

Credentials

The skill declares no required environment variables, no credentials, and no config paths. The included script takes file paths as arguments and does not request or appear to need secrets for its stated purpose.

Persistence & Privilege

always is false and the skill does not request any elevated, persistent privileges. It does not modify other skills or system-wide agent settings according to the provided files and metadata.

Assessment

This skill appears coherent and only runs a local Python script to validate pre-commit config files; it does not request credentials or install remote packages. However, the source/homepage are unknown — you are executing code from an unverified origin. Before installing or running it, review the script (scripts/precommit_validator.py) yourself or run it in a sandboxed environment to confirm there are no unwanted behaviors (network access, unexpected file I/O). If you plan to let an agent invoke it autonomously, remember it will be able to run that script on any file paths you or the agent pass to it, so avoid passing sensitive files unless you trust the code.

Validate .pre-commit-config.yaml files for correctness, completeness, and best practices.

Commands

# Full validation (all rules)
python3 scripts/precommit_validator.py validate .pre-commit-config.yaml

# Repository/rev validation only
python3 scripts/precommit_validator.py repos .pre-commit-config.yaml

# Hook definitions only
python3 scripts/precommit_validator.py hooks .pre-commit-config.yaml

# Best practices only
python3 scripts/precommit_validator.py lint .pre-commit-config.yaml

# JSON output
python3 scripts/precommit_validator.py validate .pre-commit-config.yaml --format json

# Summary only
python3 scripts/precommit_validator.py validate .pre-commit-config.yaml --format summary

# Treat warnings as errors
python3 scripts/precommit_validator.py validate .pre-commit-config.yaml --strict

# Multiple files
python3 scripts/precommit_validator.py validate file1.yaml file2.yaml

Rules (23)

Structure (5)

• S1 Invalid YAML syntax
• S2 Missing required top-level key repos
• S3 repos is not a list
• S4 Empty repos list (warning)
• S5 Unknown top-level keys (warning; known: repos, default_language_version, default_stages, ci, minimum_pre_commit_version, exclude, fail_fast, files)

Repository Entries (6)

• R1 Missing repo key in entry
• R2 Missing rev for non-local/non-meta repos
• R3 Missing or invalid hooks list
• R4 Empty hooks list (warning)
• R5 rev using a branch name instead of tag/SHA (warning: main, master, develop, dev, trunk, HEAD)
• R6 Floating rev without pinning (warning: no semver pattern or SHA)

Hook Definitions (6)

• H1 Missing id in hook
• H2 Duplicate hook IDs within the same repo (warning)
• H3 Unknown hook keys (warning; known: id, name, entry, language, files, exclude, types, types_or, stages, additional_dependencies, args, always_run, pass_filenames, require_serial, minimum_pre_commit_version, verbose, log_file, description)
• H4 Invalid stages values (known: commit, merge-commit, push, prepare-commit-msg, commit-msg, post-checkout, post-commit, post-merge, post-rewrite, manual, pre-push, pre-rebase, pre-merge-commit)
• H5 args is not a list
• H6 additional_dependencies is not a list

Local Hooks (3)

• L1 Local hook missing entry (required for repo: local)
• L2 Local hook missing language
• L3 Invalid language value (warning; known: python, node, ruby, rust, golang, docker, docker_image, dotnet, lua, perl, r, swift, system, pygrep, script, fail)

Best Practices (3)

• B1 repo: meta without check-hooks-apply or check-useless-excludes (warning)
• B2 Rev does not match semver or SHA pattern (warning)
• B3 Duplicate repo URLs (warning)
• B4 fail_fast: true may hide issues (info)

Output Formats

• text (default): Human-readable with severity icons and rule codes
• json: Machine-readable with file, diagnostics array, and counts
• summary: One-line counts by severity

Exit Codes

• 0: No issues (or warnings/info only without --strict)
• 1: Errors found (or warnings with --strict)
• 2: Parse error or file not found