prek/docs/builtin.md

Built-in Fast Hooks

Prek includes fast, Rust-native implementations of popular hooks for speed and low overhead. When a matching hook from a popular repository (for example, pre-commit/pre-commit-hooks) is detected, Prek can run an internal implementation instead of spawning external interpreters.

Currently, only pre-commit/pre-commit-hooks is implemented. More popular repositories may be added over time.

Currently implemented hooks

https://github.com/pre-commit/pre-commit-hooks

• trailing-whitespace (Trim trailing whitespace)
• check-added-large-files (Prevent committing large files)
• end-of-file-fixer (Ensure newline at EOF)
• fix-byte-order-marker (Remove UTF-8 byte order marker)
• check-json (Validate JSON files)
• check-toml (Validate TOML files)
• check-yaml (Validate YAML files)
• mixed-line-ending (Normalize or check line endings)

Notes:

• check-yaml fast path does not yet support --unsafe or --allow-multiple-documents flags; for those cases, fast path is skipped automatically.
• Fast-path detection currently matches only the repository URL (e.g., https://github.com/pre-commit/pre-commit-hooks) and does not take the rev into account.

Disabling the fast path

If you need to compare with the original behavior or encounter differences:

PREK_NO_FAST_PATH=1 prek run

This forces prek to fall back to the standard execution path.