Pre-Commit

pre-commit runs Prose when you commit, so a staged file either matches the formatted layout or the commit fails. The hook runs on staged files only, checking the code you edited rather than the whole tree.

Local Hook

Add a local hook to your .pre-commit-config.yaml:

- repo: local
  hooks:
    - id       : prose
      name     : prose
      entry    : prose format
      language : system
      types    : [python]

entry: prose format rewrites the staged file in place, so the hook fails the commit with a "fixed by Prose" diff and leaves the rewritten file on disk for you to stage again and re-commit. This is the loop pre-commit runs for every hook that fixes files (Black, isort, and autopep8 behave the same way). For a hook that fails on pending rewrites without writing anything, use entry: prose check and run prose format yourself before committing again.

language: system tells pre-commit to run the prose binary already on your PATH (see the Installation chapter) rather than installing a pinned copy into the hook's own environment. A project that prefers a pinned copy uses language: python with additional_dependencies: ["prose-formatter==<version>"].

Pairing With Ruff

A project that runs ruff format as well adds a Ruff hook above the Prose hook in the same repo: local block. pre-commit runs hooks in the order written, and Ruff's hook comes first because a later ruff format would remove the padding Prose writes:

    - id       : ruff-format
      name     : ruff format
      entry    : ruff format
      language : system
      types    : [python]

The Ruff integration page covers the pycodestyle codes to turn off so Ruff's linter does not report the whitespace Prose writes.

Upstream Hook

The Ruff pre-commit hook runs Ruff without a system install. Add this block above the repo: local block from the Local Hook section:

- repo: https://github.com/astral-sh/ruff-pre-commit
  rev: v0.15.22
  hooks:
    - id: ruff-format

rev: pins a Ruff release, and the version shown is the one Prose builds against, so the two stay in step without a separate pin.

Exit Codes

The hook reads the same Exit Codes the CLI uses. A format hook exits 0 once its rewrites are written, so it never fails on a change it made itself, whereas a check hook fails the commit whenever a change is pending.