Run `prek`, Carbon's pre-submit style and lint checker, across all files or selected changes. The skill explains its Jujutsu helper, how to handle hooks that rewrite files, and a `gpkg` workaround for dependency or security policy errors.
Instructions for running prek, the Carbon pre-submit/style/lint checker, that *MUST* be run before submitting an change.
Run score Not tested
See how to installThis skill explains how to run prek, Carbon's pre-submit style and lint checker. It shows how to check all files or specify a list of files. In a Jujutsu workspace, direct use of prek fails because it expects a standard Git repository structure; the helper script ./scripts/jj_prek.sh checks changed files instead. Some hooks, including clang-format and rumdl, rewrite files and may still cause prek to exit with a failure code. The skill explains how to review those edits and run the check again. It also describes a gpkg command prefix for dependency resolution or security policy errors in restricted environments.
Use it before submitting changes to Carbon to check style and lint. It is also useful when working in Jujutsu or when a check has rewritten files and reported a failure.
prek on only the files I changed.”The skill says to run prek before submitting changes. The Jujutsu helper always compares against trunk, so it may include files from an underlying change based on another bookmark. In restricted environments with dependency or security policy errors, the documented workaround is to prefix the command with gpkg.
This overview was written by AI (OpenAI Codex) from the public SKILL.md. Check the original below for the exact behavior.
AI checked the SKILL.md for operations that need care and for setup requirements. The score comes only from actually running the skill (hands-on test).
Not counted in the score. Rated by AI (OpenAI Codex) as of Oct 26, 2026. Treat it as a guide and read the original before installing.
Review the instructions the agent will receive before you install.
prek is the Carbon pre-submit, style, and lint checker. Running it is
mandatory before submitting any changes.
To run prek on all files:
prek run -a
To validate a specific list of files:
prek run --files <files>
If you are working in a Jujutsu workspace, running prek directly will fail
because it expects a standard Git repository structure. Instead, use the helper
script:
./scripts/jj_prek.sh
This script runs prek on all files that have changed between trunk and your
current Jujutsu @ change.
Note that the script always compares against trunk. If your change is based on
another bookmark rather than on trunk, the script also checks the files
changed by that underlying change, so a reported failure may not be in your own
work.
Some hooks, notably clang-format and rumdl, fix problems in place rather
than only reporting them. When they do, prek reports a failure and exits
non-zero even though the tree is now correct.
Re-run prek after any failure that modified files, and treat the second, clean
run as the result. Review what it changed: a reflow is expected, but a content
change may not be what you intended.
[!TIP] If
prekfails with an error about resolving dependencies or security policy, you may be running in a restricted environment where the special-purposegpkgtool is required. Prefix the command withgpkg, for example:gpkg prek run -aorgpkg ./scripts/jj_prek.sh.
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