amont

Catch the bad commit before it exists — and take the whole thing back out in one command.

A single Rust binary that checks git commit and git push — no YAML to write, no runtime to install, nothing to configure before it is useful.

• Useful in the first minute. Twenty-one built-in checks — commit-message conventions, merge-conflict markers, the linters and formatters for the languages your repository actually uses, branch rules, your test suite — and each one fires only where the repository has opted into its tool.
• A cloned repository cannot run code on your machine. Checks a repository declares for itself are inert until you review them and say amont trust — a gate pre-commit, lefthook and husky do not have.
• Nothing on the commit path but std. The hook binary links no external crates, and CI fails any build that changes that.
• Leaving is one command. amont uninstall removes exactly the four shims install wrote; a hook you or another tool put there is named and left alone.

How that stacks up against pre-commit, lefthook and husky, feature by feature: the full comparison.

Install

Linux and macOS

curl -fsSL https://raw.githubusercontent.com/fredericrous/amont/main/install/install.sh | sh

Windows (PowerShell — the line above is POSIX sh and only reaches Windows through Git Bash)

irm https://raw.githubusercontent.com/fredericrous/amont/main/install/install.ps1 | iex

Either one downloads a release binary, verifies it against the published SHA256SUMS, and puts it where the hooks already look — ~/.local/bin, or %USERPROFILE%\.local\bin. Both enable nothing: hooks are turned on per repository, by you, afterwards.

cd <your-repo> && amont install   # this repository only
amont list                        # what would run here, and why not

Prefer not to pipe a script into a shell? Download a binary and its checksum from Releases — prebuilt for Linux (gnu/musl, x86_64 and aarch64), macOS (Intel and Apple silicon) and Windows. Or build from source: cargo build --release.

From crates.io:

cargo install amont

Or with Homebrew:

brew tap fredericrous/tap
brew trust fredericrous/tap    # Homebrew asks this of every third-party tap
brew install amont

Uninstall

amont uninstall              # this repository
amont uninstall --binary     # …and remove ~/.local/bin/amont too

Uninstall is listed second on purpose. These hooks can block a commit, so the honest question to answer first is how you get out — and the answer is that uninstall removes our four shims and nothing else. A hook you wrote yourself is left where it is and named in the output, whatever it is; a hook it cannot even read is named too rather than passed over in silence. Your hook.skip and amont.severity settings are never touched, because those are your statements about your repository.

This is also why the README does not tell you to run rm $(git rev-parse --git-dir)/hooks/*. That glob deletes every hook in the directory — including ones other tools installed and ones you wrote — to remove four files that belong to us.

To bypass a single run rather than uninstall: git commit --no-verify. To turn off one check permanently, see Turning a check off, or down.

What actually runs

amont list answers that for the repository you are standing in, and it is the honest answer rather than the catalogue: most checks are inert in most repositories, because a repo with no ruff.toml never needs ruff.

pre-commit
  ● ban-terms
  ○ cargo-fmt         inert here — needs .rs + Cargo.toml
  ● lint-json-yaml
  ● merge-conflict
  ○ prettier          inert here — needs .prettierrc | .prettierrc.json | …
  ● usual-name
pre-push
  ● branch-protect
  ● branch-pattern
  ● pull-rebase
  ○ cargo-test        inert here — needs .rs + Cargo.toml

  ● runs here   ○ inert   ⊘ skipped via hook.skip   ✗ declaration unusable

Twenty-one built-in checks across four git hooks, plus any your repository declares itself. The full list, with what each one needs before it fires, is in the checks reference.

Two ways to turn hooks on

Per repository — the default, and nothing runs anywhere you did not ask:

cd <your-repo> && amont install
amont-fleet install --root ~/Developer   # or in bulk, across many repos

amont install --force replaces a hook the installer would otherwise refuse — one carrying no marker of ours, or a symlink. Even --force never writes a tracked file or a directory. The full semantics: what --force will and will not do.

Everywhere, forever — an opt-in, and a real one:

git config --global init.templateDir ~/.config/git/git-templates/templates

Git copies that directory into .git/hooks on every init and every clone, so from then on every repository you clone runs these hooks without being asked again. That is the convenience, and it is worth having.

It is also a standing grant, so it is worth stating what you granted. A cloned repository can declare its own checks in amont.conf, and with this key set those are one amont trust away from running on your first commit in a repository you may have cloned only to read. If you set this, trust deliberately rather than letting installation be the moment you decided.

One view across every repo

amont-fleet — installed separately, on purpose — answers the questions a directory full of repositories accumulates: which repos are covered, which shims went stale after an upgrade, what every check is doing where, and which repository is quietly carrying a hook.skip somebody forgot.

amont-fleet install --root ~/Developer   # shims into every repo at once
amont-fleet                              # report the fleet
amont-fleet tui                          # the dashboard above

Design record: the fleet dashboard.

Trust: a repository you clone cannot run its own checks

amont.conf is committed — that is the point, a team shares a check by committing it. The consequence is that cloning a repository and committing to it would otherwise run commands that repository chose, and neither of those acts is one anybody performs as a decision about trust.

So a cloned repository's declared checks are inert until you say otherwise:

amont trust          # show what this repo declares, and accept it
amont trust --show   # what is trusted here
amont trust --revoke

The record is keyed on the file's content, not its path, so a git pull that adds a command does not inherit the consent given to the file before it. The fingerprint is git hash-object --no-filters, and the --no-filters is not decoration: plain hash-object applies the clean filter and eol conversion that the repository's own committed .gitattributes asks for, which would let a repository choose the transform its own consent is taken through.

Full reasoning: the trust model.

Turning a check off, or down

Every check has an id, <trigger>-<name> — pre-commit-clippy. Three things name it, and both config surfaces read all three the same way:

git config --add hook.skip pre-commit-clippy   # that one check
git config --add hook.skip clippy              # that check, on either trigger
git config --add hook.skip pre-commit          # every pre-commit check

amont.severity.<key> takes the same three, and keeps the signal — the check still runs and still reports, it just stops failing the commit:

git config amont.severity.clippy warn
git config amont.severity.pre-commit warn

Where several keys reach one check the most specific wins: full id, then short name, then trigger. Nothing matches by substring — hook.skip e reaches nothing at all, and skipping lint-js leaves lint-json-yaml alone.

A skipped check is announced on every commit, so a config line nobody remembers writing cannot go on silently disabling things. More in opting out and configuration.

Making the commit convention yours

commit-msg is the one hook hook.skip and --no-verify cannot reach, so its opinions are adjustable in themselves:

amont setup     # four questions, current values as the defaults

It asks where the type's gitmoji goes — none (the default: your subject, untouched), prefix, suffix or replace — and for the subject limit, the description budget and the body wrap column. Then it prints the exact git config lines it wrote, so you can paste them into your dotfiles or hand them to a teammate.

git config amont.commit.gitmoji suffix        # feat: add a cart ✨
git config amont.commit.descriptionMax 68     # still fits a 72-col subject
git config amont.commit.bodyWrap 0            # leave my stack traces alone

The limits measure what you wrote, so a gitmoji never eats your budget, and re-running over an amended message changes nothing. Full reference: commit conventions.

Custom checks

A repository can declare checks of its own in a committed amont.conf:

# stage       name        scope   severity  command
pre-commit    shellcheck  *.sh    block     scripts/lint-shell.sh
pre-push      smoke       *       warn      make smoke

They run alongside the built-ins, obey the same hook.skip and amont.severity controls, and are inert until trusted. Full reference: custom checks.

Running the checks yourself

amont run                    # would my commit pass? (the staged set)
amont run --all-files        # does my working tree pass? (git ls-files)
amont run pre-commit-prettier
amont list                   # what would run here, and why not

The two questions are different on purpose. --all-files on a dirty tree reports on content that is not committed and may never be — which is what you want when adopting a check into an existing repository, where git add . is not an acceptable way to measure the mess.

What a push actually tests

By default pre-push runs your suite against the working tree, and says so. That is fast and usually what you want, but it is not what you are pushing: an uncommitted fix makes a broken commit look green.

git config amont.testPushedTree true

turns on the accurate answer — the suite runs in a throwaway checkout of the commits being pushed, and your tree is not touched. It costs a second checkout and a build that cannot reuse your target/ cache, which is why it is opt-in.

For coding agents

amont list --json is the same answer as amont list, machine-readable: every check's declared and effective severity, whether it fires here and why not, and its command if it is a declared external. --stage filters to one trigger; --pushed scopes to what your next push would carry (@{u}..HEAD) rather than the whole tracked tree.

amont list --json --stage pre-push --pushed
amont agents-md          # write a self-verifying pointer into AGENTS.md
amont agents-md --check  # exit non-zero if it has drifted

agents-md only ever touches a <!-- amont:start --> / <!-- amont:end --> span, so the rest of the file stays yours.

The block it writes also warns the agent that git commit and git push run their checks first — pre-commit can mean clippy building a workspace, pre-push a whole test suite — and an agent whose shell tool defaults to a two-minute timeout will kill the command mid-check and read its own impatience as a failure. Ten minutes is the safe floor, for both.

Why you can let this near your commits

A prompt theme is cosmetic. This blocks commits and pushes, reads every staged file, and runs with your credentials while nobody is watching — so the claim it has to earn is not "delightful", it is "harmless".

• The commit path links no external crates. amont and amont-runtime are std-only, and scripts/check-no-deps.sh fails a build that changes that — fails closed, so a cargo error or an unreachable registry is a failure rather than a reassuring green tick. amont-fleet takes dependencies quite happily; it is installed separately and runs when asked.
• No network, ever. The binary phones nothing home — no telemetry, no update checks, no fetches. With the commit path std-only, there is not even an HTTP client linked to do it with.
• Over six hundred tests, run on Linux, macOS and Windows, alongside cargo fmt --check, clippy -D warnings, an MSRV floor of 1.74 compiled for the commit path, and cargo-audit.
• v1.0.0 followed a full security review, and each finding landed with a committed reproduction: a drive-by RCE via a relative path in the shim; a held-store format that let a repository delete a tracked file and plant a symlink outside the worktree; a trust prompt a repository could conceal declarations from; guards that wrote through symlinks onto tracked source; a commit subject shaped like a trailer destroying commit trailers; pre-commit-pyright blocking every commit it ran on.
• Your uncommitted work is the thing that must never be lost. The release profile deliberately omits panic = "abort" so that the Drop that restores unstaged work still runs when a check panics — with a test asserting on the manifest, because cargo ignores that setting for test targets and no behavioural test could catch the regression.

Threat model and private reporting: SECURITY.md.

Windows

Everything works, and the PowerShell one-liner in Install is all the setup most machines need. One difference: there is no symlink. To build from source instead — Git for Windows ships bash and coreutils but not make:

cargo build --release
./target/release/amont install

On macOS/Linux ~/.config/git/git-templates is usually a symlink to the checkout, so init.templateDir can point at a stable XDG path. Windows does not create symlinks without Developer Mode or elevation, so point git straight at the checkout instead:

git config --global init.templateDir 'C:/path/to/amont/templates'

Nothing else changes. The shims never need the symlink: they resolve the binary at runtime, trying $GIT_HOOKS_BIN, the baked path, ~/.local/bin/amont and ~/.local/bin/amont.exe, then PATH.

Requirements

• Git 2.31+ — git rev-parse --path-format=absolute landed there, and three places depend on it. On an older git those return nothing rather than failing loudly, which is the worst shape for a version floor: the tool appears to work and quietly resolves the wrong paths.

The hooks are a single binary with no runtime dependencies. Each check brings its own tool requirement only where you have opted into that check.

Documentation

The full documentation is in docs/, versioned with the code and published as a book:

• Installing and activating
• The checks · Configuration · Opting out
• The trust model · Custom checks
• Where the hooks fit in your flow · Commit conventions · How it compares · Ideas, not a roadmap
• Decision records for maintainers: hook architecture, index fidelity and run modes, skip management, the fleet dashboard, the Rust migration

Contributing

Everything is Rust, in crates/:

crates/amont-runtime/   the checks, registry and dispatchers. std only.
crates/amont/           the hook binary. Runs on every commit. std only.
crates/amont-fleet/     the dashboard and the fleet fixer. Opt-in.

make check is the CI-parity target — run it before you push. Setup, the zero-dependency rule and when reopening it is legitimate, the house test style and the commit convention are all in CONTRIBUTING.md.

Questions, "does this work with X", ideas for checks: Discussions. Bugs: issues.

By participating you agree to the Code of Conduct.

License

MIT.