Amiss checks the links and file references in a repository's documentation against the git tree and fails the pull request when one stops resolving. It reads Markdown, MDX, AsciiDoc and reStructuredText, and it compares two commits instead of inspecting one. That second snapshot is what a link checker cannot see: a file that changed under a paragraph that did not. External http links are never fetched; the report lists them, and Amiss and link checkers shows the pipe that hands them to lychee. Amiss reads structure, not meaning: it cannot tell you whether a sentence is true, and it does not guess.

The engine keeps no state, runs nothing, never touches the network, and never writes. The same inputs through the same binary give byte-identical reports.

Install from crates.io:

cargo install --locked amiss

Or take a prebuilt binary from the release page, built for Linux x86_64 and aarch64, macOS x86_64 and aarch64, and Windows x86_64. The download has no executable bit, and the checksum file lists every asset, so the check skips the ones you did not fetch:

curl -sSLO https://github.com/HardMax71/amiss/releases/latest/download/amiss-linux-x86_64
curl -sSLO https://github.com/HardMax71/amiss/releases/latest/download/SHA256SUMS
sha256sum -c --ignore-missing SHA256SUMS
chmod +x amiss-linux-x86_64 && mv amiss-linux-x86_64 amiss

cargo binstall amiss does the same download and rename for you, and gh attestation verify amiss --repo HardMax71/amiss (gh 2.49 or later) proves the file came from this repository's release workflow.

Then check the staged state against the last commit. --object-format is sha1 for nearly every repository; git rev-parse --show-object-format prints yours. The form below names only HEAD, so it works on a depth-1 clone and on any repository with at least one commit:

amiss check --repo . --object-format sha1 \
  --base "$(git rev-parse HEAD)" --index --profile observe

The first line is the verdict, amiss: pass (fix 0, check 0, pre-existing 0, errors 0, exit 0) on a repository with nothing wrong. On one with three broken references, a row names the target with the kind and reason its places share, and each place below names the document and the position:

amiss: pass (fix 0, check 0, pre-existing 3, errors 0, exit 0)
Pre-existing target "README.md" affected places 1 explicit-target-missing heading-anchor-not-found
  "README.md":3:33
Pre-existing target "docs/guide.md" affected places 1 explicit-target-missing path-not-found
  "README.md":3:5
Pre-existing target "src/lib.rs" affected places 1 explicit-target-missing line-fragment-out-of-range
  "README.md":3:59

A Fix is a reference this change broke. A Check is a file that changed under a paragraph that did not, listed for a person to read. Pre-existing is the backlog, the problems that were already there before this change. Exit 0 means the run completed and nothing blocks. Exit 1 means a finding blocks. Exit 2 means the run itself could not be trusted, so there is no verdict.

There is no ignore file, no exclude list, and no way to silence one finding. A repository with a backlog ramps with --profile enforce-introduced, which blocks what a change introduces and leaves the pre-existing rows as warnings until they are worked off. A repository whose site is built somewhere else names its router in one line, so destinations resolve against the URLs the site publishes rather than against the source files.

In CI the same engine ships as an action that derives both commits from the event:

name: docs
on: [pull_request, merge_group]
permissions:
  contents: read
jobs:
  amiss:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
        with:
          fetch-depth: 2
      - uses: HardMax71/amiss@v0
        with:
          profile: observe

The action defaults to enforce-introduced, which blocks only what a change introduces, so the snippet starts at observe and you drop the input once the first report is triaged.

The documentation has the rest: the quickstart, running it in CI with GitLab and the pre-commit hook, every finding kind, every analysis error and working with agents. It is served as one file at llms-full.txt too.

Amiss is source-available under FSL-1.1-ALv2: you may run it in your own CI, and each release converts to Apache-2.0 two years after it ships. The terms are in the license and third-party attributions in notices.