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Documentation Index

Fetch the complete documentation index at: https://mehen.ophi.dev/llms.txt

Use this file to discover all available pages before exploring further.

The official ophidiarium/mehen GitHub Action computes changed-file metric trends on every pull request, compares them against the base branch, and publishes a sticky comment with the deltas. It is the primary consumption surface for mehen today.

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Minimal workflow

.github/workflows/mehen.yml
name: mehen
on: pull_request

jobs:
  mehen:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write
      issues: write
    steps:
      - uses: actions/checkout@v6
        with:
          fetch-depth: 0

      - uses: ophidiarium/mehen@v0
        with:
          paths: src
That’s the whole setup. The action installs the mehen CLI, runs mehen diff against the PR’s base branch, and posts a sticky comment with the per-file metric deltas.

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Polyglot monorepo

For monorepos, pass each tracked root and let mehen pick supported languages from changed files in those trees: 
- uses: ophidiarium/mehen@v0
  with:
    paths: |
      crates/api/src
      apps/web/src
      tools
    thresholds: |
      cyclomatic=5
      cognitive=4
      loc.lloc=120

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Inputs

InputDefaultDescription
version"" (latest)Version of the mehen npm package to run.
install-methodnpmHow to provide the mehen CLI: npm, cargo, or path.
mehen-pathmehenPath to a mehen executable when install-method: path.
node-version24Node.js version used by the action runner.
paths.Repository-relative files or directories to compare. Newline, comma, or semicolon separated.
include""Glob patterns to include.
exclude""Glob patterns to exclude.
exclude-teststrueExclude common test-file patterns (*_test.go, **/__tests__/**, *.spec.ts) on top of any user-provided excludes.
metrics""Comma-separated metrics passed to mehen diff.
from""Base git revision. Defaults to the PR base branch or main.
to""Head git revision. Defaults to the PR head SHA or HEAD.
show-unchangedfalseInclude files where all selected metrics are unchanged.
commenttrueCreate or update a pull request comment.
github-token(workflow token)GitHub token used to update PR comments.
thresholds""Adverse per-file delta limits, e.g. cyclomatic=5,cognitive=3,loc.lloc=100.
fail-on-thresholdtrueFail the action when any configured threshold is exceeded.
comment-title## 📊 Source Code MetricsMarkdown heading used for the sticky comment.

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Outputs

OutputDescription
violationsNumber of threshold violations.
report_jsonPath to the JSON diff report produced by mehen.
report_markdownPath to the rendered Markdown report.

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Permissions

The action needs to write PR comments: 
permissions:
  contents: read
  pull-requests: write
  issues: write
contents: read lets the runner check out the repo. pull-requests: write and issues: write let the action upsert the sticky comment.

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Sticky comment

The action posts a single comment on the PR and updates it on each push instead of stacking new comments. The Markdown layout, cell format, and callout catalog are documented on the PR comment design page.

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Markdown documentation section (preview)

When a PR touches Markdown files, mehen diff will also emit a Documentation Metrics section inside the same sticky comment, anchored by <!-- mehen-docs -->. The full specification — anchor rules, cell format, callout template catalog, planned --fail-on gating — is on the PR comment design page.
Until the Markdown renderer emits the anchor and the callout catalog is wired end-to-end, the GitHub Action only publishes the source-code metrics section.

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Examples

- uses: ophidiarium/mehen@v0
  with:
    paths: src
    thresholds: |
      cyclomatic=3
      cognitive=3
    fail-on-threshold: true

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See also