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mehen offers two per-metric gating mechanisms: repository-local mehen.toml thresholds evaluated inside the binary against absolute values, and the GitHub Action’s thresholds input evaluated against per-file deltas. This page explains how they differ, how they compose with the JSON output of mehen diff, and how to write your own gating logic in CI.

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Repository thresholds (mehen.toml)

A mehen.toml at the repository root gates every command — locally, in pre-commit hooks, and in any CI system:
mehen metrics, mehen diff (head side), and mehen top-offenders exit 1 when a reported metric crosses its limit, after a grouped stderr report that names the config table to adjust. Limits bound where a metric may be: a file over the limit fails the gate even if the current change didn’t move it. Full reference: Configuration.

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Action threshold input

The action runs mehen diff and then evaluates each per-file delta against the supplied limits. A violation:
  • Counts toward the violations output.
  • Fails the action when fail-on-threshold: true (default).
Delta limits bound how far a single PR may move a metric in the adverse direction; they say nothing about the absolute level a file already sits at. Combine them with mehen.toml thresholds to bound both.

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Adverse direction

Each metric has an adverse direction. Thresholds limit how far in the adverse direction a per-file delta is allowed to go: mehen knows the direction for the standard metrics and applies the threshold accordingly.

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Composition with diff JSON

If you want richer logic than the action provides, run mehen diff -O json yourself and pipe the JSON into a CI script:
jq and the JSON shape give you full control. The downside: you reimplement adversity rules.

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See also