PR Gate

Deterministic GitHub Action that auto-closes PRs that don't follow the project's contribution workflow. Trigger: pull_request_target: [opened, reopened].

Gate logic (first match wins)

Maintainer bypass — PR carries the bypass-pr-check label → pass. Apply this label and reopen if the gate closed something you wanted through.
Org/repo member bypass — author_association is OWNER, MEMBER, or COLLABORATOR → pass.
Approved-work bypass — PR body links an issue (via Closes #N / Fixes #N / Resolves #N) that carries the approved label, and the PR author is in the issue's assignees → pass.
Small-fix bypass — additions + deletions ≤ 50 → pass + apply small-fix label.
Otherwise — apply auto-closed-needs-issue label, post rejection comment, close.

Local testing

cd scripts/pr-gate
npm install
export GITHUB_TOKEN=ghp_... # PAT with repo scope
npx tsx index.ts --pr 1234  # always dry-run unless --no-dry-run

The CLI prints the decision and exits without touching the PR.

Toggling dry-run in production

Go to repo Settings → Secrets and variables → Actions → Variables.
Edit PR_GATE_DRY_RUN.
Set to false to make the Action take real action; any other value (or unset) keeps it in dry-run mode.

The default is true — the gate logs decisions but does not act until the maintainer flips the variable.

Tweaking rules

Thresholds, labels, comment text → config.ts
Rule logic (pure functions) → rules.ts
GitHub API calls → github.ts
Orchestration → index.ts

Known limitations

Runs only on PR open/reopen — not on synchronize. A PR that grows past 50 lines after being passed will not be re-gated.
Cross-repo issue references (owner/repo#N) are not honored.
No LLM is called. This Action is fully deterministic.