Yarn Release Age Gate

yarn-release-age-gate

Use this skill when a user has chosen Yarn (Berry / v2+, current line v4.x) as their package manager and wants release-age-gate hardening parallel to what npm-release-age-gate and pnpm-release-age-gate provide for their respective ecosystems.

Triggers

• "yarn release age gate"
• "yarn npmMinimalAgeGate"
• "yarn 4 supply chain"
• "yarn berry hardening"

Prerequisites

• Yarn 4.0+ (Berry) installed (yarn --version)
• package.json exists at repo root
• .yarnrc.yml exists (or will be created) — Berry's config file

If Yarn is below v4.0, the skill should refuse to proceed: npmMinimalAgeGate was introduced in v4.0 and earlier Berry versions (v2.x, v3.x) silently ignore the setting. Yarn Classic (v1.x) does not support a release-age gate at all — recommend migration to Berry or to pnpm/npm.

Configuration

Add the gate to .yarnrc.yml at repo root:

# Yarn 4.x release-age gate.
# Uses duration shorthand: 7d, 10d, 14d, 30d.
# Defends against newly-published malicious versions.
npmMinimalAgeGate: 7d

# High-sensitivity profile (use for publish-prep or major version bumps):
# npmMinimalAgeGate: 10d

Yarn accepts the value as a duration string (Nd for days, Nh for hours), which is cleaner than npm's days-as-bare-int and pnpm's minutes-as-int. Document the chosen value inline.

Per-environment override (optional)

For CI-only enforcement (e.g., tighter gate in publish workflows than in local dev):

# .yarnrc.yml — apply 10d gate when running on CI, 7d locally
npmMinimalAgeGate:
  exclude:
    - pattern: "@your-scope/*"  # internal packages — gate doesn't apply
  default: 7d
  override:
    - if: "$YARN_ENABLE_STRICT_AGE_GATE"
      value: 10d

Environment-conditional values are a Yarn 4 advantage over npm and pnpm (which require workflow-level wrapping).

Lockfile caveat

The gate is checked at resolution time. If yarn.lock was generated without the gate, the gate applies on the NEXT resolution pass — not retroactively.

To apply the gate retroactively:

# Force re-resolution
rm yarn.lock
yarn install

This is destructive to existing pins. Coordinate before running.

Corepack detection

Check whether the project pins a Yarn version via Corepack:

node -p "require('./package.json').packageManager"

Output like yarn@4.5.0 means Corepack will use that exact version in CI. The skill should:

1. Confirm pinned version is ≥ v4.0 (else flag — gate is silently ignored on Berry v2/v3)
2. Document the pinned version
3. Suggest a Corepack pin if the project doesn't have one:

   corepack use yarn@stable
   # writes packageManager to package.json
   

Override policy

Genuine emergency overrides:

# Bypass the gate for a single install (rare)
YARN_NPM_MINIMAL_AGE_GATE=0 yarn add <pkg>

Document every override with reason + sunset date. Add the package to the .yarnrc.yml exclude list if the bypass needs to persist across installs.

CI integration

Add a verification step to the publish/build workflow:

- name: Verify Yarn gate active
  run: |
    set -euo pipefail
    GATE=$(yarn config get npmMinimalAgeGate 2>/dev/null || echo "")
    if [ -z "$GATE" ]; then
      echo "✗ Yarn npmMinimalAgeGate is unset"
      exit 1
    fi
    echo "✓ Yarn npmMinimalAgeGate = $GATE"

What to inspect during review

• .yarnrc.yml for npmMinimalAgeGate
• package.json packageManager field for Corepack pin
• CI workflow has the verification step above
• yarn.lock was generated AFTER the gate was committed

Output format

When auditing an existing Yarn project, produce a structured report at .aiwg/security/working/yarn-release-age-audit.md:

# Yarn Release-Age Gate Audit

**Yarn version**: <version>  (Corepack pinned: yes/no)
**Gate active**: yes (7d) / yes (10d) / yes (custom: <value>) / no
**Exclude list**: <list of excluded packages>

## Findings

### <severity> — <description>

- File: <path>
- Issue: <what's wrong>
- Fix: <exact change>

## Clean Checks

- ...

## Recommendations

- ...

See Also

• npm-release-age-gate skill — npm equivalent
• pnpm-release-age-gate skill — pnpm equivalent
• bun-release-age-gate skill — Bun equivalent
• npm-supply-chain-audit skill — companion audit
• supply-chain-hardening-quickstart skill — orchestrator

References

• Yarn npmMinimalAgeGate: https://yarnpkg.com/configuration/yarnrc#npmMinimalAgeGate
• Yarn Berry (v4) docs: https://yarnpkg.com/getting-started
• Corepack: https://github.com/nodejs/corepack