proofcheck

A report-only verification skill for Claude Code and Codex. It checks whether work is actually ready using fresh, scoped evidence instead of trusting confident completion claims.

What it does

• Inspects the changed surface and project-owned scripts before selecting checks.
• Runs focused tests, typechecks, builds, and behavior checks proportional to the claim.
• Records exact commands and concise observed results.
• Classifies checks as passed, failed, skipped, or unavailable.
• Separates fresh evidence from supplied historical and unverified claims.
• Returns READY, NOT READY, or INCOMPLETE.

Proofcheck never edits code, installs dependencies, commits, pushes, deploys, approves, or silently fixes failures. Production, destructive, paid, secret-bearing, and externally mutating checks require separate explicit authorization.

Architecture

The product is Markdown-first. skills/proofcheck/SKILL.md defines the boundary and workflow; its references cover check selection and the report format. The only runtime code is a dependency-free Node.js startup update checker. Repository-only Node tests validate behavior contracts, manifests, hooks, CI policy, and packaging.

Install

Claude Code

/plugin marketplace add Kyaa-A/proofcheck
/plugin install proofcheck@proofcheck

Codex

codex plugin marketplace add Kyaa-A/proofcheck
codex plugin add proofcheck@proofcheck

Start a fresh Codex session, open /hooks, review the startup command, and trust it to enable update notices.

Plain skill

Copy skills/proofcheck into ~/.claude/skills/proofcheck or ~/.agents/skills/proofcheck. Plain copies do not receive startup update checks.

Usage

Ask naturally:

• "Verify this is ready."
• "Proofcheck this fix."
• "Are we actually safe to merge?"
• "Run the relevant checks and show me the evidence."

Explicit Codex invocation: $proofcheck verify this work.

Updates

Managed installs show an informational notice when a newer version is available. The hook never downloads or installs code.

Claude Code:

claude plugin marketplace update proofcheck
claude plugin update proofcheck@proofcheck

Codex:

codex plugin marketplace upgrade proofcheck
codex plugin remove proofcheck@proofcheck
codex plugin add proofcheck@proofcheck

Set PROOFCHECK_UPDATE_CHECK=0 to disable the managed-plugin check.

Development

Requires Node.js 20+.

npm ci
npm test
npm run validate
npm pack --dry-run

Behavioral evaluations in evals/evals.json use disposable Git repositories for passing, failing, unavailable, historical-only, and unsafe verification scenarios.

CI runs the same gates with SHA-pinned GitHub Actions.

License

MIT. Copyright (c) 2026 Asnari Pacalna.