proof-of-work

proof-of-work is a skill for Claude Code, Codex from darkroomengineering/cc-settings. It costs 56 tokens per session (1,050 once invoked), scanned A, original, MIT.

A machine-checking step that runs a project's type checks, tests, and code-style checks, plus a screenshot check for user-interface work. It reports whether the changes are ready for human review.

In plain words
What is it for?
Verifying an agent's code changes, running the available checks in a project, and confirming that interface changes include a screenshot.
Why use it?
It catches common problems before someone spends time reviewing a change, so reviewers can focus on design and behavior rather than basic failures.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also reads ~/.codex or $CODEX_HOME. Also seen: mentions Codex.

Part of the darkroom plugin — 36 skills, 10 agents, 4 hooks shipped together

Good fit Verifying an agent's code changes, running the available checks in a project, and confirming that interface changes include a screenshot.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/darkroomengineering/cc-settings/proof-of-work
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add darkroomengineering/cc-settings --skill proof-of-work
Clone the repo
git clone --depth 1 https://github.com/darkroomengineering/cc-settings

Made for: Claude Code, Codex.

Or install darkroom, the plugin that ships this one along with the rest of its 36 skills, 10 agents, 4 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for proof-of-work

README.md
[![agentmods](https://agentmods.dev/badge/skills/darkroomengineering/cc-settings/proof-of-work/github.svg)](https://agentmods.dev/skills/darkroomengineering/cc-settings/proof-of-work)
Your own site
<a href="https://agentmods.dev/skills/darkroomengineering/cc-settings/proof-of-work"><img src="https://agentmods.dev/badge/skills/darkroomengineering/cc-settings/proof-of-work/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for proof-of-work

Your own site · 80×15
<a href="https://agentmods.dev/skills/darkroomengineering/cc-settings/proof-of-work"><img src="https://agentmods.dev/badge/skills/darkroomengineering/cc-settings/proof-of-work.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,050 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00056 $0.01050
Opus 5 $0.00028 $0.00525
Sonnet 5 $0.00011 $0.00210
Haiku 4.5 $0.00006 $0.00105

Measured 9d ago against content hash bd3ce976b274, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

proof-of-work scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/proof-of-work/SKILL.md · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Proof of Work

The Amdahl-shrink move from the Orchestration Tax: human review is the serial bottleneck, so don't spend it confirming what a machine can verify. An agent's diff is review-ready only when the machine-verifiable battery is green — types, tests, lint (and a screenshot for UI). What a machine can prove shouldn't cost a human's attention.

The gate

Run the battery on the current working tree:

PROOF_RUNNER="${CODEX_HOME:-$HOME/.codex}/darkroom/source/src/scripts/proof.ts"
[ -f "$PROOF_RUNNER" ] || PROOF_RUNNER="$HOME/.claude/src/scripts/proof.ts"
bun "$PROOF_RUNNER"

This is the portable installed runner — it works in any repo. (bun run proof is a shortcut that only exists inside the cc-settings repo itself; don't reach for it in a consumer project.) It detects typecheck / test / lint from the project's package.json, runs them cheapest-first, and prints one verdict:

  • exit 0 → review-ready ✓
  • exit 1 → NOT review-ready ✗ — fix the failing gate before a human looks

Projects can opt into advisory probes by depending on the tool — the gate then runs the project's pinned binary: react-doctor (React render/quality score, telemetry off) and/or deslop (framework-agnostic cross-file dead-code count). Advisory results are reported but never flip the verdict — deterministic signals alongside the hard gates, not blockers. Silent for projects that don't depend on them.

For UI changes, attach a screenshot (/qa or the chrome-devtools MCP) as the visual half of the proof — tests can't prove "looks right".

Standalone Codex semantic probe

Use spawn_agent to create a fresh read-only reviewer, send_message to deliver context while it runs, followup_task to trigger another turn once it is idle, wait_agent to wait, and interrupt_agent only to stop its current turn. Treat findings as advisory beside the mechanical verdict. Never spawn codex-verifier and never run codex-run.ts from inside Codex. Skip the Claude bridge branch below.

Read the full file on GitHub · 66 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 66 lines · 56 tokens per session scan A bd3ce976b274

Subscribe to this mod's changes

proof-of-work is a skill published in the GitHub repository darkroomengineering/cc-settings (43 stars, last pushed 3d ago), licensed MIT. It adds 56 tokens to every session and 1,050 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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