artifact_testing

artifact_testing is a skill for Claude Code, Codex from asgeirtj/system_prompts_leaks. It costs 75 tokens per session (569 once invoked), scanned A, original, CC0-1.0.

An artifact-checking toolkit for testing files and web deliverables before they are returned. It renders items such as PDFs, presentations, Word documents, and spreadsheets so their visible result can be inspected.

In plain words
What is it for?
Use it to run format-specific checks, render documents or web pages, inspect the rendered result, and scan for leftover placeholder content.
Why use it?
It helps catch broken files, layout problems, placeholders, and other issues that code or file generation alone may not reveal. It prevents an unchecked deliverable from being sent to a user.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to run format-specific checks, render documents or web pages, inspect the rendered result, and scan for leftover placeholder content.

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Install with agentmods
npx agentmods add skills/asgeirtj/system_prompts_leaks/testing
About the project

System Prompts Leaks is a collection of captured system instructions used to guide AI chatbots and coding agents before they receive user messages. It serves researchers and developers studying how different AI assistants are directed.

asgeirtj/system_prompts_leaks · 70,425 stars · on GitHub

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 asgeirtj/system_prompts_leaks --skill testing
Clone the repo
git clone --depth 1 https://github.com/asgeirtj/system_prompts_leaks

Made for: Claude Code, Codex.

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 artifact_testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/asgeirtj/system_prompts_leaks/testing/github.svg)](https://agentmods.dev/skills/asgeirtj/system_prompts_leaks/testing)
Your own site
<a href="https://agentmods.dev/skills/asgeirtj/system_prompts_leaks/testing"><img src="https://agentmods.dev/badge/skills/asgeirtj/system_prompts_leaks/testing/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 artifact_testing

Your own site · 80×15
<a href="https://agentmods.dev/skills/asgeirtj/system_prompts_leaks/testing"><img src="https://agentmods.dev/badge/skills/asgeirtj/system_prompts_leaks/testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 75 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 569 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.
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 $0.00075 $0.00569
Opus 5.5 $0.00030 $0.00228
Sonnet 5.5 $0.00015 $0.00114
Haiku 4.5 $0.00007 $0.00057

Measured 25d ago against content hash c110e05073b8, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

artifact_testing 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 25d 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.

Meta/muse-agent/skills/artifacts/testing/SKILL.md · 45 lines

What it actually says

Artifact verification

One home for verification across the artifact namespace. The rule every kind shares: a deliverable is verified by looking at what the user will see, freshly rendered, not by trusting the code that produced it. Never return a link while a gate below fails; after three failed fix attempts, report the specific failure and ask for direction instead of iterating.

File kinds: gates, then eyes

Kind Gate
pdf render_audit.mjs with the flags the pdf skill's workflow.md names, then /opt/hatch/skills/artifacts/scripts/validate_pdf.sh
presentation assemble_deck.mjs, then render_audit.mjs with the flags workflow.md names
docx render to PDF with headless LibreOffice (soffice --headless --convert-to pdf), then rasterize (pdftoppm -jpeg -r 100)
xlsx /opt/hatch/skills/artifacts/scripts/validate_xlsx.py
csv / md parse it back (csv: a Python csv read; md: read the file)

The shared render engine is /opt/hatch/skills/artifacts/scripts/render_audit.mjs; renders outlast muse.exec's default yield, so size yield_ms past the expected runtime and read the report file the flags name rather than trusting a backgrounded command's silence.

Then look. Read every validation PNG or page image with fresh eyes - the generating context sees what it expects, not what rendered. Check first for text overflow or cut-off content, then overlaps, collisions, cramped or uneven spacing, low-contrast text, and template decoration left behind.

Placeholder scan. Before returning, search the deliverable's text for leftover scaffolding: TODO, lorem, placeholder, [insert, xxx runs, and sample rows the user never asked for. Anything found is fixed, not shipped.

Web artifacts

Web builds keep their own audit tools (web_artifacts.build and web_artifacts.audit run the same capture engine with enforcement); this skill's render-fresh and placeholder rules apply to their output all the same.

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. 25d ago First seen · 45 lines · 75 tokens per session scan A c110e05073b8

Subscribe to this mod's changes

artifact_testing is a skill published in the GitHub repository asgeirtj/system_prompts_leaks (70,425 stars, last pushed today), licensed CC0-1.0. It adds 75 tokens to every session and 569 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-10-05.