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.
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.
npx skills add asgeirtj/system_prompts_leaks --skill html-emailgit clone --depth 1 https://github.com/asgeirtj/system_prompts_leaksWrote 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.
[](https://agentmods.dev/skills/asgeirtj/system_prompts_leaks/html-email)<a href="https://agentmods.dev/skills/asgeirtj/system_prompts_leaks/html-email"><img src="https://agentmods.dev/badge/skills/asgeirtj/system_prompts_leaks/html-email/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.
<a href="https://agentmods.dev/skills/asgeirtj/system_prompts_leaks/html-email"><img src="https://agentmods.dev/badge/skills/asgeirtj/system_prompts_leaks/html-email.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00008 | $0.00623 |
| Opus 5 | $0.00004 | $0.00311 |
| Sonnet 5 | $0.00002 | $0.00125 |
| Haiku 4.5 | $0.00001 | $0.00062 |
Grade A, and why
html-email 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 11d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- html-email — 91% identical, 27 lines differ
What it actually says
HTML email
Design an HTML email as ONE self-contained .html file that survives real email clients. Email rendering is not browser rendering — Gmail, Outlook, and Apple Mail each strip or mangle different things, and the rules below are what reliably survives all three. When a rule here conflicts with normal web-design instincts, the rule wins.
Layout and styling:
- Structure with nested
<table role="presentation" cellpadding="0" cellspacing="0" border="0">— no flexbox, no grid, no floats, no position. One centered wrapper table, max-width 600px, single-column flow (stacked rows beat side-by-side columns). - Inline EVERY style on the element it styles. A
<style>block in<head>may additionally carry only what can't inline (media queries, dark-mode tweaks) — several clients drop it entirely, so the email must read correctly from inline styles alone. - No JavaScript anywhere (universally stripped). No external stylesheets. No web fonts — use email-safe stacks (Arial, Helvetica, Georgia, Verdana, Tahoma, 'Courier New') with generic fallbacks.
- Build the visual design out of colored table cells, borders, spacer cells, and type — not images. There is nowhere to host project images from here: a referenced project file will not exist for recipients. If imagery is essential, leave a clearly-marked placeholder cell with alt text and tell the user to swap in a hosted https URL before sending.
- Buttons are "bulletproof": a padded
<td>with bgcolor and inline border-radius, the<a>filling it with display:block and inline color — never an image, never a styled<button>.
Client quirks that matter:
- Outlook (Word engine): give every table/cell explicit widths; set
line-height with mso-line-height-rule:exactly; wrap Outlook-only
fixes in
<!--[if mso]> … <![endif]-->conditionals. - Gmail clips messages beyond ~100KB of HTML — stay well under.
- Add
<meta name="color-scheme" content="light dark">and pick colors that survive dark-mode inversion (avoid pure#000/#fffbackgrounds; test text on mid-tone fills).
Deliverability and accessibility:
- First element in
<body>: a hidden preheader span (~85 chars) that previews next to the subject line. - alt text on any image, lang on
<html>, real<a href>links (no dead # anchors), and a footer with a plausible unsubscribe line and postal address for anything marketing-shaped.
Show the design at 600px; mention in your reply that the file is send-ready HTML the user can drop into their email tool.
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.
- 11d ago First seen · 55 lines · 8 tokens per session scan A 9bf6423a7647
html-email is a skill published in the GitHub repository asgeirtj/system_prompts_leaks (64,614 stars, last pushed yesterday), licensed CC0-1.0. It adds 8 tokens to every session and 623 once invoked, about $0.0000 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.
Other skills, from other repositories
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pretext
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sketch
Throwaway HTML mockups: 2-3 design variants to compare.
inspecting-hermes-desktop-dom
Read the live Hermes desktop DOM/CSS over CDP.
impeccable
Frontend design guidance, upstream-maintained (impeccable).
12-brief-landing-page
Dung khi can viet brief de XAY landing page moi hoac trang ban hang moi — cau truc section, copy tung khoi, yeu cau ky thuat, tracking va timeline giao dev. Kich hoat khi user nhac 'brief landing page', 'lam trang ban hang', 'can trang dich', 'thue dev lam landing', 'landing page can gi', 'viet noi dung cho trang'.…