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 sergeyizmailov/knowledge-delta-skills --skill js-obfuscationgit clone --depth 1 https://github.com/sergeyizmailov/knowledge-delta-skillsWrote 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/sergeyizmailov/knowledge-delta-skills/js-obfuscation)<a href="https://agentmods.dev/skills/sergeyizmailov/knowledge-delta-skills/js-obfuscation"><img src="https://agentmods.dev/badge/skills/sergeyizmailov/knowledge-delta-skills/js-obfuscation/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/sergeyizmailov/knowledge-delta-skills/js-obfuscation"><img src="https://agentmods.dev/badge/skills/sergeyizmailov/knowledge-delta-skills/js-obfuscation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00051 | $0.01035 |
| Opus 5.5 | $0.00020 | $0.00414 |
| Sonnet 5.5 | $0.00010 | $0.00207 |
| Haiku 4.5 | $0.00005 | $0.00103 |
Grade B, and why
js-obfuscation scanned grade B with 1 finding 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 1mo 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.
Encoded or obfuscated payloadmediumSupply chain
base64 or hex that is decoded and executed hides what actually runs from anyone reading the file.
5. Obfuscated JS — no `eval(atob(`, `password`, known-kit signatures in source Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
How it starts
The opening of the file, as written. The whole thing — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.
JS Obfuscation & Anti-Detection
Architecture: Defense-in-Depth Layers
Request arrives
├─ L1: Server-side cloaking (IP/ASN/GeoIP) → anti-bot.md
│ ├─ L2: CAPTCHA gate (Turnstile) → anti-bot.md
│ │ ├─ L3: JS anti-bot (webdriver, fingerprint, behavior) → anti-bot.md
│ │ │ ├─ L4: Encrypted payload (AES/XOR/Unicode) → encryption.md
│ │ │ │ └─ L5: Obfuscated JS (javascript-obfuscator) → obfuscator-configs.md
│ │ │ └─ L6: One-time URLs (single use, then 404)
│ │ └─ Anti-DevTools → anti-devtools.md
Without L1 everything else just delays detection. With L1, site can live weeks.
Quick Decision Guide
| Scenario | Layers |
|---|---|
| Quick red team page | L5 (balanced) + anti-DevTools |
| Production phishing with longevity | All 6 |
| Landing page (BitB popup) | L3 + L5 + anti-DevTools |
| Cloudflare Worker | L1 (ASN via CF) + L4 + L5 |
| Email attachment HTML | L4 (AES, key in URL fragment) + L5 (max) + anti-DevTools |
Evasion Checklist (Safe Browsing / VirusTotal / PhishTank / CF WAF)
- Server-side IP/ASN/GeoIP filter — crawlers never see payload
- CAPTCHA gate (Turnstile) — scanners can't solve; CF sees "protected site"
- JS anti-bot — headless/sandbox detected and redirected
- Encrypted payload, RC4/AES — never raw base64,
atob()is a detection signature - Obfuscated JS — no
eval(atob(,password, known-kit signatures in source domainLock— code breaks on wrong domain (VirusTotal, sandboxes)- One-time URLs — reported link is already 404
- Domain rotation — flagged → reserve; aged domains (.com, 2+ years) flagged slower
- Delayed execution —
setTimeout3–5s; scanner budgets are short - Interaction-gated — real click/scroll required before payload
- Polymorphic mutation — same code for every visitor → signatures
- Email whitelist (Cephas pattern) — serve only if email matches target list
- Legit hosting (
.workers.dev,.pages.dev,.netlify.app) = high reputation; Workers/Pages get less scrutiny
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 1mo ago First seen · 87 lines · 51 tokens per session scan B 68dceee51e18
js-obfuscation is a skill published in the GitHub repository sergeyizmailov/knowledge-delta-skills (3 stars, last pushed 1mo ago), licensed MIT. It adds 51 tokens to every session and 1,035 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it B with 1 finding (encoded or obfuscated payload). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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