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 arcjet/arcjet-js --skill choose-protectionsgit clone --depth 1 https://github.com/arcjet/arcjet-jsWrote 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/arcjet/arcjet-js/choose-protections)<a href="https://agentmods.dev/skills/arcjet/arcjet-js/choose-protections"><img src="https://agentmods.dev/badge/skills/arcjet/arcjet-js/choose-protections/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/arcjet/arcjet-js/choose-protections"><img src="https://agentmods.dev/badge/skills/arcjet/arcjet-js/choose-protections.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 | $0.00045 | $0.00639 |
| Opus 5.5 | $0.00018 | $0.00256 |
| Sonnet 5.5 | $0.00009 | $0.00128 |
| Haiku 4.5 | $0.00005 | $0.00064 |
Grade A, and why
choose-protections 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 yesterday.
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.
What it actually says
Choose Arcjet protections
Load this skill when you need to pick rules. Then load @arcjet/skills#protect
or @arcjet/skills#guard to implement them.
| Problem | Rule | Where |
|---|---|---|
| Bots, scrapers, automated clients | detectBot (allow or deny, not both) |
Request only |
| SQLi / XSS / common probes | shield (mode: "LIVE") |
Request only |
| Cost / abuse quotas | tokenBucket, fixedWindow, slidingWindow |
Request and Guard |
| Jailbreaks, instruction overrides | detectPromptInjection (binary; no threshold) |
Request and Guard |
| PII in text (names, addresses, gov IDs, card, email, phone, IP) | sensitiveInfo / localDetectSensitiveInfo + backend: rampart() |
Request and Guard (server runtime) |
| Unsafe / abusive text | moderateContent |
Guard only |
| Signup spam, disposable email | validateEmail + protectSignup |
Request only |
| VPN / Tor / country / IP lists | filter |
Request only |
| Dangerous tool calls | Guard per-tool label + rate limits |
Guard only |
Token bucket: variable-cost AI (requested per call). Fixed window: hard cap.
Sliding window: no boundary burst. Request rate limits default to IP; set
characteristics: ["userId"] for a user key. Guard rate limits always need
key and bucket.
Sensitive-info rules use @arcjet/sensitive-info-rampart. Always pass
backend: rampart() on the rule; Rampart entities never match without it.
Rampart needs Node.js, Bun, or Deno – not Cloudflare Workers or edge
runtimes.
capture() records that an action happened. It is not a protection rule.
Remote bot and filter rules can be managed with the CLI or MCP without a
redeploy — load @arcjet/skills#cli or @arcjet/skills#mcp.
Claude Code / Copilot hooks are not this table. Publish a coding-agent
policy via @arcjet/skills#mcp (Execute on: Tool call, Prompt, or
Model switch) and install hooks from
https://docs.arcjet.com/coding-agents (omit ?surface=).
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.
- yesterday Changed · +1 lines 2f06706ed804
- 9d ago Changed 43b70dc4380a
- 14d ago Changed · +5 lines 47100c31ba2a
- 29d ago Changed 27e293daf03b
- 1mo ago Changed b5aee6aad9c2
- 1mo ago First seen · 45 lines · 45 tokens per session scan A d873b7cc9f30
choose-protections is a skill published in the GitHub repository arcjet/arcjet-js (692 stars, last pushed today), licensed Apache-2.0. It adds 45 tokens to every session and 639 once invoked, about $0.0002 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 2026-09-05.
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