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 mcpgit 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/mcp)<a href="https://agentmods.dev/skills/arcjet/arcjet-js/mcp"><img src="https://agentmods.dev/badge/skills/arcjet/arcjet-js/mcp/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/mcp"><img src="https://agentmods.dev/badge/skills/arcjet/arcjet-js/mcp.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 5 findings, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Agent Snooping · line 33 Skill accesses MCP server configuration files (mcp.json). MCP configs contain server URLs, authentication tokens, and tool definitions — reading them allows the skill to discover and potentially abuse other tool integrations.Fix: Remove all code or instructions that read MCP configuration files (mcp.json). MCP server details should be managed by the agent runtime, not read by individual skills.
- medium Data Exfiltration · line 3 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
- medium Data Exfiltration · line 17 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
- medium Data Exfiltration · line 27 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
- medium Data Exfiltration · line 38 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
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 | $0.00040 | $0.00478 |
| Opus 5.5 | $0.00016 | $0.00191 |
| Sonnet 5.5 | $0.00008 | $0.00096 |
| Haiku 4.5 | $0.00004 | $0.00048 |
Grade A, and why
mcp 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.
What it actually says
Arcjet MCP server
Endpoint: https://api.arcjet.com/mcp only. OAuth on first connect. Enable
write confirmations. Prefer @arcjet/skills#cli when a terminal is available.
Cursor — .cursor/mcp.json:
{
"mcpServers": {
"arcjet": {
"type": "streamable-http",
"url": "https://api.arcjet.com/mcp"
}
}
}
VS Code — .vscode/mcp.json with "type": "http" and the same URL.
Claude Code:
claude mcp add arcjet --transport http https://api.arcjet.com/mcp
Bootstrap: list-teams → list-sites → get-site-key → write ARCJET_KEY.
Agent identity (not human browser OAuth): follow https://arcjet.com/auth.md.
Investigate: analyze-traffic, list-requests, list-guards,
investigate-ip. Remote rules: create-rule (DRY_RUN) →
get-dry-run-impact → promote-rule. Guard policies (MCP-only; no CLI
commands): list-guard-policies → describe-guard-policy →
validate-guard-policy → put-guard-policy. Application policies select by
label / action. Coding-agent policies attach by Execute on (Tool call,
Prompt, or Model switch). Install Claude Code / Copilot hooks from
https://docs.arcjet.com/coding-agents — copy the templates. The hook URL
must not name a policy and must 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.
- 9d ago Changed be52125374a4
- 14d ago Changed · +3 lines eca34b92052c
- 29d ago Changed · +4 lines c12f1a31bfc8
- 1mo ago Changed f8945e1c20bf
- 1mo ago First seen · 45 lines · 40 tokens per session scan A 0efacaa30554
mcp is a skill published in the GitHub repository arcjet/arcjet-js (692 stars, last pushed today), licensed Apache-2.0. It adds 40 tokens to every session and 478 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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