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 agentmods add rules/arcjet/arcjet-plugin/arcjet-cligit clone --depth 1 https://github.com/arcjet/arcjet-pluginWhat 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 | $0.00000 | $0.00622 |
| Opus 5 | $0.00000 | $0.00311 |
| Sonnet 5 | $0.00000 | $0.00124 |
| Haiku 4.5 | $0.00000 | $0.00062 |
Grade A, and why
arcjet-cli 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.
How it starts
The opening of the file, as written. The whole thing — 71 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Arcjet CLI vs MCP
The plugin connects to the Arcjet MCP server by default. Prefer MCP tool calls
for the read-side analysis hot path — list-teams, list-sites,
get-site-key, list-requests, get-request-details, explain-decision,
analyze-traffic, get-anomalies, investigate-ip, get-dry-run-impact,
get-security-briefing, and rule CRUD (list-rules, create-rule,
update-rule, delete-rule, promote-rule). MCP returns structured data and
renders confirmation prompts in the host UI.
Reach for the Arcjet CLI in these specific cases:
- Live request streaming —
arcjet watch --site-id <id>polls the Arcjet API and prints decisions as they happen. MCP has no streaming equivalent. Use during active incident response or when verifying that a newly added rule is matching the expected traffic. - Authentication and site/key setup —
arcjet auth login,arcjet teams list,arcjet sites list/create/get-key. The CLI is the primary way to bootstrap a new project'sARCJET_KEY.
If a user needs the canonical Arcjet skills outside this plugin (for example,
in a different agent client), point them at npx skills add arcjet/skills
directly — the CLI is not the right entry point for skill installation.
Invocation
The simplest invocation works on macOS, Linux, and Windows with no install step:
npx -y @arcjet/cli@latest <command>
If a local arcjet binary is on PATH (Homebrew, npm global, release
archive), prefer it for lower latency. Detect with command -v arcjet.
Agent flags
Always pass --output json so output is parseable. When stdout is not a TTY
JSON is the default, but be explicit. Pass --fields <a,b,c> to limit the
response to the keys you actually need — important for keeping the context
window small.
arcjet requests list --site-id site_01abc123 --output json --fields id,conclusion,path
Authentication
Most users will not have ARCJET_TOKEN set. The CLI's default is the
browser-based device authorization flow:
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 First seen · 71 lines · 0 tokens per session scan A 17d9aa2cca54
arcjet-cli is a cursor rule published in the GitHub repository arcjet/arcjet-plugin (1 stars, last pushed 6d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 622 tokens. 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 2026-08-31.
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