Arcjet Plugin

Arcjet is the runtime security platform that ships with your code. Enforce budgets, stop prompt injection, detect bots, and protect personal information with Arcjet’s AI security building blocks.

The Arcjet plugin is a bundled experience for Claude Code and Cursor users who prefer a single-command install that wires up MCP, skills, and security-aware coding rules together.

The plugin pre-loads agents with knowledge of the Arcjet security platform and automatically injects the right guidance based on what you’re working on — framework-specific SDK patterns, protection rules, and best practices.

Installation

Install the plugin with a single command:

npx plugins add arcjet/arcjet-plugin

The same command works in both Claude Code and Cursor. The plugin activates automatically after installation. There are no additional setup steps or commands to learn.

Prerequisites

Claude Code or Cursor
Node.js 18+
An Arcjet account (free)

What the plugin provides

The plugin includes four main components that work together to enhance your AI coding agent:

Component	Description
MCP integration	Connects to the Arcjet MCP server for traffic analysis, request inspection, IP investigation, and remote rule management
Security-aware coding rules	Framework-specific guidance that auto-activates when you’re working in relevant files
Skills	Task-oriented workflows for implementing protection
Security analyst agent	Monitors threats, analyzes traffic patterns, and manages rules

How it works

After installing, the plugin detects what you’re working on from your tool calls, file paths, and project configuration, then injects the right expertise at the right time. You use your AI agent as you normally would and the plugin handles the rest.

Auto-activated rules

Guidance triggers automatically in specific contexts:

Context	File patterns	What it provides
SDK patterns	`*/lib/arcjet`	Single instance setup, `protect()` usage, decision handling
Next.js	`app//route.ts`, `pages/api/`	Import validation, handler vs. component distinctions
Express / Node	`**/server.ts`	Adapter packages, configuration patterns
Python	`*/.py`	Snake case API conventions, async/sync client handling
AI apps	`/chat/`, `*/api/chat`	Layered protection, token budgets, PII blocking

Skills

Invoke skills directly within your AI coding agent:

Skill	Purpose
`/arcjet:add-request-protection`	Add protection to HTTP route handlers and API endpoints — rate limiting, bot detection, email validation, and shield.
`/arcjet:add-guard-protection`	Protect non-HTTP code paths (AI tool calls, MCP handlers, queue workers, background jobs) via `@arcjet/guard` / `arcjet.guard`.

The previous skill names — /arcjet:protect-route and /arcjet:add-ai-protection — remain as deprecated aliases that emit a diagnostic on use. Migrate to the canonical names above.

The plugin’s skills track the canonical arcjet/skills package, which is the source of truth. You can install the same skills outside the plugin with npx skills add arcjet/skills.

Supported frameworks

The Arcjet Plugin supports all the languages and frameworks supported by the Arcjet SDKs:

JavaScript / TypeScript: Next.js, Express, Node.js, Fastify, NestJS, SvelteKit, Remix, React Router, Astro, Nuxt, Hono, Bun, Deno

Python: FastAPI, Flask

Using the plugin with MCP

The plugin connects to the Arcjet MCP server to give your agent access to your Arcjet account. When connected via OAuth, agents can:

Inspect requests and explain allow/deny decisions
Analyze traffic patterns and detect anomalies
Investigate suspicious IPs with geolocation and threat intelligence
Create and promote remote rules without code changes
Generate security briefings

Using the plugin with the CLI

The plugin invokes the Arcjet CLI to stream live request activity into your agent’s context — for example when you ask the agent to watch traffic on a site or investigate recent requests. The CLI exposes the same management- plane surface as the MCP server (teams, sites, rules, requests, analysis) directly from the terminal.

Source code

The plugin is open source: github.com/arcjet/arcjet-plugin