AgentGuards plugin for Claude Code

LLM security guardrails for Claude Code in one install: jailbreak and prompt-injection detection, web-content scanning, data-exfiltration blocking, and destructive-command authorization.

Enforcement is configurable: fail-closed by default for strict security, or switch to fail-open (availability-first) with a single environment variable (AGENTGUARDS_FAIL_OPEN=true).

This plugin bundles:

• the AgentGuards MCP server (check_input, authorize_action, validate_output, evaluate_policy, health_check),
• enforcing hooks — UserPromptSubmit input scanning, PreToolUse Bash authorization, and PostToolUse web-content scanning/redaction,
• the AgentGuards security instructions (the guardrails skill).

Install

/plugin marketplace add alelaguard/agentguards-plugins
/plugin install agentguards-claude@agentguards

Then provide your API key (get one at https://agentguards.co/dashboard/keys) so both the MCP server and the hooks can authenticate:

export AGENTGUARDS_API_KEY=ag_your_token_here

Add that line to your shell profile (~/.bashrc, ~/.zshrc, …) and restart Claude Code. Or just run /agentguards:setup and it will walk you through it.

No shell profile? (Claude Desktop's Code tab, or any GUI-launched session that doesn't read ~/.bashrc.) Set it in ~/.claude/settings.json instead — this feeds both the hooks and the MCP server, exactly like a shell export:

{
  "env": {
    "AGENTGUARDS_API_KEY": "ag_your_token_here"
  }
}

The plugin's Configure screen also accepts a key, but it is only a fallback for the hooks — the bundled MCP server reads the environment variable. Prefer one of the two options above so both halves authenticate.

Claude Desktop's Chat and Cowork tabs are not supported. They sync from your claude.ai account rather than ~/.claude, so there is no environment for the key to come from, and hooks do not run in Chat. Use the Code tab.

Alternative: npm install @agentguardsco/claude-plugin. Fetches these same files for programmatic use (pinned versions, CI, custom tooling) — it does not register with Claude Code on its own; use /plugin install above for that.

Commands

• /agentguards:setup — set your API key and verify everything is wired up.
• /agentguards:status — report whether the guardrails are active and healthy.

Configuration

| Variable | Required | Default | Purpose | |---|---|---|---| | AGENTGUARDS_API_KEY | yes | — | Your ag_ token. Drives both the MCP header and the hooks. | | AGENTGUARDS_URL | no | https://prod.agentguards.co | Override only for a self-hosted instance. | | AGENTGUARDS_FAIL_OPEN | no | false | Hooks fail closed by default (block when the service is unreachable). Set true to allow on error. |

How it works

The hooks call the AgentGuards REST API on every prompt, before every Bash command, and after every web fetch — blocking or redacting when AgentGuards flags a risk. The MCP tools let Claude cooperatively check inputs and authorize actions as described in the bundled guardrails skill.

Learn more at https://agentguards.co.