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io.github.ExpertVagabond/guardrails

Official registry Security

AI Agent Guardrails MCP server - security layer

Source code Documentation

What can you do with io.github.ExpertVagabond/guardrails?

  • Prompt Injection Detection -- 12 regex patterns for jailbreak, DAN mode, system prompt override
  • PII Detection and Redaction -- SSN, credit card, email, phone, IP, API keys, AWS keys, JWT, passwords, private keys, connection strings
  • Malicious Code Blocking -- eval, exec, subprocess, child_process, shell injection
  • Policy Engine -- Block sensitive paths, dangerous tools, unauthenticated destructive ops, URL allowlist, maintenance windows
  • Rate Limiting -- Per-user sliding window (configurable requests/minute)
  • Audit Logging -- Timestamped events with metrics, log rotation, external handler support

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

NPM package guardrails-mcp-server
Claude Code 
claude mcp add guardrails -- npx -y guardrails-mcp-server@1.0.1
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "guardrails": {
            "command": "npx",
            "args": [
                "-y",
                "guardrails-mcp-server@1.0.1"
            ]
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. guardrails-mcp-server
  2. Tools
  3. Security Features
  4. Install
  5. Configuration
  6. Project Structure
  7. License

guardrails-mcp-server

\ \ \

MCP server for AI agent security guardrails. Provides input validation, prompt injection detection, PII redaction, output filtering, policy enforcement, rate limiting, and comprehensive audit logging.

Tools

ToolDescription
validate_inputValidate and sanitize incoming requests through all guardrail checks
filter_outputFilter and redact sensitive data (PII, secrets, credentials) from responses
check_policyEvaluate a request against security policies (RBAC, resource access, quotas)
get_audit_logsQuery the audit log with filtering by type, user, time range
get_statsGet engine statistics including active users, block rate, request counts
update_configUpdate guardrail configuration at runtime

Security Features

  • Prompt Injection Detection -- 12 regex patterns for jailbreak, DAN mode, system prompt override
  • PII Detection and Redaction -- SSN, credit card, email, phone, IP, API keys, AWS keys, JWT, passwords, private keys, connection strings
  • Malicious Code Blocking -- eval, exec, subprocess, child_process, shell injection
  • Policy Engine -- Block sensitive paths, dangerous tools, unauthenticated destructive ops, URL allowlist, maintenance windows
  • Rate Limiting -- Per-user sliding window (configurable requests/minute)
  • Audit Logging -- Timestamped events with metrics, log rotation, external handler support

Install

npm install

Configuration

{
  "mcpServers": {
    "guardrails": {
      "type": "stdio",
      "command": "node",
      "args": ["/path/to/guardrails-mcp-server/index.js"]
    }
  }
}

Project Structure

src/engine/GuardrailsEngine.js    # Core orchestration
src/validators/InputValidator.js   # Prompt injection and PII detection
src/filters/OutputFilter.js        # Redaction and harmful content blocking
src/policies/PolicyEngine.js       # RBAC, quotas, maintenance windows
src/audit/AuditLogger.js           # Event logging and metrics

License

MIT

Frequently asked questions

What is io.github.ExpertVagabond/guardrails?

AI Agent Guardrails MCP server - security layer

How do I install io.github.ExpertVagabond/guardrails?

It runs on your machine. In Claude Code: claude mcp add guardrails -- npx -y guardrails-mcp-server@1.0.1. For other clients, paste the JSON configuration from this page into their MCP settings.

Does io.github.ExpertVagabond/guardrails need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is io.github.ExpertVagabond/guardrails open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains io.github.ExpertVagabond/guardrails?

It is published by ExpertVagabond. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.