{
  "markdown": "# guardrails-mcp-server\n\n[\\![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)\n[\\![MCP](https://img.shields.io/badge/MCP-Compatible-blue.svg)](https://modelcontextprotocol.io)\n[\\![Node.js](https://img.shields.io/badge/Node.js-18%2B-green.svg)](https://nodejs.org)\n\nMCP server for AI agent security guardrails. Provides input validation, prompt injection detection, PII redaction, output filtering, policy enforcement, rate limiting, and comprehensive audit logging.\n\n## Tools\n\n| Tool | Description |\n|------|-------------|\n| `validate_input` | Validate and sanitize incoming requests through all guardrail checks |\n| `filter_output` | Filter and redact sensitive data (PII, secrets, credentials) from responses |\n| `check_policy` | Evaluate a request against security policies (RBAC, resource access, quotas) |\n| `get_audit_logs` | Query the audit log with filtering by type, user, time range |\n| `get_stats` | Get engine statistics including active users, block rate, request counts |\n| `update_config` | Update guardrail configuration at runtime |\n\n## Security Features\n\n- **Prompt Injection Detection** -- 12 regex patterns for jailbreak, DAN mode, system prompt override\n- **PII Detection and Redaction** -- SSN, credit card, email, phone, IP, API keys, AWS keys, JWT, passwords, private keys, connection strings\n- **Malicious Code Blocking** -- eval, exec, subprocess, child_process, shell injection\n- **Policy Engine** -- Block sensitive paths, dangerous tools, unauthenticated destructive ops, URL allowlist, maintenance windows\n- **Rate Limiting** -- Per-user sliding window (configurable requests/minute)\n- **Audit Logging** -- Timestamped events with metrics, log rotation, external handler support\n\n## Install\n\n```bash\nnpm install\n```\n\n## Configuration\n\n```json\n{\n  \"mcpServers\": {\n    \"guardrails\": {\n      \"type\": \"stdio\",\n      \"command\": \"node\",\n      \"args\": [\"/path/to/guardrails-mcp-server/index.js\"]\n    }\n  }\n}\n```\n\n## Project Structure\n\n```\nsrc/engine/GuardrailsEngine.js    # Core orchestration\nsrc/validators/InputValidator.js   # Prompt injection and PII detection\nsrc/filters/OutputFilter.js        # Redaction and harmful content blocking\nsrc/policies/PolicyEngine.js       # RBAC, quotas, maintenance windows\nsrc/audit/AuditLogger.js           # Event logging and metrics\n```\n\n## License\n\n[MIT](LICENSE)\n",
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  "repo_slug": "expertvagabond/guardrails-mcp-server",
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}