io.github.ExpertVagabond/guardrails
AI Agent Guardrails MCP server - security layer
Open source Open in the app JSON README (API)
About
AI Agent Guardrails MCP server - security layer
Details
- Kind
- MCP servers
- Topic
- No topic detected
- Publisher
- expertvagabond
- Origin
- official
- Category
- ferramentas
- Transport
- local
- Version
- 1.0.1
- Stars
- 1
- Last push
- 2026-09-08T02:24:06Z
- Repository state
- ativo
- Language
- Rust
- License
- MIT
- Added
- 2026-08-29 03:01:54
- Updated
- 2026-08-29 03:01:54
- Origin id
io.github.ExpertVagabond/guardrails
README
# guardrails-mcp-server
[\](https://opensource.org/licenses/MIT)
[\](https://modelcontextprotocol.io)
[\](https://nodejs.org)
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
| Tool | Description |
|------|-------------|
| `validate_input` | Validate and sanitize incoming requests through all guardrail checks |
| `filter_output` | Filter and redact sensitive data (PII, secrets, credentials) from responses |
| `check_policy` | Evaluate a request against security policies (RBAC, resource access, quotas) |
| `get_audit_logs` | Query the audit log with filtering by type, user, time range |
| `get_stats` | Get engine statistics including active users, block rate, request counts |
| `update_config` | Update 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
```bash
npm install
```
## Configuration
```json
{
"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](LICENSE)