GuardRail MCP
Hybrid multi-language security analysis over MCP for AI-assisted workflows.
---
GuardRail exposes tools that scan source and infrastructure text for high-signal issues (secrets, dangerous APIs, injection patterns, IaC misconfigurations), with optional tree-sitter structural checks, dependency inventory/OSV, SARIF/SBOM export, and an enterprise policy gateway.
| Resource | URL |
|----------|-----|
| Website | https://secret4422.github.io/guardrail-mcp/ |
| AlphaTech Studio | https://alphatech.studio |
| MCPize listing | https://mcpize.com/mcp/guardrail |
| Accuracy policy | [docs/ACCURACY.md](docs/ACCURACY.md) |
| Security / threat model | [docs/SECURITY_MODEL.md](docs/SECURITY_MODEL.md) |
| Examples | [docs/EXAMPLES.md](docs/EXAMPLES.md) |
| Performance | [docs/PERFORMANCE.md](docs/PERFORMANCE.md) |
| Test results | [docs/test-results.md](docs/test-results.md) |
| Enterprise | [docs/ENTERPRISE.md](docs/ENTERPRISE.md) |
## Scope (read this)
- **Does:** static analysis of text you provide; redacts many secret-shaped substrings in excerpts.
- **Does not:** execute scanned code; replace commercial SAST/DAST; guarantee zero false positives/negatives; provide SOC2 certification by itself.
- **Website playground:** browser-only demonstration (`docs/ACCURACY.md`). Production use = Python MCP/CLI.
## Quick start
### Option 1: Fast run with `uvx` (zero installation)
```bash
uvx --from git+https://github.com/SECRET4422/guardrail-mcp.git guardrail-mcp
```
### Option 2: Clone and install editable (Cross-platform: Windows, macOS, Linux)
```bash
git clone https://github.com/SECRET4422/guardrail-mcp.git
cd guardrail-mcp
pip install -e .
# Run test suite
python -m unittest discover -s tests -v
# Start MCP stdio server
guardrail-mcp
```
### MCP client configuration
Add GuardRail to your Claude Desktop or Cursor configuration (`claude_desktop_config.json`):
```json
{
"mcpServers": {
"guardrail": {
"command": "guardrail-mcp",
"args": ["serve", "--mode", "stdio"]
}
}
}
```
Or when running via direct Python executable in a local virtual environment:
```json
{
"mcpServers": {
"guardrail": {
"command": "python",
"args": ["-m", "guardrail.server", "serve", "--mode", "stdio"],
"cwd": "/absolute/path/to/guardrail-mcp"
}
}
}
```
### CLI scan (ground truth)
```bash
python - <<'PY'
from pathlib import Path
from guardrail.hybrid_scan import hybrid_scan
r = hybrid_scan(
Path("examples/vulnerable_sample.py").read_text(encoding="utf-8"),
filename="examples/vulnerable_sample.py",
)
print(r["status"], r["security_verdict"], r["issue_count"], r.get("engines"))
PY
```
`examples/` contains **intentional insecure fixtures** for tests and demos only (labeled in-file). Values are synthetic.
## Capabilities
| Area | Implementation |
|------|----------------|
| Secrets / high-signal patterns | `rules.py`, language grids |
| Python AST + multi-hop taint | `ast_engine.py`, `taint.py` |
| Tree-sitter (optional grammars) | `treesitter_engine.py` |
| Repo / git-diff scan | `repo_scan.py`, `git_scan.py` |
| Dependencies / OSV | `deps.py` (network optional) |
| SARIF / SBOM | `sarif_export.py`, `sbom.py` |
| Enterprise auth, RBAC, policy | `guardrail/enterprise/` |
| Custom rules / plugins | `rule_engine.py`, `plugins.py` |
## Tests
```bash
python -m unittest discover -s tests -v
```
Or with `pytest`:
```bash
pytest
```
Published summary: [docs/test-results.md](docs/test-results.md) (reproduce with the command above).
## Performance
Indicative micro-benchmarks are in [docs/PERFORMANCE.md](docs/PERFORMANCE.md) and `benchmarks/`. Re-run on your machine before relying on numbers.
## Enterprise mode
Optional multi-tenant gateway (API keys/JWT, RBAC, path sandbox, audit, rate limits). See [docs/ENTERPRISE.md](docs/ENTERPRISE.md). Do not deploy HTTP enterprise mode without authentication.
## Hosted listing
Optional commercial listing: [mcpize.com/mcp/guardrail](https://mcpize.com/mcp/guardrail).
Self-hosting the MIT core remains free. Pricing on MCPize is set in that marketplace dashboard.
## Security
- Threat model: [docs/SECURITY_MODEL.md](docs/SECURITY_MODEL.md)
- Vulnerability reporting: [SECURITY.md](SECURITY.md)
- Claims policy: [docs/ACCURACY.md](docs/ACCURACY.md)
## License
MIT — [LICENSE](LICENSE).