GuardianShield

Universal AI security layer — an open-source MCP server for code scanning, PII detection, prompt injection defense, secret detection, dependency auditing, and audit logging.

Zero dependencies · 27 MCP tools · 5 safety profiles · 108+ detection patterns

Features

Code Vulnerability Scanning — SQL injection, XSS, command injection, path traversal with CWE IDs and auto-fix remediation
Cross-line Data Flow Analysis — DeepEngine tracks tainted data from sources to sinks across multiple lines using AST-based taint propagation (Python) and regex (JS/TS)
Dependency Security — Version-aware CVE matching against OSV.dev for PyPI, npm, Go, and Packagist ecosystems
Manifest Parsing — Auto-detects 11 formats (requirements.txt, package.json, yarn.lock, go.mod, composer.json, and more)
Prompt Injection Defense — 9+ detection patterns for instruction override, role hijacking, ChatML injection
PII Detection — Email, SSN, credit card, phone, IP — with automatic redaction in findings
Secret Detection — AWS keys, GitHub tokens, Stripe keys, JWTs, passwords, connection strings
Safety Profiles — 5 built-in profiles (general, education, healthcare, finance, children)
Audit Logging — SQLite-backed scan history with finding retrieval and filtering

Install

Terminal

pip install guardianshield

Quick Start

bash

# Register with Claude Code
claude mcp add guardianshield -- guardianshield-mcp

# Or run directly
guardianshield-mcp

Editor Integration

bash

# Claude Code
claude mcp add guardianshield -- guardianshield-mcp

# VS Code (.vscode/mcp.json)
{"servers": {"guardianshield": {"type": "stdio", "command": "guardianshield-mcp"}}}

# Cursor (.cursor/mcp.json)
{"mcpServers": {"guardianshield": {"command": "guardianshield-mcp"}}}

# Claude Desktop (claude_desktop_config.json)
{"mcpServers": {"guardianshield": {"command": "guardianshield-mcp"}}}

MCP Tools

Scanning

Tool	Description
`scan_code`	Scan source code for vulnerabilities and hardcoded secrets
`scan_file`	Scan a single file (auto-detects language from extension)
`scan_directory`	Recursively scan a directory with filtering and progress streaming
`scan_input`	Check user/agent input for prompt injection attempts
`scan_output`	Check AI output for PII leaks and content violations
`check_secrets`	Detect hardcoded secrets and credentials
`scan_files`	Scan multiple files in one call
`scan_diff`	Parse unified diff and scan only added lines

Dependency Security

Tool	Description
`check_dependencies`	Check packages for known CVEs via OSV.dev (PyPI, npm, Go, Packagist)
`sync_vulnerabilities`	Sync the local OSV vulnerability database
`parse_manifest`	Parse any supported manifest file (11 formats) into dependency objects
`scan_dependencies`	Scan a directory for manifest files and check all deps for vulnerabilities

False Positive Management

Tool	Description
`mark_false_positive`	Mark a finding as false positive (flags future matches)
`list_false_positives`	List active false positive records with optional filter
`unmark_false_positive`	Remove a false positive record by fingerprint

Engine Management

Tool	Description
`list_engines`	List available analysis engines with capabilities
`set_engine`	Set active analysis engines for code scanning

Three engines ship built-in: regex (line-by-line pattern matching, enabled by default), deep (cross-line taint tracking), and semantic (structure-aware confidence adjustment).

CI & Developer Workflow

Tool	Description
`export_sarif`	Export findings as SARIF 2.1.0 JSON for GitHub Code Scanning and CI
`save_baseline`	Save current findings as a baseline for delta scanning
`scan_with_baseline`	Scan code and report only new findings vs. baseline
`check_quality_gate`	Evaluate findings against severity thresholds (pass/fail/warn)
`scan_files`	Scan multiple files in one call
`scan_diff`	Parse unified diff and scan only added lines

Configuration & Utilities

Tool	Description
`get_profile`	Get current safety profile configuration
`set_profile`	Switch safety profile (general, education, healthcare, finance, children)
`test_pattern`	Test a regex pattern against sample code for custom pattern development
`audit_log`	Query the security audit log
`get_findings`	Retrieve past findings with filters
`shield_status`	Get health, configuration, and OSV cache statistics

Configuration

Set environment variables to customize behavior:

Variable	Description	Default
`GUARDIANSHIELD_PROFILE`	Default safety profile	`general`
`GUARDIANSHIELD_AUDIT_PATH`	Path to SQLite audit database	`~/.guardianshield/audit.db`
`GUARDIANSHIELD_DEBUG`	Enable debug logging (`1`)	disabled

Documentation

Full documentation: sparkvibe-io.github.io/GuardianShield

License

Apache 2.0