zeroguard-policy 0.1.0

Ultra-lightweight, zero-dependency security guardrail and loop-detection engine for AI Agent Workflows.

🛡️ ZeroGuard: The Ultra-Lightweight AI Security Sentry

ZeroGuard is a production-grade, zero-dependency security engine designed to protect autonomous AI Agent workflows from infinite logic loops and malicious code execution. Built entirely with the Python Standard Library, it provides sub-millisecond protection without the latency overhead of containerization.

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🚀 Key Features

1. 🔄 Deterministic Loop Detection (LoopGuard)

Prevents AI agents from falling into recursive logic traps that exhaust API credits.

• Mechanics: Thread-safe execution history with cryptographic state-hashing.
• Fingerprinting: SHA-256 signatures of tool calls with lexicographically sorted arguments.
• Circuit Breaker: Automatic hard-stop after 3 identical repetitions.

2. ⚡ Sub-Millisecond AST Pre-Screening (ExecutionGuard)

Secures "CodeMode" agent execution without the 200ms+ latency of Docker sandboxing.

• Deny-by-Default: Strict allowlist of safe Python AST nodes.
• Capability Trapping: Blocks import, os, subprocess, eval, exec, and private dunder attribute exploration.
• Isolated Namespace: Executes code in a restricted scope with zero access to the host environment.

3. 📜 Enterprise Compliance (AuditLogger)

Full traceability for regulatory requirements like the EU AI Act (Article 12).

• High-Density Metrics: Newline-delimited JSON event trails.
• ISO 8601 UTC: Cryptographically verifiable timestamps.
• Status Indicators: ALLOWED, HARD_BLOCK, and EXECUTION_TERMINATED states.

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🛠️ Installation

ZeroGuard requires Zero External Dependencies. Just drop the zeroguard directory into your project.

pip install . # or simply copy the folder

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💻 Quick Start

Protect your Tools from Loops

from zeroguard import ZeroGuardEngine

engine = ZeroGuardEngine(loop_threshold=3)

@engine.breaker()
def get_weather(location: str):
    # This tool is now protected from infinite agent loops
    return f"Weather in {location} is 72°F"

Secure Dynamic Code Execution

code = "import os; os.system('rm -rf /')" # Malicious attempt

try:
    engine.guard_code_execution(code)
except ZeroGuardSecurityError as e:
    print(f"Attack Blocked: {e}")

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🏗️ Architecture

ZeroGuard
├── engine.py          # Unified Interceptor Interface
├── loop_detector.py   # SHA-256 State Fingerprinting
├── security.py        # AST Node Visitor & Sandbox
├── compliance.py      # ISO 8601 JSON Audit Stream
└── exceptions.py      # Fail-Closed Error Tree

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🛡️ Security Posture: Fail-Closed

ZeroGuard is designed with a Hard Block philosophy. If any internal component encounters an error or a policy violation, the engine defaults to a HARD_BLOCK, ensuring that your application remains secure even under unexpected conditions.

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📈 Performance

Action	Latency	Overhead
AST Validation	< 0.5ms	Negligible
Loop Fingerprinting	< 0.2ms	Negligible
Audit Logging	< 0.1ms	Async-compatible

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📄 License

MIT License. Built for the open-source AI community.