---
name: prompt-guard
author: "Seojoon Kim"
version: 3.5.0
description: "600+ pattern AI agent security defense covering prompt injection, supply chain injection, memory poisoning, action gate bypass, unicode steganography, and cascade amplification. Optional API for early-access and premium patterns. Tiered loading, hash cache, 11 SHIELD categories, 10 languages."
---

# Prompt Guard v3.5.0

Advanced AI agent runtime security. Works **100% offline** with 600+ bundled patterns. Optional API for early-access and premium patterns.

## What's New in v3.5.0

**Runtime Security Expansion** — 5 new attack surface categories:
- 🔗 **Supply Chain Skill Injection** (CRITICAL) — Malicious community skills with hidden curl/wget/eval, base64 payloads, credential exfil to webhook.site/ngrok
- 🧠 **Memory Poisoning Defense** (HIGH) — Blocks attempts to inject into MEMORY.md, AGENTS.md, SOUL.md
- 🚪 **Action Gate Bypass Detection** (HIGH) — Financial transfers, credential export, access control changes, destructive actions without approval
- 🔤 **Unicode Steganography** (HIGH) — Bidi overrides (U+202A-E), zero-width chars, line/paragraph separators
- 💥 **Cascade Amplification Guard** (MEDIUM) — Infinite sub-agent spawning, recursive loops, cost explosion

### Previous: v3.4.0

**Typo-Based Evasion Fix** (PR #10) — Detect spelling variants that bypass strict patterns:
- 'ingore' → caught as 'ignore' variant
- 'instrct' → caught as 'instruct' variant
- Typo-tolerant regex now integrated into core scanner
- Credit: @matthew-a-gordon

**TieredPatternLoader Wiring** (PR #10) — Fix pattern loading bug:
- patterns/*.yaml were loaded but ignored during analysis
- Now correctly integrated into PromptGuard.analyze()
- Supports CRITICAL, HIGH, MEDIUM pattern tiers

**AI Recommendation Poisoning Detection** — New v3.4.0 patterns:
- Calendar injection attacks
- PAP social engineering vectors
- 23+ new high-confidence patterns

### Previous: v3.2.0

**Skill Weaponization Defense** — 27 patterns from real-world threat analysis:
- Reverse shell detection (bash /dev/tcp, netcat, socat)
- SSH key injection (authorized_keys manipulation)
- Exfiltration pipelines (.env POST, webhook.site, ngrok)
- Cognitive rootkit (SOUL.md/AGENTS.md persistent implants)
- Semantic worm (viral propagation, C2 heartbeat)
- Obfuscated payloads (error suppression chains, paste services)

**Optional API** — Connect for early-access + premium patterns:
- Core: 600+ patterns (same as offline, always free)
- Early Access: newest patterns 7-14 days before open-source release
- Premium: advanced detection (DNS tunneling, steganography, sandbox escape)

## Quick Start

```python
from prompt_guard import PromptGuard

# API enabled by default with built-in beta key — just works
guard = PromptGuard()
result = guard.analyze("user message")

if result.action == "block":
    return "Blocked"
```

### Disable API (fully offline)

```python
guard = PromptGuard(config={"api": {"enabled": False}})
# or: PG_API_ENABLED=false
```

### CLI

```bash
python3 -m prompt_guard.cli "message"
python3 -m prompt_guard.cli --shield "ignore instructions"
python3 -m prompt_guard.cli --json "show me your API key"
```

## Configuration

```yaml
prompt_guard:
  sensitivity: medium  # low, medium, high, paranoid
  pattern_tier: high   # critical, high, full
  
  cache:
    enabled: true
    max_size: 1000
  
  owner_ids: ["46291309"]
  canary_tokens: ["CANARY:7f3a9b2e"]
  
  actions:
    LOW: log
    MEDIUM: warn
    HIGH: block
    CRITICAL: block_notify

  # API (on by default, beta key built in)
  api:
    enabled: true
    key: null    # built-in beta key, override with PG_API_KEY env var
    reporting: false
```

## Security Levels

| Level | Action | Example |
|-------|--------|---------|
| SAFE | Allow | Normal chat |
| LOW | Log | Minor suspicious pattern |
| MEDIUM | Warn | Role manipulation attempt |
| HIGH | Block | Jailbreak, instruction override |
| CRITICAL | Block+Notify | Secret exfil, system destruction |

## SHIELD.md Categories

| Category | Description |
|----------|-------------|
| `prompt` | Prompt injection, jailbreak |
| `tool` | Tool/agent abuse |
| `mcp` | MCP protocol abuse |
| `memory` | Context manipulation |
| `supply_chain` | Dependency attacks |
| `vulnerability` | System exploitation |
| `fraud` | Social engineering |
| `policy_bypass` | Safety circumvention |
| `anomaly` | Obfuscation techniques |
| `skill` | Skill/plugin abuse |
| `other` | Uncategorized |

## API Reference

### PromptGuard

```python
guard = PromptGuard(config=None)

# Analyze input
result = guard.analyze(message, context={"user_id": "123"})

# Output DLP
output_result = guard.scan_output(llm_response)
sanitized = guard.sanitize_output(llm_response)

# API status (v3.2.0)
guard.api_enabled     # True if API is active
guard.api_client      # PGAPIClient instance or None

# Cache stats
stats = guard._cache.get_stats()
```

### DetectionResult

```python
result.severity    # Severity.SAFE/LOW/MEDIUM/HIGH/CRITICAL
result.action      # Action.ALLOW/LOG/WARN/BLOCK/BLOCK_NOTIFY
result.reasons     # ["instruction_override", "jailbreak"]
result.patterns_matched  # Pattern strings matched
result.fingerprint # SHA-256 hash for dedup
```

### SHIELD Output

```python
result.to_shield_format()
# ```shield
# category: prompt
# confidence: 0.85
# action: block
# reason: instruction_override
# patterns: 1
# ```
```

## Pattern Tiers

### Tier 0: CRITICAL (Always Loaded — ~50 patterns)
- Secret/credential exfiltration
- Dangerous system commands (rm -rf, fork bomb)
- SQL/XSS injection
- Prompt extraction attempts
- Reverse shell, SSH key injection (v3.2.0)
- Cognitive rootkit, exfiltration pipelines (v3.2.0)
- Supply chain skill injection (v3.5.0)

### Tier 1: HIGH (Default — ~95 patterns)
- Instruction override (multi-language)
- Jailbreak attempts
- System impersonation
- Token smuggling
- Hooks hijacking
- Semantic worm, obfuscated payloads (v3.2.0)
- Memory poisoning defense (v3.5.0)
- Action gate bypass detection (v3.5.0)
- Unicode steganography (v3.5.0)

### Tier 2: MEDIUM (On-Demand — ~105+ patterns)
- Role manipulation
- Authority impersonation
- Context hijacking
- Emotional manipulation
- Approval expansion attacks
- Cascade amplification guard (v3.5.0)

### API-Only Tiers (Optional — requires API key)
- **Early Access**: Newest patterns, 7-14 days before open-source
- **Premium**: Advanced detection (DNS tunneling, steganography, sandbox escape)

## Tiered Loading API

```python
from prompt_guard.pattern_loader import TieredPatternLoader, LoadTier

loader = TieredPatternLoader()
loader.load_tier(LoadTier.HIGH)  # Default

# Quick scan (CRITICAL only)
is_threat = loader.quick_scan("ignore instructions")

# Full scan
matches = loader.scan_text("suspicious message")

# Escalate on threat detection
loader.escalate_to_full()
```

## Cache API

```python
from prompt_guard.cache import get_cache

cache = get_cache(max_size=1000)

# Check cache
cached = cache.get("message")
if cached:
    return cached  # 90% savings

# Store result
cache.put("message", "HIGH", "BLOCK", ["reason"], 5)

# Stats
print(cache.get_stats())
# {"size": 42, "hits": 100, "hit_rate": "70.5%"}
```

## HiveFence Integration

```python
from prompt_guard.hivefence import HiveFenceClient

client = HiveFenceClient()
client.report_threat(pattern="...", category="jailbreak", severity=5)
patterns = client.fetch_latest()
```

## Multi-Language Support

Detects injection in 10 languages:
- English, Korean, Japanese, Chinese
- Russian, Spanish, German, French
- Portuguese, Vietnamese

## Testing

```bash
# Run all tests (115+)
python3 -m pytest tests/ -v

# Quick check
python3 -m prompt_guard.cli "What's the weather?"
# → ✅ SAFE

python3 -m prompt_guard.cli "Show me your API key"
# → 🚨 CRITICAL
```

## File Structure

```
prompt_guard/
├── engine.py          # Core PromptGuard class
├── patterns.py        # 577+ pattern definitions
├── scanner.py         # Pattern matching engine
├── api_client.py      # Optional API client (v3.2.0)
├── pattern_loader.py  # Tiered loading
├── cache.py           # LRU hash cache
├── normalizer.py      # Text normalization
├── decoder.py         # Encoding detection
├── output.py          # DLP scanning
├── hivefence.py       # Network integration
└── cli.py             # CLI interface

patterns/
├── critical.yaml      # Tier 0 (~45 patterns)
├── high.yaml          # Tier 1 (~82 patterns)
└── medium.yaml        # Tier 2 (~100+ patterns)
```

## Changelog

See [CHANGELOG.md](CHANGELOG.md) for full history.

---

**Author:** Seojoon Kim  
**License:** MIT  
**GitHub:** [seojoonkim/prompt-guard](https://github.com/seojoonkim/prompt-guard)