dual-gate prompt and output scanning with unified scanner interface
Implements a modular scanner framework where both input (pre-LLM) and output (post-LLM) validators follow a common interface returning (sanitized_text, is_valid, risk_score) tuples. Scanners are composed independently and can be chained in arbitrary order, enabling flexible security pipelines. The architecture decouples scanner logic from orchestration, allowing developers to enable/disable scanners via configuration without code changes.
Unique: Unified scanner interface (scan() method returning triplet) across 36+ independent scanners (15 input, 21 output) allows arbitrary composition without coupling; architecture prioritizes modularity and configuration-driven behavior over monolithic validation logic
vs alternatives: More granular and composable than monolithic content filters; unlike generic ML-based content moderation APIs, LLM Guard provides specialized scanners for LLM-specific threats (prompt injection, token smuggling) with local execution and no external API dependencies
prompt injection detection via multiple pattern and semantic approaches
Detects prompt injection attacks using a multi-strategy approach combining regex-based pattern matching for known injection signatures, semantic similarity analysis against injection templates, and structural analysis of prompt delimiters and role-switching patterns. The scanner identifies attempts to override system instructions, inject new directives, or manipulate LLM behavior through adversarial prompt crafting.
Unique: Combines regex pattern matching for known injection signatures with semantic similarity scoring against injection templates and structural analysis of delimiter patterns; uses local embedding models rather than external APIs, enabling offline detection without cloud dependencies
vs alternatives: More specialized for LLM-specific injection vectors than generic input validation; faster than API-based detection services because it runs locally; more comprehensive than simple keyword filtering by combining multiple detection strategies
onnx model optimization for low-latency and resource-constrained deployment
Supports ONNX (Open Neural Network Exchange) optimization for transformer-based scanners, enabling faster inference and reduced memory footprint. Converts HuggingFace models to ONNX format with quantization options (int8, float16), enabling deployment on CPU-only or edge devices. Configuration-driven ONNX enablement allows switching between full-precision and optimized models without code changes. Reduces model inference latency by 2-10x compared to PyTorch, enabling real-time scanning in latency-sensitive applications.
Unique: Provides configuration-driven ONNX optimization with quantization support (int8, float16) enabling 2-10x latency reduction; supports switching between full-precision and optimized models via configuration without code changes; enables deployment on CPU-only and edge devices where GPU acceleration is unavailable
vs alternatives: Faster inference than PyTorch models because ONNX Runtime is optimized for inference; more flexible than fixed-optimization approaches because quantization level is configurable; enables deployment scenarios (edge, serverless, CPU-only) that would be infeasible with full-precision models
configurable scanner composition and policy-driven security pipelines
Enables developers to compose scanners into custom security pipelines via configuration files (YAML) or code, selecting which scanners to enable, their order, and their parameters. Supports conditional scanner execution (e.g., run PII scanner only if prompt contains certain keywords), scanner chaining (output of one scanner feeds into next), and policy-driven behavior (different scanner sets for different user roles or risk profiles). Eliminates need to write custom orchestration code for complex security workflows.
Unique: Supports configuration-driven scanner composition via YAML or code, enabling policy-driven security pipelines without custom orchestration code; supports conditional scanner execution and chaining, enabling complex security workflows; enables different policies per deployment/user without code changes
vs alternatives: More flexible than hardcoded scanner sequences because policies are configuration-driven; more maintainable than custom orchestration code because logic is declarative; enables non-developers to modify security policies via configuration files
observability and audit logging for security scanning decisions
Provides hooks for logging and monitoring all scanning decisions, enabling compliance auditing and security analysis. Integrates with standard Python logging framework and supports custom observability backends. Logs include scanner name, input text, risk score, sanitization actions, and decision (allow/block). Enables teams to audit security decisions, identify patterns in attacks, and monitor scanner performance. Supports structured logging (JSON) for integration with log aggregation systems (ELK, Datadog, Splunk).
Unique: Integrates with Python logging framework enabling flexible log destination configuration; supports structured logging (JSON) for log aggregation systems; provides detailed audit trail of all scanning decisions including risk scores and sanitization actions
vs alternatives: More flexible than hardcoded logging because it integrates with Python logging framework; more comprehensive than simple decision logging because it includes risk scores and scanner details; enables compliance auditing and attack pattern analysis
batch scanning with multi-text processing
Supports scanning multiple prompts or outputs in a single API call, enabling efficient batch processing for high-throughput scenarios. Processes batches through the scanner pipeline with optimized tensor operations and optional parallelization, reducing per-item overhead compared to individual requests.
Unique: Supports batch processing of multiple texts through the scanner pipeline with optimized tensor operations, reducing per-item overhead compared to individual scans. Enables efficient processing of large datasets without requiring separate API calls per text.
vs alternatives: More efficient than individual scans because it amortizes model loading and tokenization overhead across multiple texts; more flexible than fixed batch sizes because batch size is configurable.
risk score aggregation and policy-based decision making
Aggregates risk scores from multiple scanners using configurable strategies (weighted sum, maximum, AND/OR logic) to produce a final security decision. Enables policy-based rules (e.g., 'block if any scanner scores > 0.8 OR toxicity > 0.9') for nuanced security decisions beyond binary allow/block.
Unique: Provides configurable risk score aggregation with policy-based decision rules, enabling organizations to define nuanced security policies that weight different threats differently. Supports multiple aggregation strategies (weighted sum, maximum, AND/OR logic) for flexible policy expression.
vs alternatives: More flexible than binary scanners because it enables nuanced decisions based on risk scores; more maintainable than hardcoded logic because policies are declarative and configurable.
pii detection and anonymization with stateful vault storage
Detects personally identifiable information (names, emails, phone numbers, SSNs, credit cards, etc.) in prompts and outputs using pattern matching and NER (Named Entity Recognition) models. Detected PII can be anonymized by replacing with tokens and storing original values in a stateful Vault object, enabling later de-anonymization. The Vault class maintains in-memory or persistent storage of PII mappings, supporting workflows where sensitive data must be redacted from LLM context but recovered in responses.
Unique: Integrates stateful Vault class for PII storage and recovery, enabling reversible anonymization workflows; combines regex pattern matching for structured PII (SSN, credit card) with NER models for unstructured PII (names, organizations), supporting both detection and remediation in a single component
vs alternatives: More comprehensive than simple regex-based PII detection because it includes NER for context-aware entity recognition; unlike external PII masking services, runs locally with no API calls, enabling offline operation and compliance with data residency requirements; Vault system enables de-anonymization, supporting workflows where original values must be recovered
+7 more capabilities