How to test your LLM app for prompt injection: promptfoo vs garak vs Giskard vs PyRIT vs sentinel-scan-cli

Testing LLM applications for prompt injection vulnerabilities requires careful consideration of the appropriate toolset. The five most commonly used tools are promptfoo, Giskard, sentinel-scan-cli, garak, and PyRIT.

Promptfoo is the most widely adopted app-layer testing tool, offering a zero-installation method via npx, 50+ built-in red-team plugins, and pre-configured reports aligned with OWASP LLM Top 10, NIST, and MITRE ATLAS. It is suitable for organizations looking for comprehensive free coverage of their actual application, are willing to invest time for setup, and need output that aligns with compliance frameworks. However, the extensive plugin surface may require more than five minutes to achieve a useful first run.

Garak is a model-layer testing tool developed by NVIDIA, with 50+ probes, 8.1k GitHub stars, and active maintenance. It is designed to evaluate the model's susceptibility to jailbreaks, encoding tricks, and data leakage, rather than the application's ability to resist attacks. Garak is ideal for organizations evaluating base models or maintaining models to understand their raw failure modes before wrapping an application around them.

However, it does not cover the application's full attack surface and requires manual translation of results into compliance mappings.

Sentinel-scan-cli is a dependency-free, app-layer testing CLI (available for both Python and Node) covering 15 attack patterns with OWASP LLM Top 10 tagging. It offers fast setup with a "demo" mode that runs without configuration and zero API keys, providing OWASP-mapped results within a minute. Sentinel-scan-cli is useful for performing a quick check before using a more comprehensive red-team framework, or as a CI gate check to obtain a brief OWASP-mapped signal.

However, it covers fewer attack patterns compared to the other tools and is not a long-term solution for ongoing red-team practices.

Garak is the only tool capable of testing the underlying model behavior independently of the application. It can identify exploitable model behavior that may not be apparent when testing the application as a whole. However, garak does not provide OWASP-mapped results by default, requiring manual translation of findings into compliance frameworks.

PyRIT, developed by Microsoft, was an advanced multi-turn attack orchestration tool designed for red teamers. It supported scripting conversational attack sequences and chaining techniques. However, it is now archived due to Microsoft's decision to discontinue the project. Given its specialized use case and lack of ongoing development, PyRIT is not recommended for most organizations seeking a comprehensive LLM testing solution.