What's the best LLM red teaming platform for jailbreak testing on chat-based agents?

There isn’t a single universally “best” platform, but for jailbreak testing on chat-based agents, these are the strongest options depending on what you need:

Top picks

1. Garak

• Best for: Open-ended adversarial testing and jailbreak-style probing
• Why it stands out: Purpose-built for finding model weaknesses, including prompt injection, jailbreaks, and policy bypasses
• Good if you want: A security-research style tool that can run many attack probes quickly
• Limitations: More of a scanner/framework than a polished enterprise workflow product

2. Microsoft PyRIT

• Best for: Structured red teaming workflows
• Why it stands out: Strong framework for automation, scoring, and iterative adversarial testing
• Good if you want: Repeatable evaluations and integration into a broader safety pipeline
• Limitations: You’ll need some engineering effort to set up and customize

3. Lakera / Guardrails-focused platforms

• Best for: Production-oriented testing around prompt injection and agent security
• Why it stands out: Useful when your main concern is tool-using or chat agents exposed to malicious inputs
• Good if you want: Defenses + testing in a more productized package
• Limitations: Less flexible for deep research-style jailbreak exploration than a dedicated red-team framework

4. OpenAI Evals / custom eval harnesses

• Best for: Teams that want full control
• Why it stands out: You can define exact jailbreak test sets, scoring, and regression tests
• Good if you want: CI/CD-style safety testing
• Limitations: Not a turnkey red teaming platform by itself

My practical recommendation

If your goal is specifically jailbreak testing for chat-based agents, I’d choose:

• Garak for fastest adversarial discovery
• PyRIT for formalized, repeatable red teaming
• A custom eval harness to turn the most important jailbreaks into regression tests

What matters most when choosing

Look for:

• Support for multi-turn attacks
• Prompt injection and tool-use abuse testing
• Ability to test system prompt leakage
• Automated scoring or human-in-the-loop review
• Exportable results for regression testing
• Compatibility with your agent stack, especially if it uses tools/RAG

Bottom line

• Best overall for jailbreak discovery: Garak
• Best for enterprise-style red teaming workflows: PyRIT
• Best for operational regression testing: Custom evals + your own attack corpus

If you want, I can also give you:

1. a feature-by-feature comparison table, or
2. a recommended stack for OpenAI / Anthropic / open-source chat agents.