From PentestGPT to production: The state of AI-assisted offensive security with Charles Grandjean

LimaCharlie

May 28, 2026

Join us for this week's Defender Fridays as Charles Grandjean, CTO and Co-founder at Hexiagon AI, breaks down where AI-assisted pen testing actually stands today and what it means for both red teams and defenders.

At Defender Fridays, we delve into the dynamic world of information security, exploring its defensive side with seasoned professionals from across the industry. Our aim is simple yet ambitious: to foster a collaborative space where ideas flow freely, experiences are shared, and knowledge expands.

What We'll Discuss

In this episode, Charles Grandjean draws on his experience building an AI-powered continuous pen testing platform to trace how LLM capabilities have evolved for offensive security, and what the rise of autonomous attack tooling means for defenders.

Key Topics:

How AI pen testing has progressed from unreliable single commands to chaining complex attack sequences
Why the last six months marked a turning point in LLM planning and long-context reasoning
When to use in-context learning and RAG versus fine-tuning, and why most teams should start with the former
Why privacy considerations push serious pen testing operations toward self-hosted models
How the balance between model control and code control has shifted as models have improved
Why unrestricted and fine-tuned open-weights models are lowering the barrier for malicious actors
What automated offense means for defense teams and why the response needs to match the scale of the threat

About Our Guest

Charles Grandjean is the CTO and Co-founder of Hexiagon AI, a company focused on automating penetration testing through AI to enable continuous, around-the-clock security validation. He has been building and iterating on AI-assisted offensive tooling for the past two years, tracking the evolution of LLM capabilities firsthand from early prototype to production system.

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